1
|
Pereira RP, de Oliveira D, Rocha MG, Roulet JF, Geraldeli S, Sinhoreti M. Effect of butylated hydroxytoluene (BHT) concentrations on polymerization shrinkage stress and other physicochemical properties of experimental resin composites. J Mech Behav Biomed Mater 2024; 157:106652. [PMID: 38970944 DOI: 10.1016/j.jmbbm.2024.106652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/20/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024]
Abstract
The present study examined different concentrations of the butylated hydroxytoluene (BHT) inhibitor on the kinetics of conversion, polymerization shrinkage stress, and other correlated physicochemical properties of experimental resin composites (ERC). A model composite was formulated with 75 wt% filler containing 0.5 wt% camphorquinone and 1 wt% amine with BHT concentrations of 0.01 wt% (BHT-0.01); 0.1 wt% (BHT-0.1); 0.25 wt% (BHT-0.25); 0.5 wt% (BHT-0.5); 1 wt% (BHT-1), and control (no BHT). They were tested on polymerization shrinkage stress (PSS; n = 5), degree of conversion (DC; n = 3), maximum polymerization rate (RpMAX; n = 5), water sorption (Wsp; n = 0), and solubility (Wsl; n = 10), flexural strength (FS; n = 10), flexural modulus (FM; n = 10), Knoop microhardness (KH; n = 10), and microhardness reduction (HR; n = 10). Data concerning these tests were submitted to one-way ANOVA and Tukey's test (α = 0.05; β = 0.2). BHT-0.25, BHT-0.5, and BHT-1 showed a gradually significant decrease in PSS (p = 0.037); however, BHT-1 demonstrated a decrease in the physicochemical properties tested. Thus, within the limitations of this study, it was possible to conclude that BHT concentrations between 0.25 and 0.5 wt% are optimal for reducing shrinkage stress without affecting other physicochemical properties of ERCs.
Collapse
Affiliation(s)
- Roberta Pinto Pereira
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Dayane de Oliveira
- Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Mateus Garcia Rocha
- Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Jean-François Roulet
- Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Saulo Geraldeli
- Division of Biomedical Materials, School of Dental Medicine, East Carolina University, Greenville, NC, USA
| | - Mário Sinhoreti
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
| |
Collapse
|
2
|
Limvisitsakul A, Komalsingsakul A, Thamsrithip P, Thammasupapong Y, Chaisomsukrudee S, Aramlerttrakul S, Senawongse P. The color stability of artificial white spot lesions treated with resin infiltration after exposure to staining beverages. BMC Oral Health 2024; 24:940. [PMID: 39143593 PMCID: PMC11323408 DOI: 10.1186/s12903-024-04693-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 07/30/2024] [Indexed: 08/16/2024] Open
Abstract
BACKGROUND To evaluate the effect of staining beverages on the color-changing of resin-infiltrated artificial white spot lesions (WSLs). METHODS Thirty-five artificial WSLs were created by pH cycling on flat bovine teeth specimens. The WSLs were treated with resin infiltration and were divided into five groups based on staining beverages: artificial saliva, coffee, wine, green tea, and Coca-Cola. These specimens were subjected to a 28-day exposure to the respective beverages. Color stability was assessed using a spectrophotometer at different time points: baseline, after 7, 14, 21, and 28 days of exposure, and repolishing. The color difference (∆E) between each time point and the baseline was calculated. Statistical analysis was performed using two-way measures ANOVA with a significance level of p = 0.05. RESULTS All resin-infiltrated specimens exposed to staining beverages for 7 days exhibited more significant color changes than those exposed to artificial saliva. The color change patterns varied based on the type of beverage. The color alterations intensified with extended immersion in the wine and Coca-Cola groups, while there were no significant differences in the color of specimens after 28 days of immersion in the coffee and green tea groups. However, after cleaning with pumice powder, all specimens showed significantly reduced color changes compared to those observed after 28 days of immersion, except those immersed in coffee. CONCLUSIONS Exposure of resin-infiltrated bovine tooth specimens to staining beverages resulted in a significant color alteration as the immersion time increased. However, the staining effect could be minimized by cleaning with pumice powder, except for the coffee group. CLINICAL RELEVANCE After resin infiltration treatment, patients should be advised to minimize the consumption of colored beverages to prevent staining that could impact esthetic appearance.
Collapse
Affiliation(s)
- Apinya Limvisitsakul
- Division of Operative Dentistry, Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand.
| | - Anisha Komalsingsakul
- Division of Operative Dentistry, Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| | - Pongsakorn Thamsrithip
- Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| | - Yod Thammasupapong
- Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| | - Supada Chaisomsukrudee
- Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| | - Sorawit Aramlerttrakul
- Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| | - Pisol Senawongse
- Division of Operative Dentistry, Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, 6 Yothi Road, Ratchathewi District, Bangkok, 10400, Thailand
| |
Collapse
|
3
|
Lee SY, Shimada Y, Sadr A, Tabata T, Sato T, Byun JE, Han SH. Degree of conversion and interfacial adaptation of touch-cure resin cement polymerized by self-curing or dual-curing with reduced light. Clin Oral Investig 2024; 28:463. [PMID: 39090476 DOI: 10.1007/s00784-024-05858-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 07/23/2024] [Indexed: 08/04/2024]
Abstract
OBJECTIVES The first aim of this study was to determine whether there is a difference in degree of conversion (DC) of touch-cure cements polymerized by self-curing with adhesive or dual-curing under reduced light. The second aim was to compare interfacial adaptation of zirconia restoration cemented using touch-cure cements self-cured or dual-cured by reduced light. METHODS The DC of touch-cure resin cements with adhesive was measured continuously using Fourier transform infrared spectrometry. Experimental groups differed depending on touch-cure cement. Each group had three subgroups of polymerization method. For subgroup 1, the DC was measured by self-curing. For subgroups 2 and 3, the DCs were measured by dual-curing with reduced light penetrating 3 mm and 1 mm zirconia blocks, respectively. For interfacial adaptation evaluation, Class I cavity was prepared on an extracted third molar, and zirconia restoration was fabricated. The restoration was cemented using the same cement. Groups and subgroups for interfacial adaptation were the same as those of the DC measurement. After thermo-cycling, interfacial adaptation at the tooth-restoration interface was evaluated using swept-source optical coherence tomography imaging. RESULTS The DC of touch-cure cement differed depending on the measurement time, resin cement, and polymerization method (p < 0.05). Interfacial adaptation was different depending on the resin cement and polymerization method (p < 0.05). CONCLUSION For touch-cure cement, light-curing with higher irradiance presented a higher DC and superior interfacial adaptation than light-curing with lower irradiance or self-curing. CLINICAL RELEVANCE Although some adhesives accelerate the self-curing of touch-cure cement, light-curing for touch-cure cement is necessary for zirconia cementation.
Collapse
Affiliation(s)
- Su Young Lee
- Department of Prosthodontics, Seoul St. Mary's Dental Hospital, College of Medicine, The Catholic University of Korea, Banpo-daero 222, Seocho-gu, Seoul, 06591, Republic of Korea
| | - Yasushi Shimada
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Alireza Sadr
- Department of Restorative Dentistry, School of Dentistry, University of Washington, 1959 NE Pacific St, B162, Seattle, WA, 98195, USA
| | - Tomoko Tabata
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Takaaki Sato
- Department of Oral Biomedical Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Ji-Eun Byun
- Department of Conservative Dentistry, College of Dentistry, Yonsei University, #50 Yonsei-ro, Seodaemun-gu, Seoul, Korea
| | - Seung-Hoon Han
- Department of Conservative Dentistry, St. Vincent Hospital, College of Medicine, The Catholic University of Korea, 93 Jungbu-daero, Paldal-gu, Suwon, Gyeonggi-do, 16247, South Korea.
| |
Collapse
|
4
|
Sengupta A, Naka O, Mehta SB, Banerji S. The clinical performance of bulk-fill versus the incremental layered application of direct resin composite restorations: a systematic review. Evid Based Dent 2023; 24:143. [PMID: 37402908 PMCID: PMC10516750 DOI: 10.1038/s41432-023-00905-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 06/09/2023] [Indexed: 07/06/2023]
Abstract
OBJECTIVES To systematically review the scientific evidence comparing the clinical effectiveness of bulk-fill versus incrementally layered conventional resin composites and to evaluate if one method offers clear merits with specific clinical outcomes. MATERIALS AND METHODS Using relevant mesh terms and pre-established eligibility criteria in PubMed, Embase, Scopus and Web of Science, a thorough scientific search was conducted with an end-date of 30.04.2023. Randomized controlled clinical trials that involved the direct comparison of Class I and Class II resin composite restorations applied using incremental layering techniques versus bulk-filled in permanent teeth with an observation period of at least six months were considered. To evaluate the bias risk of the finalized records, a revised version of the Cochrane risk-of-bias tool for randomized trials was implemented. RESULTS Out of the 1445 records determined, 18 eligible reports were chosen for qualitative analysis. Data obtained was categorized as per, the cavity design, the intervention, the comparator(s), the methods of success/failure assessment, the outcomes, and follow-up. Two studies demonstrated an overall low-risk of bias, fourteen studies raised some concerns, and two studies exhibited high-risk. CONCLUSION Bulk filled resin composite restorations demonstrated clinical outcomes similar to those of incrementally layered resin composite restorations within a review interval of 6 months to 10 years.
Collapse
Affiliation(s)
- Arjita Sengupta
- Faculty of Dentistry Oral and Craniofacial Sciences, King's College London, London, UK
| | - Olga Naka
- Faculty of Dentistry Oral and Craniofacial Sciences, King's College London, London, UK.
- School of Dentistry, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
| | - Shamir B Mehta
- Faculty of Dentistry Oral and Craniofacial Sciences, King's College London, London, UK
| | - Subir Banerji
- Faculty of Dentistry Oral and Craniofacial Sciences, King's College London, London, UK
| |
Collapse
|
5
|
Sreevarun M, Ajay R, Suganya G, Rakshagan V, Bhanuchander V, Suma K. Formulation, Configuration, and Physical Properties of Dental Composite Resin Containing a Novel 2π + 2π Photodimerized Crosslinker - Cinnamyl Methacrylate: An In Vitro Research. J Contemp Dent Pract 2023; 24:364-371. [PMID: 37534502 DOI: 10.5005/jp-journals-10024-3480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
AIM To formulate and characterize the chemical structure of a new dental composite with photodimerized cinnamyl methacrylate (PD-CMA) photo-crosslinking comonomer and to evaluate the monomer-to-polymer conversion (MPC) and glass transition temperature (Tg) of the new composite copolymers. MATERIALS AND METHODS CMA was PD by ultraviolet C-type (UVC) irradiation. The research groups were a control group C0 without PD-CMA and two trial groups: E10 (10 wt. % PD-CMA substituted in the base comonomers (B) and diluent (D) mixture); E20 (20 wt.% PD-CMA completely replacing the diluent (D) monomer). Infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies were employed for ascertaining copolymerization (CP). The surface features and composition of the copolymers were explained by field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy, respectively. The MPC and Tg of the copolymers were assessed using FTIR and differential scanning calorimetry, respectively. Statistical tests were used to compare the groups. RESULTS The configuration of the new copolymers P (BD-Co-CMA) and P(B-Co-CMA) was confirmed. The MPC% and T g of the copolymers were better than the control. PD-CMA at 20 wt. % in the P (B-Co-CMA) copolymer exhibited the highest MPC% and Tg. CONCLUSION The incorporation of PD-CMA in the composite resin resulted in new P (BD-Co-CMA) and P (B-Co-CMA) copolymers with improved MPC% and Tg. CLINICAL SIGNIFICANCE The substitution with PD-CMA offset the shortcomings of the conventional BD comonomers concerning the mechanical properties and biocompatibility of the restorative composite resin. This might ameliorate the restorations in vivo longevity and serviceability.
Collapse
Affiliation(s)
- Murugesan Sreevarun
- Department of Dentistry, Vinayaka Missions Medical College & Hospital (VMRF-DU), Karaikal, Puducherry, India
| | - Ranganathan Ajay
- Department of Prosthodontics and Crown and Bridge, Vivekanandha Dental College for Women, Namakkal, Tamil Nadu, India, Phone: +91 8754120490, e-mail:
| | - Ganesan Suganya
- Department of Pharmacology, Vinayaka Missions Medical College & Hospital (VMRF-DU), Karaikal, Puducherry, India
| | - Vikraman Rakshagan
- Department of Prosthodontics and Implant Dentistry, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
| | - Vayadadi Bhanuchander
- Department of Prosthodontics and Crown and Bridge, Army College of Dental Sciences, Secunderabad, Telangana, India
| | - Karthigeyan Suma
- Department of Prosthodontics and Crown and Bridge, Government Dental College, Cuddalore, Tamil Nadu, India
| |
Collapse
|
6
|
Jakupović S, Pervan N, Mešić E, Gavranović-Glamoč A, Bajsman A, Muratović E, Kazazić L, Kantardžić-Kovačević A. Assessment of Microhardness of Conventional and Bulk-Fill Resin Composites Using Different Light-Curing Intensity. Polymers (Basel) 2023; 15:polym15102250. [PMID: 37242825 DOI: 10.3390/polym15102250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/25/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
(1) Background: This study evaluates the effect of a conventional/low-voltage light-curing protocol (LV protocol) (10 s with 1340 mW/cm2) and high-voltage light-curing protocol (HV protocol) (3 s with 3440 mW/cm2) on the microhardness (MH) of dental resin-based composites (RBCs). Five resin composites were tested: conventional Evetric (EVT), Tetric Prime (TP), Tetric Evo Flow (TEF), bulk-fill Tetric Power Fill (PFL), and Tetric Power Flow (PFW). (2) Materials and Methods: Two tested composites (PFW and PFL) were designed for high-intensity light curing. The samples were made in the laboratory in specially designed cylindrical molds; diameter = 6 mm and height = 2 or 4 mm, depending on the type of composite. Initial MH was measured on the top and bottom surfaces of composite specimens 24 h after light curing using a digital microhardness tester (QNESS 60 M EVO, ATM Qness GmbH, Mammelzen, Germany). The correlation between the filler content (wt%, vol%) and the MH of the RBCs was tested. For the calculation of depth-dependent curing effectiveness, the bottom/top ratio for initial MH was used. (3) Conclusions: MH of RBCs is more dependent on material composition than on light-curing protocol. Filler wt% has a greater influence on MH values compared to filler vol%. The bottom/top ratio showed values over 80% for bulk composites, while for conventional sculptable composites, borderline or suboptimal values were measured for both curing protocols.
Collapse
Affiliation(s)
- Selma Jakupović
- Department of Restorative Dentistry and Endodontics, Faculty of Dentistry with Clinics, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Nedim Pervan
- Department of Mechanical Design, Faculty of Mechanical Engineering, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Elmedin Mešić
- Department of Mechanical Design, Faculty of Mechanical Engineering, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Alma Gavranović-Glamoč
- Department of Prosthodontics, Faculty of Dentistry with Clinics, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Anita Bajsman
- Department of Dental Morphology with Dental Anthropology and Forensics, Faculty of Dentistry with Clinics, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Enis Muratović
- Department of Mechanical Design, Faculty of Mechanical Engineering, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | - Lejla Kazazić
- Department of Prosthodontics, Faculty of Dentistry with Clinics, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina
| | | |
Collapse
|
7
|
Lehmann A, Nijakowski K, Drożdżyńska A, Przybylak M, Woś P, Surdacka A. Influence of the Polymerization Modes on the Methacrylic Acid Release from Dental Light-Cured Materials-In Vitro Study. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15248976. [PMID: 36556780 PMCID: PMC9786925 DOI: 10.3390/ma15248976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 05/14/2023]
Abstract
The study focuses on the problem of lowering the pH around a composite filling concerning the polymerization modes and methacrylic acid release, which may affect not only the oral health but also the whole organism. A total of 90 specimens (30 of each: Filtek Bulk Fill, Evetric and Riva LC) were placed in 90 sterile hermetic polyethene containers with saline and incubated at 37 °C. Ten samples of each material were light-cured for 40 s with one of the three curing modes: full power mode (FPM), ramping mode (RM) and pulse mode (PM). The pH and methacrylic acid release evaluation were performed at the following time points: after 2 h and after 3, 7, 21 and 42 days from the specimen preparation. Regardless of light-curing mode, all used materials were characterized by a gradual elevation in methacrylic acid concentration. Only for Filtek Bulk Fill, increased methacrylic acid release was closely associated with lower pH. The choice of the polymerization mode has no significant influence on the methacrylic acid release. However, further research about composite light-curing is necessary to create the procedure algorithm, reducing the local and systemic complications associated with composite fillings.
Collapse
Affiliation(s)
- Anna Lehmann
- Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Kacper Nijakowski
- Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
- Correspondence:
| | - Agnieszka Drożdżyńska
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 60-627 Poznan, Poland
| | - Martyna Przybylak
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 60-627 Poznan, Poland
| | - Patryk Woś
- Student’s Scientific Group in Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Anna Surdacka
- Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| |
Collapse
|
8
|
Saccucci M, Corridore D, Di Carlo G, Bonucci E, Cicciù M, Vozza I. Assessment of Enamel Color Stability of Resins Infiltration Treatment in Human Teeth: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11269. [PMID: 36141540 PMCID: PMC9517161 DOI: 10.3390/ijerph191811269] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 06/16/2023]
Abstract
(1) The evolution of techniques and materials used in dentistry has led to the introduction of a technique known as micro-infiltration, using ICON infiltrating resin. The purpose of this study was to evaluate whether the resin infiltrant can remain stable in the enamel color of human teeth over time or if it causes discoloration and review current knowledge on color stability based on the literature selected solely on studies performed on human teeth and to provide a perspective on the methods proposed by clinicians in the infiltration procedure; (2) Methods: This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement; (3) Results: Twelve studies were selected for this review. The study results suggest that the device content is sufficiently comprehensive. The reviewers expressed strong support for the device's content for assessing the quality of reviews. The paper summarizes current reports regarding the color stability assessment of enamel treated by in- filtration resin confirmed in in vitro and in vivo studies; (4) Conclusions: Based on these considerations, the resin infiltration method can be recommended to improve the appearance of enamel lesions. The infiltrated lesions remained chromatically stable, showing no significant color changes in the long term.
Collapse
Affiliation(s)
- Matteo Saccucci
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Denise Corridore
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Gabriele Di Carlo
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Elisa Bonucci
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Marco Cicciù
- Department of Biomedical and Dental Sciences and Morphological and Functional Imaging, Messina University, 98100 Messina, Italy
| | - Iole Vozza
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| |
Collapse
|
9
|
Han SH, Shimada Y, Sadr A, Tagami J, Tabata T, Nakagawa H, Yang SE. Effects of Material Thickness and Pretreatment on the Interfacial Gap of Translucent Zirconia Restorations with Self-adhesive Resin Cement. Oper Dent 2022; 47:535-548. [DOI: 10.2341/21-024-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2021] [Indexed: 11/07/2022]
Abstract
SUMMARY
Purpose
The first objective was to determine if the dual-curing of self-adhesive resin cement (SAC) with reduced light penetrating through zirconia had an effect on interfacial gap of zirconia restorations. The second purpose was to examine whether pretreatment methods for universal adhesive affected interfacial gap. The last aim was to compare the microhardness of SAC polymerized under different zirconia thicknesses.
Methods and Materials
This study evaluated self-adhesive resin cement (RelyX U200, 3M ESPE) after different pretreatment with universal adhesive (Single Bond Universal, 3M ESPE) under different polymerization conditions. CAD/CAM inlay cavities were prepared on extracted third molars. Translucent zirconia restorations were milled using Katana UTML (Kuraray). The teeth were divided into three groups: Groups I, II, and III in which the restoration thicknesses were 1, 2, and 3 mm. Each Group had three subgroups according to different pretreatment methods. For subgroup-1, no pretreatment was done on the prepared cavity. For subgroup-2, universal adhesive was applied and light-cured before cement placement (precure method). For subgroup-3, universal adhesive was applied; however, light-curing was done after cement placement (cocure method). After thermo-cycling, the interfacial gap at the restoration-tooth interface was investigated using swept-source optical coherence tomography imaging. Finally, microhardness was measured for SAC under different zirconia thicknesses. For statistical analysis, the interfacial gap was analyzed using two-way analysis of variance (ANOVA) to test the effect of cavity depth and pretreatment. In terms of each cavity depth and pretreatment, the interfacial gap was compared using one-way ANOVA and Scheffe’s test. One-way ANOVA was also performed for comparison of the Vickers hardness results.
Results
Different thicknesses of the restoration resulted in differences in interfacial gaps except between the precure method of Groups I and II (p<0.05). The effect of universal adhesive pretreatment was different depending on the restoration thickness with exceptions in Groups I and III (p<0.05). Vickers hardness number decreased as the low radiant exposure of light was applied (p<0.05).
Conclusion
Interfacial gap of zirconia restorations can differ depending on the material thickness, pretreatment, and activation mode. Reduced light intensity penetrating through zirconia may lead to higher interfacial gap percentage and lower microhardness of the self-adhesive resin cement. Application of a universal adhesive showed similar or reduced interfacial gaps in the cement space.
Collapse
Affiliation(s)
- S-H Han
- Seung-Hoon Han, DDS, PhD, assistant professor, Department of Conservative Dentistry, St Vincent Hospital, College of Medicine, The Catholic University of Korea
| | - Y Shimada
- Yasushi Shimada, DDS, PhD, professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - A Sadr
- Alireza Sadr, DDS, PhD, associate professor, Department of Restorative Dentistry, School of Dentistry, University of Washington
| | - J Tagami
- Junji Tagami, DDS, PhD, professor emeritus, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - T Tabata
- Tomoko Tabata, DDS, PhD, assistant professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - H Nakagawa
- Hisaichi Nakagawa, DDS, PhD, assistant professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - S-E Yang
- *Sung-Eun Yang, DDS, PhD, professor, Department of Conservative Dentistry, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| |
Collapse
|
10
|
Mechanical characterization and adhesive properties of a dental adhesive modified with a polymer antibiotic conjugate. J Mech Behav Biomed Mater 2022; 129:105153. [DOI: 10.1016/j.jmbbm.2022.105153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 01/05/2022] [Accepted: 02/27/2022] [Indexed: 11/22/2022]
|
11
|
Albeshir EG, Alsahafi R, Albluwi R, Balhaddad AA, Mitwalli H, Oates TW, Hack GD, Sun J, Weir MD, Xu HHK. Low-Shrinkage Resin Matrices in Restorative Dentistry-Narrative Review. MATERIALS (BASEL, SWITZERLAND) 2022; 15:2951. [PMID: 35454643 PMCID: PMC9029384 DOI: 10.3390/ma15082951] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 02/06/2023]
Abstract
Dimethacrylate-based resin composites restorations have become widely-used intraoral materials in daily dental practice. The increasing use of composites has greatly enhanced modern preventive and conservative dentistry. They have many superior features, especially esthetic properties, bondability, and elimination of mercury and galvanic currents. However, polymeric materials are highly susceptible to polymerization shrinkage and stresses that lead to microleakage, biofilm formation, secondary caries, and restoration loss. Several techniques have been investigated to minimize the side effects of these shrinkage stresses. The primary approach is through fabrications and modification of the resin matrices. Therefore, this review article focuses on the methods for testing the shrinkage, as well as formulations of resinous matrices available to reduce polymerization shrinkage and its associated stress. Furthermore, this article reviews recent cutting-edge developments on bioactive low-shrinkage-stress nanocomposites to effectively inhibit the growth and activities of cariogenic pathogens and enhance the remineralization process.
Collapse
Affiliation(s)
- Ebtehal G. Albeshir
- Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; (E.G.A.); (R.A.)
- Department of Restorative Dentistry, King Abdul-Aziz Medical City, Ministiry of National Guard—Health Affairs, Riyadh 11426, Saudi Arabia;
- King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia
- King Abdullah International Medical Research Center, Ministiry of National Guard—Health Affairs, Riyadh 11426, Saudi Arabia
| | - Rashed Alsahafi
- Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; (E.G.A.); (R.A.)
- Department of Restorative Dental Sciences, College of Dentistry, Umm Al-Qura University, Makkah 24381, Saudi Arabia
| | - Reem Albluwi
- Department of Restorative Dentistry, King Abdul-Aziz Medical City, Ministiry of National Guard—Health Affairs, Riyadh 11426, Saudi Arabia;
- King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia
- King Abdullah International Medical Research Center, Ministiry of National Guard—Health Affairs, Riyadh 11426, Saudi Arabia
| | - Abdulrahman A. Balhaddad
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman bin Faisal University, Dammam 31441, Saudi Arabia;
| | - Heba Mitwalli
- Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Thomas W. Oates
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (T.W.O.); (G.D.H.)
| | - Gary D. Hack
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (T.W.O.); (G.D.H.)
| | - Jirun Sun
- The Forsyth Institute, A Harvard School of Dental Medicine Affiliate, 245 First Street, Cambridge, MA 02142, USA
| | - Michael D. Weir
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (T.W.O.); (G.D.H.)
| | - Hockin H. K. Xu
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (T.W.O.); (G.D.H.)
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| |
Collapse
|
12
|
Aldhafyan M, Silikas N, Watts DC. Influence of curing modes on thermal stability, hardness development and network integrity of dual-cure resin cements. Dent Mater 2021; 37:1854-1864. [PMID: 34593244 DOI: 10.1016/j.dental.2021.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/20/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To explore the effect of different curing modes of conventional and self-adhesive dual-cure resin cements on their rates of thermal decomposition, hardness development and network integrity. METHODS Five self-adhesive (PANAVIA SA, RelyX Universal Resin, RelyX Unicem 2, Bifix SE and SpeedCEM Plus) and three conventional (PANAVIA V5, Nexus Third Generation and RelyX Ultimate Universal) dual-cure resin cements were investigated. Thermal decomposition stages, initial onset temperatures, the maximum rate of mass-loss and the filler mass-fraction of each resin cement were analysed by thermogravimetric analysis (TGA). Surface hardness was measured at 1h post-cure and after 24h of dry storage at 37°C. The relative network integrities were estimated from reductions in hardness after 168h of water storage. Data were analysed via one-way ANOVA, Tukey post-hoc tests and paired/independent sample t-tests (a=0.05). RESULTS No difference was apparent between TGA data for self-cured and light-cured specimens. Numerical differentiation of mass-loss versus temperature showed either single or multiple peaks. For the set of 8 cements, the maximum rate of mass-loss (%/°C) correlated negatively with residual mass at 600°C. All dry-stored cements increased in hardness from 1 to 24h, ranging from 20.4% to 52.6% for light-cure mode and from 41.3% to 112.6% for self-cure. After 168h water storage, the hardness of cements decreased: by 18.5%-36.2% for light-cured and by 9.8%-17.9% for self-cured. Overall, surface hardness was greater for light-cured cements. The initial onset temperature (IOT) of thermal decomposition correlated negatively with the hardness decrease produced by water-storage: r2=0.77 for light-cure and r2=0.88 for self-cure. This provided the basis for a relative scale of composite network integrity, probably reflecting differences in cross-link density. SIGNIFICANCE Light-curing, where possible, remains beneficial to the hardness and related properties of dual-cure resin cements. Combination of TG analysis and solvent softening experiments give an indication of relative network integrity - between materials - and their relative cross-link densities.
Collapse
Affiliation(s)
- Mohammed Aldhafyan
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Division of Dental Biomaterials Science, College of Dentistry, King Saud University, Saudi Arabia
| | - Nikolaos Silikas
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK.
| | - David C Watts
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Photon Science Institute, University of Manchester, UK.
| |
Collapse
|
13
|
Ilie N, Diegelmann J. Impact of ultra-fast (3 s) light-cure on cell toxicity and viscoelastic behavior in a dental resin-based composite with RAFT-mediated polymerization. J Mech Behav Biomed Mater 2021; 124:104810. [PMID: 34500355 DOI: 10.1016/j.jmbbm.2021.104810] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The aim of the study was to determine the effects of ultra-fast (3 s) light-curing on the viscoelastic behaviour at clinically relevant frequencies, and cell toxicity, in a resin-based composite (RBC) with reversible addition-fragmentation-chain transfer (RAFT) mediated polymerization. METHODS Three different protocols were used to cure cylindrical samples (height = 4 mm, ϴ = 5 mm), including ultra-fast (3s) cure with high radiant emittance, 10 s and 20 s cure with moderate radiant emittance. The properties of the light curing device were evaluated in all curing protocols by spectrophotometry up to an exposure distance of 10 mm. The light transmission through the samples was determined in real-time with the same spectrophotometer. Absorbance was calculated as a function of wavelength. The quasi-static (indentation hardness/HIT, indentation modulus/EIT) and viscoelastic (storage modulus/E', loss modulus/E″, loss factor/tan δ) material behavior was determined in an instrumented indentation test with a DMA (Dynamic Mechanical Analysis) module for 10 frequencies (0.5-5 Hz) by profiling the center of the samples in 330 μm steps from top to bottom. Cellular toxicity on human gingival fibroblast (HGF-1) was assessed using a WST-1 colorimetric assay after incubation time of up to 3 months. One and multiple-way analysis of variance (ANOVA) with Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05) were applied. RESULTS The irradiance transmitted through a 4 mm high sample was less than 7% of the incident irradiance, and the absorbance was similar for all curing protocols, showing a decrease with wavelength. Similar quasi-static and viscoelastic parameters were observed regardless of the curing protocol. HIT increased slightly and EIT, E', E″ and tan δ decreased with frequency. Occasionally, slightly higher confidence intervals were observed for the ultra-fast curing group, which were related to a potential accumulation of stress. The curing protocol had no effect on cell viability (p = 0.326) but the eluate age (p < 0.001, ηP2 = 0.879) did. None of the groups showed cell toxicity at any point in time with respect to the corresponding negative control. CONCLUSIONS The ultra-fast curing with high irradiance induced no cell toxicity and an equivalent viscoelastic behavior as with conventional curing protocols in a RAFT-modified RBC.
Collapse
Affiliation(s)
- Nicoleta Ilie
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU, Germany.
| | - Julia Diegelmann
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU, Germany
| |
Collapse
|
14
|
Mayer J, Stawarczyk B, Vogt K, Hickel R, Edelhoff D, Reymus M. Influence of cleaning methods after 3D printing on two-body wear and fracture load of resin-based temporary crown and bridge material. Clin Oral Investig 2021; 25:5987-5996. [PMID: 33811531 DOI: 10.1007/s00784-021-03905-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/19/2021] [Indexed: 12/29/2022]
Abstract
OBJECTIVES To investigate the impact of different cleaning methods on the fracture load and two-body wear of additively manufactured three-unit fixed dental prostheses (FDP) for long-term temporary use, compared to the respective outcomes of milled provisional PMMA FDPs. MATERIALS AND METHODS Shape congruent three-unit FDPs were 3D printed using three different resin-based materials [FPT, GCT, NMF] or milled [TEL] (N = 48, n = 16 per group). After printing, the FDPs were cleaned using: Isopropanol (ISO), Yellow Magic 7 (YEL), or centrifugal force (CEN). Chewing simulation was carried out with a vertical load of 50 N (480,000 × 5 °C/55 °C). Two-body wear and fracture load were measured. Data were analyzed using global univariate ANOVA with partial eta squared, Kruskal-Wallis H, Mann-Whitney U, and Spearman's rho test (p < 0.05). RESULTS TEL showed less wear resistance than FPT (p = 0.001) for all cleaning methods tested. Concerning vertical material loss, NMF and GCT were in the same range of value (p = 0.419-0.997), except within FDPs cleaned in ISO (p = 0.021). FPT showed no impact of cleaning method on wear resistance (p = 0.219-0.692). TEL (p < 0.001) showed the highest and FPT (p < 0.001) the lowest fracture load. Regarding the cleaning methods, specimens treated with ISO showed lower fracture load than specimens cleaned with CEN (p = 0.044) or YEL (p = 0.036). CONCLUSIONS The material selection and the cleaning method can have an impact on two-body wear and fracture load results. CLINICAL RELEVANCE Printed restorations showed superior two-body wear resistance compared to milled FDPs but lower fracture load values. Regarding cleaning methods, ISO showed a negative effect on fracture load compared to the other methods tested.
Collapse
Affiliation(s)
- Johannes Mayer
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Konstantin Vogt
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Reinhard Hickel
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Daniel Edelhoff
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Marcel Reymus
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| |
Collapse
|
15
|
Biocompatibility, mechanical, and bonding properties of a dental adhesive modified with antibacterial monomer and cross-linker. Clin Oral Investig 2020; 25:2877-2889. [PMID: 33006665 DOI: 10.1007/s00784-020-03605-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/23/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVES This study investigated the antibacterial, cytotoxicity, and mechanical properties of a dental adhesive modified with quaternary ammonium monomer ((2-acryloyloxyethyl)dimethyldodecylammonium bromide) and cross-linker (bis(2-acryloyloxyethyl)methyldodecylammonium bromide). MATERIALS AND METHODS Monomer (M), cross-linker (C), or a combination of these (M + C) were incorporated into adhesive Adper Single Bond Plus (SB) in 5, 10, or 25% (as wt%). A colony-forming unit and MTT assays were used to evaluate antibacterial properties against Streptococcus mutans and cell viability. Resin-dentin beams (0.9 ± 0.1 mm2) were evaluated for micro-tensile bond strength (μTBS) after 24 h, 6 months, and 3 years. Hourglass specimens were evaluated for ultimate tensile strength (UTS) after 24 h, 1 week, and 6 months. Micro-hardness measurements after softening in ethanol were taken as an indirect assessment of the polymer cross-linking density. Kruskal-Wallis, one-way ANOVA, two-way ANOVA, and Student's t test were used for analysis of the antibacterial, cytotoxicity, μTBS, UTS, and hardness data, all with a significance level of p < 0.05. RESULTS 10%M and 25%M demonstrated a significant reduction in S. mutans relative to SB (p < 0.001). No differences in cytotoxicity were detected for any of the groups. After 6 months, no changes in μTBS were shown for any of the groups. After 3 years, all groups evidenced a significant decrease in μTBS (p < 0.05) except 5%M, 5%C, and 5%M + 5%C. All groups demonstrated either stable or significantly increased UTS after 6 months. Except for the cross-linker groups, a significant decrease in micro-hardness was shown for all groups after softening in ethanol (p < 0.05). CONCLUSIONS A 5-10% of monomer may render the resin antibacterial without a compromise to its mechanical and bonding properties. CLINICAL RELEVANCE Biomodification of a resin adhesive with an antibacterial monomer and cross-linker may help improve the life span of adhesive restorations.
Collapse
|
16
|
Bragança GF, Vianna AS, Neves FD, Price RB, Soares CJ. Effect of exposure time and moving the curing light on the degree of conversion and Knoop microhardness of light-cured resin cements. Dent Mater 2020; 36:e340-e351. [PMID: 32950244 DOI: 10.1016/j.dental.2020.08.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/07/2020] [Accepted: 08/29/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To evaluate the effect of exposure time and moving the light-curing unit (LCU) on the degree of conversion (DC) and Knoop microhardness (KH) of two resin cements that were light-cured through ceramic. METHODS Two resin cements: AllCem Veneer APS (FGM) and Variolink Esthetic LC (Ivoclar Vivadent) were placed into a 0.3 mm thick matrix in 6 locations representing the canine to canine. The resins were covered with 0.5 mm thick lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent). A motorized device moved the LCUs over the ceramic when the LCU was on. Two single-peak LCUs: Elipar DeepCure-L (3M Oral Care) and Emitter C (Schuster), and one multi-peak: Bluephase G2 (Ivoclar Vivadent) were used with 3 different exposure protocols: a localized exposure centered over each tooth for 10 or 40 s; moving the tip across the 6 teeth for a total exposure time of 10 or 40 s; and moving the tip across the 6 teeth resins for a total exposure time of 60 or 240 s. After 24 h, the DC and KH were measured on the top surfaces and the data was analyzed using three-way ANOVA and Tukey's tests (α = 0.05). RESULTS Interposition of 0.5 mm of ceramic reduced the irradiance received by the resin by approximately 50%. The 40 s localized exposure over each tooth always produced significantly higher DC and KH values. Moving the LCUs with a total exposure time of 10 s resulted in the lowest DC and KH. There was no beneficial effect on the DC or KH when the multi-peak (violet-blue) LCU (Elipar DeepCure-L or Bluephase G2), but the lower light output from a small tip LCU reduced the DC and KH values (Emitter C). SIGNIFICANCE Moving the LCUs when photo-curing light-cured resin cements is not recommended. This study showed that a single-peak LCU could activate a resin cement that uses Ivocerin™ as well as the multi-peak LCU.
Collapse
Affiliation(s)
- Gabriel Felipe Bragança
- Biomechanical, Biomaterials and Cell Biology Research Center, Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
| | - Arthur Silva Vianna
- School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
| | - Flávio Domingues Neves
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Richard Bengt Price
- Department of Occlusion and Prosthodontic, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
| | - Carlos José Soares
- Biomechanical, Biomaterials and Cell Biology Research Center, Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
| |
Collapse
|
17
|
Urcuyo Alvarado MS, Escobar García DM, Pozos Guillén ADJ, Flores Arriaga JC, Romo Ramírez GF, Ortiz Magdaleno M. Evaluation of the Bond Strength and Marginal Seal of Indirect Restorations of Composites Bonded with Preheating Resin. Eur J Dent 2020; 14:644-650. [PMID: 32932533 PMCID: PMC7536092 DOI: 10.1055/s-0040-1716630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Objective
Preheated resins (PR) are considered a cementing agent option for indirect adhesive restorations of composite inlays and onlays. The objective of this in vitro study was to evaluate the marginal sealing, adhesive interface, and microtensile bond strength of indirect adhesive restorations of composites in terms of dentin cemented with PR.
Materials and Methods
Standardized Class II preparations were performed on 30 extracted human premolars, impressions were taken, and indirect composite restorations were manufactured. In total, 15 restorations were cemented with PR (ENA HRi, SYNCA), and 15 restorations were cemented with self-adhesive resinous cement (RC) (Relyx U200, 3M ESPE), followed by a thermocycling regime. After that, these were segmented sagittally and longitudinally to evaluate the marginal sealing and the adhesive interface with scanning electron microscopy and confocal microscopy. Microtensile bond strength was assessed with a mechanical device (TA. XT Plus C, Stable Micro System).
Statistical analysis
Statistical analysis was conducted using the two-sample Student’s
t
-test.
Results
The results showed that there is no statistically significant difference in the degree of microfiltration using PR or RC; however, microtensile bond strength is greater when the restoration is cemented with RC (278.75 N/cm
3
) than with PR (144.49 N/cm
3
), and better adjustment and sealing were observed for composite restorations with PR.
Conclusion
PR comprise an alternative cementing agent for indirect composite restorations in Class II cavities in premolars.
Collapse
Affiliation(s)
- Manuel Salvador Urcuyo Alvarado
- Department of the Specialty in Aesthetic, Cosmetic, Restorative, and Implantological Dentistry, Faculty of Stomatology, Autonomous University of San Luis Potosí, San Luis Potosí, México
| | - Diana María Escobar García
- Laboratory of Basic Science, Faculty of Dentistry, Autonomous University of San Luis Potosí, San Luis Potosí, México
| | - Amaury de Jesús Pozos Guillén
- Laboratory of Basic Science, Faculty of Dentistry, Autonomous University of San Luis Potosí, San Luis Potosí, México
| | - Juan Carlos Flores Arriaga
- Laboratory of Basic Science, Faculty of Dentistry, Autonomous University of San Luis Potosí, San Luis Potosí, México
| | - Gabriel Fernando Romo Ramírez
- Department of the Specialty in Aesthetic, Cosmetic, Restorative, and Implantological Dentistry, Faculty of Stomatology, Autonomous University of San Luis Potosí, San Luis Potosí, México
| | - Marine Ortiz Magdaleno
- Laboratory of Basic Science, Faculty of Dentistry, Autonomous University of San Luis Potosí, San Luis Potosí, México
| |
Collapse
|
18
|
Ebeid K, Sabet A, Rafla N, Al-Haj Husain N, Özcan M. Effect of photo-polymerization mode on the degree of conversion of resin cement under different ceramic materials. Minerva Dent Oral Sci 2020; 70:147-154. [PMID: 32698563 DOI: 10.23736/s2724-6329.20.04354-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND This study evaluated the effect of different polymerization modes and duration on the degree of conversion (DC) of resin cement under different types of ceramics. METHODS Ceramic materials were divided into 3 groups (N.=60): group 1, Cerasmart; group 2, Vita Enamic; and group 3, Vita Mark II. Each group was then divided into three subgroups (N.=20) according to the polymerization mode (A: low-intensity; B: high-intensity; and C: soft-start). Subgroups were then divided into two further groups according to the polymerization time (I: 10 s; and II: 20 s). DC of light-cured resin cement beneath different kinds of ceramics was tested using FTIR spectroscopy. Results were compared to a control group cured without overlying ceramic. RESULTS While the type of ceramic and mode of polymerization showed a significant effect on the DC of resin cement, polymerization duration did not. Vita Mark II group showed the highest DC of resin cement followed by Vita Enamic and Cerasmart. High- and low-intensity polymerization modes did not show significant difference, but both showed significantly lower DC when compared to soft start mode. CONCLUSIONS Type of ceramic and polymerization mode showed a direct effect on the DC of resin cement.
Collapse
Affiliation(s)
- Kamal Ebeid
- Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt -
| | - Ahmed Sabet
- Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.,Department of Fixed Prosthodontics, British University, Cairo, Egypt
| | - Nancy Rafla
- Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Nadin Al-Haj Husain
- School of Dental Medicine, Department of Reconstructive Dentistry and Gerodontology, University of Bern, Bern, Switzerland
| | - Mutlu Özcan
- Division of Dental Biomaterials, Center for Dental and Oral Medicine, Clinic for Reconstructive Dentistry, University of Zurich, Zurich, Switzerland
| |
Collapse
|
19
|
The effect of rapid high-intensity light-curing on micromechanical properties of bulk-fill and conventional resin composites. Sci Rep 2020; 10:10560. [PMID: 32601442 PMCID: PMC7324583 DOI: 10.1038/s41598-020-67641-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/11/2020] [Indexed: 01/08/2023] Open
Abstract
Rapid high-intensity light-curing of dental resin composites is attractive from a clinical standpoint due to the prospect of time-savings. This study compared the effect of high-intensity (3 s with 3,440 mW/cm2) and conventional (10 s with 1,340 mW/cm2) light-curing on micromechanical properties of conventional and bulk-fill resin composites, including two composites specifically designed for high-intensity curing. Composite specimens were prepared in clinically realistic layer thicknesses. Microhardness (MH) was measured on the top and bottom surfaces of composite specimens 24 h after light-curing (initial MH), and after subsequent immersion for 24 h in absolute ethanol (ethanol MH). Bottom/top ratio for initial MH was calculated as a measure of depth-dependent curing effectiveness, whereas ethanol/initial MH ratio was calculated as a measure of crosslinking density. High-intensity light-curing showed a complex material-dependent effect on micromechanical properties. Most of the sculptable composites showed no effect of the curing protocol on initial MH, whereas flowable composites showed 11–48% lower initial MH for high-intensity curing. Ethanol/initial MH ratios were improved by high-intensity curing in flowable composites (up to 30%) but diminished in sculptable composites (up to 15%). Due to its mixed effect on MH and crosslinking density in flowable composites, high-intensity curing should be used with caution in clinical work.
Collapse
|
20
|
Surface Characteristics and Color Stability of Gingiva-Colored Resin Composites. MATERIALS 2020; 13:ma13112540. [PMID: 32503174 PMCID: PMC7321486 DOI: 10.3390/ma13112540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/10/2020] [Accepted: 06/01/2020] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to investigate the surface characteristics and color stability of gingiva-colored composite restorative materials (Anaxgum—ANG, Ceramage—CMG and Gradia Gum—GRG). The microstructure, composition, degree of conversion (DC %) and 3D roughness (Sa, Sz, Sdr, Sc) were examined by LV-SEM/EDS, ATR-FTIR and optical profilometry, respectively. For the color stability (CIE L*, a*, b* system) and hardness (HV), measurements were performed at baseline and after 30 days storage in distilled water, coffee and red wine. The ANG and GRG contain prepolymerized particles in aromatic and aliphatic resin matrices, respectively, whereas CMG contains inorganic zirconia silicate/silica particles, in an aromatic resin matrix, with a smaller particle size and a higher surface area fraction. Urethane monomers were mainly identified in CMG and GRG. The DC% showed statistically insignificant differences between the materials. The same applied for the roughness parameters, except for the greatest Sdr in CMG. ANG showed a color difference (ΔE) of > 3.3 after immersion in all media, CMG in coffee and wine and GRG only in coffee. Sc was the only roughness parameter demonstrating correlations with the ΔL*, Δb* and ΔE*. The HV values showed insignificant differences between the storage conditions per material. There are important differences in the color stability of the materials tested, which were mostly affected by the roughness parameters due to variations in their microstructure.
Collapse
|
21
|
Lima AF, Salvador MVO, Dressano D, Saraceni CHC, Gonçalves LS, Hadis M, Palin WM. Increased rates of photopolymerisation by ternary type II photoinitiator systems in dental resins. J Mech Behav Biomed Mater 2019; 98:71-78. [PMID: 31203099 DOI: 10.1016/j.jmbbm.2019.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/26/2022]
Abstract
To evaluate the effects of Type I and Type II photoinitiator systems on curing efficiency, degree of conversion (DC) and chemico-physical properties of resin based materials. A comonomer base containing 50%wt 2.2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA) and 50%wt triethyleneglycol dimethacrylate (TEGDMA) was formulated with either 0.5 or 1mol% of Type II camphoroquinone (CQ), Type I monoacylphosphine oxide (MAPO) or bis-acylphosphine oxide (BAPO) photoinitiators. The Type II system was either a binary (1: 2 CQ:amine) or ternary system (1: 2 CQ:amine + 0.5 mol% DPI). Degree and rate of polymerization was measured by Fourier Transform Infrared Spectroscopy (FTIR). Knoop micro-hardness prior to and following ethanol immersion was assessed. Flexural strength and modulus was measured under three-point bend test. Water sorption and solubility was also evaluated. The photoinitiator absorption spectra and the total absorbed energy per unit volume (Eabs) for 0.5mol% photoinitiator in each material was calculated. Despite the reduced total absorbed energy per unit volume for CQ based systems, ternary Type II system significantly improved curing efficiency (P < 0.05) compared to both Type I photoinitiators and degree of conversion compared to MAPO only, whilst exhibiting comparable mechanical and physical properties compared to both Type I based materials at equivalent molar concentrations of photoinitiator (P > 0.05). Ternary Type II systems is an efficient alternative to improve the polymerization of resin materials, promoting similar or even better properties than Type I initiators. DPI can increase the reactivity of CQ systems and promote polymerization rates superior than Type I photoinitiators.
Collapse
Affiliation(s)
- Adriano Fonseca Lima
- Dental Research Division, Paulista University, Sao Paulo Brazil. Rua Doutor Bacelar, 1212. CEP: 04026-002, Sao Paulo, Brazil.
| | | | - Diogo Dressano
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil. Av Limeira, 901 Mail Box 52, Piracicaba, Sao Paulo, 13414-903, Brazil.
| | - Cintia Helena Coury Saraceni
- Dental Research Division, Paulista University, Sao Paulo Brazil. Rua Doutor Bacelar, 1212. CEP: 04026-002, Sao Paulo, Brazil.
| | - Luciano Souza Gonçalves
- Department of Conservative Dentistry, Federal University of Rio Grande do Sul School of Dentistry, Av. Paulo Gama, 110 - Farroupilha, Porto Alegre, RS, 90040-060, Porto Alegre, RS, Brazil.
| | - Mohammed Hadis
- Biomaterials Unit, University of Birmingham, College of Medical and Dental Sciences, School of Dentistry, St Chad's Queensway, Birmingham, B4 6NN, UK.
| | - William M Palin
- Biomaterials Unit, University of Birmingham, College of Medical and Dental Sciences, School of Dentistry, St Chad's Queensway, Birmingham, B4 6NN, UK.
| |
Collapse
|
22
|
Hughes KO, Powell KJ, Hill AE, Tantbirojn D, Versluis A. Delayed Photoactivation of Dual-cure Composites: Effect on Cuspal Flexure, Depth-of-cure, and Mechanical Properties. Oper Dent 2019; 44:E97-E104. [DOI: 10.2341/18-140-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objectives:
This study tested whether delayed photoactivation could reduce shrinkage stresses in dual-cure composites and how it affected the depth-of-cure and mechanical properties.
Methods and Materials:
Two dual-cure composites (ACTIVA and Bulk EZ) were subjected to two polymerization protocols: photoactivation at 45 seconds (immediate) or 165 seconds (2 minutes delayed) after extrusion. Typodont premolars with standardized preparations were restored with the composites, and cuspal flexure caused by polymerization shrinkage was determined with three-dimensional scanning of the external tooth surfaces before restoration (baseline) and at 10 minutes and one hour after photoactivation. Bond integrity (intact interface) was verified with dye penetration. Depth-of-cure was determined by measuring Vickers hardness through the depth at 1-mm increments. Elastic modulus and maximum stress were determined by four-point bending tests (n=10). Results were analyzed with two- or three-way analysis of variance and pairwise comparisons (Bonferroni; α=0.05).
Results:
Delayed photoactivation significantly reduced cuspal flexure for both composites at 10 minutes and one hour (p≤0.003). Interface was >99% intact in every group. Depth-of-cure, elastic modulus, and flexural strength were not significantly different between the immediate and delayed photoactivation (p>0.05). The hardness of ACTIVA reduced significantly with depth (p<0.001), whereas the hardness of Bulk EZ was constant throughout the depth (p=0.942).
Conclusions:
Delayed photoactivation of dual-cure restorative composites can reduce shrinkage stresses without negatively affecting the degree-of-cure or mechanical properties (elastic modulus and flexural strength).
Collapse
Affiliation(s)
- KO Hughes
- K Olivia Hughes, DDS student, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - KJ Powell
- Kipley J Powell, DDS student, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - AE Hill
- Anne E Hill, DDS, assistant professor, Department of General Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - D Tantbirojn
- Daranee Tantbirojn, DDS, MS, PhD, professor, Department of General Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - A Versluis
- Antheunis Versluis, PhD, professor, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| |
Collapse
|
23
|
Knežević A, Želježić D, Kopjar N, Duarte S, Tarle Z. In Vitro Biocompatibility of Preheated Giomer and Microfilled-Hybrid Composite. Acta Stomatol Croat 2019; 52:286-297. [PMID: 30666059 PMCID: PMC6336444 DOI: 10.15644/asc52/4/2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Objective The aim of this study was to evaluate cytotoxic potencies of two light cured composite materials after heating on different temperatures and cured directly and through CAD/CAM overlay. Materials and methods Composite materials (microfilled-hybrid Gradia Direct Posterior and Beautifil II) were heated in a Calset warming unit at three different temperatures (T1:37°C, T2:54°C, T3:68°C). A small amount of heated composite material was placed in a round mold (diameter 6mm; 0.65mm thick), covered with Mylar sheet, pressed and polymerized with Bluephase LED unit. One group of samples were polymerized directly, and the other group through 2mm thick CAD/CAM ceramic-reinforced polymer (CRP) and CAD/CAM lithium disilicate ceramic (LDC) overlay for 20 and 40 seconds. The polymerized samples were placed immediately after curing in a lymphocyte cell culture. The viability of peripheral blood lymphocytes was evaluated using a dye exclusion technique by simultaneous staining with ethidium bromide and acridine orange. Quantitative assessments were made by determination of the percentage of viable, apoptotic and necrotic cells. The Pearson chi-square test was used for statistical analysis. Results In case of 20 seconds polymerization, the highest number of viable cells polymerization were recorded when materials were heated at 37°C (T1), while in case of 40 seconds polymerization, the highest number of viable cells were recorded when the materials were heated at 54°C (T2). The samples polymerized through CAD/CAM overlays showed less cytotoxicity than samples polymerized directly. Conclusion Apart from composite material composition, the cell viability was also influenced by curing time, temperature of pre-heating and polymerization pattern.
Collapse
Affiliation(s)
- Alena Knežević
- Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Norris Dental Science Center, 925 W 34th St, Los Angeles, CA 90089, USA
| | - Davor Želježić
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Ksaverska c. 2, 10000 Zagreb, Croatia
| | - Nevenka Kopjar
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Ksaverska c. 2, 10000 Zagreb, Croatia
| | - Sillas Duarte
- Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Norris Dental Science Center, 925 W 34th St, Los Angeles, CA 90089, USA
| | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia
| |
Collapse
|
24
|
Effect of pulse width modulation-controlled LED light on the polymerization of dental composites. Dent Mater 2018; 34:1836-1845. [DOI: 10.1016/j.dental.2018.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 11/20/2022]
|
25
|
Silva Prezotto AF, Silva DB, Vitti RP, Sinhoreti MAC, Brandt WC. Light curing and ratio of glass/fumed silica fillers on degree of conversion and mechanical properties of experimental composite resins. J Appl Polym Sci 2018. [DOI: 10.1002/app.47008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- A. F. Silva Prezotto
- University of CampinasPiracicaba Dental School, Department Restorative Dentistry Piracicaba SP Brazil
| | - D. B. Silva
- University of Santo AmaroSchool of Dentistry, Department of Implantology São Paulo SP Brazil
| | - R. P. Vitti
- University of TaubatéSchool of Dentistry, Department of Prosthodontics Taubaté SP Brazil
| | - M. A. C. Sinhoreti
- University of CampinasPiracicaba Dental School, Department Restorative Dentistry Piracicaba SP Brazil
| | - W. C. Brandt
- University of Santo Amaro, School of DentistryDepartment of Implantology São Paulo SP Brazil
| |
Collapse
|
26
|
Çetindemir AB, Şermet B, Öngül D. The effect of light sources and CAD/CAM monolithic blocks on degree of conversion of cement. J Adv Prosthodont 2018; 10:291-299. [PMID: 30140396 PMCID: PMC6104501 DOI: 10.4047/jap.2018.10.4.291] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/27/2018] [Accepted: 05/08/2018] [Indexed: 12/04/2022] Open
Abstract
PURPOSE To assess the degree of conversion (DC) and light irradiance delivered to light-cured and dual-cured cements by application of different light sources through various types of monolithic computer-aided design and computer-aided manufacturing (CAD/CAM) materials. MATERIALS AND METHODS RelyX Ultimate Clicker light-cured and dual-cured resin cement specimens with 1.5-mm thicknesses (n=300, 10/group), were placed under four types of crystalline core structure (Vita Enamic, Vita Suprinity, GC Ceresmart, Degudent Prettau Anterior). The specimens were irradiated for 40 seconds with an LED Soft-Start or pulse-delay unit or 20 seconds with a QTH unit. DC ratios were determined by using Fourier transform infrared spectroscopy (FTIR) after curing the specimen at 1 day and 1 month. The data were analyzed using the Mann-Whitney U test (for paired comparison) and the Kruskal-Wallis H test (for multiple comparison), with a significance level of P<.05. RESULTS DC values were the highest for RelyX Ultimate Clicker light-cure specimens polymerized with the LED Soft-Start unit. The combination of the Vita Suprinity disc and RelyX Ultimate Clicker dual-cure resin cement yielded significantly higher values at both timepoints with all light units (all, P<.05). CONCLUSION Within the limitations of this study, we conclude that the DC of RelyX Ultimate Clicker dual-cure resin cement was improved significantly by the use of Vita Suprinity and the LED Soft-Start light unit. We strongly recommend the combined use of an LED light unit and dual-cure luting cement for monolithic ceramic restorations.
Collapse
Affiliation(s)
| | - Bülent Şermet
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - Değer Öngül
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| |
Collapse
|
27
|
de Paula AB, Taparelli JR, Alonso RCB, Innocentini-Mei LH, Puppin-Rontani RM. Synthesis and application of triclosan methacrylate monomer in resin composites. Clin Oral Investig 2018; 23:965-974. [DOI: 10.1007/s00784-018-2521-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 06/07/2018] [Indexed: 11/28/2022]
|
28
|
Han SH, Park SH. Incremental and Bulk-fill Techniques With Bulk-fill Resin Composite in Different Cavity Configurations. Oper Dent 2018; 43:631-641. [PMID: 29630486 DOI: 10.2341/17-279-lr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE: To compare the microtensile bond strengths of incremental and bulk-fill techniques under different C-factor and compliance conditions. METHODS AND MATERIALS: Extracted human third molars were divided into three experimental groups. For group I, Class I cavities were prepared. For group II, MOD cavities of the same size were prepared. For group III, the cavities were prepared the same way as group II only with high compliance cavity walls. The cavity wall compliance of the specimens was evaluated. Each of these groups was divided into four subgroups. The teeth were restored using two different materials: TB (Tetric N-Ceram Bulk Fill; Ivoclar Vivadent, Hanau, Germany) and VB (Venus Bulk Fill; Heraeus Kulzer, Armonk, NY, USA), and two methods, either an incremental or bulk-fill technique. Then, the microtensile bond strengths (μ-TBSs) were measured and compared. The polymerization stresses of the composites were calculated using a custom-made device. The results were statistically analyzed using the Kruskal-Wallis test and Weibull analysis. RESULTS: In group I, the μ-TBS obtained using the incremental technique was significantly higher than that obtained by the bulk-fill technique ( p<0.05). In contrast, no difference of the μ-TBS value was observed between the two techniques in groups II and III. The μ-TBS value of group I was significantly lower than those of groups II and III ( p<0.05). No statistical difference in the μ-TBS was observed when the cavities were filled with either TB or VB ( p>0.05). CONCLUSIONS: The incremental technique showed higher bond strength than did the bulk-fill technique in high C-factor cavities. However, no difference was found between the two techniques in the low C-factor cavities. The bond strength in the high C-factor cavities was significantly lower than that of the low C-factor cavities.
Collapse
|
29
|
Lanza MDS, Andreeta MRB, Pegoraro TA, Pegoraro LF, Carvalho RMD. Influence of curing protocol and ceramic composition on the degree of conversion of resin cement. J Appl Oral Sci 2018; 25:700-707. [PMID: 29211292 PMCID: PMC5701541 DOI: 10.1590/1678-7757-2016-0270] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 03/20/2017] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Due to increasing of aesthetic demand, ceramic crowns are widely used in different situations. However, to obtain long-term prognosis of restorations, a good conversion of resin cement is necessary. To evaluate the degree of conversion (DC) of one light-cure and two dual-cure resin cements under a simulated clinical cementation of ceramic crowns. MATERIAL AND METHODS Prepared teeth were randomly split according to the ceramic's material, resin cement and curing protocol. The crowns were cemented as per manufacturer's directions and photoactivated either from occlusal suface only for 60 s; or from the buccal, occlusal and lingual surfaces, with an exposure time of 20 s on each aspect. After cementation, the specimens were stored in deionized water at 37°C for 7 days. Specimens were transversally sectioned from occlusal to cervical surfaces and the DC was determined along the cement line with three measurements taken and averaged from the buccal, lingual and approximal aspects using micro-Raman spectroscopy (Alpha 300R/WITec®). Data were analyzed by 3-way ANOVA and Tukey test at =5%. RESULTS Statistical analysis showed significant differences among cements, curing protocols and ceramic type (p<0.001). The curing protocol 3x20 resulted in higher DC for all tested conditions; lower DC was observed for Zr ceramic crowns; Duolink resin cement culminated in higher DC regardless ceramic composition and curing protocol. CONCLUSION The DC of resin cement layers was dependent on the curing protocol and type of ceramic.
Collapse
Affiliation(s)
| | - Marcello Rubens Barsi Andreeta
- Universidade Federal de São Carlos, Departamento de Engenharia de Materiais, Laboratório de Materiais Vítreos, São Carlos, SP, Brasil
| | - Thiago Amadei Pegoraro
- Universidade do Sagrado Coração, Departamento de Prótese e Implantodontia, Bauru, SP, Brasil
| | - Luiz Fernando Pegoraro
- Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Prótese e Periodontia, Bauru, SP, Brasil
| | - Ricardo Marins De Carvalho
- University of British Columbia, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, Division of Biomaterials, Vancouver, Canada
| |
Collapse
|
30
|
Lise DP, Van Ende A, De Munck J, Yoshihara K, Nagaoka N, Cardoso Vieira LC, Van Meerbeek B. Light irradiance through novel CAD–CAM block materials and degree of conversion of composite cements. Dent Mater 2018; 34:296-305. [DOI: 10.1016/j.dental.2017.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/20/2017] [Accepted: 11/09/2017] [Indexed: 11/25/2022]
|
31
|
Ólafsson VG, Ritter AV, Swift EJ, Boushell LW, Ko CC, Jackson GR, Ahmed SN, Donovan TE. Effect of composite type and placement technique on cuspal strain. J ESTHET RESTOR DENT 2018; 30:30-38. [PMID: 29034597 PMCID: PMC5815887 DOI: 10.1111/jerd.12339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare the cuspal strain in Class II restorations made with bulk-fill and conventional composite resins. MATERIALS AND METHODS Fifty extracted maxillary premolars were mounted into phenolic rings and divided into five groups (n = 10). Specimens received standardized MOD preparations. A two-step self-etch adhesive was applied and the preparations were restored using a custom matrix as follows: Filtek Supreme Ultra in eight 2-mm increments (FSUI); Filtek Supreme Ultra in bulk (FSUB); SonicFill in bulk (SF); SureFil SDR flow in bulk, covered with a 2-mm occlusal layer of Filtek Supreme Ultra (SDR/FSU); Tetric EvoCeram Bulk Fill in bulk (TEBF). Strain gages bonded to the buccal and lingual cusps recorded cuspal strain during restorations. End strain values were determined and data were subjected to Kruskal-Wallis testing, followed by one-way ANOVA and Tukey´s post hoc test. RESULTS Combined strain values and standard deviations (in µɛ) were: FSUI: 723 ± 102.8, FSUB: 929.2 ± 571.9, SF: 519.1 ± 80.2, SDR-FSU: 497.4 ± 67.6 and TEBF: 604.5 ± 127.1. A significant difference was found between group FSUI and groups SF, SDR-FSU, and TEBF. Group FSUB showed significantly higher mean strain and greater standard deviation than all other groups due to cuspal fractures, and was thus excluded from the statistical analysis. CONCLUSIONS The tested bulk-fill composite resins exerted less strain onto tooth structure than the incrementally placed conventional composite resin, although the magnitude of generated strain was product-dependent. Bulk-filling with conventional composite resins is contraindicated. CLINICAL SIGNIFICANCE Bulk-fill composite resins exerted less strain onto adjacent tooth structure than a traditional composite, even when that composite is was placed incrementally. Bulk-filling with traditional composite resins is unpredictable and contraindicated.
Collapse
Affiliation(s)
- Vilhelm G. Ólafsson
- Department of Operative Dentistry and Cariology, Faculty of Odontology, University of Iceland, Vatnsmyrarvegur 16, 101, Reykjavik, Iceland
- Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7450
| | - André V. Ritter
- Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, 440 Brauer Hall, CB #7450, Chapel Hill, North Carolina 27599-7450
| | - Edward J. Swift
- School of Dentistry, University of North Carolina at Chapel Hill, 1611 Koury Oral Health Sciences Building, CB #7450, Chapel Hill, North Carolina 27599-7450
| | - Lee W. Boushell
- Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, 448 Brauer Hall, CB #7450, Chapel Hill, North Carolina 27599-7450
| | - Ching-Chang Ko
- Department of Orthodontics, School of Dentistry, University of North Carolina at Chapel Hill, 275 Brauer Hall, CB #7454, Chapel Hill, North Carolina 27599-7454
| | - Gabrielle R. Jackson
- Department of Prosthodontics, School of Dentistry, University of North Carolina at Chapel Hill, 330 Brauer Hall, CB #7450, Chapel Hill, North Carolina, 27599-7450
| | - Sumitha N. Ahmed
- Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, 441 Brauer Hall, CB #7450, Chapel Hill, North Carolina 27599-7450
| | - Terence E. Donovan
- Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, 437 Brauer Hall, CB #7450, Chapel Hill, North Carolina 27599-7450
| |
Collapse
|
32
|
Soares CJ, Faria-E-Silva AL, Rodrigues MDP, Vilela ABF, Pfeifer CS, Tantbirojn D, Versluis A. Polymerization shrinkage stress of composite resins and resin cements - What do we need to know? Braz Oral Res 2017; 31:e62. [PMID: 28902242 DOI: 10.1590/1807-3107bor-2017.vol31.0062] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 05/22/2017] [Indexed: 11/22/2022] Open
Abstract
Polymerization shrinkage stress of resin-based materials have been related to several unwanted clinical consequences, such as enamel crack propagation, cusp deflection, marginal and internal gaps, and decreased bond strength. Despite the absence of strong evidence relating polymerization shrinkage to secondary caries or fracture of posterior teeth, shrinkage stress has been associated with post-operative sensitivity and marginal stain. The latter is often erroneously used as a criterion for replacement of composite restorations. Therefore, an indirect correlation can emerge between shrinkage stress and the longevity of composite restorations or resin-bonded ceramic restorations. The relationship between shrinkage and stress can be best studied in laboratory experiments and a combination of various methodologies. The objective of this review article is to discuss the concept and consequences of polymerization shrinkage and shrinkage stress of composite resins and resin cements. Literature relating to polymerization shrinkage and shrinkage stress generation, research methodologies, and contributing factors are selected and reviewed. Clinical techniques that could reduce shrinkage stress and new developments on low-shrink dental materials are also discussed.
Collapse
Affiliation(s)
- Carlos José Soares
- Universidade Federal de Uberlândia - UFU, Dental School, Department of Operative Dentistry and Dental Materials, Uberlândia, Minas Gerais, Brazil
| | - André Luis Faria-E-Silva
- Universidade Federal de Sergipe - UFS, Dental School, Department of Dentistry, Aracaju, Sergipe, Brazil
| | - Monise de Paula Rodrigues
- Universidade Federal de Uberlândia - UFU, Dental School, Department of Operative Dentistry and Dental Materials, Uberlândia, Minas Gerais, Brazil
| | - Andomar Bruno Fernandes Vilela
- Universidade Federal de Uberlândia - UFU, Dental School, Department of Operative Dentistry and Dental Materials, Uberlândia, Minas Gerais, Brazil
| | - Carmem Silvia Pfeifer
- Oregon Health and Science University - OHSU, School of Dentistry, Department of Restorative Dentistry, Portland, OR, United States of America
| | - Daranee Tantbirojn
- University of Tennessee Health Science Center, College of Dentistry, Department of Restorative Dentistry, Memphis, TN, United States of America
| | - Antheunis Versluis
- University of Tennessee Health Science Center, College of Dentistry, Department of Bioscience Research, TN, United States of America
| |
Collapse
|
33
|
Shimokawa C, Sullivan B, Turbino ML, Soares CJ, Price RB. Influence of Emission Spectrum and Irradiance on Light Curing of Resin-Based Composites. Oper Dent 2017; 42:537-547. [PMID: 28581917 DOI: 10.2341/16-349-l] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE This study examined the influence of different emission spectra (single-peak and broad-spectrum) light-curing units (LCUs) delivering the same radiant exposures at irradiance values of 1200 or 3600 mW/cm2 on the polymerization and light transmission of four resin-based composites (RBCs). METHODS AND MATERIALS Two prototype LCUs that used the same light tip, but were either a single-peak blue or a broad-spectrum LED, were used to deliver the same radiant exposures to the top surfaces of the RBCs using either standard (1200 mW/cm2) or high irradiance (3600 mW/cm2) settings. The emission spectrum and radiant power from the LCUs were measured with a laboratory-grade integrating sphere coupled to a spectrometer, and the light beam was assessed with a beam profiler camera. Four RBCs (Filtek Supreme Ultra A2, Tetric EvoCeram A2, Tetric EvoCeram T, and TPH Spectra High Viscosity A2) were photoactivated using four different light conditions: single-peak blue/standard irradiance, single-peak blue/high irradiance, broad-spectrum/standard irradiance, and broad-spectrum/high irradiance. The degree of conversion (N=5) and microhardness at the top and bottom of 2.3-mm-diameter by 2.5-mm-thick specimens (N=5) were analyzed with analysis of variance and Tukey tests. The real-time light transmission through the RBCs was also measured. RESULTS For all light conditions, the 2.3-mm-diameter specimens received a homogeneous irradiance and spectral distribution. Although similar radiant exposures were delivered to the top surfaces of the RBCs, the amount of light energy emitted from the bottom surfaces was different among the four RBCs, and was also greater for the single-peak lights. Very little violet light (wavelengths below 420 nm) reached the bottom of the 2.5-mm-thick specimens. The degree of conversion and microhardness results varied according to the RBC (p<0.05). The RBCs that included alternative photoinitiators had greater microhardness values at the top when cured with broad-spectrum lights, while at the bottom, where little violet light was observed, the results were equal or higher when they were photoactivated with single-peak blue lights. With the exception of the microhardness at the top of TPH, equivalent or higher microhardness and degree-of-conversion values were achieved at the bottom surface when the standard (1200 mW/cm2) irradiance levels were used compared to when high irradiance levels were used. CONCLUSIONS Considering the different behaviors of the tested RBCs, the emission spectrum and irradiance level influenced the polymerization of some RBCs. The RBCs that included alternative photoinitiators produced greater values at the top when cured with broad-spectrum lights, while at the bottom, results were equal or higher for the RBCs photoactivated with single-peak blue lights.
Collapse
|
34
|
Yazici AR, Antonson SA, Kutuk ZB, Ergin E. Thirty-Six-Month Clinical Comparison of Bulk Fill and Nanofill Composite Restorations. Oper Dent 2017; 42:478-485. [PMID: 28581919 DOI: 10.2341/16-220-c] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the clinical performance of a nanofill and a bulk fill resin composite in class II restorations. METHODS AND MATERIALS In accordance with a split-mouth design, 50 patients received at least one pair of restorations, restored with a nanofill resin composite (Filtek Ultimate [FU]) and with a bulk fill resin composite (Tetric EvoCeram Bulk Fill [TB]). Each restorative resin was used with its respective adhesive system according to the manufacturers' instructions. A total of 104 class II restorations were placed by two operators. The restorations were blindly evaluated by two examiners at baseline and at six, 12, 18, 24, and 36 months using modified US Public Health Service Ryge criteria. The comparison of the two restorative materials for each category was performed with the chi-square test (α=0.05). The baseline scores were compared with those at the recall visits using the Cochran Q-test. RESULTS At six, 12, 18, and 24 months, the recall rate was 100%, 98%, 94%, and 82%, respectively, with a retention rate of 100%. At 36 months, 81 restorations were evaluated in 39 patients with a recall rate of 78%. For marginal adaptation, four restorations from the TB group and 10 from the FU group rated as Bravo. Two restorations from the TB and eight restorations from the FU group showed marginal discoloration. There were statistically significant differences between the two restorative resins in terms of marginal adaptation and marginal discoloration (p<0.05). No differences were observed between the restorative resins in terms of retention (p>0.05). One restored tooth from the FU group was crowned. The retention rates for the TB and the FU groups were 100%. In the FU group, two restorations showed slightly rough surfaces, and two showed a slight mismatch in color. None of the restorations showed postoperative sensitivity, secondary caries, or loss of anatomic form. CONCLUSIONS The tested bulk fill restorative resin demonstrated better clinical performance in terms of marginal discoloration and marginal adaptation.
Collapse
|
35
|
Food Simulating Organic Solvents for Evaluating Crosslink Density of Bulk Fill Composite Resin. Int J Dent 2017; 2017:1797091. [PMID: 28487739 PMCID: PMC5405598 DOI: 10.1155/2017/1797091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/11/2017] [Accepted: 03/29/2017] [Indexed: 11/17/2022] Open
Abstract
Objectives. To evaluate crosslink densities of two bulk fill composite resins and determine if the used Food Simulating Organic Solvent (FSOS) affected them. Methods. Forty specimens were prepared from SureFill and SonicFill bulk fill composite resins, 20 each. All specimens were stored dry for 24 h. Each group was divided into 2 subgroups: stored in ethanol (E) 75% or in methyl ethyl ketone (MEK) 100% for 24 h. Crosslink density was evaluated by calculating the difference between the Vickers hardness numbers of the specimens stored dry and after their storage in FSOS. The data were statistically analyzed using t-test. Results. The means of crosslink density in E and MEK were 6.99% and 9.44% for SureFill and 10.54% and 11.92% for SonicFill, respectively. t-test displayed significant differences between crosslink densities of SureFill and SonicFill: (P < 0.0001) in E and (P = 0.02) in MEK and between crosslink densities of SureFill in E and MEK (P = 0.02). Conclusions. Crosslink density of bulk fill composite resin can be evaluated using E or MEK. SureFill has higher crosslink density than SonicFill in both E and MEK.
Collapse
|
36
|
Heintze SD, Ilie N, Hickel R, Reis A, Loguercio A, Rousson V. Laboratory mechanical parameters of composite resins and their relation to fractures and wear in clinical trials-A systematic review. Dent Mater 2016; 33:e101-e114. [PMID: 27993372 DOI: 10.1016/j.dental.2016.11.013] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/29/2016] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To evaluate a range of mechanical parameters of composite resins and compare the data to the frequency of fractures and wear in clinical studies. METHODS Based on a search of PubMed and SCOPUS, clinical studies on posterior composite restorations were investigated with regard to bias by two independent reviewers using Cochrane Collaboration's tool for assessing risk of bias in randomized trials. The target variables were chipping and/or fracture, loss of anatomical form (wear) and a combination of both (summary clinical index). These outcomes were modelled by time and material in a linear mixed effect model including random study and experiment effects. The laboratory data from one test institute were used: flexural strength, flexural modulus, compressive strength, and fracture toughness (all after 24-h storage in distilled water). For some materials flexural strength data after aging in water/saliva/ethanol were available. Besides calculating correlations between clinical and laboratory outcomes, we explored whether a model including a laboratory predictor dichotomized at a cut-off value better predicted a clinical outcome than a linear model. RESULTS A total of 74 clinical experiments from 45 studies were included involving 31 materials for which laboratory data were also available. A weak positive correlation between fracture toughness and clinical fractures was found (Spearman rho=0.34, p=0.11) in addition to a moderate and statistically significant correlation between flexural strength and clinical wear (Spearman rho=0.46, p=0.01). When excluding those studies with "high" risk of bias (n=18), the correlations were generally weaker with no statistically significant correlation. For aging in ethanol, a very strong correlation was found between flexural strength decrease and clinical index, but this finding was based on only 7 materials (Spearman rho=0.96, p=0.0001). Prediction was not consistently improved with cutoff values. SIGNIFICANCE Correlations between clinical and laboratory outcomes were moderately positive with few significant results, fracture toughness being correlated with clinical fractures and flexural strength with clinical wear. Whether artificial aging enhances the prognostic value needs further investigations.
Collapse
Affiliation(s)
| | - Nicoleta Ilie
- Department of Operative Dentistry and Periodontology, University Hospital, Ludwig-Maximilian-University, Munich, Germany
| | - Reinhard Hickel
- Department of Operative Dentistry and Periodontology, University Hospital, Ludwig-Maximilian-University, Munich, Germany
| | - Alessandra Reis
- Department of Restorative Dentistry, State University of Ponta Grossa, Brazil
| | | | - Valentin Rousson
- Division of Biostatistics, Institute for Social and Preventive Medicine, University Hospital Lausanne, Switzerland
| |
Collapse
|
37
|
Abstract
According to the ‘total energy concept’, properties of light-cured resin composites are determined only by energy density because of reciprocity between power density and exposure duration. The kinetics of polymerization is complex, and it was hypothesized that degree of cure, flexural strength, and flexural modulus were influenced not only by energy density, but also by power density per se. A conventional resin composite was cured at 3 energy densities (4, 8, and 16 J/cm2) by 6 combinations of power density (50, 100, 200, 400, 800, and 1000 mW/cm2) and exposure durations. Degree of cure, flexural strength, and flexural modulus increased with increasing energy density. For each energy density, degree of cure decreased with increasing power density. Flexural strength and modulus showed a maximum at intermediate power density. Within clinically relevant power densities, not only energy density but also power density per se had significant influence on resin composite properties.
Collapse
Affiliation(s)
- A Peutzfeldt
- Department of Dental Materials, School of Dentistry, University of Copenhagen, 20 Nørre Allé, 2200 Copenhagen N, Denmark.
| | | |
Collapse
|
38
|
Abstract
AIM AND OBJECTIVES To evaluate the elution of bisphenol A-glycidyl methacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) from two bulk-fill composites at different polymerization times, for different storage periods when cured with quartz-tungsten-halogen (QTH) curing unit. MATERIALS AND METHODS Tetric N-Ceram bulk fill and EverX Posterior were analyzed using high-performance liquid chromatography unit. Totally, 68 samples were prepared, two groups (n = 17) from both the composites, one for each tested polymerization time. Each sample was cured with a QTH curing unit, using soft-start curing technique and stored in 2 ml of ethanol for 24 h. Storage medium was renewed and then stored again for 1 week. Data acquired were statistically analyzed. RESULTS The elution of BisGMA was significantly higher from Tetric N-Ceram bulk fill and BisGMA and TEGDMA from EverX Posterior composite at the end of 24 h, irrespective of the curing time. In EverX Posterior, a higher amount of TEGDMA was eluted at the end of 24 h, while at the end of 1 week, significantly higher amount of BisGMA was released. CONCLUSION A significant amount of the release of BisGMA as well as TEGDMA was seen from both the composites when stored for different time intervals.
Collapse
Affiliation(s)
- Ankit Rajesh Sajnani
- Department of Conservative Dentistry and Endodontics, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Karanataka, India
| | - Mithra Nidharsh Hegde
- Department of Conservative Dentistry and Endodontics, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Karanataka, India
| |
Collapse
|
39
|
Physicochemical and bioactive properties of innovative resin-based materials containing functional halloysite-nanotubes fillers. Dent Mater 2016; 32:1133-43. [DOI: 10.1016/j.dental.2016.06.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 01/23/2016] [Accepted: 06/22/2016] [Indexed: 11/22/2022]
|
40
|
Khoroushi M, Ghasemi M, Abedinzadeh R, Samimi P. Comparison of immediate and delayed light-curing on nano-indentation creep and contraction stress of dual-cured resin cements. J Mech Behav Biomed Mater 2016; 64:272-80. [PMID: 27544311 DOI: 10.1016/j.jmbbm.2016.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 10/21/2022]
Abstract
STATEMENT OF PROBLEM Polymerization protocol of dual-cured resin cements plays a great role in the success of restorations. Knowledge about the effect of light-curing protocol on the contraction stress value and the mechanical properties would assist in the development, selection and handling of the resin cement material. PURPOSE This study was undertaken to assess the effects of two different light-curing protocols on the polymerization shrinkage stress and nano-creep of two current dual-cured resin cements. MATERIALS AND METHODS Twenty-four soda-lime glass disks, measuring 1mm in thickness, with a perforation in their center that measured 3mm in diameter, received four Vickers indentations at a distance of 500µ from the margin. The indent cracks were measured before and at 15-, 30- and 60-min intervals after restoration of the cavity with either CLEARFIL™ SA or RelyX™ Ultimate cement. Twelve specimens were prepared from each resin cement and divided into two groups according to the curing protocol used: immediate and delayed light-curing. Stresses at the indent impression were calculated by considering glass fracture toughness and the increase in crack length. Stress at the bonded interface was calculated using the Lame equation for thick-walled cylinder under an internal pressure. Nano-indentation hardness, modulus of elasticity and creep of each cement were measured under a 10-mN load for 20s holding time. The specimens were stored in distilled water at 37°C for 24h before the nano-indentation tests. Data were analyzed with two-way and repeated-measures ANOVA (α≤0.05). RESULTS Curing protocol had a significant effect on both resin cements; higher stress values were recorded with the immediate curing mode (P=0.033). Curing mode did not exert a significant effect on the modulus of elasticity (P=0.595) and hardness (P=0.454) of resin cements. However, in relation to creep, it exhibited significant effects (P<0.0001). CONCLUSIONS Immediate light-curing resulted in higher polymerization stress and lower nano-creep values compared to the delayed protocol with the resin cements assessed.
Collapse
Affiliation(s)
- Maryam Khoroushi
- Dental Materials Research Center, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maede Ghasemi
- Dental Materials Research Center, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Reza Abedinzadeh
- Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr/Isfahan, Iran
| | - Pouran Samimi
- Dental Materials Research Center, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
| |
Collapse
|
41
|
Borges A, Caneppele T, Luz M, Pucci C, Torres C. Color stability of resin used for caries infiltration after exposure to different staining solutions. Oper Dent 2016; 39:433-40. [PMID: 24967985 DOI: 10.2341/13-150-l] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
UNLABELLED PURPOSE : The aim of this study was to investigate the staining behavior of demineralized enamel infiltrated by low-viscosity resin. METHODS AND MATERIALS : Bovine enamel/dentin cylindrical samples (3 × 2 mm) were assigned into four groups (n=45) according to the enamel treatment: sound enamel (control), demineralization + artificial saliva, demineralization + daily application of 0.05% NaF, demineralization + resin infiltration (Icon, DMG). Artificial white spot lesions were produced in groups with demineralization. After the treatments, color was assessed by spectrophotometry, using the CIE L*a*b* system. The specimens (n=15) were then immersed in deionized water, red wine, or coffee for 10 minutes daily for eight days. Color was measured again, and the specimens were repolished with sandpaper discs. The final color was assessed. Data were analyzed by two-way analysis of variance and Tukey tests (α=0.05). A paired t-test was used for comparison between staining and repolishing conditions. RESULTS : There were significant differences for surface treatment and dye after staining and repolishing. Immersion in wine and coffee resulted in significantly increased color alteration (ΔE) compared with water (p=0.001). The resin-infiltrated group exhibited the highest staining values (p=0.001). The repolishing procedures resulted in significantly decreased color change. CONCLUSION The exposure of specimens to colored solutions resulted in significant color alteration. The demineralized enamel treated with resin infiltration showed significantly higher staining than all other tested groups; however, the repolishing of the specimens minimized the staining effect.
Collapse
|
42
|
Bacchi A, Feitosa VP, da Silva Fonseca ASQ, Cavalcante LMA, Silikas N, Schneider LFJ. Shrinkage, stress, and modulus of dimethacrylate, ormocer, and silorane composites. J Conserv Dent 2015; 18:384-8. [PMID: 26430302 PMCID: PMC4578183 DOI: 10.4103/0972-0707.164051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Purpose: to evaluate the shrinkage, polymerization stress, elastic and bulk modulus resulting from composites formulated by siloranes, 2nd generation ormocers, and dimethacrylates. Materials and Methods: The bonded disc method was used to evaluate volumetric shrinkage. The polymerization stress was evaluated by mean of the Bioman. Cylindrical specimens (5 mm thickness and 6 mm diameter) were submitted to gradual loading. Young's and bulk modulus were obtained from the slope of the stress/strain curve. Data were analyzed using one-way analysis of variance and Tukey's test (5%). Results: Grandio and ormocer showed significant higher elastic and bulk modulus. Silorane presented significant lowest bulk modulus and maximum shrinkage. Ormocer and silorane presented lower values for the maximum rate of shrinkage. Extra-low shrinkage (ELS) composite presented the greatest maximum shrinkage. The higher maximum rate of shrinkage was attained by Grandio and ELS, statistically similar from each other. The silorane showed lower values of maximum stress and maximum rate of stress. The higher values of maximum stress were presented by ELS and Grandio, statistical similar between them. Grandio showed the significantly greatest maximum rate of stress. Conclusion: Silorane showed to promote lower shrinkage/stress among the composites, with the lowest elastic modulus. Ormocer showed lower shrinkage/stress than methacrylates despite of its high modulus.
Collapse
Affiliation(s)
- Atais Bacchi
- Department of Prosthetic Dentistry, School of Dentistry, Meridional Faculty - IMED, Passo Fundo, RS, Brazil
| | - Victor Pinheiro Feitosa
- Department of Restorative Dentistry, School of Dentistry, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | | | - Nikolaos Silikas
- Biomaterials Science Research Group, School of Dentistry, University of Manchester, Manchester, United Kingdom
| | | |
Collapse
|
43
|
Tauböck TT, Tarle Z, Marovic D, Attin T. Pre-heating of high-viscosity bulk-fill resin composites: effects on shrinkage force and monomer conversion. J Dent 2015; 43:1358-64. [PMID: 26232610 DOI: 10.1016/j.jdent.2015.07.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 07/22/2015] [Accepted: 07/27/2015] [Indexed: 10/23/2022] Open
Abstract
OBJECTIVES To investigate the influence of pre-heating of high-viscosity bulk-fill composite materials on their degree of conversion and shrinkage force formation. METHODS Four bulk-fill composite materials (Tetric EvoCeram Bulk Fill-TECBF, x-tra fil-XF, QuixFil-QF, SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were used. The test materials were either kept at room temperature or pre-heated to 68°C by means of a commercial heating device, before being photoactivated with a LED curing unit for 20s at 1170mW/cm(2). Shrinkage forces (n=5) of 1.5-mm-thick specimens were recorded in real-time for 15min inside a temperature-controlled chamber at 25°C (simulating intraoral temperature after rubber dam application) with a custom-made stress analyzer. Degree of conversion (n=5) was determined at the bottom of equally thick (1.5mm) specimens using Fourier transform infrared spectroscopy. Data were analyzed with Student's t-test, ANOVA and Tukey's HSD post-hoc test (α=0.05). RESULTS Composite pre-heating significantly increased the degree of conversion of TECBF, but had no effect on monomer conversion of the other materials investigated. For each of the test materials, pre-heated composite generated significantly lower shrinkage forces than room-temperature composite. At both temperature levels, TECBF created the significantly highest shrinkage forces, and QF caused significantly higher shrinkage forces than both XF and TEC. CONCLUSIONS Both the composite material and the pre-cure temperature affect shrinkage force formation. Pre-heating of bulk-fill and conventional restorative composites prior to photoactivation decreases polymerization-induced shrinkage forces without compromising the degree of conversion. CLINICAL SIGNIFICANCE Composite pre-heating significantly reduces shrinkage force formation of high-viscosity bulk-fill and conventional resin composites, while maintaining or increasing the degree of monomer conversion, dependent upon the specific composite material used.
Collapse
Affiliation(s)
- Tobias T Tauböck
- Department of Preventive Dentistry, Periodontology and Cariology, Center for Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
| | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, HR-10000 Zagreb, Croatia
| | - Danijela Marovic
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, HR-10000 Zagreb, Croatia
| | - Thomas Attin
- Department of Preventive Dentistry, Periodontology and Cariology, Center for Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland
| |
Collapse
|
44
|
Degree of conversion and surface hardness of bulk-fill composite versus incremental-fill composite. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.tdj.2015.01.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
45
|
Subbiya A, Pearlin Mary NSG, Suresh M, Vivekanandhan P, Dhakshinamoorthy M, Sukumaran VG. Comparison of variation in the light curing cycle with a time gap and its effect on polymerization shrinkage, degree of conversion and microhardness of a nanohybrid composite. J Conserv Dent 2015; 18:154-8. [PMID: 25829697 PMCID: PMC4379658 DOI: 10.4103/0972-0707.153055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 12/27/2014] [Accepted: 01/15/2015] [Indexed: 11/28/2022] Open
Abstract
Background: Giving a time gap and distance during curing can decrease the polymerization shrinkage. Aim: To evaluate the effect of time gap and distance between the curing tip and restoration on the polymerization shrinkage, degree of monomer conversion (DOC), and microhardness of a nanohybrid composite. Materials and Methods: A total of 50 standardized cylindrical specimens (Z350, 3M ESPE) were fabricated using a brass mould. The curing was done in contact with the sample surface for 20 seconds in the control group. In the four experimental groups, curing was initiated at 1-cm distance, followed by variation in the time gap and the curing cycle. The polymerization shrinkage, DOC, microhardness was calculated. Statistical Analysis: One-way analysis of variance (ANOVA) and post hoc-Dunnett test were used to analyze the data. Results: Curing at 1-cm distance for 10 seconds with a gap of 10 seconds and finishing the curing cycle with 20 seconds at 0 cm proved to be an appropriate technique to reduce the polymerization shrinkage without significantly affecting the DOC and microhardness. Conclusion: A simple innovative modification of varying the distance of curing and a time gap in the curing cycle can decrease the polymerization shrinkage without affecting the DOC and microhardness.
Collapse
Affiliation(s)
- Arunajatesan Subbiya
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| | - Newbegin Selvakumar Gold Pearlin Mary
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| | - Malathi Suresh
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| | - Paramasivam Vivekanandhan
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| | - Malarvizhi Dhakshinamoorthy
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| | - Vridhachalam Ganapathy Sukumaran
- Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India
| |
Collapse
|
46
|
Zorzin J, Maier E, Harre S, Fey T, Belli R, Lohbauer U, Petschelt A, Taschner M. Bulk-fill resin composites: Polymerization properties and extended light curing. Dent Mater 2015; 31:293-301. [DOI: 10.1016/j.dental.2014.12.010] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 11/07/2014] [Accepted: 12/16/2014] [Indexed: 12/15/2022]
|
47
|
Evaluation of polymerization shrinkage of dental composites by an optical method. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 47:70-6. [DOI: 10.1016/j.msec.2014.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/23/2014] [Accepted: 11/05/2014] [Indexed: 11/19/2022]
|
48
|
Alshali RZ, Salim NA, Satterthwaite JD, Silikas N. Post-irradiation hardness development, chemical softening, and thermal stability of bulk-fill and conventional resin-composites. J Dent 2014; 43:209-18. [PMID: 25511301 DOI: 10.1016/j.jdent.2014.12.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/05/2014] [Accepted: 12/07/2014] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVES To measure bottom/top hardness ratio of bulk-fill and conventional resin-composite materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). METHODS Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional resin-composite materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested (n=5). Initial and 24h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was re-measured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t-test (α=0.05). RESULTS All materials showed significant increase of microhardness after 24h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all materials. All materials showed significant decrease of microhardness after 24h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of post-irradiation hardness development was positively correlated to the extent of ethanol softening (R(2)=0.89, p<0.001). Initial thermal decomposition temperature assessed by TGA was variable and was correlated to ethanol softening. CONCLUSIONS Bulk-fill resin-composites exhibit comparable bottom/top hardness ratio to conventional materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. CLINICAL SIGNIFICANCE The manufacturer recommended depth of cure of bulk-fill resin-composites can be reached based on the microhardness method. Characterization of the primary polymer network of a resin-composite material should be considered when evaluating its stability in the aqueous oral environment.
Collapse
Affiliation(s)
- Ruwaida Z Alshali
- School of Dentistry, The University of Manchester, Higher Cambridge Street, Manchester, UK; Department of Oral and Maxillofacial Rehabilitation, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Nesreen A Salim
- Prosthodontic Department, University of Jordan, Amman, Jordan
| | - Julian D Satterthwaite
- School of Dentistry, The University of Manchester, Higher Cambridge Street, Manchester, UK
| | - Nick Silikas
- School of Dentistry, The University of Manchester, Higher Cambridge Street, Manchester, UK.
| |
Collapse
|
49
|
Amato PAF, Martins RP, dos Santos Cruz CA, Capella MV, Martins LP. Time reduction of light curing: Influence on conversion degree and microhardness of orthodontic composites. Am J Orthod Dentofacial Orthop 2014; 146:40-6. [PMID: 24974997 DOI: 10.1016/j.ajodo.2014.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/01/2014] [Accepted: 03/01/2014] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The aim of this study was to assess the influence of curing time and power on the degree of conversion and surface microhardness of 3 orthodontic composites. METHODS One hundred eighty discs, 6 mm in diameter, were divided into 3 groups of 60 samples according to the composite used-Transbond XT (3M Unitek, Monrovia, Calif), Opal Bond MV (Ultradent, South Jordan, Utah), and Transbond Plus Color Change (3M Unitek)- and each group was further divided into 3 subgroups (n = 20). Five samples were used to measure conversion, and 15 were used to measure microhardness. A light-emitting diode curing unit with multiwavelength emission of broad light was used for curing at 3 power levels (530, 760, and 1520 mW) and 3 times (8.5, 6, and 3 seconds), always totaling 4.56 joules. Five specimens from each subgroup were ground and mixed with potassium bromide to produce 8-mm tablets to be compared with 5 others made similarly with the respective noncured composite. These were placed into a spectrometer, and software was used for analysis. A microhardness tester was used to take Knoop hardness (KHN) measurements in 15 discs of each subgroup. The data were analyzed with 2 analysis of variance tests at 2 levels. RESULTS Differences were found in the conversion degree of the composites cured at different times and powers (P <0.01). The composites showed similar degrees of conversion when light cured at 8.5 seconds (80.7%) and 6 seconds (79.0%), but not at 3 seconds (75.0%). The conversion degrees of the composites were different, with group 3 (87.2%) higher than group 2 (83.5%), which was higher than group 1 (64.0%). Differences in microhardness were also found (P <0.01), with lower microhardness at 8.5 seconds (35.2 KHN), but no difference was observed between 6 seconds (41.6 KHN) and 3 seconds (42.8 KHN). Group 3 had the highest surface microhardness (35.9 KHN) compared with group 2 (33.7 KHN) and group 1 (30.0 KHN). CONCLUSIONS Curing time can be reduced up to 6 seconds by increasing the power, with a slight decrease in the degree of conversion at 3 seconds; the decrease has a positive effect on the surface microhardness.
Collapse
Affiliation(s)
| | - Renato Parsekian Martins
- Invited professor, Orthodontic Program, Araraquara School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil; private practice, Araraquara, São Paulo, Brazil.
| | - Carlos Alberto dos Santos Cruz
- Associate professor, Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil
| | - Marisa Veiga Capella
- Assistant professor, Department of Physical Chemistry, Araraquara Institute of Chemistry, São Paulo State University, Araraquara, São Paulo, Brazil
| | - Lídia Parsekian Martins
- Chairman, Department of Orthodontics, Araraquara School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil
| |
Collapse
|
50
|
Giorgi MCC, Lima DANL, Marchi GM, Ambrosano GM, Aguiar FHB. Influence of softening test and light-activation protocols on resin composite polymer structure. Eur J Dent 2014; 8:9-14. [PMID: 24966740 PMCID: PMC4054039 DOI: 10.4103/1305-7456.126233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE This study analyzed the influences of the light-activation protocol and softening test on the degree of conversion (DC) and Knoop Hardness (KHN) of a microhybrid resin composite. MATERIALS AND METHODS Filtek Z250 (3M ESPE) was light-activated with a third-generation light-emitting diode (Valo Ultradent) by three protocols - standard, high power, and plasma emulation - or with a quartz-tungsten halogen XL 3000 (3M ESPE) in conventional mode. All modes were set to deliver 19 J/cm(2). The DC (N = 20) was determined by Fourier transform infrared spectrometry on the top (T) and bottom (B) surfaces. For the KHN test, samples were subdivided in four groups (n = 5 each) according to the storage media: absolute ethanol, 75% ethanol, distilled water, and air (control group). The KHN values were evaluated on T and B before and 24 h after immersion in the storage media. Data were analyzed by split-plot analysis of variance (ANOVA; for DC) or repeated-measures split-plot ANOVA (for KHN), followed by Tukey's test (α = 0.05). RESULTS For the DC, the light-activation protocol did not influence the results and there was no difference between T and B. For the KHN test, the light-activation protocol did not influence the results and T showed higher microhardness values than B for all experimental conditions. There were significant differences in KHN depending on the storage media. Samples immersed in absolute ethanol generally presented lower KHN values, with no differences compared to samples in 75% ethanol. CONCLUSION The storage media affected the outcomes of the softening test.
Collapse
Affiliation(s)
| | | | - Giselle Maria Marchi
- Department of Restorative Dentistry Piracicaba Dental School, University of Campinas, Piracicaba-SP, Brazil
| | - Gláucia Maria Ambrosano
- Department of Social Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba-SP, Brazil
| | | |
Collapse
|