1
|
Chen WC, Lai TW, Li CL, Chen TYF, Chang CH, Chuang SF. Assessments of polymerization shrinkage by optical coherence tomography-based digital image correlation analysis-Part II: Effects of restorative composites. Dent Mater 2024:S0109-5641(24)00102-7. [PMID: 38777732 DOI: 10.1016/j.dental.2024.05.001] [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: 08/08/2023] [Revised: 04/27/2024] [Accepted: 05/03/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVES To examine the polymerization shrinkage of different resin-based composite (RBC) restorations using optical coherence tomography (OCT) image-based digital image correlation (DIC) analysis. METHODS The refractive index (RI) of three RBCs, Filtek Z350XT (Z350), Z350Flowable (Z350F), and BulkFill Posterior (Bulkfill), was measured before and after polymerization to calibrate their axial dimensions under OCT. Class I cavities were prepared in bovine incisors and individually filled with these RBCs under nonbonded and bonded conditions. A series of OCT images of these restorations were captured during 20-s light polymerization and then input into DIC software to analyze their shrinkage behaviors. The interfacial adaptation was also examined using these OCT images. RESULTS The RI of the three composites ranged from 1.52 to 1.53, and photopolymerization caused neglectable increases in the RI values. For nonbonded restorations, Z350F showed maximal vertical displacements on the top surfaces (-16.75 µm), followed by Bulkfill (-8.81 µm) and Z350 (-5.97 µm). In their bonded conditions, all showed increased displacements. High variations were observed in displacement measurements on the bottom surfaces. In the temporal analysis, the shrinkage of nonbonded Z350F and Bulkfill decelerated after 6-10 s. However, Z350 showed a rebounding upward displacement after 8.2 s. Significant interfacial gaps were found in nonbonded Z350 and Z350F restorations. SIGNIFICANCE The novel OCT image-based DIC analysis provided a comprehensive examination of the shrinkage behaviors and debonding of the composite restorations throughout the polymerization process. The flowable composite showed the highest shrinkage displacements. Changes in the shrinkage direction may occur in nonbonded conventional composite restorations.
Collapse
Affiliation(s)
- Wei-Chi Chen
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Dentistry, Sin-Lau Hospital, Tainan, Taiwan
| | - Ting-Weng Lai
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Chia-Ling Li
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Terry Yuan-Fang Chen
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Han Chang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Fen Chuang
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan.
| |
Collapse
|
2
|
Ghani SMA, Hassan MIA, Abdullah AH, Ghani ARA, Izra'ai SI, Aregawi W, Chew HP, Fok A. Linear and volumetric shrinkage displacements of resin composite restorations with and without debonding. Dent Mater J 2023; 42:659-668. [PMID: 37612060 DOI: 10.4012/dmj.2023-023] [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: 08/25/2023]
Abstract
The study aimed to compare shrinkage displacements of fully and partially bonded resin composite restorations (RCRs). Two groups (n=5) Class-I RCR evaluated: Group 1 (G1) fully bonded and Group 2 (G2) debonded at the floor. Experimental results were compared with predictions from simple theory and finite element analysis (FEA). The experimental linear surface displacement (LSD) was G1 62.5±5.2 µm and G2 32.8±4.0 µm. Theoretically-predicted LSD for G1 60.1±7.4 µm and G2 31.3±7.5 µm. FEA-predicted LSD were G1 65.2 µm and G2 34.6 µm. The experimental volumetric surface displacement (VSD) was G1 1.22±0.2 mm3 and G2 0.63±0.2 mm3. Theoretically-predicted VSD for G1 1.36±0.2 mm3 and G2 0.67±0.2 mm3. No significant difference (p>0.05) was found in LSD and VSD among the experimental, theoretical and FEA in the same group. Significant differences (p<0.05) were noted between the two groups, with LSD and VSD of G2 values being almost half of G1. This pattern gave an insight of a debond restoration characteristics.
Collapse
Affiliation(s)
- Siti Mariam Ab Ghani
- Center for Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA
| | | | | | | | | | - Wondwosen Aregawi
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota
| | - Hooi Pin Chew
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota
| | - Alex Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota
| |
Collapse
|
3
|
Tseng PC, Chuang SF, Kaisarly D, Kunzelmann KH. Simulating the shrinkage-induced interfacial damage around Class I composite resin restorations with damage mechanics. Dent Mater 2023; 39:513-521. [PMID: 37031095 DOI: 10.1016/j.dental.2023.03.020] [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: 12/26/2022] [Revised: 03/20/2023] [Accepted: 03/28/2023] [Indexed: 04/10/2023]
Abstract
OBJECTIVES To investigate the shrinkage-induced damage at the composite-tooth interface by finite element analysis (FEA) using the cohesive zone model (CZM). METHODS Axisymmetric models of Class I restorations were created to illustrate the interfacial damage around composite resin restorations of different dimensions, with polymerization shrinkage modeled analogously to thermal shrinkage. The damage to the adhesive interface was determined using a CZM based on the fracture strength and fracture energy. To show the effects of damage, conventional models with perfectly bonded composite resin restorations were created as controls. RESULTS The results indicated interfacial damage at the butt-joint cavosurface margin, dentinoenamel junction, and internal line angle. The percentage of damaged interfacial area was found to increase with decreasing diameter for restorations of the same height. For a given diameter, the damage was more severe for restorations of greater depth. The effects of the damage were further illustrated in the model with a restoration of 2-mm diameter and height. The interfacial damage occurred primarily at the internal line angle (83.3 % of all the damaged interfacial area), leading to local stress relief (from 18.3 MPa to 12.8 MPa), but also higher stress at the damage fronts. Greater local shrinkage was found in composites adjacent to the damage. SIGNIFICANCE The damage mechanics-based CZM is an essential refinement of the FEA to predict interfacial damage and its implications. The extent of damage was found to be greater around restorations with smaller diameters and greater depths. The entire simulation is available via an open-source platform to facilitate further applications in adhesive dentistry.
Collapse
Affiliation(s)
- Po-Chun Tseng
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Munich, Germany.
| | - Shu-Fen Chuang
- School of Dentistry and Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Dalia Kaisarly
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Munich, Germany; Biomaterials Department, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt
| | - Karl-Heinz Kunzelmann
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Munich, Germany
| |
Collapse
|
4
|
Time-lapse submicrometer particle motion reveals residual strain evolution and damaging stress relaxation in clinical resin composites sealing human root canals. Acta Biomater 2022; 140:350-363. [PMID: 34740856 DOI: 10.1016/j.actbio.2021.10.052] [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: 07/20/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 11/20/2022]
Abstract
Polymer based composites are widely used for treatment, for example as biofilm resistant seals of root canal fillings. Such clinical use, however, fails more frequently than other dental composite restorations, due to stress-related misfits. The reason for this is that the biomaterials used are inserted as viscous masses that may bond to the substrate, yet shrinkage stresses arising during setting of the cross-linking polymer, work against durable adhesion. Here we combine phase contrast enhanced time-lapse radiography (radioscopy), digital image correlation (DIC) and submicrometer resolution phase-contrast enhanced microtomography (PCE-CT), to reveal the spatial and temporal dynamics of composite polymerization and strain evolution. Radioscopy of cavities located in the upper part of human root canals demonstrates how the composite post-gelation "densification" is dominated by viscous flow with quantifiable motion of both particles and entrapped voids. Thereafter, these composites enter a "stress-relaxation" stage and exhibit several structural adaptations, induced by residual shrinkage stresses. Consequently critical alterations to the final biomaterial geometry emerge: (i) entrapped bubbles expand; (ii) microscopic root filling pull-out occurs; (iii) the cavity walls deform inwards, and (iv) occasionally delamination ensues, propagating out from the root canal filling along buried restoration-substrate interfaces. Our findings shed new light on the interactions between confined spaces and biomedical composites that cross-link in situ, highlighting the crucial role of geometry in channeling residual stresses. They further provide new insights into the emergence of structural flaws, calling attention to the need to find new treatment options. STATEMENT OF SIGNIFICANCE: This work quantifies recurring spatial and temporal material redistribution in composites used clinically to fill internal spaces in teeth. This knowledge is important for both promoting biomaterial resistance against potentially pathologic biofilms and for improving structural capacity to endure years of mechanical function. Our study demonstrates the significant role of geometry and the need for improved control over stress raisers to develop better treatment protocols and new space filling materials. The use of high-brilliance X-rays for time-lapse imaging at submicrometer resolution provides dynamic information about the damaging effects of stress relaxation due to polymerization shrinkage.
Collapse
|
5
|
Lin F, Ordinola-Zapata R, Fok ASL, Lee R. Influence of minimally invasive endodontic access cavities and bonding status of resin composites on the mechanical property of endodontically-treated teeth: A finite element study. Dent Mater 2021; 38:242-250. [PMID: 34930622 DOI: 10.1016/j.dental.2021.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/27/2021] [Accepted: 12/08/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To study the mechanical behavior of endodontically-treated teeth with minimally invasive endodontic access cavities and resin composite restorations under different bonding conditions using finite element analysis (FEA). METHODS Four Class-II endodontic access cavities including the mesio-occlusal minimally-invasive (MO-MIE), mesio-occlusal conventional (MO-CONV), disto-occlusal minimally-invasive (DO-MIE), and disto-occlusal conventional (DO-CONV) cavities were prepared in 3D-printed maxillary first molars. Each tooth was subjected to root canal preparation and scanned using micro-CT to provide a 3D structural model which was virtually restored with resin composite. An intact 3D-printed molar was used as control. FEA was conducted under a 250-N vertical load. Three different interfacial bonding conditions between dentin/enamel and resin composite were considered, i.e. fully bonded, partially debonded, and fully debonded. The maximum principal stress of dentin and the normal tensile stress at the interfaces were recorded. The risk factor of failure for each component was then calculated. RESULTS In the fully-bonded tooth, the dentin-composite interface showed significantly higher stress and a higher risk factor than dentin, indicating that debonding at the dentin-composite interface would occur prior to dentin fracture. With the dentin-composite interface debonded, the enamel-composite interface exhibited higher stress and a higher risk factor than dentin, indicating that debonding at the enamel-composite interface would occur next, also prior to dentin fracture. With the resin composite fully debonded from the tooth, stress in dentin increased significantly. Irrespective of the bonding status, the CONV groups exhibited higher median stresses in dentin than the MIE groups. SIGNIFICANCE Within the limitation of this study, it was shown that debonding of the resin composite restoration increased the stress in dentin and hence the risk of dentin fracture in endodontically-restored teeth. Minimally-invasive access cavities could better safeguard the fracture resistance of interproximally-restored teeth compared to conventional ones.
Collapse
Affiliation(s)
- Fei Lin
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
| | - Ronald Ordinola-Zapata
- Division of Endodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alex S L Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Roy Lee
- Division of Endodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| |
Collapse
|
6
|
Yoon S, Jung HJ, Knowles JC, Lee HH. Digital image correlation in dental materials and related research: A review. Dent Mater 2021; 37:758-771. [PMID: 33715864 DOI: 10.1016/j.dental.2021.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Digital image correlation (DIC) is a non-contact image processing technique for full-field strain measurement. Although DIC has been widely used in engineering and biomechanical fields, it is in the spotlight only recently in dental materials. Therefore, the purpose of this review paper is introducing the working principle of the DIC technique with some modifications and providing further potential applications in various dental materials and related fields. METHODS The accuracy of the algorithm depending on the environmental characteristics of the DIC technique, as well as the advantages and disadvantages of strain measurement using optical measurements, have been elaborated in dental materials and related fields. Applications to those researches have been classified into the following categories: shrinkage behavior of light-cured resin composite, resin-tooth interface, mechanical properties of tooth structure, crack extension and elastic properties of dental materials, and deformation of dental restoration and prosthesis. This classification and discussion were performed using literature survey and review based on numerous papers in the international journals published over the past 20 years. The future directions for predicting the precise deformation of dental materials under various environments, as well as limitations of the DIC technique, was presented in this review. RESULTS The DIC technique was demonstrated as a more effective tool to measure full-field polymerization shrinkage of composite resin, even in a simulated clinical condition over the existing methods. Moreover, the DIC combined with other technologies can be useful to evaluate the mechanical behavior of material-tooth interface, dentine structure and restorative and prosthetic materials with high accuracy. Three-dimensional DIC using two cameras extended the measurement range in-plane to out-of-plane, enabling measure of the strain directly on the surface of dental restorations or prosthesis. SIGNIFICANCE DIC technique is a potential tool for measuring and predicting the full-field deformation/strain of dental materials and actual prostheses in diverse clinical conditions. The versatility of DIC can replace the existing complex sensor devices in those studies.
Collapse
Affiliation(s)
- Sungsik Yoon
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hyung-Jo Jung
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - J C Knowles
- UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea; Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, London, UK
| | - Hae-Hyoung Lee
- Department of Biomaterials Science, College of Dentistry, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea; Institute of Tissue Regeneration Engineering, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea.
| |
Collapse
|
7
|
Gallo M, Abouelleil H, Chenal JM, Adrien J, Lachambre J, Colon P, Maire E. Polymerization shrinkage of resin-based composites for dental restorations: A digital volume correlation study. Dent Mater 2019; 35:1654-1664. [PMID: 31554599 DOI: 10.1016/j.dental.2019.08.116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/24/2019] [Accepted: 08/31/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Resin-based composites are widely used in dental restorations; however, their volumetric shrinkage during polymerization leads to several issues that reduce the restoration survival rates. For overcoming this problem, a deep study of shrinkage phenomena is necessary. METHODS In this study, micro-tomography (μ-CT) is combined with digital volume correlation (DVC) to investigate the effect of several factors on the polymerization strain of dental composites in model cavities: the presence/absence of an adhesive, the use of transparent/blackened cavities, and irradiation times between 1 and 40s. RESULTS The results indicate that the presence of an adhesive at the interface between the cavity and composite does not reduce the total strain but instead limits it to a preferential direction. In addition, regardless of the conditions, the main strain is generated along the axis parallel to the polymerization irradiation (the vertical axis). Finally, the total strain appears to occur in the first 5s of irradiation, with no further evolution observed for longer irradiation times. SIGNIFICANCE This work provides new insight into resin-based composite shrinkage and demonstrates the benefit of coupling DVC and μ-CT to better understand the degradation mechanisms of these materials.
Collapse
Affiliation(s)
- Marta Gallo
- University of Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Saint Exupery, 23 Av. Jean Capelle, F-69621 Villeurbanne, France
| | - Hazem Abouelleil
- Laboratoire des Multimateriaux et Interfaces, UMR CNRS 5615, Universite Lyon 1, Villeurbanne, France
| | - Jean Marc Chenal
- University of Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Saint Exupery, 23 Av. Jean Capelle, F-69621 Villeurbanne, France
| | - Jérôme Adrien
- University of Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Saint Exupery, 23 Av. Jean Capelle, F-69621 Villeurbanne, France
| | - Joël Lachambre
- University of Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Saint Exupery, 23 Av. Jean Capelle, F-69621 Villeurbanne, France
| | - Pierre Colon
- Laboratoire des Multimateriaux et Interfaces, UMR CNRS 5615, Universite Lyon 1, Villeurbanne, France; UFR d'odontologie, Université Paris Diderot, APHP, Hôpital Rothschild, Service d'odontologie, Paris, France
| | - Eric Maire
- University of Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Saint Exupery, 23 Av. Jean Capelle, F-69621 Villeurbanne, France.
| |
Collapse
|