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Pilecco RO, Machry RV, Baldi A, Tribst JPM, Sarkis-Onofre R, Valandro LF, Kleverlaan CJ, Scotti N, Pereira GKR. Influence of CAD-CAM milling strategies on the outcome of indirect restorations: A scoping review. J Prosthet Dent 2024; 131:811.e1-811.e10. [PMID: 38480018 DOI: 10.1016/j.prosdent.2024.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/19/2024] [Accepted: 02/20/2024] [Indexed: 05/13/2024]
Abstract
STATEMENT OF PROBLEM The influence of computer-aided manufacturing (CAM) parameters and settings on the outcomes of milled indirect restorations is poorly understood. PURPOSE The purpose of this scoping review was to summarize the current CAM systems, parameters, and setting changes, and their effects on different outcomes of milled indirect restorations and aspects related to their manufacture. MATERIAL AND METHODS The protocol of this review is available online (https://osf.io/x28ps/). Studies that used at least 2 different parameters (CAM units, number of axes, digital spacers, or protocols with different rotatory instruments, grit-sizes, milling speed, or others) for milling indirect restorations were included. A structured search up to July 2023 was performed by 2 independent reviewers for articles written in English in LILACS, MEDLINE via PubMed, EMBASE, Web of Science, and Scopus. RESULTS Of 1546 studies identified, 22 were included in the review. Discrepancies were found between the planned and actual measured cement space, with a decreasing linear relationship impacting restoration adaptation at different points. The CEREC MC XL milling machine was the most used system in the included studies, with variations in bur types, milling modes, and number of burs uses affecting internal fit and surface trueness. The results demonstrated the better adaptation of restorations made with 5-axis over 3-axis milling machines. Lithium disilicate and zirconia were the most commonly used materials, and crowns and inlays were popular designs. Marginal and internal adaptation were the primary outcomes assessed using the various techniques. CONCLUSIONS The study presented a comprehensive exploration of CAM systems and parameters, and their influence on indirect restorations. The planned cement space was not properly reproduced by the milling. Bur characteristics can affect restoration fit and trueness. The 5-axis units seem to result in better-adapted restorations compared with 3- and 4-axis units.
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Affiliation(s)
- Rafaela Oliveira Pilecco
- Postgraduate student, Postgraduate Program in Oral Sciences (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Renan Vaz Machry
- Postdoctoral student, Postgraduate Program in Oral Sciences (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Andrea Baldi
- Postdoctoral student, Department of Surgical Sciences, Dental School, Turin, Italy
| | - João Paulo Mendes Tribst
- Assistant Professor, Department of Reconstructive Oral Care, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, North Holland, The Netherlands.
| | - Rafael Sarkis-Onofre
- Associate Professor, Graduate Program in Dentistry, Meridional Faculty, IMED, Passo Fundo, Brazil
| | - Luiz Felipe Valandro
- Full Professor, Postgraduate Program in Oral Sciences (Prosthodontics Unit), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Cornelis Johannes Kleverlaan
- Full Professor, Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, North Holland, The Netherlands
| | - Nicola Scotti
- Associate Professor, Department of Surgical Sciences, Dental School, Turin, Italy
| | - Gabriel Kalil Rocha Pereira
- Adjunct Professor, Postgraduate Program in Oral Sciences (Prosthodontics Unit), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
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de Matos JDM, da Rocha Scalzer Lopes G, Queiroz DA, Campos TMB, de Carvalho Ramos N, Bottino MA. Effect of staining layer on roughness after progressive wear of monolithic ceramics. J ESTHET RESTOR DENT 2023; 35:927-936. [PMID: 37203879 DOI: 10.1111/jerd.13067] [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: 04/13/2023] [Revised: 05/03/2023] [Accepted: 05/09/2023] [Indexed: 05/20/2023]
Abstract
PURPOSE The aim of this study was to evaluate staining layer behavior applied to high-translucency zirconia (YZHT), feldspathic ceramics (FD), and zirconia-reinforced lithium silicate (ZLS) surfaces against different antagonists. METHODS AND MATERIALS Monolithic ceramic discs (n = 120) (ø 12 mm; thickness, 1.2 mm; ISO 6872) were obtained, 30 from YZHT and FD, and 60 from ZLS CAD/CAM blocks (staining layer applied before or after the crystallization procedure). The specimens were divided into 12 subgroups (n = 10) according to the antagonists: steatite, polymer-infiltrated ceramic, or zirconia. Mechanical cycling (1.5 × 104 cycles; 15 N; horizontal displacement, 6 mm; 1.7 Hz) and flexural strength tests (1 mm/min-1000 kg cell) were performed. The differences between final and initial roughnesses (Ra, Rz, and Rsm), the mass loss, and the flexural strength data were individually analyzed by two-way ANOVA and Tukey's test (α = 0.05). RESULTS The roughnesses of all ceramics did not present a statistically significant difference before wear simulation: Ra (p = 0.3348), Rz (p = 0.5590), and Rsm (p = 0.5330). After the wear simulation, the Ra parameter was not affected by an interaction between ceramic and antagonist (p = 0.595). The Rz and Rsm parameters were affected only by the antagonist pistons (both, p = 0.000). The ceramics used in this study showed statistically significant differences in mass loss after the wear test (p < 0.0001). The additional firing (2 steps) of the ZLS2 led to a higher lost mass quantity. CONCLUSION All ceramics presented similar initial roughnesses and similar roughnesses after the wear simulation. The zirconia antagonist showed better performance against ceramics with high crystalline content. CLINICAL SIGNIFICANCE It is clear that restorative materials must be carefully selected by dental practitioners according to indications, properties, and antagonists. The steatite antagonist, that is, an enamel analog, showed better performance against vitreous ceramics, while the zirconia antagonist showed better performance against ceramics with high crystalline content. Wear affects the surface roughnesses of the ceramics. Additional firing for the staining of the zirconia-reinforced lithium silicate ceramic led to a greater loss of mass.
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Affiliation(s)
- Jefferson David Melo de Matos
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology of Sao Jose dos Campos, Sao Paulo State University (UNESP), Sao Jose dos Campos, Brazil
| | - Guilherme da Rocha Scalzer Lopes
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology of Sao Jose dos Campos, Sao Paulo State University (UNESP), Sao Jose dos Campos, Brazil
| | - Daher Antonio Queiroz
- Department of Restorative Dentistry & Prosthodontics, The University of Texas Health Science Center at Houston (UTHealth) School of Dentistry, Houston, Texas, USA
| | | | - Nathalia de Carvalho Ramos
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology of Sao Jose dos Campos, Sao Paulo State University (UNESP), Sao Jose dos Campos, Brazil
| | - Marco Antonio Bottino
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology of Sao Jose dos Campos, Sao Paulo State University (UNESP), Sao Jose dos Campos, Brazil
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Demachkia AM, Velho HC, Valandro LF, Dimashkieh MR, Samran A, Tribst JPM, de Melo RM. Endocrown restorations in premolars: influence of remaining axial walls of tooth structure and restorative materials on fatigue resistance. Clin Oral Investig 2023:10.1007/s00784-023-04895-6. [PMID: 36781479 DOI: 10.1007/s00784-023-04895-6] [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: 11/12/2022] [Accepted: 02/01/2023] [Indexed: 02/15/2023]
Abstract
OBJECTIVES To evaluate the effect of the remaining tooth structure and different CAD/CAM materials on the fatigue performance and failure mode of endodontically treated premolars restored with endocrowns. MATERIALS AND METHODS Ninety maxillary premolars were endodontically treated and assigned into 6 groups (n = 15) according to the number of remaining axial walls (four, three, and two) and restorative materials (ultra-translucent zirconia 5Y-PSZ [KATANA UTML] and lithium disilicate [IPS e.max-CAD]). The specimens were subjected to cyclic fatigue loading test (initial load 200 N; 20 Hz). An incremental step load of 100 N per 10,000 cycles was applied until failure. The fatigue failure load (FFL) and number of failure cycles (CFFs) data were statistically analyzed with two-way ANOVA and Kaplan-Meier test (α = 0.05). Failed specimens were examined under a stereomicroscope 25 × and failure modes were determined. RESULTS FFL and CFF were significantly influenced by restorative material (p < 0.05). 5Y-PSZ endocrowns showed significantly higher FFL when compared with lithium disilicate. The number of remaining walls did not affect the fatigue behavior or failure mode of the specimens. Of the lithium disilicate restorations, 51% had repairable failures, while 95% 5Y-PSZ restorations had non-repairable failures. CONCLUSIONS Zirconia endocrowns showed better FFL than lithium disilicate endocrowns, regardless of the number of remaining axis walls. Lithium disilicate and 5Y-PSZ endocrowns showed FFL higher than the normal masticatory loads. CLINICAL RELEVANCE Restoring endodontically treated premolars with endocrown could be a promising treatment, regardless of the remaining axial walls. However, precaution should be taken in material selection since it affects the fatigue resistance and failure mode.
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Affiliation(s)
- Amir Mohidin Demachkia
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), Av. Engenheiro Francisco José Longo,777. 12245000, São José Dos Campos, São Paulo, Brazil.
| | - Helder Callegaro Velho
- Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande Do Sul State, Brazil
| | - Luiz Felipe Valandro
- Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande Do Sul State, Brazil
| | - Mohiddin Rida Dimashkieh
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al-Uloom University, Riyadh, Saudi Arabia
| | - Abdulaziz Samran
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al-Uloom University, Riyadh, Saudi Arabia
| | - João Paulo Mendes Tribst
- Department of Oral Regenerative Medicine, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Renata Marques de Melo
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), Av. Engenheiro Francisco José Longo,777. 12245000, São José Dos Campos, São Paulo, Brazil
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A brief review on fatigue test of ceramic and some related matters in Dentistry. J Mech Behav Biomed Mater 2023; 138:105607. [PMID: 36549251 DOI: 10.1016/j.jmbbm.2022.105607] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
The characteristics of dental ceramics have been extensively studied over the years to provide highly qualified materials for use in prosthetic restorations. The ability to adhere to dental substrates, outstanding aesthetics (translucency, color, and substrate masking ability) and improved mechanical properties provide these materials with optical features and high strength to withstand masticatory stimuli. Different classifications are adopted, and it is generally considered that glass-ceramics have better optical characteristics due to the high glass content, and polycrystalline ceramics have superior strength favored by their densified and organized crystals, hampering crack growth. This knowledge was largely built-up during years of scientific research through different testing methodologies, but mainly employing static loads. It is important to not only take into account the intensity of loads that these materials will be exposed to, but also the effect of the intermittence of cyclic load application leading to mechanical fatigue and the influence of factors related to the crack origin and their propagation under this condition. Furthermore, the bonding surface of ceramic restorations requires surface treatments that improve the bond strength to luting agents; however, these treatments require caution because of their potential to produce defects and affect the structural behavior. Moreover, ceramic restorations often require internal adjustments for proper seating or external adjustments for fitting the occlusal contact with the antagonist. In this sense, finishing/polishing protocols may alter the defect population, as luting agents may also interact by filling in the superficial defects on the restoration intaglio surface. Thus, the balance among all these factors will define the performance of a restorative setup, as well as the posterior exposure to the humid environment and the masticatory stimuli (cyclical loading), which may favor developing slow and subcritical growth of cracks in ceramic materials and the degradation of the bond interface. Therefore, it is essential that the concepts which explain the fatigue mechanism are understood, as well as the crack propagation and failure patterns of restorative ceramic materials.
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Madruga CFL, Dal Piva AMDO, Pereira GKR, Caneppele TMF, Valandro LF, Bottino MA. Sintering mode of a translucent Y-TZP: Effects on its biaxial flexure fatigue strength, surface morphology and translucency. J ESTHET RESTOR DENT 2022; 34:1197-1205. [PMID: 35560703 PMCID: PMC9790507 DOI: 10.1111/jerd.12923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/08/2022] [Accepted: 04/25/2022] [Indexed: 12/30/2022]
Abstract
OBJECTIVE This investigation evaluated the effect of two sintering modes of a translucent zirconia (Y-TZP) on its surface roughness, topography, phase-transformation (t → m), translucency and biaxial flexure fatigue strength. MATERIALS AND METHODS To do so, 50 Y-TZP discs (Ø = 15 mm; thickness = 1.2 mm; IPS e.max ZirCAD LT) were prepared and divided into two groups: Standard mode (SM) and Fast mode (FM). Staircase fatigue testing was performed (piston-on-three balls set-up, ISO 6872:2015), as well as surface roughness, profilometry, scanning electron microscopy (SEM-FEG), energy dispersive X-ray spectroscopy (EDX), phase transformation (t → m) using X-ray diffraction analysis (XRD), translucency parameter analysis (TP and TP00 ) and fractography. RESULTS The results showed no statistical significant differences for roughness parameters (p > 0.05, SM: Ra = 0.13 ± 0.02, Rz = 1.21 ± 0.26 and RSm = 24.91 ± 2.19; FM: Ra = 0.14 ± 0.03, Rz = 1.32 ± 0.25 and RSm = 24.68 ± 2.16) or flexural fatigue strength (SM: 512 (464-560) MPa; FM: 542 (472-611) MPa) between the groups. In addition, similarity in surface morphological features (SEM and profilometry), composition and phases (EDX and XRD) was observed between the firing protocols. Fractography showed that the failure origin occurred on the tensile side. Sintering mode did not affect the TP (F = 0.001, p = 0.97) and TP00 (F = 0.12, p = 0.72). CONCLUSIONS Therefore, the fast-sintering mode is suggested as a viable alternative to the standard mode since it does not influence the evaluated surface morphology, microstructure, fatigue strength and translucency of a translucent monolithic zirconia. CLINICAL SIGNIFICANCE The fast sintering mode is a viable alternative for zirconia without compromising its topography, microstructure, mechanical performance or translucency.
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Affiliation(s)
- Camila Ferreira Leite Madruga
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
| | - Amanda Maria de Oliveira Dal Piva
- Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA)Universiteit van Amsterdam and Vrije UniversiteitAmsterdamNoord‐HollandThe Netherlands
| | - Gabriel Kalil Rocha Pereira
- Post‐Graduate Program in Oral Science (Prosthodontics Units), Faculty of DentistryFederal University of Santa Maria (UFSM)Santa MariaRio Grande do Sul StateBrazil
| | - Taciana Marco Ferraz Caneppele
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
| | - Luiz Felipe Valandro
- Post‐Graduate Program in Oral Science (Prosthodontics Units), Faculty of DentistryFederal University of Santa Maria (UFSM)Santa MariaRio Grande do Sul StateBrazil
| | - Marco Antonio Bottino
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
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Tan K, Dudley J. The marginal gaps of sequentially milled lithium disilicate crowns using two different milling units. Aust Dent J 2022; 67:239-248. [PMID: 35225358 PMCID: PMC9790678 DOI: 10.1111/adj.12909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/13/2021] [Accepted: 02/24/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND The purpose of this study was to compare the marginal gaps of sequentially milled lithium disilicate (LDS) crowns using two different milling units. METHODS One lower left first molar typodont tooth prepared for an LDS crown by an undergraduate student in a simulation clinic was selected. The crown preparation was scanned by a TRIOS 3 scanner and twelve LDS crowns milled by an E4D (E4DM) and a Sirona inLab MC X5 (MCX5) milling unit using identical settings. The crowns were seated onto the original crown preparation and three vertical marginal gap measurements were taken at four locations (mid-buccal, mid-lingual, mid-mesial and mid-distal) using a stereomicroscope. The mean marginal gap (MMG) was calculated for each individual tooth surface and each crown. RESULTS The MMG for the E4DM (100.40 μm) was not significantly different to the MCX5 (101.08 μm) milling unit (P = 0.8809). In both units, there was a statistically significant trend of increasing MMG with sequentially milled crowns using the same burs (E4DM P = 0.0133; MCX5 P = 0.0240). CONCLUSIONS The E4DM and MCX5 milling units produced LDS crowns with similar MMG's and within a clinically acceptable range but with a trend of increasing MMG when analysed sequentially. © 2022 Australian Dental Association.
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Affiliation(s)
- K Tan
- Adelaide Dental SchoolThe University of AdelaideAdelaideSAAustralia
| | - J Dudley
- Adelaide Dental SchoolThe University of AdelaideAdelaideSAAustralia
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Dalla-Nora F, Guilardi LF, Zucuni CP, Valandro LF, Rippe MP. Adhesion to a Zirconia-reinforced Lithium Silicate Ceramic: Effects of Ceramic Surface Treatments and Resin Cements. Oper Dent 2022; 47:320-329. [PMID: 35604819 DOI: 10.2341/20-226-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study had the objective to test the effect of ceramic surface treatments on the microshear bond strength (μSBS) of different resin cements to a zirconia-reinforced lithium silicate (ZLS). METHODS AND MATERIALS ZLS blocks were sectioned, embedded in acrylic resin, and then allocated into nine groups considering two study factors: "ceramic surface treatment" (HF - hydrofluoric acid; EP - self-etching primer; TBS - tribochemical silica coating) and "resin cements" (nMDP - without MDP monomer; MDP - with MDP monomer; SA - self-adhesive). Starch tubes (n=36) were placed on the treated ceramic surface and the cement was applied. Starch tubes were removed after 24 hours of storage, and the specimens were thermocycled (5,000×; 5°C-55°C). Next, the μSBS test was performed using the wire-loop technique, and topographic and failure analyses were performed. RESULTS The factors "ceramic surface treatment" and "resin cement" statistically influenced the μSBS results. Considering the surface treatment factor, the TBS produced statistically lower values when the MDP resin cement was applied, being only similar to the MDP plus EP group. For the resin cement factor, no difference was found for nMDP and SA groups, apart from the surface treatments. Failure analysis showed that the groups treated with EP had a greater number of pre-test failures. The surface treatments induced noteworthy topographic alterations when compared to control (no treatment). CONCLUSION The ZLS ceramic surface treatment with tribochemical silica coating associated with the MDP-containing resin cement resulted in lower bond strength values.
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Affiliation(s)
- F Dalla-Nora
- Fernanda Dalla-Nora, DDS, MSciD Post-Graduate Program in Oral Science (Prosthodontics Unit), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil
| | - L F Guilardi
- Luís Felipe Guilardi, DDS, MSciD, PhD, professor, Division of Prosthodontics, Department of Restorative Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil
| | - C P Zucuni
- Camilla Pauliski Zucuni, DDS, MSciD, PhD, Post-Graduate Program in Oral Science (Prosthodontics Unit), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil
| | - L F Valandro
- Luiz Felipe Valandro, DDS, MSciD, PhD, associate professor, Division of Prosthodontics, Department of Restorative Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil
| | - M P Rippe
- *Marília Pivetta Rippe, DDS, MSciD, PhD, adjunct professor, Division of Prosthodontics, Department of Restorative Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil
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Effect of repeated millings on the surface integrity of diamond burs and roughness of different CAD/CAM materials. Clin Oral Investig 2022; 26:5325-5337. [PMID: 35449245 DOI: 10.1007/s00784-022-04500-2] [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: 11/01/2021] [Accepted: 04/13/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES This study evaluated the surface integrity of two types of diamond burs and their effect on the roughness of different CAD/CAM materials. MATERIALS AND METHODS CAD/CAM materials, Vita Mark II (VM), IPS e.max CAD (EM), Celtra Duo (CD), G-Ceram (GC), and Lava Ultimate (LU) blocks were milled with CEREC MCXL. Five pairs of pointed cylinder burs (CB) and step burs (SB) were used repeatedly. The wear rate of burs was analyzed before and after milling with a scanning electron microscope (SEM) and weighing the burs. The milling time of the blocks at different milling stages was recorded from 2 (M2) to 8 times (M8) of use. The surface roughness (Ra) of blocks was measured with a profilometer. Data from the differences in surface roughness were analyzed using univariate analyses of variance and Kruskal-Wallis tests (alpha = 0.05). RESULTS For M2, the highest roughness (2.12 ± 0.1 μm) was observed with the VM block. EM blocks presented the highest roughness values (1.82 ± 0.3 μm, 1.85 ± 0.1 μm, and 1.86 ± 0.04 μm) at M4, M6, and M8, respectively. While the highest Ra values were observed for VM (2.12 to 1.43 µm), LU provided the lowest mean Ra (1.62 to 1.33 µm) among the tested materials. After the repeated use of burs up to 8 times, the surface roughness of all the tested materials decreased. Milling of LU resulted in chip deposits on the CB surface in SEM images. The duration of cutting was higher for CD and EM materials than those of other materials, but the milling duration for VM, GC, and LU blocks was similar. SB burs exhibited more wear than CB after repeated milling. CONCLUSIONS A repeated number of millings more than 4 times decreased the surface integrity of the milling burs, increased the surface roughness of CAD/CAM blocks except for LU, and increased the milling duration. Increased material hardness was more detrimental on bur surface integrity. CLINICAL RELEVANCE During milling CAD/CAM blocks, clinicians should note that the surface integrity of milling burs decreases after 4 times of use as a function of material hardness where step burs wear quicker than pointed cylinder burs.
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Guilardi LF, Werner A, Jager ND, Pereira GKR, Kleverlaan CJ, Rippe MP, Valandro LF. The influence of roughness on the resistance to impact of different CAD/CAM dental ceramics. Braz Dent J 2022; 32:54-65. [PMID: 35019019 DOI: 10.1590/0103-6440202103951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 02/15/2021] [Indexed: 11/21/2022] Open
Abstract
This study aimed to investigate the effect of surface roughness (polished vs. CAD/CAM milling simulation) on impact strength of five dental ceramics for manufacturing CAD/CAM monolithic restorations. Specimens of five ceramics (FC- feldspathic glass-ceramic; PICN- polymer-infiltrated ceramic-network; ZLS- zirconia-reinforced lithium silicate glass-ceramic; LD- lithium disilicate glass-ceramic; YZ- yttria-stabilized tetragonal zirconia polycrystal ceramic) to be tested under impact (15×10×2mm3; n= 15) were divided into two groups, according to surface treatment: polishing (pol) and grinding (gri) as CAD/CAM milling simulation. Impact strength was tested using the Dynstat method. Roughness, topographic, fractographic and finite element analyses were performed. The impact strength data were analyzed by Weibull, and Pearson correlation was used to correlate roughness and impact strength data. The CAD/CAM milling simulation led to significantly (p<0.05) greater roughness (Ra and Rz) and statistically reduced the impact strength for PICN (polPICN= 4.59 to griPICN= 1.09; ±76% decrease), for LD (polLD= 17.69 to griLD= 10.09; ±43% decrease) and for YZ (polYZ= 74.99 to griYZ= 20.67; ±72% decrease) ceramics; and also promoted a more irregular topography with scratches and grooves. Fractographic and FEA analyses depicted the origin of failure at the higher stress concentration side during the impact test, where the pendulum impacted. The CAD/CAM milling simulation significantly decreased the impact strength of the evaluated ceramic materials.
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Affiliation(s)
- Luis Felipe Guilardi
- Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil
| | - Arie Werner
- Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil
| | - Niek de Jager
- Academic Centre for Dentistry Amsterdam - ACTA, Department of Dental Materials Science, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands
| | - Gabriel Kalil Rocha Pereira
- Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil
| | - Cornelis Johannes Kleverlaan
- Academic Centre for Dentistry Amsterdam - ACTA, Department of Dental Materials Science, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands
| | - Marilia Pivetta Rippe
- Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil
| | - Luiz Felipe Valandro
- Federal University of Santa Maria, Faculty of Dentistry, Department of Restorative Dentistry, Santa Maria, RS, Brazil
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Effects of repeated use of tungsten carbide burs on the surface roughness and contact angles of a CAD-CAM PMMA denture base resin. J Prosthet Dent 2022; 128:1358-1362. [PMID: 35012770 DOI: 10.1016/j.prosdent.2021.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 11/22/2022]
Abstract
STATEMENT OF PROBLEM The surface roughness (Ra) and wettability of complete denture base materials must meet certain clinical requirements. Although computer-aided design and computer-aided manufacturing (CAD-CAM) systems have recently become popular for the fabrication of complete dentures, the effects of the repeated usage of milling burs on the surface properties of CAD-CAM denture base acrylic resins have not yet been fully investigated. PURPOSE The purpose of this in vitro study was to evaluate the effects of new and used burs on the Ra and contact angles (wettability) of a CAD-CAM polymethylmethacrylate (PMMA) denture base material. MATERIAL AND METHODS A total of 40 Ø2×10-mm disks were fabricated from 1 brand of CAD-CAM PMMA resin (Polident). Half of the specimens (group N) were milled with a new tungsten carbide bur set, while the other half (group U) was milled with a used tungsten carbide bur set. Moreover, half of the specimens (groups NT and UT) were subjected to thermocycling before Ra and contact angle testing. Ra was tested by using a profilometer, and the surfaces were also examined by scanning electron microscopy (SEM). The contact angle was measured by using the sessile drop method. Data were analyzed with the Kruskal-Wallis and Dunn Pairwise Comparison tests (α=.05). RESULTS The mean contact angle was highest for group U (80 degrees) and lowest for group UT (66 degrees) (P<.05). Ra values were highest for group N (1.3 μm) and lowest for group U (0.93 μm) (P<.05). CONCLUSIONS Specimens milled with new tungsten carbide burs had lower mean contact angles and higher Ra values than specimens milled with used burs. The contact angles of CAD-CAM PMMA resin specimens milled with used burs decreased significantly after thermocycling. Regardless of whether or not thermocycling was performed, contact angle values decreased as Ra values increased.
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May JT, Arata A, Cook NB, Diefenderfer KE, Lima NB, Borges ALS, Feitosa S. Stepwise stress testing of different CAD-CAM lithium disilicate veneer application methods applied to lithium disilicate substructures. J Prosthet Dent 2021; 128:794-802. [PMID: 34272064 DOI: 10.1016/j.prosdent.2020.05.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 10/20/2022]
Abstract
STATEMENT OF PROBLEM Whether a computer-aided design and computer-aided manufacture (CAD-CAM) fabricated high-translucency lithium disilicate veneer on a lithium disilicate substructure would increase the strength of the restoration compared with a traditional feldspathic porcelain veneer is unclear. PURPOSE The purpose of this in vitro study was to evaluate the effect of different lithium disilicate veneer application methods on a lithium disilicate substructure on their biaxial flexural stress (BFS). MATERIAL AND METHODS Lithium disilicate disks were fabricated so that when combined with the veneering disks, they had a dimension of 12×1.2 mm. Experimental groups were as follows (n=15): resin-bonded lithium disilicate veneer, lithium disilicate veneer adhesively cemented to lithium disilicate; sintered lithium disilicate veneer, lithium disilicate veneer sintered to lithium disilicate; sintered feldspathic veneer, feldspathic porcelain applied to lithium disilicate; and monolithic lithium disilicate, the control group. Weibull distribution survival analysis was used to compare the differences in the resistance to fracture after fatigue. The total number of cycles was analyzed by using 1-way ANOVA (α=.05). A finite element analysis (FEA) was also performed. The maximum principal stress (MPS) was used as the failure criterion. RESULTS The sintered feldspathic veneer group had significantly lower fatigue resistance than sintered lithium disilicate veneer or resin-bonded lithium disilicate veneer (P<.05). The resin-bonded lithium disilicate veneer group showed significantly more fractured fragments than the other groups. No statistical difference was observed in the number of cycles. The lithium disilicate veneered groups presented similar resistance to fatigue as the monolithic specimens of the same overall dimensions. Higher peaks of MPS were observed for groups monolithic lithium disilicate, sintered lithium disilicate veneer, and sintered feldspathic veneer than for resin-bonded lithium disilicate veneer. CONCLUSIONS Veneering a lithium disilicate substructure with a lithium disilicate veneer, bonded or sintered, increased resistance to fatigue compared with a feldspathic porcelain veneer. The lithium disilicate veneer groups had similar fatigue resistance to that of the monolithic group.
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Affiliation(s)
- Jaren T May
- Graduate student, Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry (IUSD), Indianapolis, Ind
| | - Anelyse Arata
- Research collaborator-volunteer, Nuclear and Energy Research Institute, Department of Materials Science and Technology Center, Sao Paulo, Brazil
| | - Norman B Cook
- Clinical Associate Professor, Department of Cariology, Operative Dentistry, and Dental Public Health, Indiana University School of Dentistry (IUSD), Indianapolis, Ind
| | - Kim E Diefenderfer
- Clinical Associate Professor, Department of Cariology, Operative Dentistry, and Dental Public Health, Indiana University School of Dentistry (IUSD), Indianapolis, Ind
| | - Nelson B Lima
- Research collaborator-volunteer, Nuclear and Energy Research Institute, Department of Materials Science and Technology Center, Sao Paulo, Brazil
| | - Alexandre L S Borges
- Associate Professor, Department of Dental Materials and Prosthodontics, Sao Paulo State University, Institute of Science and Technology, UNESP, Sao Jose dos Campos, Brazil
| | - Sabrina Feitosa
- Clinical Assistant Professor, Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry (IUSD), Indianapolis, Ind.
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Daguano JKMB, Dantas L, Soares VO, Alves MFRP, Santos CD, Zanotto ED. Optimizing the microstructure of a new machinable bioactive glass-ceramic. J Mech Behav Biomed Mater 2021; 122:104695. [PMID: 34293695 DOI: 10.1016/j.jmbbm.2021.104695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/28/2021] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES This study aimed to optimize the crystallization process and the microstructure of a new bioactive glass-ceramic (GC) previously developed by our research group to obtain machinable glass-ceramics. METHODS Differential scanning calorimetry (DSC) analyses were conducted to explore the characteristic temperatures and construct a semi-quantitative nucleation curve. The GC specimens were characterized by X-ray diffraction (XRD) and Rietveld refinement. Their brittleness index (B) and machinability were characterized and compared with IPS e.max-CAD®. Their Young's modulus, fracture toughness, and hardness were assessed. RESULTS We found that the maximum crystal nucleation rate temperature of this GC is ~470 °C. Treatments were designed based on the 1st DSC peak onset (570 °C), 1st peak offset (650 °C), and 2nd peak offset (705 °C) crystallization temperatures of lithium metasilicate (LS, LiSi2O3) and lithium disilicate (LS2, Li2Si2O5). Rietveld refinement indicated an increase in LS2 and a reduction in LS and amorphous phase for increased temperatures and longer treatment times. Their B values indicate good machinability compared with that of the control group based on statistical analyses. As expected, lower levels of LS2 increase the machinability regardless of the rotation speed adopted, leading to a greater depth of cut and reduced Edge Chipping Damage Depth (ECDD). CONCLUSION This bioactive GC with optimized microstructure presents high machinability. For treatment temperatures above 570 °C, the number of elongated LS2 crystals increases and decreases the amorphous phase content, which reduce the machinability of the GC, and should therefore be avoided. The best results were obtained using heat treatment at 570 °C, which produces LS crystals embedded in a glassy matrix (67%) with small contents of secondary phases.
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Affiliation(s)
- Juliana K M B Daguano
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC, São Bernardo do Campo, SP, Brazil; Center for Information Technology Renato Archer, Campinas, SP, Brazil
| | - Laís Dantas
- Vitreous Materials Laboratory, Materials Engineering Department, Federal University of São Carlos, São Carlos, SP, Brazil
| | - Viviane O Soares
- Vitreous Materials Laboratory, Materials Engineering Department, Federal University of São Carlos, São Carlos, SP, Brazil
| | - Manuel F R P Alves
- Materials and Processes Laboratory, Faculty of Technology, State University of Rio de Janeiro, Resende, RJ, Brazil
| | - Claudinei Dos Santos
- Materials and Processes Laboratory, Faculty of Technology, State University of Rio de Janeiro, Resende, RJ, Brazil.
| | - Edgar D Zanotto
- Vitreous Materials Laboratory, Materials Engineering Department, Federal University of São Carlos, São Carlos, SP, Brazil
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Al Hamad KQ, Al Quran FA, Jwaied SZ, Al-Dwairi ZN, Al-Rashdan BA, Baba NZ. Effect of CAD/CAM Bur Deterioration on the Surface Roughness of Ceramic Crowns. J Prosthodont 2021; 31:320-325. [PMID: 34213056 DOI: 10.1111/jopr.13404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2021] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To evaluate the effect of repetitive milling on the surface roughness of ceramic crowns. MATERIALS AND METHODS Twenty feldspathic ceramic crowns (VITABLOCS Mark II; Vita Zahnfabrik, Bad Säckingen, Germany) milled with hard milling protocol, and 20 zirconia crowns (5Y-TZP, inCoris TZI; Dentsply Sirona, York, PA) milled with soft milling protocol, using a 5-axis milling machine (inLab MC X5; Dentsply Sirona) were investigated. Atomic force microscopy (SPM SmartSPM™-1000) was used for surface roughness measurements (Ra, RMS). Pearson correlation between bur deterioration percentage as provided by the software of the milling machine and surface roughness was performed with an (r) range between 1 and -1. Trend analysis between the 2-half and among the 4-quarter bur lifetime was performed with linear contrast analysis and partial eta squared (η) for estimate of effect size. Analysis of mean variance between the zirconia and feldspathic ceramic groups was performed with a t-test, with α = 0.05. RESULTS Correlation analysis showed small correlation for Ra, RMS (r = -0.02, -0.16 for the feldspathic ceramic crowns and r = 0.044, 0.034 for the zirconia crowns), and no significant differences for the 2-half and 4-quarter groups (p > 0.05) for both crown types. Estimate of effect size was rated as medium for the 2-half groups (Ra = 0.420, RMS = 0.395) and large for the 4-quarter groups (RA = 0.22, F = 1.48, RMS = 0.19, F = 1.26) for the feldspathic ceramic crowns, and small effect size for the 2-half groups (Ra = 0.18, RMS = 0.20) and the 4-quarter groups (Ra = 0.035, RMS = 0.037) for the zirconia crowns. There was no significant difference (p = 0.178, F = 0.016. p = 0.088, F = 0.002) between the feldspathic ceramic and zirconia crowns with medium and large effect size (0.45, 0.57) for RA and RMS. CONCLUSIONS Milling zirconia and feldspathic ceramic crowns had small correlation between bur deterioration and surface roughness when the burs were used within their recommended lifetime. However, hard milled feldspathic ceramic crowns had higher surface roughness than the soft milled zirconia crowns. Bur deterioration had a larger effect on the surface roughness of the feldspathic ceramic crowns than the zirconia crowns.
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Affiliation(s)
- Khaled Q Al Hamad
- Department of Prosthodontics, Jordan University of Science & Technology, Irbid, Jordan
| | - Firas A Al Quran
- Department of Prosthodontics, Jordan University of Science & Technology, Irbid, Jordan
| | - Sawsan Z Jwaied
- Department of Prosthodontics, Jordan University of Science & Technology, Irbid, Jordan
| | - Ziad N Al-Dwairi
- Department of Prosthodontics, Jordan University of Science & Technology, Irbid, Jordan
| | | | - Nadim Z Baba
- Advanced Specialty Education Program in Implant Dentistry, Loma Linda University, School of Dentistry, Loma Linda, CA
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Payaminia L, Moslemian N, Younespour S, Koulivand S, Alikhasi M. Evaluating the effect of repeated use of milling burs on surface roughness and adaptation of digitally fabricated ceramic veneers. Heliyon 2021; 7:e06896. [PMID: 33997414 PMCID: PMC8105639 DOI: 10.1016/j.heliyon.2021.e06896] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 02/18/2021] [Accepted: 04/20/2021] [Indexed: 11/15/2022] Open
Abstract
Objectives This study aimed to evaluate how repeated use of milling diamond burs with different coarseness affects surface roughness, and marginal and internal adaptation of CAD/CAM veneers. Methods Forty leucite-reinforced glass-ceramic veneers were milled in 2 groups based on the milling mode (with fine or extra-fine bur sets). In each group, every 10 veneers were milled with a new bur set. All veneers were cemented to bovine teeth and then polished. Labial surface roughness was measured before cementation, and after polishing. Marginal and internal discrepancies were measured using a field emission scanning electron microscope. Three-way and two-way mixed repeated measures ANOVA were applied to assess changes in surface roughness values of veneers and discrepancy values, respectively. The Bonferroni correction was applied for multiple comparisons. Results Repeated use of a milling diamond bur set had a significant effect on surface roughness of the veneers (P < .001). Mean surface roughness of the fine milling mode was significantly higher in comparison to that of extra-fine mode before (P = .002) and after (P = .01) polishing. After polishing a significant decrease in surface roughness occurred in fine (P = .02), but not in extra-fine milling mode (P = .99). Repeated use of milling burs significantly affected marginal and internal adaptation between some repeated uses. Conclusions Marginal and internal adaptation were significantly affected by repeated use of milling diamond burs up to 10 times between some repeated uses. However, no specific pattern could be established. Clinical significance Repeated use of milling burs could affect surface roughness, surface microcracks, critical defects, and adaptation of CAD/CAM restorations. Therefore, it plays a major role in clinical success of the restorations.
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Affiliation(s)
- Leila Payaminia
- Dental Research Center, Dental Implant Research Center, Dentistry Research Institute, Department of Prosthodontics, Tehran University of Medical Sciences, Tehran, Iran
| | - Naeime Moslemian
- Department of Prosthodontics, School of Dentistry, Hamedan University of Medical Sciences, Hamedan, Iran
| | - Shima Younespour
- Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Soudabeh Koulivand
- Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marzieh Alikhasi
- Dental Research Center, Dental Implant Research Center, Dentistry Research Institute, Department of Prosthodontics, Tehran University of Medical Sciences, Tehran, Iran
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Al-Aali KA, Bin-Shuwaish MS, Alhenaki AM, Al Ahdal K, Al Deeb L, Maawadh AM, AlHelal A, Alshehri H, Vohra F, Abduljabbar T. Influence of milling systems and marginal configurations on the fit of yttrium stabilized tetragonal zirconia polycrystals (Y-TZP)' copings. J Appl Biomater Funct Mater 2020; 18:2280800020924514. [PMID: 33356766 DOI: 10.1177/2280800020924514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE The aim of this study was to evaluate marginal fit of yttrium tetragonal zirconia polycrystals (Y-TZP)' copings with different finish line designs fabricated with various digital scanners and milling systems. METHODS Three model plastic teeth were prepared with three finish line designs: Design-1, continuous chamfer; Design-2, chamfer with shallow depression; Design-3, chamfer with deep depression. The "master models" were replicated using elastomeric polyvinyl siloxane impression material and poured in type IV stone generating 90 dies, 30 dies for each design. Dies were scanned and copings were milled utilizing three digital scanners and computer-aided design/computer-aided manufacturing (CAD/CAM) systems: System-1, InEos Red Scan (Sirona Dental Systems, Germany), Vitablocks® Mark II (VITA, Germany) copings milled by Cerec® inLab (Sirona Dental Systems, Germany); System-2, Cerec® AC Connect with BlueCam (Sirona Dental Systems, Germany), Vitablocks® Mark II (VITA, Germany) copings milled by Cerec® inLab (Sirona Dental Systems, Germany); and System-3, NobleProcera™ Optical Scanner (NobleBiocare™), procera zirconia coping milled by a Noble Procera™ milling machine (NobleBiocare™). Copings were seated on their respective "master models" and secured with uniform force. Eight measurements per coping were performed at pre-established points, with a metallurgical microscope (Zeiss, Germany) connected to a high precision digital video-micrometer (Javelin JV6000, California, USA) at 200 × magnification. RESULTS The tested systems demonstrated marginal gaps ranging from 12.4 to 26.6 µm. Results for marginal fit of milled copings fabricated using three systems with different finish line designs differed significantly (p < 0.05). Procera zirconia copings scanned and milled with NobleProcera™ exhibited significantly lower marginal gaps compared to other specimen groups. However, InEos Red Scan/Vitablocks® Mark II/Cerec® inLab showed maximum marginal gaps among the study specimens. CONCLUSIONS CAD-CAM manufactured Y-TZP' copings exhibited marginal gaps ranging from 12.49 to 26.6 µm. The CAD-CAM fabrication system was a significant factor influencing the marginal misfit of Y-TZP' copings. Margin design exhibited system dependent influence on the marginal misfit. Marginal misfit observed for all systems were within clinically acceptable parameters.
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Affiliation(s)
- Khulud A Al-Aali
- Department of Clinical Dental Sciences, College of Dentistry, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Mohammed S Bin-Shuwaish
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Aasem M Alhenaki
- Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Khold Al Ahdal
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Laila Al Deeb
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed M Maawadh
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Abdulaziz AlHelal
- Department of Preventive Dental Science, College of Dentistry, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Hiba Alshehri
- Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Fahim Vohra
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Research Chair for Biological Research in Dental Health, Riyadh, Saudi Arabia
| | - Tariq Abduljabbar
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Research Chair for Biological Research in Dental Health, Riyadh, Saudi Arabia
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Ozdogan A, Ozdemir H. Effects of multiple firing processes on the mechanical properties of lithium disilicate glass-ceramics produced by two different production techniques. J Prosthet Dent 2020; 125:527.e1-527.e7. [PMID: 33243470 DOI: 10.1016/j.prosdent.2020.10.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 11/17/2022]
Abstract
STATEMENT OF PROBLEM Repeated firings cause materials to be exposed to additional heat treatments. The effect of these additional heat treatments on the mechanical properties of lithium disilicate glass-ceramics is not fully known. PURPOSE The purpose of this in vitro study was to determine the effects of repeated firing on the mechanical properties of lithium disilicate glass-ceramics produced by 2 different techniques, press and computer-aided design and computer-aided manufacturing (CAD-CAM). MATERIAL AND METHODS Eighty rectangular (25×4×2 mm) lithium disilicate glass-ceramic specimens were used in this study, 40 produced by heat pressing and 40 by milling, and divided into 4 groups (n=10) with a different number of veneer porcelain firings (1 to 4). After firing, the Vickers hardness, flexural strength (3-point bend test), and fracture toughness were determined, and the specimens were analyzed with an environmental scanning electron micrograph. Data were analyzed with analysis of variance (ANOVA) (α=.05). RESULTS The repeat firing processes did not affect the flexural strength of the specimens in either group (P>.05), while the surface hardness and fracture toughness were significantly changed (P<.05). CONCLUSIONS Increasing the number of firings adversely affected the mechanical properties of lithium disilicate glass-ceramics.
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Affiliation(s)
- Alper Ozdogan
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
| | - Hatice Ozdemir
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
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Diniz V, Condé Oliveira Prado PH, Meireles Rodrigues JV, Monteiro JB, Zucuni C, Valandro LF, Melo RM. Ceramic firing protocols and thermocycling: effects on the load-bearing capacity under fatigue of a bonded zirconia lithium silicate glass-ceramic. J Mech Behav Biomed Mater 2020; 110:103963. [DOI: 10.1016/j.jmbbm.2020.103963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/24/2020] [Accepted: 06/28/2020] [Indexed: 12/19/2022]
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Raposo LH, Borella PS, Ferraz DC, Pereira LM, Prudente MS, Santos-Filho PC. Influence of Computer-aided Design/Computer-aided Manufacturing Diamond Bur Wear on Marginal Misfit of Two Lithium Disilicate Ceramic Systems. Oper Dent 2020; 45:416-425. [PMID: 31860389 DOI: 10.2341/19-089-l] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2019] [Indexed: 11/23/2022]
Abstract
CLINICAL RELEVANCE Marginal misfit of monolithic lithium disilicate ceramic crowns obtained from a chairside computer-aided design/computer-aided manufacturing system is affected after successive millings using a single diamond bur set. This fact can be critical for the longevity of indirect restorations. SUMMARY
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Alves DM, Cadore-Rodrigues AC, Prochnow C, Burgo TADL, Spazzin AO, Bacchi A, Valandro LF, Rocha Pereira GK. Fatigue performance of adhesively luted glass or polycrystalline CAD-CAM monolithic crowns. J Prosthet Dent 2020; 126:119-127. [PMID: 32636073 DOI: 10.1016/j.prosdent.2020.03.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/23/2020] [Accepted: 03/23/2020] [Indexed: 11/17/2022]
Abstract
STATEMENT OF PROBLEM Data comparing the fatigue performance of adhesively luted glass or polycrystalline ceramic systems for computer-aided design and computer-aided manufacturing (CAD-CAM) are scarce. PURPOSE The purpose of this in vitro study was to evaluate and compare the fatigue performance of monolithic crowns manufactured from glass or polycrystalline CAD-CAM ceramic systems adhesively luted to a dentin analog. MATERIALS AND METHODS Fifty-four pairs of standardized preparations of dentin analog (NEMA Grade G10) and simplified ceramic crowns of 1.5-mm thickness were obtained with 3 ceramic materials: lithium disilicate (LD) glass-ceramic (IPS e.max CAD); zirconia-reinforced lithium silicate (ZLS) glass-ceramic (Vita Suprinity); and translucent yttrium fully stabilized polycrystalline zirconia (Trans YZ) (Prettau Anterior). The simplified crowns (n=15) were adhesively cemented onto the preparations and subjected to step-stress fatigue test (initial load of 400 N, 20 Hz, 10 000 cycles, followed by 100-N increment steps until failure). Collected data (fatigue failure load [FFL] and cycles for failure [CFF]) were submitted to survival analysis with the Kaplan-Meier and Mantel-Cox post hoc tests (α=.05) and to Weibull analysis (Weibull modulus and its respective 95% confidence interval). Failed crowns were submitted to fractography analysis. The surface characteristics of the internal surface (roughness, fractal dimension) of additional crowns were accessed, and the occlusal cement thickness obtained in each luted system was measured. RESULTS Trans YZ crowns presented the highest values of FFL, CFF, and survival rates, followed by ZLS and LD (mean FFL: 1740 N>1187 N>987 N; mean CFF: 149 000>92 613>73 667). Weibull modulus and cement thickness were similar for all tested materials. LD presented the roughest internal surface, followed by ZLS (mean Ra: 226 nm>169 nm>93 nm). The LD and ZLS internal surfaces also showed higher fractal dimension, pointing to a more complex surface topography (mean fractal dimension: 2.242=2.238>2.147). CONCLUSIONS CAD-CAM monolithic crowns of Trans YZ show the best fatigue performance. In addition, ZLS crowns also showed better performance than LD crowns.
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Affiliation(s)
- Daniela Meira Alves
- Post-Graduate Program in Dentistry, School of Dentistry, Meridional Faculty, IMED, Passo Fundo, Rio Grande do Sul, Brazil
| | - Ana Carolina Cadore-Rodrigues
- PhD student, MSciD and PhD Post-Graduate Program in Oral Science (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Catina Prochnow
- MSciD and PhD Post-Graduate Program in Oral Science (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Thiago Augusto de Lima Burgo
- Adjunct Professor, Department of Physics, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Aloísio Oro Spazzin
- Professor, Post-Graduate Program in Dentistry, School of Dentistry, Meridional Faculty, IMED, Passo Fundo, Rio Grande do Sul, Brazil
| | - Ataís Bacchi
- Professor, Post-Graduate Program in Dentistry, School of Dentistry, Meridional Faculty, IMED, Passo Fundo, Rio Grande do Sul, Brazil
| | - Luiz Felipe Valandro
- Professor, MSciD and PhD Post-Graduate Program in Oral Science (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Gabriel Kalil Rocha Pereira
- Adjunct Professor, MSciD and PhD Post-Graduate Program in Oral Science (Prosthodontics Units), Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
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Tribst JPM, Dal Piva AMDO, Madruga CFL, Valera MC, Bresciani E, Bottino MA, de Melo RM. The impact of restorative material and ceramic thickness on CAD\CAM endocrowns. J Clin Exp Dent 2019; 11:e969-e977. [PMID: 31700569 PMCID: PMC6825739 DOI: 10.4317/jced.56002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/09/2019] [Indexed: 12/01/2022] Open
Abstract
Background Endocrown restorations as a conservative approach to restore endodontically treated teeth still need in vitro investigation under fatigue and made in different materials. This study evaluated the effect of restorative material and restoration thickness on the maximum fracture load of endocrowns subjected to cyclic loading. Material and Methods Sixty (60) third molar teeth received an endocrown preparation with three different heights of remaining dental tissue (1.5, 3.0 or 4.5 mm). A leucite-based ceramic (LEU) and a lithium disilicate (LD) based ceramic were selected to manufacture the CAD/CAM endocrown restorations, totaling 6 groups (n=10). The specimens were subjected to fatigue loading (200N, 2 x 106 cycles, water) and then to the single load to failure test (1 mm/min crosshead speed). Data were analyzed by using two-way ANOVA and Tukey tests (p< 0.05). Results All endocrowns survived the fatigue test. The thickness did not influence the restoration’s fracture load (p=0.548) instead the restorative material (p=0.003). LD showed higher mean values (1714.43 N)A than LEU (1313.47 N)B. Conclusions Endocrowns manufactured with CAD/CAM lithium disilicate blocks showed superior fracture load than the leucite-based blocks after mechanical fatigue. Nevertheless, both materials presented acceptable survival and fracture load as long as the material’s minimum thickness and the enamel adhesion are respected. Key words:Endocrown, CAD/CAM, Endodontically treated teeth, Failure load, Minimal intervention dentistry.
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Affiliation(s)
- João-Paulo-Mendes Tribst
- DDs, MSc, PhD Student in Prosthodontics, Department of Dental Materials and Proshodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos / SP, Brazil
| | - Amanda-Maria-de Oliveira Dal Piva
- DDs, MSc, PhD Student in Prosthodontics, Department of Dental Materials and Proshodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos / SP, Brazil
| | - Camila-Ferreira-Leite Madruga
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, n° 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil
| | - Marcia-Carneiro Valera
- Department of Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, n° 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil
| | - Eduardo Bresciani
- Department of Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, n° 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil
| | - Marco-Antonio Bottino
- DDs, MSc, PhD, Professor, Department of Dental Materials and Proshodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos / SP, Brazil
| | - Renata-Marques de Melo
- DDs, MSc, PhD, Researcher III, Department of Dental Materials and Proshodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos / SP, Brazil
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Tribst JPM, Alves LMM, Piva AMDOD, Melo RMD, Borges ALS, Paes-Junior TJA, Bottino MA. Reinforced Glass-ceramics: Parametric Inspection of Three-Dimensional Wear and Volumetric Loss after Chewing Simulation. Braz Dent J 2019; 30:505-510. [DOI: 10.1590/0103-6440201902699] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/28/2019] [Indexed: 11/22/2022] Open
Abstract
Abstract The aim of this study was to investigate the three-dimensional wear, volumetric loss and surface roughness after chewing simulation of two glass ceramics. Lithium disilicate (LD, Emax CAD, Ivoclar) and Zirconia reinforced lithium silicate (ZLS, Vita Suprinity, Vita Zhanfabrick) discs (n=20/g) were scanned to obtain stereolithography (STL) files for each sample. All discs were submitted to chewing simulation with sliding configuration (30 N, 300,000 cycles, 6 mm and 1.7 Hz) with steatite as antagonist. The samples were then scanned again and the volume loss and the deepest defect depth was measured using the superimposed file from the baseline using three-dimensional digital parametric inspection software (GOM Inspect, Braunschweig, Germany). Surface roughness (Ra and Rz) was analyzed with a contact profilometer. Data were analyzed by one-way ANOVA and Tukey test (α=0.5%). ANOVA showed significant differences among the groups. Considering the ceramic volume loss, wear depth defect length and Rz roughness, LD (-22.09±5.57%; 0.80±0.06 µm; 3.08±1.02 µm) showed higher mean values than ZLS (-15.67±4.51%; 0.56±0.09 µm; 1.51±0.90 µm). Ra mean values were similar for both materials (p=0.064). All discs exhibited slight surface scratches along with the sliding direction with pitted wear patterns, while large cracks were observed on wear traces. These same areas can be identified in blue, overlapping the STL files before and after chewing simulation in inspection software. The linear reduction generated by sliding contact shows a graph with a similar wear pattern shape. ZLS was more resistant to wear than LD, with less volume loss and shallower surface defects.
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Schmitt de Andrade G, Diniz V, Datte CE, Pereira GKR, Venturini AB, Campos TMB, Amaral M, Bottino MA, Valandro LF, Marques de Melo R. Newer vs. older CAD/CAM burs: Influence of bur experience on the fatigue behavior of adhesively cemented simplified lithium-disilicate glass-ceramic restorations. J Mech Behav Biomed Mater 2019; 95:172-179. [PMID: 31009901 DOI: 10.1016/j.jmbbm.2019.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 10/27/2022]
Abstract
This study evaluated the effect of the CAD/CAM burs experience (newer vs older as consequence of the milling sequence) on fatigue failure load (FFL), number of cycles for failure (CFF), and survival rates of lithium disilicate glass-ceramic simplified restorations adhesively cemented to a dentin analogue substrate. Three sets of CAD/CAM burs were used to mill disc-shaped ceramic specimens (1 bur set - 18 milled discs with 10 mm diameter and 1.5 mm thickness), considering the bur experience as a result of the milling sequence to compose the study groups: G1-6 - discs obtained from the 1st to 6th milling of each bur set; G7-12 - specimens from the 7th to 12th milling; G13-18 - discs from the 13th to 18th. Discs of dentin analogue (G10, 10 mm diameter and 2.0 mm thickness) were made to serve as substrate (base material) and randomly assigned into pairs with the respective ceramic discs. Then, the ceramic discs were adhesively cemented onto the dentin analogue substrate, composing a three-layer specimen that mimics a monolithic restoration of a posterior tooth. Specimens were tested under stepwise fatigue approach: frequency = 20 Hz, 5000 cycles at maximum load of 400 N to accommodate the testing assembly, followed by incremental steps of 200 N with initial load ranging from 10 to 1000 N, to a maximum of 20,000 cycles/each step, until the occurrence of failure (radial crack). FFL and CFF were recorded at the end of the testing and subjected to statistical analysis. Supplementary roughness analysis of the milled surface was performed (n = 18) using a contact profilometer. Residual stress after milling and acid etching were accessed via X-ray Diffractometry analysis. FFL and CFF were not affected by increase on bur experience (no statistical differences among groups), despite that, it affected both Ra and Rz parameters (G1-6 had the smoothest surface). The residual stress concentration was negligible (milling did not induce residual stress concentration). It is concluded that the fatigue behavior of adhesively cemented lithium-disilicate glass-ceramic restorations was not influenced by CAD/CAM bur experience (newer vs older as consequence of the milling sequence), and so the residual stress concentration induced by milling was negligible.
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Affiliation(s)
- Guilherme Schmitt de Andrade
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil.
| | - Vandeberg Diniz
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil.
| | - Carlos Eduardo Datte
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil.
| | | | - Andressa Borin Venturini
- Oral Science, Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
| | | | - Marina Amaral
- Department of Dentistry (Prosthetic Dentistry), University of Taubaté (UNITAU), Taubaté, Brazil.
| | - Marco Antonio Bottino
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil.
| | - Luiz Felipe Valandro
- Oral Science, Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
| | - Renata Marques de Melo
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil.
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