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Dental Materials : Official Publication... Jan 2023To seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace...
OBJECTIVE
To seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace human dentine in a crown fatigue laboratory test.
METHODS
A woven glass fibre-filled epoxy (NEMA grade G10; G10) and a glass fibre-reinforced polyamide-nylon (30% glass fibre reinforced polyamide-nylon 6,6; RPN) were investigated and compared with human dentine (HD). Flexural strength and elastic modulus (n = 10) were tested on beam-shaped specimens via three-point bending, while indentation hardness (n = 3) was tested after fracture. Abutment substrates of G10, RPN and HD were prepared and resin-bonded with monolithic lithium disilicate crowns (n = 10), then subjected to wet cyclic loading in a step-stress manner (500 N initial load, 100 N step size, 100,000 cycles per step, 20 Hz frequency). Data were statistically analysed using Kruskal-Wallis one-way ANOVA followed by post-hoc comparisons (α = 0.05). Survival probability estimation was performed by Mantel-Cox Log-Rank test with 95% confidence intervals. The fatigue failure load (FFL) and the number of cycles until failure (NCF) were evaluated with Weibull statistics. Finite Element Models of the fatigue test were established for stress distribution analysis and lifetime prediction. Fractographic observations were qualitatively analysed.
RESULTS
The flexural strength of HD (164.27 ± 14.24 MPa), G10 (116.48 ± 5.93 MPa), and RPN (86.73 ± 3.56 MPa) were significantly different (p < 0.001), while no significant difference was observed in their flexural moduli (p = 0.377) and the indentation hardness between HD and RPN (p = 0.749). The wet cyclic fatigue test revealed comparable mean FFL and NCF of G10 and RPN to HD (p = 0.237 and 0.294, respectively) and similar survival probabilities for the three groups (p = 0.055). However, RPN promotes higher stability and lower deviation of fatigue test results than G10 in Weibull analysis and FEA.
SIGNIFICANCE
Even though dentine analogue materials might exhibit similar elastic properties and fatigue performance to human dentine, different reliabilities of fatigue on crown-dentine analogues were shown. RPN seems to be a better substrate that could provide higher reliability and predictability of laboratory study results.
Topics: Humans; Ceramics; Reproducibility of Results; Nylons; Materials Testing; Surface Properties; Dental Stress Analysis; Dental Porcelain; Crowns; Dentin; Computer-Aided Design
PubMed: 36503862
DOI: 10.1016/j.dental.2022.11.020 -
Journal of Applied Biomaterials &... 2024Despite the development of implant-supported prostheses, there are still patients for whom conservative treatments such as resin-bonded fixed dental prostheses (RBFDPs)... (Review)
Review
Despite the development of implant-supported prostheses, there are still patients for whom conservative treatments such as resin-bonded fixed dental prostheses (RBFDPs) are more appropriate. This study's objective was to analyze the available research on full-ceramic RBFDPs. In this study, Web of Science, MEDLINE/PubMed, Scopus, Embase, Cochrane Library, and Google Scholar databases were searched for articles published in English between 2010 and 2020. A total of 14 studies were reviewed based on the eligibility criteria. The results showed that using a cantilever design with one abutment had an advantage over two abutments. Additionally, it was proposed that preparations designed with retentive aids, such as a proximal box, groove, and pinhole, could improve RBFDP survival rates. IPS e.max ZirCAD, In-Ceram alumina, and zirconia CAD/CAM were the most commonly used framework materials. Most studies used air abrasion, salinization, or hydrofluoric acid for surface treatment. Adhesive resin cements were the most frequently used type of cement. The survival rate of In-Ceram ceramics (85.3%-94.8%) was lower than that of In-Ceram zirconia and IPS e.max ZirCAD. Debonding, followed by framework fracture, was the leading cause of failure. Following 3-10 years follow-up, the survival percentage of all-ceramic RBFDPs ranged from 76% to 100%. Although RBFDPs have demonstrated satisfactory success as a conservative treatment, long-term follow-ups and higher sample sizes in clinical research are required to gain more reliable outcomes on the clinical success rate of various RBFDP designs.
Topics: Humans; Ceramics; Resin Cements; Dental Porcelain; Dental Prosthesis, Implant-Supported; Denture, Partial, Fixed, Resin-Bonded; Zirconium
PubMed: 38706266
DOI: 10.1177/22808000241250118 -
Journal of Prosthodontics : Official... Dec 2023The use of porcelain laminate veneers (PLVs) is a minimally invasive technique that is often used in restorative dentistry due to esthetic considerations. The aim of...
PURPOSE
The use of porcelain laminate veneers (PLVs) is a minimally invasive technique that is often used in restorative dentistry due to esthetic considerations. The aim of this study was to evaluate PLVs according to the Fédération Dentaire Internationale (FDI) World Dental Federation clinical criteria.
MATERIALS AND METHODS
This clinical study included 11 patients (7 female and 4 male) who had been admitted to the Uşak University Faculty of Dentistry between February 2019 and February 2021. Before taking part in the study, patients were informed about alternative treatment procedure options. A total of 30 PLVs were fabricated and cemented, and patients were evaluated according to the FDI criteria (with a follow-up after 2 years).
RESULTS
Restorations were evaluated by two trained researchers. During the follow-up evaluation, no fractures or cracks were observed in any restoration. Further, 73% (n = 22) of the PLVs had perfect marginal adaptation and only 27% (n = 8) had small marginal fractures that could be removed by polishing. Moreover, 57% (n = 17) of the PLVs were evaluated as a good color match (no difference in shade and/or translucency), whereas 33% (n = 13) had only minor deviations. In periodontal examinations, 23% (n = 7) of the PLVs had no plaque, inflammation, or pockets, whereas 77% (n = 23) had minor plaque inflammation and no pocket development.
CONCLUSIONS
As there were no fractures, fails, or need for removal of the restorations after 2 years, PLVs showed clinically satisfactory performance. The performance of PLVs can be considered highly favorable due to the minimally invasive and periodontally-compatible nature, with a good color match when carefully planned.
Topics: Humans; Male; Female; Dental Porcelain; Dental Veneers; Esthetics, Dental; Dentistry; Inflammation
PubMed: 36651602
DOI: 10.1111/jopr.13641 -
British Dental Journal Feb 2022Alumina is a well-known dental ceramic material that has made waves within the dental industry for its good aesthetics and strength when compared to older materials for...
Alumina is a well-known dental ceramic material that has made waves within the dental industry for its good aesthetics and strength when compared to older materials for fixed prostheses, such as crown and bridgework. To be able to confidently use this material, a clinician should understand the physical and optical properties so as to know why and how this material might work in various clinical settings. This part of the ceramic series aims to explore the various alumina-based ceramic systems available on the market and discuss their properties, applications and indications. We also intend to briefly describe the preparation design requirements and cementation protocol for this type of ceramic.
Topics: Aluminum Oxide; Ceramics; Dental Porcelain; Esthetics, Dental; Surface Properties
PubMed: 35217739
DOI: 10.1038/s41415-022-3937-z -
Journal of the Mechanical Behavior of... Feb 2022The aim of the present scoping review was to identify and discuss the methods, testing parameters, and characteristics used to induce cyclic fatigue on non-anatomic... (Review)
Review
The aim of the present scoping review was to identify and discuss the methods, testing parameters, and characteristics used to induce cyclic fatigue on non-anatomic dental ceramic specimens. In vitro studies written in English which evaluated commercially-available non-anatomic dental ceramic specimens subjected to mechanical cyclic fatigue were selected. The search was performed in the PubMed, Scopus and Web of Science databases. The initial search yielded 1,636 articles, of which 81 were included. Based on the collected data, most of the included studies evaluated dental ceramic specimens cemented to supporting substrate (n= 42; 51.9%); used step-stress (n= 35; 42.2%) accelerated fatigue test, loading frequencies above 10 Hz (n= 31, 35.6%), stainless steel (n = 28, 32.6%) load applicator with spherical shaped tip 40 mm diameter (n= 25, 30.9%); applied only axial loads (n= 77, 95.1%); and considered a wet testing environment (n= 65, 78.3%). The definition of test geometry, method, and testing parameters must be cautiously considered according to the study objective and the scenario that is simulated. Accelerated fatigue tests, load frequencies up to 20 Hz, a 40 mm stainless steel spherical load applicator and a wet testing environment are the major common defined parameters presented in the existing literature. More studies exploring the influence of such factors on fatigue mechanism are necessary.
Topics: Ceramics; Dental Porcelain; Dental Restoration Failure; Dental Stress Analysis; Materials Testing; Surface Properties
PubMed: 34861521
DOI: 10.1016/j.jmbbm.2021.104985 -
The Journal of Prosthetic Dentistry Dec 2022Whether procedures performed before the cementation of computer-aided design and computer-aided manufacturing (CAD-CAM) glass-ceramic restorations, including milling,... (Meta-Analysis)
Meta-Analysis Review
STATEMENT OF PROBLEM
Whether procedures performed before the cementation of computer-aided design and computer-aided manufacturing (CAD-CAM) glass-ceramic restorations, including milling, fitting adjustment, and hydrofluoric acid etching introduce defects on the ceramic surface that affect the mechanical and surface properties is unclear.
PURPOSE
A systematic review and meta-analysis were conducted to assess the effect of milling, fitting adjustments, and hydrofluoric acid etching (HF) on the flexural strength and roughness (Ra) of CAD-CAM glass-ceramics.
MATERIAL AND METHODS
Literature searches were performed up to June 2020 in the PubMed/MEDLINE, Web of Science, and Scopus databases, with no publication year or language limits. The focused question was "Do milling, fitting adjustments, and hydrofluoric acid etching affect the flexural strength and roughness of CAD-CAM glass-ceramics?" For the meta-analysis, flexural strength and Ra data on milling, fitting adjustment, and HF etching versus control (polishing) were analyzed globally. A subgroup analysis assessed the effect of etching parameters (HF concentration and time) on the flexural strength and roughness of CAD-CAM glass-ceramics with different microstructures. Comparisons were performed with random-effect models at 5% significance.
RESULTS
Fourteen studies from 2764 potentially relevant records were included in the qualitative syntheses, and 12 in the meta-analysis. Milling and fitting adjustments increased roughness and reduced the flexural strength of CAD-CAM glass-ceramics. The effect of HF etching was dependent on the glass-ceramic microstructure, HF concentration, and etching time. For feldspathic- and leucite-reinforced ceramics, HF 5% applied for between 30 and 120 seconds increased roughness without affecting flexural strength. For lithium disilicate glass-ceramics, HF concentrations greater than 4.9% used for 20 seconds or more reduced the strength without affecting the surface roughness.
CONCLUSIONS
The flexural strength of CAD-CAM glass-ceramic is reduced by grinding procedures such as milling and fitting adjustment. Ceramic microstructure, HF concentration, and etching time determined the effect of hydrofluoric acid etching on the flexural strength and surface roughness of glass-ceramic materials.
Topics: Hydrofluoric Acid; Materials Testing; Dental Porcelain; Ceramics; Computer-Aided Design; Flexural Strength; Surface Properties
PubMed: 33865557
DOI: 10.1016/j.prosdent.2021.02.031 -
Journal of Prosthodontics : Official... Dec 2021To assess the feasibility of manufacturing a dental crown with internal color gradient and graded structure design using additive manufacturing technology, a mandibular...
To assess the feasibility of manufacturing a dental crown with internal color gradient and graded structure design using additive manufacturing technology, a mandibular first molar was prepared and a monolayer dental crown with 1.5 mm uniform thickness was designed in a dental software (STL ). The monolayer crown design was sliced into multiple layers of 0.1 mm thickness and a design for a multilayer crown was obtained (STL ). A multilayer crown was manufactured with gradient color and graded structure using a material jetting printer. Different materials with different colors and properties were used and mixed in different ratios during manufacturing to achieve the prospected design. The feasibility of manufacturing such a crown was reported. This report confirms that multilayer dental crowns with internal gradient color and graded structure are possible when using a multimaterial jetting printer.
Topics: Color; Computer-Aided Design; Crowns; Dental Porcelain; Dental Prosthesis Design; Molar
PubMed: 34297467
DOI: 10.1111/jopr.13410 -
The Journal of Prosthetic Dentistry Aug 2023New computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate glass-ceramics have been marketed. However, information concerning their...
STATEMENT OF PROBLEM
New computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate glass-ceramics have been marketed. However, information concerning their biomechanical behavior is lacking.
PURPOSE
The purpose of this in vitro study was to compare the fit and fatigue behavior of two recently introduced CAD-CAM lithium disilicate materials with the standard IPS e.max CAD ceramic and to investigate the effect of the thermal treatment for crystallization on crown fit.
MATERIAL AND METHODS
Monolithic crowns (n=15) were milled from 3 CAD-CAM lithium disilicates: IPS e.max CAD (Ivoclar AG), Rosetta SM (Hass), and T-lithium (Shenzhen Upcera Dental Technology). Marginal and internal fit were evaluated using the replica technique before and after crystallization, and the fatigue behavior of the luted crowns was evaluated by the step-stress method. One-way ANOVA and the Tukey test were used to compare fit among the materials. Fatigue failure load was evaluated by the Kaplan-Meier and Mantel-Cox tests. The effect of crystallization on fit was evaluated with the paired t test (α=.05).
RESULTS
Marginal fit was different between IPS e.max CAD (74 μm) and Rosetta SM (63 μm) (P=.02). T-lithium was similar to the other ceramics (68 μm) (P>.05). Occlusal internal space was similar among all materials (P=.69). Fatigue failure loads of Rosetta SM (1160 N) and T-lithium (1063 N) were similar to IPS e.max CAD (1082 N) (P>.05). The fatigue failure load of Rosetta SM was higher than that of T-lithium (P=.04). Crystallization reduced the axial internal space of all materials (P<.05) without significantly affecting marginal fit (P>.05).
CONCLUSIONS
The fit and fatigue behavior of Rosetta SM and T-lithium were similar to that of IPS e.max CAD. Crystallization reduced the internal space of the crowns.
Topics: Ceramics; Lithium; Dental Prosthesis Design; Surface Properties; Dental Marginal Adaptation; Dental Impression Technique; Dental Stress Analysis; Materials Testing; Dental Porcelain; Crowns; Computer-Aided Design
PubMed: 37328406
DOI: 10.1016/j.prosdent.2023.05.007 -
Journal of Nanoscience and... Sep 2020Various surface treatments on zirconia have been reported for dental porcelain veneer. However, it has not been determined which of these treatments provide the highest...
Various surface treatments on zirconia have been reported for dental porcelain veneer. However, it has not been determined which of these treatments provide the highest bond strength. The purpose of this study is to compare the effect of airborne particle abrasion and atmospheric pressure plasma treatment on the shear bond strength between zirconia and dental porcelain veneer. The groups were divided into four groups according to the surface treatment method: the control group, the atmospheric pressure plasma treated group (group P), the airborne particle abrasion group (group A), the atmospheric pressure plasma treated group after the airborne particle abrasion (group AP). Atmospheric pressure plasma was applied on the specimens using a plasma generator (Plasma JET, POLYBIOTECH Co. Ltd., Gwangju, Korea) and airborne-particle abraded with 110 m. The characteristics of surface treated zirconia were analyzed by 3D-OP, XRD, XPS and contact angle. The shear bond strength was tested using a universal testing machine. The shear bond strength of group was significantly increased compared to that of the control group ( < 0.05). The shear bond strength of group AP was significantly increased as compared to group A ( < 0.05). There was no significant difference between the group P and group A ( > 0.05). As a result of this study, the atmospheric pressure plasma treatment showed significantly higher shear bond strength than control group, but similar to the airborne particle abrasion, and the atmospheric pressure plasma treatment after the airborne particle abrasion provided the highest shear bond strength. This study demonstrated that application atmospheric pressure plasma treatment on zirconia may be useful for increasing bond strength between zirconia and dental porcelain veneer.
Topics: Atmospheric Pressure; Ceramics; Dental Bonding; Dental Porcelain; Materials Testing; Microscopy, Electron, Scanning; Shear Strength; Surface Properties; Zirconium
PubMed: 32331159
DOI: 10.1166/jnn.2020.17668 -
Dental Materials Journal Jan 2023This review describes the development of ultra-high translucent zirconia (referred to as UHTZ) using new manufacturing technology and its characterization results. The... (Review)
Review
This review describes the development of ultra-high translucent zirconia (referred to as UHTZ) using new manufacturing technology and its characterization results. The development of UHTZ was primarily due to the adoption of two basic manufacturing technologies, "Cyclic CIP" and "Plus Y Technology". This manufacturing technology could provide stable processing characteristics, which improves chipping resistance during milling. Furthermore, the enlargement factor (processing coefficient) for UHTZ is smaller than those for conventional products. In general, the higher the light transmittance, the lower the flexural strength. Despite its extremely high translucency, the most significant feature of UTHZ is that its flexural strength is comparable to that of 5Y. Furthermore, UHTZ has higher chemical durability and uniform microstructure, which results in less wear on the opposing teeth and superior discoloration resistance. Therefore, UHTZ is a new option for inlay, onlay, and laminate veneer applications, where lithium disilicate glass ceramics has been widely used.
Topics: Materials Testing; Dental Porcelain; Ceramics; Zirconium; Flexural Strength; Surface Properties
PubMed: 36631076
DOI: 10.4012/dmj.2022-243