scholarly journals Influence of Cement Thickness on the Polymerization Shrinkage Stress of Adhesively Cemented Composite Inlays: Photoelastic and Finite Element Analysis

Oral ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 168-180
Author(s):  
Larissa Mendes Campaner ◽  
Alana Barbosa Alves Pinto ◽  
Amir Mohidin Demachkia ◽  
Tarcísio José de Arruda Paes-Junior ◽  
Clóvis Pagani ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Film Thickness ◽  
Resin Cement ◽  
Shrinkage Stress ◽  
Element Analysis ◽  
Polymerization Shrinkage ◽  
Photoelastic Analysis ◽  
Group 2 ◽  
Group 1

The objective of this study was to analyze the effect of cement thickness on the strain and stresses resulting from the polymerization of resin cement using photoelasticity and Finite Element Analysis (FEA). For this study, twenty upper first premolars with inlay cavity preparation were constructed from photoelastic resin and restored with composite resin inlay. The samples were divided into two groups (n = 10) according to the film thickness of resin cement material. For Group 1, the film thickness was 100 μm; for Group 2, the film thickness was 400 μm. After polymerization of the cement, photoelastic analysis and finite element analysis (FEA) were performed. In the photoelastic analysis, Group 2 showed higher strain with the presence of second-order fringe even after 24 h. In Group 1, the formation of first order fringes was not observed, even after 24 h. In the FEA analysis, the greatest cusp deflection and tensile stress occurred in Group 2 (0.00026 mm and 0.305 MPa, respectively) due to the polymerization shrinkage in the lingual cusp compared to Group 1 (0.000107 mm and 0.210 MPa, respectively). It can be concluded that the thickness of the resin cement influences the cusp deflection, with the greater thickness of the cement layer, the greater stresses and deformations in the tooth structure occur.

Post-gel and Total Shrinkage Stress of Conventional and Bulk-fill Resin Composites in Endodontically-treated Molars

2020 ◽  
Vol 45 (5) ◽  
pp. E217-E226
Author(s):  
RA da Silva Pereira ◽  
GF de Bragança ◽  
ABF Vilela ◽  
RA de Deus ◽  
RR Miranda ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Resin ◽  
Composite Resins ◽  
Shrinkage Stress ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Polymerization Shrinkage ◽  
Total Shrinkage ◽  
Selection Of

Clinical Relevance The clinician should consider the polymerization shrinkage stress when selecting a composite resin for posterior restorations. The use of post-gel shrinkage values should guide the selection of a composite resin for posterior teeth. SUMMARY Objectives: The objective of this study was to evaluate the effect of the method used for calculation of polymerization shrinkage, total or post-gel, on the shrinkage stress of conventional and bulk-fill composite resins for restoring endodontically treated teeth using finite element analysis. Methods and Materials: Four composite resins were tested for post-gel shrinkage (P-Shr) by the strain-gauge test and total shrinkage (TShr) using an optical method (n=10). Two conventional composite resins, Filtek Z350 XT (3M-ESPE; Z350) and TPH3 Spectrum (Dents-ply; TPH3) and two bulk-fill composite resins. Filtek Bulk-Fill Posterior (3M-ESPE; POST) SureFil SDR flow (Dentsply; SDR) were tested. Elastic modulus (E), diametral tensile strength (DTS), and compressive strength (CS) were also determined (n=10). The residual shrinkage stress was evaluated by finite element analysis with four restorative techniques: incremental with Z350 and TPH3; SDR/TPH3 (two bulk increments of 4 mm and two occlusal increments); and two bulk increments of 5 mm for POST. Data for P-Shr, T-Shr, E, DTS, and CS were analyzed by analysis of variance and Tukey’s test (α=0.05), and residual shrinkage was analyzed quantitatively and qualitatively by the modified von Mises criteria. Results: SDR had the lowest CS values, POST and TPH3 had similar and intermediate values, and Z350 had the highest CS. TPH3 and Z350 had similar DTS values and values higher than SDR. Z350 and POST had higher P-Shr, and SDR had lower T-Shr. T-Shr resulted in higher shrinkage stress than P-Shr values. SDR/TPH3 resulted in higher shrinkage stress when using T-Shr and lower values when using the P-Shr value. Conclusion: T-Shr resulted in higher stress in the enamel and in root dentin close to the pulp chamber than P-Shr values. The selection of the T-Shr or P-Shr changed the ranking of the shrinkage stress of the tested composite resin.

scholarly journals Influence of Post and Resin Cement on Stress Distribution of Maxillary Central Incisors Restored with Direct Resin Composite

10.2341/08-73 ◽  
2009 ◽  
Vol 34 (2) ◽  
pp. 223-229 ◽  
Author(s):  
A. O. Spazzin ◽  
D. Galafassi ◽  
A. D. de Meira-Júnior ◽  
R. Braz ◽  
C. A. Garbin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Resin Composite ◽  
Resin Cement ◽  
Zirconia Ceramic ◽  
Element Analysis ◽  
Fiber Posts ◽  
Stress Levels ◽  
Glass Fiber Posts

Clinical Relevance According to finite element analysis, the zirconia ceramic post created higher stress levels in the post and slightly less in dentin compared with glass fiber posts. Resin cement with a high elastic modulus created higher stress levels in the cement layer. The different film thicknesses of cement did not create significant changes in stress levels.

Yield Inception of a Coated Substrate Indented by a Rigid Sphere

2011 ◽  
Author(s):  
Wenping Song ◽  
Longqiu Li ◽  
Andrey Ovcharenko ◽  
Ding Jia ◽  
Guangyu Zhang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Yield Strength ◽  
Film Thickness ◽  
Young’S Modulus ◽  
Material Properties ◽  
Rigid Sphere ◽  
Element Analysis ◽  
Strong Function ◽  
Coated Substrate

Yield inception of a coated substrate indented by a rigid sphere is analyzed using finite element analysis. The critical interference is studied as a function of film thickness and material properties of both the film and the substrate. The results show that critical interference, corresponding to yield inception of the coated substrate, is a strong function of the film thickness, the Young’s modulus, and the yield strength of both the film and the substrate.

scholarly journals Effect of Resin Cement Porosity on Retention of Glass-Fiber Posts to Root Dentin: An Experimental and Finite Element Analysis

2015 ◽  
Vol 26 (6) ◽  
pp. 630-636 ◽  
Author(s):  
Natércia Rezende da Silva ◽  
Grazielle Crystine Rodrigues Aguiar ◽  
Monise de Paula Rodrigues ◽  
Aline Aredes Bicalho ◽  
Priscilla Barbosa Ferreira Soares ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Confocal Microscopy ◽  
Stress Distribution ◽  
Resin Cement ◽  
Element Analysis ◽  
Adhesive Resin ◽  
Fiber Posts ◽  
Root Dentin ◽  
Push Out

The aim of this study was to evaluate the effect of porosity of self-adhesive resin on the stress distribution, post retention and failure mode of fiber post cemented to human root dentin. Ten human central upper incisors with circular root canal were selected. They were sectioned with 15 mm and were endodontically filled. The roots were scanned using micro-CT after post space preparation for root filling remaining evaluation. Fiber posts were cemented using self-adhesive resin cement (Rely X U200, 3M-ESPE). Two 1-mm-thick slices from the cervical, medium and apical thirds were scanned for resin cement bubbles volume measurements and submitted to a push-out test (PBS). Three operators using stereomicroscopy and confocal laser microscopy classified the failure mode. Stress distributions during the push-out test were analyzed using 3D finite element analysis. PBS values (MPa) were submitted to one-way ANOVA and Tukey's post hoc tests and the failure modes using the Kappa coefficient to assess inter-operator agreement. Chi-square test was used to determine significant differences between the methods ( = 0.05). Push-out bond strength was significantly affected by the bubbles presence in all root depth (p<0.05). The stress concentration was higher when the bubbles were present. Adhesive dentin/resin cement interface failure was the most frequent type of failure. Confocal microscopy was better than stereomicroscopy for failure analysis. Bubbles generated during resin cement insertion into the root canal negatively affect the stress distribution and the bond strength. The use of confocal microscopy is recommended for failure analysis.

scholarly journals Durability Optimization of Fiber Grating Hydrogen Sensor Based on Residual Stress

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7657
Author(s):  
Wenbo Ma ◽  
Yuyang Li ◽  
Ning Yang ◽  
Li Fan ◽  
Yanli Chen ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optical Fiber ◽  
Film Thickness ◽  
Equivalent Stress ◽  
Hydrogen Sensor ◽  
Fiber Grating ◽  
Durability Test ◽  
Element Analysis ◽  
The Times

In this paper, in order to improve the durability of optical fiber grating hydrogen sensors, an optical fiber grating hydrogen sensor with high precision, stability, and durability is prepared. Based on the simplified two-dimensional model and finite element analysis, the effects of film thickness, coating speed, and coating times on the residual Mises equivalent stress between the sensor film and substrate were studied, and the optimum coating parameters were determined. The finite element analysis results show that the residual equivalent stress between the film and the substrate increases with the increase in the film thickness between 50 and 150 nm. The range of 200–250 nm is relatively stable, and the value is small. The coating speed has almost no effect on the residual equivalent stress. When the thickness of the film is 200 nm, the residual equivalent stress decreases with the increase in coating times, and the equivalent force is the lowest when the film is coated three times. The best coating parameters are the thickness of 200 nm, the speed of 62.5 μm/s, and the times of coating three times. The results of finite element analysis are verified by the hydrogen sensitivity test and durability test.

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