Elsevier

The Journal of Prosthetic Dentistry

Volume 124, Issue 6, December 2020, Pages 800.e1-800.e7
The Journal of Prosthetic Dentistry

Research and Education
Flexural strength of CAD-CAM and conventional interim resin materials with a surface sealant

https://doi.org/10.1016/j.prosdent.2020.09.004Get rights and content

Abstract

Statement of problem

The flexural strength of computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional interim resin materials when they are used with a surface sealant is unclear.

Purpose

The purpose of this in vitro study was to evaluate the flexural strength of different CAD-CAM polymethyl methacrylate (PMMA)-based polymers and conventional interim resin materials, autopolymerized bisacrylate composite resin and polyethyl methacrylate (PEMA) with and without a surface sealant after thermocycling.

Material and methods

Fourteen rectangular-shaped specimens (25×2×2 mm) were fabricated from 5 different interim resin materials, 3 different CAD-CAM PMMA-based polymers: Polident-PMMA, Telio CAD, M-PM-Disc; 2 different conventional interim resin materials, and 1 autopolymerized bisacrylate composite resin: Acyrtemp and 1 PEMA resin: Bosworth Trim according to ISO 10477:2018. Two different types of surface treatments (n=7), conventional polishing and surface sealant application, were applied to 1 surface of the specimens. Ten thousand thermocycles were applied in distilled water for all specimens (5 °C and 55 °C). A 3-point bend test was used to measure the flexural strength of specimens in a universal testing device at a 1 mm/min crosshead speed. The flexural strength data (σ) were calculated in megapascals (MPa) and analyzed by using a 2-way ANOVA. Post hoc pairwise comparisons and independent t test analysis were done (α=.05).

Results

According to the 2-way ANOVA, material type (P<.001) significantly affected the flexural strength. Surface treatment type (P=.818) had no significant effect on flexural strength, and no significant interaction was found between material type and surface treatment type (P=.111). CAD-CAM PMMA-based polymers had significantly higher flexural strength than the conventional interim resin materials. However, no significant difference was found within groups of the same type. Also, no significant difference was found in flexural strength values between the conventional polishing and surface sealant groups within each interim resin material (P≥.162).

Conclusions

The flexural strength of CAD-CAM PMMA-based polymers was higher than the flexural strength of conventional bisacrylate composite resin and PEMA interim resin materials after thermocycling. The surface treatment type (conventional polishing and surface sealant application) was not found to affect the flexural strength of CAD-CAM PMMA-based polymers, conventional bisacrylate composite resin, or PEMA interim resin materials.

Section snippets

Material and methods

The materials used in this study are listed in Table 1. Rectangular (25×2×2 mm) specimens were fabricated from each material (n=14) according to ISO 10477:2018 (Dentistry-polymer-based crown and veneering materials).37 For the fabrication of CAD-CAM PMMA-based polymer specimens, a rectangular-shaped plate (25×2×thickness [h] mm) was digitally designed by using a software program (Dental System Software; 3Shape A/S), converted to a standard tessellation language (STL) file, and wet-milled (M1

Results

The means and 95% confidence limits for FS values of different IR materials and both surface treatment groups are presented in Figure 1. According to the 2-way analysis of variance (Table 2), only material type (P<.001) significantly affected the FS. The surface treatment type (P=.818) had no significant effect on the FS, and no significant interaction was found between material type and surface treatment type (P=.111). A plot of the interaction between the surface treatment type and the

Discussion

The first null hypothesis that the FS of different IR materials would not differ with and without the surface sealant was rejected because material type significantly affected the FS (P<.001). CAD-CAM PMMA-based polymers reported significantly higher FS than the conventional IR materials (P<.001). The effect of material type was significant, which was an indicator of the statistical power of the study design that enabled the detection of the significant differences. The FS was similar among PD,

Conclusions

Based on the findings of this in vitro study, the following conclusions were drawn:

  • 1.

    The FS of CAD-CAM PMMA-based polymers was higher than the FS of conventional bisacrylate composite resin and PEMA IR materials.

  • 2.

    The FS was similar among tested CAD-CAM PMMA-based polymers and between conventional bisacrylate composite resin and PEMA IR materials.

  • 3.

    The surface treatment type (CP and SS) was not found to affect the FS of CAD-CAM PMMA-based polymers, conventional bisacrylate composite resin, or PEMA IR

Acknowledgments

The authors thank Merz Dental GmbH for supplying the materials used in this study. This research was conducted when Dr Çakmak was a Visiting Professor to The Ohio State University.

CRediT authorship contribution statement

Gülce Çakmak: Conceptualization, Methodology, Investigation, Writing - original draft, Funding acquisition. Hakan Yilmaz: Formal analysis, Validation, Data curation. Özge Aydoğ: Resources, Writing - original draft, Funding acquisition. Burak Yilmaz: Conceptualization, Writing - review & editing, Supervision.

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