Comparing Marginal Gap and Flexural Strength Between Additive and Subtractive Manufactured Provisional and Permanent Crown Materials
Abstract
Purpose: The purpose of this study was to compare the flexural strength, Weibull reliability, marginal gap, and internal discrepancy amongst different types of provisional and permanent crown materials fabricated using additive and subtractive manufacturing processes. Materials and Methods: IPS e.max CAD (EC) and Paradigm MZ100 (PM) for subtractive manufacturing, and FormLabs Permanent Crown (PCR) and Temporary CB (TCR) resins for additive manufacturing were investigated. Flexural strength was tested using sectioned bars (1.3 x 4 x 18 mm) for EC and PM, and printed bars for PCR and TCR (n = 15 per material). The EC bars were crystallized. All bars were polished and subjected to a 3-point bend test using a universal testing machine (Instron E3000). Additionally, a mandibular left first molar typodont tooth was prepared, optically scanned, designed, and crowns were milled (in EC and PM) and 3D-printed (in PCR and TCR) (n = 5 per material). Marginal gap and internal discrepancy were measured using micro-computed tomography (SkyScan 1172). Weibull modulus and characteristic strength were computed per group. Flexural strength and marginal discrepancy data was analyzed with t-test and compared using one-way ANOVA with Tukey HSD post-hoc comparisons (alpha = 0.05). Results: Flexural strengths were significantly different between sectioned (EC and PM) and printed (PCR and TCR) bars. Mean flexural strength (MPa) in descending order were EC =335.50 + or - 28.97, PM = 154.34 + or - 21.03, PCR = 128.09 + or - 7.30, and TCR = 126.29 + or - 9.23. One-way ANOVA revealed significant differences amongst EC, PM, and the 3-D printed groups (F =426.460, p < 0.001). No statistically significant difference in flexural strength was observed between PCR and TCR. For the Weibull modulus, PCR (21.07) presented with the highest modulus followed by EC (13.70), TCR (16.52). PM (8.77) resulted in the lowest modulus indicating its poor reliability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2023
- Accession Number
- AD1222336
Entities
People
- Matthew H. Firestone
Organizations
- Uniformed Services University of the Health Sciences