In Vitro Analysis of Shear Bond Strength in Repaired Cohesive and Adhesive Fractures of Conventional and DMLS Porcelain-fused-to-metal Crowns.

Abstract

Aim: Porcelain-fused-to-metal (PFM) restorations are essential in fixed prosthodontics for their strength and esthetics, but are prone to fractures due to material disparities and stress factors. This study evaluates the shear bond strength (SBS) of two porcelain repair systems for cohesive and adhesive fractures in conventional PFM and direct metal laser-sintered (DMLS) restorations, addressing clinical repair needs.

Materials and methods: Thirty metal-ceramic discs were fabricated and divided into two main groups based on the fabrication method: Conventional casting and DMLS. Each group had three subgroups: Conventional casting (A: Control, B: Cohesive defect, C: Adhesive defect) and DMLS (D: Control, E: Cohesive defect, F: Adhesive defect), each with 5 specimens. Shear bond strength was measured using a Universal Testing Machine (UTM) at 0.5 mm/min. Data were analyzed with a one-way ANOVA (α = 0.05), and Tukey's post hoc test was used for significant differences. Student's t-tests compared SBS between control groups.

Results: A one-way ANOVA revealed significant differences in SBS among Conventional Casting subgroups (p < 0.001). Subgroup A (36.282 ± 1.692 MPa) had higher SBS than B (13.202 ± 1.336 MPa) and C (17.033 ± 1.634 MPa), with Tukey's test confirming significant differences (p < 0.001). For DMLS subgroups, subgroup D (37.768 ± 0.560 MPa) had higher SBS than E (22.381 ± 1.137 MPa) and F (13.245 ± 0.693 MPa), with Tukey's test showing significant differences (p < 0.001). No significant difference was found between subgroups A and D (p = 0.10). Subgroup E had a higher SBS than B (p < 0.001), and subgroup C had a higher SBS than F (p = 0.001).

Conclusion: This study offers insights into the performance of two porcelain repair systems, aiding clinicians in selecting effective materials and techniques for PFM restoration repairs.

Clinical significance: Understanding the bond strength of these repair systems can enhance clinical outcomes by guiding the selection of optimal repair materials and techniques, improving the longevity and durability of fractured PFM restorations. How to cite this article: Irissan R, Mohan A, Augustine C, et al. In Vitro Analysis of Shear Bond Strength in Repaired Cohesive and Adhesive Fractures of Conventional and DMLS Porcelain-fused-to-metal Crowns. J Contemp Dent Pract 2024;25(8):726-731.