Enhancing dental porcelain repair strength: the impact of chairside plasma surface treatment-an in vitro study.

Abstract

The success of intraoral repair for fractured porcelain restorations has been questioned for many years. The longevity of the repaired restoration should be extended with effective methods that provide more sustainable clinical success. This study aimed to evaluate the effect of chairside plasma surface treatment on dental porcelain repair bond strength. Five hundred-fifteen rectangular specimens (12 × 14 × 1 mm) were fabricated from Cr-Co metal alloy (M) by lost wax technique, from zirconia (Z) and feldspathic (F) ceramic using the precision cutting device from CAD-CAM blocks. Specimens were pre-aged with 10,000 thermocycles to simulate intraoral conditions, and then divided into twenty-three subgroups: No treatment (M0, Z0, F0 groups/N = 45, n = 15), only plasma (MP, ZP, FP groups /N = 75, n = 25), only tribochemical silica coating via CoJet (MC, ZC groups/N = 30, n = 15), only hydrofluoric acid for feldspathic ceramic (FA group/n = 15), bonding agent (MB, ZB, FA groups /N = 75, n = 25), and their combinations (MCB, MCP, MPB, MCPB, ZCB, ZCP, ZPB, ZCPB, FPB, FAP, FAPB groups/N = 275, n = 25). Surface roughness (n = 10/per group), contact angle (n = 5/per group), shear bond strength (n = 10/per group), and failure modes (n = 10/per group) were evaluated. Statistical analyses were performed with a two-way analysis of variance at a significance level of α = 0.05. According to the results, plasma surface treatment increased the wettability of the materials without affecting surface roughness. When plasma was applied before the bonding agent, shear bond strength values were significantly improved (p < 0.001). The effectiveness of plasma and tribochemical silica coating was similar for zirconia (p = 0.960) and metal alloy substructures (p = 0.219). The MCPB, ZCPB, and FAPB groups had the highest bonding values within their main material groups (p < 0.001). Conclusively, chairside plasma surface treatment significantly enhances the shear bond strength of the repair material applied to the Cr-Co alloy, zirconia, and feldspathic ceramics without changing the surface roughness. It cannot replace HF acid or bonding agents, but it can serve as a substitute for tribochemical silica coating for dental porcelain repair procedures.