Comparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses

Background Porcelain fracture or chipping in metal-ceramic fixed dental prostheses (FDPs) is a frequent clinical complication, necessitating reliable repair strategies. Direct intraoral and indirect laboratory-based repair systems represent the two principal approaches, yet their comparative performance remains incompletely characterized. Objectives To evaluate and compare shear bond strength, surface roughness, and time efficiency of direct intraoral and indirect porcelain repair systems in metal-ceramic FDPs under controlled in-vitro conditions. Materials and Methods Eighty-eight standardized nickel-chromium/porcelain disc specimens were fabricated and divided equally into two groups: Group I (Direct Intraoral Repair) and Group II (Indirect Porcelain Repair). A standardized 2 mm defect was introduced in each specimen. Shear bond strength was measured using a Universal Testing Machine (UNITEK 94100), surface roughness (Ra) was assessed with a profilometer, and procedure time was recorded with a stopwatch. Statistical analysis employed independent t-tests, one-way ANOVA, and the Mann-Whitney U test (α = 0.05). Results The indirect repair system demonstrated significantly higher mean shear bond strength (21.77 ± 1.38 MPa) compared to the direct system (18.49 ± 1.55 MPa) (p < 0.001). Surface roughness was comparable between groups (Direct: 0.801 µm; Indirect: 0.815 µm; p = 0.860). Direct repairs were substantially faster (mean: 13.41 min) than indirect repairs (mean: 50.11 min) (p < 0.001). All failures were adhesive in nature. Conclusion Indirect porcelain repair systems provide superior bond strength and are recommended for extensive or high-stress fractures. Direct intraoral systems offer a time-efficient, clinically viable alternative for minor fractures. The choice of technique should be guided by fracture extent, functional demands, and clinical circumstances.