Pressable Glass Ceramic as a Repair Material for Fractures in Metal-Ceramic Restorations

Porcelain repair of fractured metal-ceramic restorations is a common challenge in the dental field. The current study introduces a novel technique for intraoral repair of porcelain fracture utilizing pressable glass ceramic (GC) as the repair material. The shear bond strength (SBS) of GC to different components of the metal-ceramic restoration (metal, porcelain, and metal-porcelain combination) under different surface treatments was also evaluated. The SBS was tested under the following five surface treatments: control, sandblasted with silica, sandblasted with silica then glow-discharge-treated, sandblasted with alumina, and sandblasted with alumina then etched with hydrofluoric acid. A self-adhesive resin cement and silane were used for bonding. Surface roughness was evaluated before and after each treatment. One-way ANOVA and post-hock Tukey's tests were used for data analysis. The results showed that SBS of GC to all surface-treated substrata ranging from 37 to 55MPa was significantly higher than that of untreated surfaces ranging from 10 to 26MPa. For all bonded surfaces, blasting with silica showed higher bond strength than blasting with alumina. On the contrary, alumina groups showed higher surface roughness than silica groups. Pressable glass ceramic in conjunction with all tested surface treatments, especially silica blasting, can be used successfully for fractured porcelain repair.