Effect of Silane Heat Treatment by Laser on the Bond Strength of a Repair Composite to Feldspathic Porcelain

Purpose Ceramic restoration fracture may occur in the oral cavity. Intraoral repair of fractured porcelain could be advantageous to both patient and dentist. The aim of this study was to evaluate the effect of heat treatment of the silane coupling agent by Er:YAG and CO2 lasers on the microshear bond strength of a repair composite to feldspathic porcelain. Materials and Methods Sixty ceramic blocks were prepared and randomly divided into six groups (n = 10): (i) HF + silane (HS); (ii) silane + CO2 laser (SC); (iii) CO2 laser + silane (CS); (iv) silane + Er:YAG laser (SE); (v) Er:YAG laser + silane (ES); (vi) bur + HF + silane (BuHS). An adhesive resin was applied to the prepared ceramic surfaces and light-cured. Two transparent plastic tubes were placed perpendicularly to each ceramic block. The composite resin was then placed on the treated ceramic surface and light-cured for 40 seconds. The bonded blocks were stored in distilled water at 37 degrees C for 24 hours and subjected to 3000 thermocycles. Microshear bond strength (mu SBS) tests were performed using a wire and loop method. Data were analyzed using one-way ANOVA and Duncan's multiple range tests (p <= 0.05). Results The comparison of the mean mu SBS values showed no significant differences between the ES and HS groups (p = 0.914). On the other hand, the specimens in these groups exhibited significantly higher bond strengths than those in the other groups (p < 0.01). The mean mu SBS of the BuHS group was statistically similar to that of CS and SE groups (p > 0.05). The mu SBS for the SC group was significantly lower than that of the other groups (p < 0.01), with the exception of the CS group (p = 0.674). Conclusions Treatment with Er:YAG laser prior to silane application can be as effective as HF etching. Heat treatment of silane by CO2 or Er:YAG lasers does not improve the bond strength between feldspathic porcelain and composite resin.