PHOTOMEDICINE AND LASER SURGERY, vol.29, no.3, pp.197-203, 2011 (SCI-Expanded)
Objective: The purpose of this study was to evaluate the microtensile bond strength of resin cement to a feldspathic ceramic after treating the surface with (a) hydrofluoric (HF) acid, (b) air abrasion, (c) Er:YAG laser irradiation, (d) Nd:YAG laser irradiation, and (e) HF acid etching after either air abrasion or laser irradiation. Background Data: It is unknown whether the laser application or its combination with another treatment method can be used as a tool to roughen the surface of a feldspathic ceramic in order to increase the bond strength between the resin cement and ceramic surface. Materials and Methods: Forty feldspathic ceramic blocks (Ceramco (TM)) were prepared and divided into eight equal groups (n=5) according to the following surface treatments: no treatment; etching with 9.5% HF acid; air abrasion with 50 mu m Al2O3; Er:YAG laser irradiation; Nd:YAG laser irradiation; air abrasion plus acid etching; Er:YAG laser plus acid etching; and Nd:YAG laser plus acid etching. After surface treatment, a silane-coupling agent and resin cement (Panavia F (TM)) were applied to each block. After storing for 24 h at 37 degrees C and thermocycling between 5 degrees C and 55 degrees C for 1000 cycles, the microtensile bond strength of each specimen was measured. Results: The highest bond strength was obtained from HF acid etching. HF acid etching after each laser irradiation significantly increased the bond strength (p < 0.05). However, HF acid etching after air abrasion decreased bond strength when compared to air abrasion alone. Conclusions: HF acid etching is the most effective surface treatment method for a feldspathic ceramic. However, laser irradiation with either the Er:YAG or Nd:YAG laser is not an adequate method for improving the bond strength of Panavia F. The laser application should be combined with HF acid etching.