Effect of surface preparation with Nd

Abstract

At present, one of the best methods to treat fractured ceramic restorations is to repair them with composite resins. Furthermore, one of the recently introduced techniques to prepare the porcelain surfaces is to apply laser beams to achieve a high-quality bond between the porcelain and composite resin. The aim of the present study was to evaluate the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin after surface preparation with Nd:YAG and Er,Cr:YSGG lasers. Materials and methods: A total of 102 lithium disilicate glass ceramic samples (IPS e.max Press), 5 mm in diameter and 4 mm in thickness were randomly divided into 6 groups (n=17): group 1: no surface preparation (control); group 2: acid etching with 9.5% hydrofluoric acid (HF); group 3: surface preparation with 4.5-W Nd:YAG laser; group 4: surface preparation with 6-W Nd:YAG laser; group 5: surface preparation with 1.5-W Er,Cr:YSGG laser; and group 6: surface preparation with 6-W Er,Cr:YSGG laser. After preparation of surfaces and application of silane, all the samples were repaired with a silorane-based composite resin, followed by storage in distilled water at 37C for 24 hours and thermocycling. Finally, the samples were subjected to a shearing bond strength test and the fracture modes were determined under stereomicroscope. Results: The differences between the HF group and the other groups were significant (P<0.001). Two-by-two comparison of the other groups did not reveal any significant differences (P>0.05). Conclusion: Use of HF proved the most effective surface preparation technique to increase the repair bond strength between lithium disilicate glass ceramic and silorane-based composite resin; application of Nd:YAG and Er,Cr:YSGG lasers did not increase the bond strength compared to the control group.