Comparative Study for Evaluating the Effectiveness of Two Different Cleaning Methods for Ceramic Veneers Debonded With Er:YAG and Intended for Rebonding

Abstract

Objective: To compare the effectiveness of two cleaning methods -heating at 454ºC for 10 minutes and at 650ºC for 1 minute- each followed by sandblasting for rebonding debonded ceramic veneers.

Materials and methods: Twenty extracted permanent human maxillary central incisors were randomly divided into two groups (n=10). All teath were prepared to receive lithium disilicate veneers. The surfaces of the veneers in the first group were treated with hydrofluoric acid, while in the second group were treated with Er:YAG laser. After bonding, all veneers were debonded using Er:YAG laser. Each group was subdivided based on cleaning methods: heating at 454ºC (10 min) or 650ºC (1 min), followed by sandblasting. Veneer surfaces were examined under stereomicroscope and scanning electron microscope (SEM).

Results: Stereomicroscope examination revealed complete removal of resin cement in all samples. SEM analysis confirmed the absence of residual resin cement and showed no evidence of cracks in the ceramic structure.

Conclusion: Both heating protocols, followed by sandblasting, are effective in completely removing resin cement from the internal surfaces of lithium disilicate veneers making them suitable for rebonding.