Análise da resistência de união em novas cimentações de laminados cerâmicos após remoção com laser Er:YAG ou ponta diamantada

Abstract

The longevity of ceramic laminate veneers can be affected by several factors, which may necessitate their removal. With the advancement of minimally invasive approaches in restorative dentistry, the Er:YAG laser has gained prominence as an effective tool for clinical retreatments. In cases such as fractures, aesthetic alterations, poor adaptation, or patient dissatisfaction, the removal of previously placed ceramic veneers may be required. In such scenarios, laser-assisted removal enables controlled debonding of restorations without significantly compromising the underlying dental structure, allowing for the conservative and safe placement of new ceramic restorations in the same location. Although laser removal appears to be a promising technique to facilitate this process, its effects on tooth structure and influence on subsequent adhesive procedures have been under investigation. The objective of this in vitro study was to evaluate and analyze the bond strength of lithium disilicate ceramic veneers cemented onto bovine dentin, where the previous veneer had been removed using either an Er:YAG laser or a diamond bur. Thirty bovine incisor crowns were used and randomly divided into the following groups (n = 10): G1 – Cementation of ceramic veneer without prior removal (control); G2 – Cementation after veneer removal with Er:YAG laser; G3 – Cementation after veneer removal with a diamond bur. All veneers were bonded using a conventional adhesive system and light-cured resin cement. The veneers were removed following the protocol for each group, and new veneers of the same material were bonded using the same adhesive technique. Subsequently, shear bond strength testing and fracture pattern analysis were conducted. Data were analyzed using oneway ANOVA with a significance level of 0.05. No statistically significant difference in shear bond strength was found among the groups (F(2, 27) = 0.79; p = 0.466), and the predominant fracture pattern in all groups was cohesive (Type 3 – within the resin cement). These findings indicate that the method used for removing the previous ceramic veneer—either diamond bur or highpower laser—did not affect the bond strength of the newly bonded veneer.