Evaluation of Shear Bond Strength of Composite to Feldspathic Porcelain after Porcelain Surface Treatment with CO2 and Er:YAG lasers

بررسي استحكام پيوند برشي كامپوزيت به پرسلن فلدسپاتيك پس از آماده سازي سطح پرسلن با دو ليزر Co2 و Er:YAG

Abstract Background and Aim: Fractured ceramic crowns can sometimes be repaired with com-posite resin. The aim of the current study was to determine the shear bond strength of composite to feldspathic porcelain after CO2 and Er:YAG laser porcelain surface prepara-tion. Materials and Methods: In this in-vitro study, 36 feldspathic porcelain blocksmeasuring 1*10*10 mm were divided into 3 groups of 12. Porcelain surfacesinthe first and second groupswere treated with 1.8W CO2 laser and 5W Er:YAG laserirradiation, respectively. Third group specimens were subjected to 9.5% hydrofluoric acid surface conditioning. Allgroups received application ofsilane and adhesiveafterwards. A composite cylinder with 3.5 mm diameter and 5 mm height was bonded to specimens. In order to evaluate the shear bond strength,aUniversal Testing Machine withacrosshead speed of 1 mm/min was used. Statistical analysis was performed using one-way ANOVA and Tukey’s HSD test and P < 0.05 was considered statistically significant. Results: The mean shear bond strength values (MPa) were 13.03±2.57%, 12.02 ±3.4 and 19.23±4.62, for the first, second and third groups respectively. One-way ANOVA revealed a statistically significant difference in this respect between the three groups (P < 0.001). Tukey’s HSD testdemonstratedsignificant differences betweenthefirst and third groups (P= 0.000) as well as the second and third groups (P=0.000). However, no significant dif-ference was detected betweenthe first and second groups (P =0.778). Conclusion: Consideringthe study results, CO2or Er:YAG laser irradiationis not suggested as an appropriate alternative to hydrofluoric acid for surface preparationoffeldspathic porcelain. Key Words: Dental porcelain , laser , hydrofluoric acid , shear strength