[Evaluation of shear bond strength of composite to feldspathic porcelain after porcelain surface treatment with CO2 and Er:YAG lasers]

ABSTRACT

Fractured ceramic crowns can sometimes be repaired with composite resin. The aim of the current study was to determine the shear bond strength of composite to Feld spathic porcelain after CO[2] and ErYAG laser porcelain surface preparation. In this in-vitro study, 36 Feldspathic porcelain blocksmeasuring 1*10*10 mm were divided into 3 groups of 12. Porcelain surfaces in the first and second groups were treated with 1.8W CO[2] laser and 5W ErYAG laser irradiation, respectively. Third group specimens were subjected to 9.5% hydrofluoric acid surface conditioning. All groups received application of silane and adhesive after wards. A composite cylinder with 3.5 mm diameter and 5 mm height was bonded to specimens. In order to evaluate the shear bond strength, a Universal Testing Machine with crosshead 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. 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 test demonstrated significant differences between the first and third groups [P= 0.000] as well as the second and third groups [P=0.000]. However, no significant difference was detected between the first and second groups [P =0.778]. Considering the study results, CO[2] or ErYAG laser irradiation is not suggested as an appropriate alternative to hydrofluoric acid for surface preparation of Feld spathic porcelain