The effect of different surface treatments, ultrasonic vibration and light direction on bond strength and microleakage of laminate veneers

The most common problems of the laminate veneers are connection failure and microleakage. The purpose of this study is to evaluate the effect of different surface roughening methods, the application of ultrasonic vibrations during bonding and change the direction of the light used for the polymerization on connection strength and microleakage of laminate veneers. 32 bovine lower central incisor tooth are tapered lingual surfaces which will fit the human central incisor. The buccal surfaces abraded straightly within the limits of the enamel and 0.8 mm thick resin nano ceramic laminate veneers are bonded with light-cured resin cement. 37% orthophosphoric acid and Er: YAG laser roughened separately in a standard way half of the teeth during bonding ultrasonic vibration applied to the other half did not apply. To start the polymerization, for the half of ultrasonic vibration and non-ultrasonic vibration groups light was applied from buccal, for the other half applied from lingual. Microshear test was used to evaluate bond strength, dye penetration method was used to evaluate microleakage. Datas were analyzed by ANOVA and DUNCAN statistical tests. Bond strength and microleakage values compared by methods etching, bonding, and effect of light direction were statistically significant (p<0,05). The highest values of bond strength test were found in acid etching, bonding with ultrasonic vibration, light from the lingual aspect in groups, the lowest values of bond strength test were found in laser etching, normal bonding, light from the buccal aspect groups. The lowest values of microleakage test were found in acid etching, bonding with ultrasonic vibration, light from the lingual aspect groups, the highest values of microleakage test were found in laser etching, normal bonding, light from the buccal aspect groups. As a result, the clinical use of these methods is expected to increase the success of the restoration. Keywords: direction of Light, the beef out of the enamel, the ultrasonic vibration, the Er:YAG laser roughening with micro-scissors