Effect of various porcelain surface treatment methods on shear bond strength of orthodontic adhesive

Abstract

Objective: to evaluate the effect of different treatment methods of porcelain surfaces before bonding on the shear bond strength of orthodontic adhesive. Material and methods: This study was conducted on a sample of sixty feldspathic porcelain cylinders stored in artificial saliva for a week. The sample was divided into five equal groups twelve each according to the applied surface treatment, Gp1 diamond bur roughening, and Gp2 etching 37% phosphoric acid GP3 Laser etching Gp4 9% hydrofluoric acid etching Gp5 sandblasting 50 micron aluminum oxide particles. Randomly one specimen from each group was scanned by electron microscope while the other specimens were bonded to metal brackets and stored in artificial saliva for one week then mounted in acrylic blocks to allow measuring the shear bond strength using Instron universal testing machine. Results: Diamond bur group showed significant difference with all other groups. There is significant difference between phosphoric acid and laser on one hand and sand blasting and hydrofluoric on the other hand. But for both phosphoric acid and laser groups there is no significant difference and for both sand blasting and Volume 50 -December 2016 hydrofluoric acid groups there is no significant difference. Conclusion: The diamond bur group showed the highest bond strength, while phosphoric acid showed the least one.