Comparison of Shear Bond Strength of Orthodontic Brackets Bonded to Enamel Prepared by Er: Yag Laser and Conventional Acid Etching Technique-An in-Vitro Study

Abstract

Background: Brackets are one of the important components in orthodontic treatment which helps in transferring forces to the teeth to appreciate teeth movement. So, it is very important to have a better bond strength between brackets and teeth which can be achieved by different materials and techniques. Initially, etching (surface preparation) was done on the surface of the teeth by acid (37% phosphoric acid) to bond brackets directly to the teeth. Later with the introduction of lasers, surface preparation was done using Er: YAG laser which was considered as an alternative and better technique when compared with the conventional acid technique. Objective: To compare the differences in shear bond strength of orthodontic brackets bonded to enamel prepared by Er: Yag laser and conventional acid etching technique. Results: The shear bond strength of the acid group showed the least bond strength. ARI Index shows that group 3 laser etched group had major bond failure at favorable site with most number of score value between score1 to 3. ARI Index of group A & B showed most number of score value between score4 to 5 with major bond failure at unfavorable site. Conclusion: ANOVA and Chi-square test revealed statistically significant difference between 3 different groups on assessing the SBS and ARI Index. Group C (laser etched group at W. 1mJ & 10Hz) showed better bond strength at a clinically acceptable level and also had major bond failure at favorable site which produces least damage to the enamel surface. Group B laser etched group even though had higher bond strength of 15.95 MPa, their value highly deviates from the clinically required level of 8Mpa.