Abstract :
Background: The aim of this study is to determine whether bonding of stainless steel orthodontic brackets to tooth enamel prepared by laser etching would result in a similar bonding capability as those prepared by acid etching using 37 % phosphoric acid; and also to compare the shear bond strength.
Materials and Methods: Eighty four samples were prepared for the study. The 4 groups were Group 1-The enamel was etched with 37 % phosphoric acid, Group 2- Er: YAG laser etching was done at 1W power output, Group 3- Er: YAG laser etching was done at 2W power output and Group 4- Er:YAG laser etching was done at 3W power output. All groups have 20 teeth for shear bond strength testing and one tooth for SEM evaluation. Shear bond strength testing was performed on all teeth using Instron universal testing machine.
Results: Analysis of the variance indicated a significant difference (P < 0>Conclusion: The results showed that at that laser etching at 2 W to the tooth surface for 15 seconds
had statistically significant higher shear bond strength in comparison to conventional 37% phosphoric acid technique. The use of increasing the laser power output more than 2 W did not significantly increase the bond strength. The shear bond strength of all the three Laser etched groups was clinically acceptable. Enamel etching with Er: YAG Laser (2W for 15 seconds) produced maximum bond strength than acid etching and could be a viable alternative method.
Keyword :
Lasers erbium yttrium - aluminum garnet (Er YAG) acid etching, Shear bond strength (SBS), Universal Testing Machine (Instron)