Comparative evaluation of effect of heat treatment of three different types of lingual retainer wires on their shear bond strength an in-vitro study

Aim: To evaluate and compare the shear bond strength of three different lingual retainer wires before and after heat treatment. Materials and Methods: A total of 120 human extracted premolar teeth were mounted in pairs and 60 blocks were made and divided into 6 groups (n=10) and colour coded. Retainer wires used were Orthodirect Braided retainer wire TM (0.016” x 0.022”), Modern Co-axial wireTM (0.0175”) and Custom-made twisted Stainless-steel ligature wire (0.010”) of 10 mm length on each specimen. Piezo gas burner was used for heat treatment of the retainer wires. Three groups were boned with as manufactured retainer wires and other three groups were bonded with heat treated wires using Tetric-N-Flow flowable composite. After storage in artificial saliva for 24 h, the samples were subjected to shear bond strength test at a speed of 1 mm/min until debonding of retainer to determine shear bond strength in Newtons. Data were analyzed using the one-way ANOVA. Results: The result demonstrated that there was significant difference in shear bond strength of Co-axial retainer wire after heat treatment while non-significant difference for Orthodirect Braided retainer wire and Custom-made twisted Stainless-steel ligature wire. The mean shear bond strength of as manufactured Custom-made stainless-steel twisted ligature wire was found to be the highest. Conclusion: The finding of this investigation indicates that coaxial wire after heat treatment and as manufactured custom-made stainless-steel twisted ligature wire might be better retained on the teeth and would provide the efficient result.