Frictional resistance of four self-ligating metallic brackets in combination with two diameters of stainless steel archwires

Aim: This study was conducted to evaluate and compare the dynamic frictional resistance of stainless steel archwires in combination with 4 types of self ligating brackets (IOS ,3 M, American and Damon Q, brackets).
Materials and methods : The sample of the study included forty eight pre-adjusted brackets for maxillary right canine (Roth prescription) with 0.022 × 0.028 inch slot. The sample was divided into eight groups, each one included six brackets. Groups 1 and 2 were IOS brackets, groups 3 and 4 were 3 M brackets, group 5 and 6 were American Orthodontics brackets while groups7 and 8 were Damon Q brackets .Groups 1, 3,5 and 7 were tested in combination with 0.016x0.022 inch diameter stainless steel arch wires while , groups 2, 4 ,6 and 8 tested in combination with 0.018 inch stainless steel arch wires. Universal testing machine with a new design simulating the oral cavity were used. The statistical mean and standard deviation of the kinetic frictional of eight groups were calculated to evaluate the significant difference between the groups during canine retraction.
Essential results : showed that IOS brackets using 0.016x0.022 stainless steel arch wire produced the highest frictional force followed by 3M brackets in combination with 0.016x0.22 archwire while the Damon Q brackets using 0.018 stainless steel brackets produced least frictional force.
Conclusions : Rectangular stainless steel archwires produced higher frictional resistance with all bracket types than the round ones. Damon Q brackets with round archwire produced the least frictional resistance.