ABSTRACT
Ligating between brackets and orthodontic wire is considered one of the important factor affecting the frictional resistance during sliding movements. For these reasons this investigation aimed to compare the friction associating with sliding movement for two types of brackets: self-ligating brackets and conventional brackets ; along stainless steel arch wires. 40 first upper premolar brackets made from stainless steel were tested, 20 of them were self-ligating brackets [Quick brackets] and the rest were conventional [Sprint brackets] with elasting ligature; all of the 40 brackets were tested with two different sizes of stainless steel wires. The frictional resistance was recorded during the tests by instron machine designed specially for this reason. The results showed significant decrease in the magnitude of friction with the self-ligating brackets compared with the conventional one; whatever the orthodontic wire using in the test. This study recommend the importantance of choose the proper type of brackets and the used technique for each orthodontic treatment; and suggest the need of more scientific investigations aiming to know the frictional property of modern types of brackets in the markets