A number of laboratory studies have shown very low levels of archwire friction for self-ligating brackets when compared to conventional ligation methods. However, justifiable reservations have been expressed as to the in vivo relevance of these findings. This study was designed to compare treatment efficiency with conventional fully programmed brackets and Damon SL self-ligating brackets. Thirty consecutively finished cases treated by the author with Damon SL brackets were compared with 30 matched cases treated by the author with conventional brackets. Parallel studies quantified the incidence of technical problems with Damon SL brackets and with conventional ligatures and also the chairside time required for ligation/slide closure and ligature removal/slide opening with these two bracket types. The Damon SL cases required an average of four fewer months and four fewer visits to be treated to an equivalent level of occlusal regularity as measured by the PAR scores.