Assessment of slot sizes in self-ligating brackets using electron microscopy.

Objective: To measure the slot dimensions of 0.022 inch self-ligating upper central incisor brackets from six manufacturers using electron microscopy, to compare the measured dimensions with the manufacturers' published dimensions, and to determine if the walls of the slots were parallel.

Materials: Six self-ligating upper central incisor brackets from four manufacturers (SmartClip and Clarity SL, 3M Unitek, Monrovia, CA, USA; Speed, Strite Industries Ontario, Canada; Damon MX, Ormco, Orange, CA, USA; In-Ovation R and In-Ovation C, Dentsply GAC, Bohemia NY, USA) were imaged with a scanning electron microscope and the slots heights measured.