Dimensional evaluation of metallic brackets slots

Abstract

The aim of this study was to evaluate the dimensions of height and depth of the metallic bracket slots of different alloys and manufacturing processes as well as to verify if there are differences between them and the amount disclosed by the manufacturer. The heights and depths of slots of 45 metal brackets from 9 types were evaluated by an Universal Measurement Optical Microscope (RBC Mitutoyo) increased 5X, 20 ± 0.5ºC and 55% ± 10% of relative humidity. Means and standard deviations of the heights and depths of slots of brackets in each group were obtained. The difference between the average size and the announced by the manufacturer was calculated and converted into percentage. The dimensions of the slots were higher than the ones showed by the manufacturer with a variation from 1.82% to 10.91% height and from 8.21% to 49% depth, except those of group 5 (stainless steel, light series, injection molding, American Orthodontics) that showed 0.4%, which was inferior in relation to what was presented. It is concluded that the real dimension of the metallic brackets slot tested is greater than that presented by the manufacturer. Key words: Orthodontics. Corrective orthontics. Orthodontic brackets.