Effects of the passive self-ligating system on alveolar bone thickness, dental inclinations, and arch dimensions

We aimed to evaluate changes in buccal bone thickness (BBT), buccolingual dental inclinations (BLI), and transversal widths (TW) after treatment using a passive self-ligating system.

Pre- and posttreatment cone-beam computed tomography images (CBCT) of 21 Class I patients (initial mean age: 14.99 ± 1.27 years; initial crowding of at least 4mm) treated without extractions using passive self-ligating appliances were evaluated. Buccal bone thickness, dental inclinations, and transversal widths were measured, and their changes were compared using paired t-test. The associations were assessed using the Pearson correlation coefficient.

BBT showed statistically significant decreases in both arches, mainly for the posterior teeth. Most teeth were proclinated after treatment, with more buccal tipping occurring for the anterior teeth and second premolars in both arches. The results demonstrated significant increases in maxillary and mandibular TW, except for maxillary intercanine distance. Negative correlations between BBT and buccal inclination were observed for the maxillary right lateral incisor, maxillary left second premolar, right mandibular canine, and between BBT and TW for the maxillary left second premolar. A positive association was observed between BBT and TW only for the mandibular right first premolar.

In general, the treatment with passive self-ligating system showed an expansion of the dental arches followed by a decrease in BBT, probably caused by buccal inclination in both arches. Key words:Orthodontic Brackets, Cone-Beam Computed Tomography, Periodontium, Orthodontics.