Dental arch dimensional changes in deep bite adults treated with orthodontic fixed appliances in conjunction with maxillary incisor vs. canine bite turbos during the levelling and aligning phase: a randomized clinical trial

Introduction This randomized clinical trial compared arch dimensional changes, dentoskeletal changes, and the rate of overbite correction in deep bite adults treated with fixed appliances and either maxillary incisor bite turbos (IBT) or canine bite turbos (CBT). Materials and methods Forty-six deep bite subjects treated with fixed appliances were randomized into IBT (n = 23) and CBT (n = 23) groups. Changes in intercanine width (ICW), arch height (AH), and Little’s Irregularity Index (LII) were analyzed from before treatment (T 0 ) to 3 months after aligning with 0.012” NiTi archwires in both arches (T 1 ). Cephalometric changes between T 0 and the visit when normal overbite was achieved (T 2 ) were assessed. Within-group and between-group comparisons were analyzed at a significance level of 0.05. Results In both groups, mandibular ICW, and maxillary and mandibular AH significantly increased while maxillary and mandibular LII decreased. Maxillary and mandibular incisor proclination and molar extrusion were observed. The IBT group showed significantly greater changes in mandibular ICW, maxillary and mandibular AH, and mandibular incisor proclination than the CBT group. However, the overbite correction rate and the LII reduction were not significantly different between the groups. Conclusions The IBT and CBT produced similar effects on arch dimensions and dentoskeletal changes. However, the IBT group demonstrated greater arch dimensional changes. Clinical relevance Clinicians may consider IBT if flaring incisors is desired. Alternatively, CBT is better for cases with limited incisor proclination and where minimizing arch dimension change is needed, such as in narrow ridge situations. Clinical trial registration The trial was registered at Thai Clinical Trial Registry on https://www.thaiclinicaltrials.org , under the identifier TCTR20230811013.