Mandibular asymmetry in young adult patients with unilateral posterior crossbite: A controlled retrospective CBCT study

Summary Objective This study aimed to evaluate the mandibular skeletal asymmetry in pre-orthodontic patients with the unilateral posterior dental crossbite (UPCB). Materials and methods Using a retrospective design, 30 pre-orthodontic patients with a UPCB, (16 on the right side, 14 on the left side), 18 females and 12 males were selected (mean age: 21.2 ± 4.92 years), along with 30 controls matched by age and sex with cl I occlusal relationship (mean age: 21.9 ± 4.80 years). The patients were from an Orthodontic Department of Dental Faculty of Hamadan University of Medical Sciences and a private office from 2009 to 2013. In the UPCB group, at least one molar tooth was in the crossbite position. All the patients had initial CBCT 1 and pre-orthodontic study models. 10 linear and 3 angular measurements were performed to evaluate the mandibular skeletal asymmetry. repeated measure-ANCOVA 2 by controlling the effect of age and sex, T-test and paired-samples t-test were used for comparisons. Measurement's reliability was measured with ICC 3 test. Results There was a positional deviation of mandible to the crossbite side 95% CI 4 (0.166 - 1.087). The intergroup analysis showed that Corpus Length (P ≤ 0.014), Ramus Angle in frontal view (P ≤ 0.046), and Condylar-Width in axial view (P ≤ 0.029) in the crossbite side of the case group were significantly smaller than the control group. In the subjects with UPCB, mandibular condylar width was smaller in the crossbite side (17.31 ± 2.50) relative to the non-crossbite side (18.06 ± 2.18). Conclusions The adults with dental UPCB, in addition to deviation to crossbite side, may show smaller condylar head and Corpus length in crossbite side relative to the control group.