Abstract: Aim The aim of this study was to assess the dynamic activity of the mandible by means of a computerised kinesiograph in Class II patients treated with orthodontic therapy and to compare the results of this group with those of a sample of untreated Class II patients.
Methods Twenty young adolescents who had undergone orthodontic treatment for correction of Class II malocclusion and twenty age and sex-matched adolescents exhibiting Class II malocclusion, whose parents refused the orthodontic treatment, were enrolled. Maximum vertical opening (MVO), maximum anterior-posterior movement (MAPM), maximum right deviation (MRD), maximum left deviation (MLD), MVO/MAPM ratio, maximum velocity in opening (MVIO), maximum velocity in closure (MVIC), verticality (ID-V), anterior-posteriority (ID-AP) and laterality (ID-L) were recorded during the kinesiographic evaluations. Differences in the kinesiographic data were analysed using the Wilcoxon sum rank test; data are expressed as means and standard deviations (SD). Differences between groups in age were analysed using unpaired t-test, while differences in gender distribution were assessed using the Fisher’s exact test. The level of significance was set at p < 0.05.
Results No differences were detected in the distribution of sex and age between the two groups. Significant differences between the two groups were observed for MVO, MAPM, that were higher in the control group, and MLD, which was higher in the case group; no other significant differences were detected for MRD, MVO/MAPM, MVIO, MVIC, ID-V, ID-AP, ID-L.
Conclusion Orthodontic treatment of young patients with Class II malocclusion may reduce the maximum vertical opening as well as the maximum anterior-posterior movement and enhance the lateral displacement; however, further studies are needed to assess the relationship between impaired mandible kinetics of orthodontic treatment in patients with Class II malocclusion and craniomandibular disorders.