Evaluation and Comparison of Cervical Spine Posture in Class II Division I Patients Treated with Twin Block Appliances, Forsus Appliances, and Bilateral Sagittal Split Osteotomy: A Cephalometric Study.

Background: It has been speculated that a change in cervical spine posture occurs due to forward repositioning of the mandible. Therefore, this study aimed to evaluate and compare the cervical spine posture in Class II division one patient treated with three different treatment modalities.

Materials and methods: A retrospective cohort study was conducted using pre and post-treatment lateral cephalograms of Class II Division one patients who have undergone orthodontic therapy using twin block appliance, Forsus, and bilateral sagittal split osteotomy (BSSO). This study included a total of 57 subjects comprising 19 subjects in each group. Seven cervical, three sagittal, and one vertical parameters were compared within and between each group. The data were tested using the Dependent t-test, One-way analysis of variance, and Tukey's post hoc test.

Results: A significant difference existed between the pre- and post-treatment angular measurements within the three groups showing a change in the cervical spine posture with forward positioning of the mandible. A comparison of mean changes in angular measurements between the three groups showed a significant difference in SNA, SNB, ANB, and odontoid process tangent-cervical vertebral tangent (OPT-CVT), indicating a change in the cervical posture.

Conclusion: OPT-CVT angle predicts a change in cervical spine posture after treatment with a significant difference in the Twin Block group (P = 0.029) compared to Forsus and BSSO groups. Thus, the twin block group results in a more upright craniocervical posture than the other two treatment groups.