The anatomy of cervical spine plays a pivotal role in maintaining the head posture and craniofacial morphology. It was also essential for the normal functioning of the stomatognathic system. Studies show an association between subjects with Class II Skeletal malocclusion due to retrognathic mandible, and altered craniofacial morphology. These subjects are prone to develop compensatory cervical hypolordosis. The aim of this study was to evaluate the changes in cervical lordosis before and after treatment of Class II skeletal patients with retrognathic mandible by Twin block therapy. MATERIALS & METHODS: Sixteen subjects (8 Males &8 females) aged between 10-13 years with skeletal Class II malocclusion with retrognathic mandible were chosen for the study. They were given standard twin block appliance and evaluated for changes in cervical curvature after the Twin blockphase. Pre and post treatment craniofacial skeletal changes and cervical curvature change were assessed using lateral cephalograms. Paired t test was used to evaluate the cephalometric changes between T0 and T1. RESULTS: There was no statistically significant difference in the age and treatment duration among the subjects. In the lateral cephalogram, between T0 and T1, there was a significant difference in the SNB, ANB, ARGO, AR-GN, LI-GO-GN and the craniocervical angles SN/CVT and MP/CVT. However there was no statistically significant difference in SNA, MP and the craniocervical angles SN/OPT and MP/OPT and the cervical lordosis angles OPT/CVT and CVT/EVT. CONCLUSION: The null hypothesis was rejected because there was a difference in the cervical curvature before and after mandibular advancement by Twin block therapy. There was improvement in the sagittal relationship between maxilla and mandible after Twin block therapy. There was a significant change in the middle segment of the cervical column, which could indicate a change in the cervical curvature to a normal lordotic curve.

Keywords : Twin block, cervical column, Lordotic curve