Soft tissue esthetic improvements following a modified twin block appliance: A prospective study

Cl II div 1 patients often suffer from several adverse facial characteristics which may impair their social well-being. The objective of the current study was to evaluate the esthetic improvements in such patients by using a modified twin block appliance. Thirty five adolescent patients with mandibular deficiency underwent treatment with a modified twin block for a mean period of 13 months. The esthetic changes before and after therapy, were compared using parametric Paired t-tests analysis. P values less than 0.05 were considered significant. Before the study, informed patient consent was obtained from the patients and the protocol of the study was approved by the respective university research ethics committee. The pre and post treatment lateral photographs were obtained with the patients head in the natural head position, by a single operator. The photographs were then scanned and transferred to a computer. Adobe Photoshop software was used to produce silhouettes for evaluation of the soft tissue changes. The pre and post treatment silhouettes were then coded to blind the evaluator. The silhouettes were then manually traced and analyzed by a previously calibrated examiner on a blind basis.Facial convexity, lip incompetence, upper lip protrusion and columellar inclination significantly decreased (p<0.05) while Merrifield’s Z-angle nasolabial angle, lower lip length, and mentolabial angle significantly increased (p<0.05). Vertical facial height ratio, lower lip protrusion, upper lip length as well as nasal projection and inclination, did not change significantly (p>0.05)Our findings indicated that a modified form of twin block can be effective in profile improvement of patients with minimum untoward effects. Our findings indicated that a modified form of twin block can be effective in profile improvement of patients with minimum untoward effects.