Assessment of soft tissue profile changes following use of tongue guard in the patients with class III malocclusion and maxillary deficiency

Background and Objective: One of the dentoalveolar abnormalities is class III malocclusion with maxillary deficiency. Correction of this malocclusion in growth ages using orthopedic appliances to avoid further extensive surgical treatment and improvement in soft tissue profile will help to reach beauty. The objective of this study was to survey changes in soft tissue profile following tongue guard in class III patients with maxillary deficiency. Methods: In this experimental study, 20 class III patients (4 males and 16 females) with maxillary deficiency and reserve overjet with mean age of 7.5 years old referring to orthodontic department of Babol dental school in the year 2000 were treated by tongue guard at least for 6 months. 2 lateral cephalometry were obtained before and after treatment for each patient and after tracing results were compared. Findings: After cephalometric analyzing and comparison between before and after tracing, an obvious increase was found in forward movement of subnasal soft tissue (3.59mm), superior labial sulcus (3.12mm), incisal edge of centrals (3.38mm), upper lip prominence (4.53mm). Lower lip prominence (1.05mm), inferior labial sulcus (1.47 mm) and the most anterior point of chin (1.56mm) move anteriorly to some extent. Vertical distance of subnasal soft tissue (2.03 mm), superior labial sulcus (2.22mm), upper lip prominence (2.65mm), inferior labial sulcus (3.41mm), the most prominent point of chin (2.59mm) and incisal edge (3.47mm) have increased significantly. Nasolabial angle (-1.44°), mentolabial angle (1.82°) and soft tissue convexity angle (-2.36°) have decreased. Upper lip thickness decreased. Distance between upper lip and esthetic line decreased and distance between lower lip and E-line increased. Conclusion: Due to results of our study in class III patients with maxillary deficiency treated by tongue guard because of change in position of inferior hard tissue and teeth. We can expect an improvement in soft tissue profile due to movement of mid third of face forwardly and downward and backward rotation of mandible