Cephalometric study of the soft tissue characteristics of patients with Class III malocclusion

Introduction: Class III malocclusion is defined as anteroposterior discrepancy, which may occur as result of maxillary deficiency and/or mandibular excess. Objective: Evaluate the characteristics of the soft tissue of individuals with Class III in the city of Mossoró, state of Rio Grande do Norte and to observe if there is association between these characteristics with male and female genders.Material and method: It was selected a retrospective sample of 52 lateral cephalometric radiograph of adults, with concave facial profile, negative ANB and negative AOBO. The radiographs were analyzed in the program Radiocef Studio 2. Then, descriptive analysis was performed for all cephalometric variables, calculating mean, standard deviation, maximum and minimum. In order to detect the differences between genders, the t test for independent data was used.Result: The facial profile presented as mean 176,9°±5,9; the nasolabial angle, 91.9°±13.1; the mentolabial sulcus, 137.9°±13.3; and the nasal projection, 16,2mm±4,5; the upper and lower facial thirds, 60,7mm±14,3 and 70,5mm±19, respectively. For the upper and lower lip thicknesses, were found: 13,4mm±5,1 e 13,9mm±4,8. The upper lip protrusion showed 3.3mm±2,7 and the lower, 4mm±3,1.Conclusion: The main cephalometric features found were: concave facial profile, normal nasolabial angle, greater mentolabial sulcus, normal nasal projection, normal height of the middle third and increased height of the lower third, thick lips, normal upper lip protrusion and protruded lower lip. Among the measures evaluated, there wasn't difference between genders. For better understanding about the subject, further studies are required with larger samples and more sophisticated methodological designs.