Document Type : Original Articles

Abstract

Introduction: A main problem in the treatment of patients with skeletal Class III malocclusion is making the decision whether only orthodontic therapy or a combination of orthodontic therapy and surgery will solve the problem, which usually has to be made at a young age. The aim of this study was to evaluate the relationship between the frontal sinus surface area and size of mandible in adults to assess the possibility of the use of this anatomic structure as an indicator for prediction of mandibular growth in future studies. Materials and Methods: In this cross-sectional study, 71 cephalograms from a private orthodontic clinic were analyzed, consisting of 20 adults with skeletal Class I, 19 adults with skeletal Class II and 32 adult patients with skeletal Class III malocclusions of both male and female subjects. The surface area of the frontal sinus (mm2), SNA, SNB, ANB, Wits, overjet, saddle angle, gonial angle, facial angle, mandibular length and body length were assessed on cephalograms. Pearson’s correlation test was used to assess the relationship between frontal sinus area and other cephalometric indices at a significant level of 0.95. Results: The results revealed significant direct relationships between frontal sinus size and SNB, gonial angle, facial angle, body length and mandibular length and inverse relationships with ANB, Wits and overjet. The frontal sinus area showed the highest correlations with mandibular length (r = 0.69) and body length (r = 0.60) (p value < 0.0001). Conclusion: The frontal sinus surface area can possibly be used as an additional indicator for predicting the final mandibular size, with a valuable role in the diagnosis and treatment planning. Key words: Frontal, Malocclusion, Mandible, Sinus.