Fahimeh Farzanegan - Department of Orthodontics, Faculty of Dentistry and Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Ali Goya - Department of Prosthodontics, Faculty of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Introduction: The purpose of this study was to evaluate the relationship between the position of mandibular third molar (M3) and vertical skeletal malocclusions. Methods: Materials for the study consisted of panoramic radiographs and lateral cephalograms of 73 fifteen to nineteen-year-old class I patients (girls=66%, boys= 34%). Patients were classified into three groups based on four vertical cephalometric indices: FMA, PFH/AFH, LAFH/TAFH, and Y-axis. Analysis of the position of mandibular M3 and its relation to the bone and other teeth were determined by three variables on panoramic view: evaluation of the space for mandibular M3, vertical position of the mandibular M3 in relation to occlusal plane, and spatial relationship between the mandibular second molar (M2) and M3. Results: In girls, there was a significant relationship between the retromolar space in both sides of the jaw and different vertical skeletal malocclusions (P<0.001 and P=0.001, respectively). In boys, significant relationship existed between the retromolar space in both sides of the jaw, spatial relationship between the mandibular M2 and mandibular M3 in the left side of the jaw and various vertical skeletal malocclusions (P=0.021, P=0.026, and P=0.017, respectively). Conclusion: The present study showed significant correlation between the retromolar space and various vertical skeletal malocclusions in boys and girls.

mandibular third molar, retromolar space, vertical skeletal malocclusion