prevalence of Anterior Open Bite and the associated dentoskeletal malformations in 9-14 year-old students of Qazvin

Background: Anterior Open Bite (AOB) is one of the most severe orthodontic diseases to treat and often with poor prognosis. However, an early diagnosis accompanied with proper evaluation of etiological factors may lead to a shorter therapeutic period and also a better prognosis. Objective: To determine the prevalence of AOB and the associated clinical and cephalometerical changes in 9-14 -year-old students of Qazvin. Methods: 1461 students (males: 701, female: 760) were evaluated and AOB was found in 56 students (32 boys and 24 girls). Thirty students out of 56 were referred to the School of Dentistry for a lateral cephalometric radiography. Thirty lateral cephalogram x-rays were also taken from students with normal occlusion as control group. Findings: The prevalence of AOB in 9-14-year-old students in Qazvin was 3.83% which was significantly higher in girls than boys. From a cephalometric point of view, the articular, gonial, sum of post, SN-MP and basal angles significantly increased but and UAFH were decreased. Conclusion: Patients with Anterior Open Bite showed a downward backward lower jaw rotation with a growth pattern in their faces more vertical than horizontal. The posterior upper teeth in patients were also over-erupted which must be considered in treatment plan.