Abstract

BACKGROUND: Genetics, environment, and ethnic factors are major contributors to the prevalence and variations of malocclusion. AIM: The aim of study was to determine the prevalence of interarch problems in school-aged children, 9 - 11 years, living in Tehran; and to describe the role of ethnicity, education, and economic status on them. METHODS: The present data were part of the Comprehensive Evaluation of Skeleto-Dental Anomalies (CESDA) study conducted in 2015 among children living in Tehran, Iran. Cluster random sampling was applied among 19 districts of Tehran. A total of 38 schools were selected, and out of 1585 participants, the data of 1429 children were collected (response rate = 90). The Chi-square test and binary logistic regression analysis were used for statistical analyses. RESULTS: Of all participants, 758 were boys and 671 were girls. The mean age was 121 +/- 8 months. The most significant background determinants associated with molar relationship were ethnicity and place of residence. Class I right molar relationship was seen in 57.9 of the children and was generally more frequent in boys. Normal overjet was observed in 47.1; 41.5 had an increased overjet, 16.2 had an anteroposterior cross-bite, and 11.8 had a lateral cross-bite. Midline discrepancy was seen among 61.1 of the children. Ideal anteroposterior, vertical, and horizontal relationship were observed in 31, 53, and 34 of the children, respectively. Only 10 of the children aged 9 - 11 years old had an ideal interarch relationship. Gender and place of residence had persistently significant association with having an ideal anteroposterior, vertical, horizontal, and interarch relationships (P < 0.002) in all four binary logistic regression models. CONCLUSIONS: The majority of the children aged 9 - 11 years old have at least one interarch problem, although it is commonly preventable. RELEVANCE FOR PATIENTS: Early detection of children's orthodontic problems may help with effective prevention of further advanced anomalies.