Prevalence of Tooth Ankylosis and its Related Factors among School Children in Mashhad

Statement of Problem: Ankylosis of the primary teeth in the mixed dentition leads to dental arch circumference reduction and postpones the eruption of the successor teeth. To the best of our knowledge, there has not been a comprehensive research about tooth ankylosis and its related factors in the city of Mashhad, Iran. The purpose of this study was to determine the prevalence of tooth ankylosis and evaluate its effects among school children in Mashhad.Methods and Material: The experimental sample of this cross-sectional study consists of 1000 six to eleven year old students in seven areas of Mashhad. Stratified cluster sampling was used for the selection. Data were gathered using both clinical and radiography examination, examination of the siblings affected with ankylosis and interviews with parents. The examination methods were inspection, palpation, and auscultation. The data were analyzed by Chi-square, and Kruskal-Wallis tests using SPSS software (V.16). The prevalence of tooth ankylosis in clinical examinations was 8% for the total sample with no significant difference between the two genders. The most frequent ankylosed tooth was the lower first molar (56.7%) (p < 0.001). As to the severity of ankylosis, the moderate form was the most frequent type (55.3%) (p =0.012). In the cases with unilateral ankylosed teeth, the frequency of midline deviation was significantly higher than bilateral cases (p = 0.023). The prevalence of ankylosis was noticeable in children, indicating the importance of careful periodic examination of children by dentists.