Haleh Hali - Assistant Professor, Department of Pediatric Dentistry, Faculty of Dentistry, Mazandaran University of Medical Sciences, Sari, Iran.
Maede Salehi - Assistant Professor, Department of Oral Medicine, Dental Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
Tahereh Molania Jelodar - Associate Professor, Department of Oral Medicine, Dental Research Center, Mazandaran University of Medical Sciences, Sari, Iran
Foroozan Farahbod - Assistant Professor, Department of Oral and Maxillofacial Radiology, Dental Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
Hamzeh Maghfouri - Dentistry Student, Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran

Background Ectopic eruption is a tooth eruption disorder in which the tooth does not erupt in its proper eruption path. The most common type of ectopic eruption is the mesial eruption of the maxillary first permanent molar, which results in the loss of the second deciduous molars, resulting in a reduction in arch length and loss of space. Therefore, this study aimed to investigate the prevalence of ectopic growth of this tooth in children. Materials and Methods: This descriptive cross-sectional study was performed on panoramic radiographic images of children aged between ۵-۸ years. Census sampling method was used in this study. A general dentist under the supervision of an oral and maxillofacial radiologist assessed ectopic eruption according to a grading system described by Barberia et al., all radiographs. The data was analyzed using SPSS software version ۱۶.۰. Results: ۷۷۲ panoramic radiographs were examined in this study, panoramic radiographs of ۷۹ patients were considered to have ectopic eruption, which ۶۱% of cases were in girls and ۳۹% in boys. ۲۵.۶% of the patients had a mild, ۶۰.۳% had a moderate, and ۱۴.۱% had a severe ectopic eruption. All patients (except one) had a mesial ectopic eruption, ۱۹% of the ectopic eruptions occurred in the maxilla, ۵۹.۴% in the mandible, and ۵۹.۵% in both jaws. Ectopic eruption in the mandible was more frequent in the mandible than in the maxilla and this finding was statistically significant (P <۰.۰۵). Conclusion The results of the present study showed that the frequency of ectopic eruption of the first permanent molars in Sari was ۱۰.۲%, which is higher than the values reported in studies in other regions of Iran.

Children, Ectopic Eruption, normal tooth eruption, panoramic