Prevalence of ectopic eruption of permanent first molars in a group of children aged 5–8 years in Ankara, Türkiye: a retrospective cross-sectional study

Ectopic eruption (EE) of permanent first molars (PFMs) occurs due to the abnormal eruption path, which may result in the PFMs being impacted under the distal undercut of primary second molars (PSMs). This study aimed to investigate the prevalence of EE of PFMs and the findings associated with root resorption observed in PSMs. In this retrospective observational study, panoramic radiographs of 4426 patients (17704 PFMs) aged 5 to 8 (≈ 7.92) years were investigated. The patients’ date of birth, date of panoramic radiography taken, age (year and month), sex, presence of EE of PFMs and associated findings (right-left, unilateral-bilateral, upper and lower jaw) and the degree of EE were recorded. EE was graded (I to IV) by using based on the resorption of the PSMs. Data was analyzed using Chi-Square and Binomial tests. The statistical significance level was set at 5%. EE was diagnosed in 67 cases (1.51%) and in 107 PFMs (0.60%). Of the cases diagnosed with EE, 44.78% (n = 30) were female and 55.22% (n = 37) were male and the sex distribution among EE cases did not deviate from the expected 1:1 ratio (p = 0.464). The mean age of the patients diagnosed with EE was 6.68 ± 0.76 years. Among 107 PFMs diagnosed with EE, 96 (89.72%) were in the upper jaw and 11 (10.28%) in the lower jaw. This distribution deviated markedly from an expected 1:1 ratio (p < 0.001). The difference in the bilateral/unilateral distribution between the upper and lower jaws was not statistically significant (p = 0.494). Also, no statistically significant difference was observed between PFM type and EE grades (p = 0.318). Within the limitations of this study, the results showed EE occurred most commonly in the upper jaw and no statistically significant associations were observed between EE and sex or side (right and left). These findings emphasize the importance of early radiographic evaluation to guide timely interceptive treatment in pediatric patients. Also, further studies that more accurately predict risk indicators for PFMs affected by EE may enable more reliable assessment of cases in this regard.