Association between tooth agenesis and root morphology assessed by periapical radiographs

OBJECTIVE: To evaluate the association between tooth agenesis and root morphology alterations. METHODS: This retrospective observational study initially analyzed 27,707 medical records of patients from radiological centers in southeastern Brazil. After applying the inclusion and exclusion criteria, 1193 sets of periapical radiographs of maxillary incisors were selected from eligible patients aged between 8 and 30 years. The root morphology of the upper incisors was classified into five categories: normal, short, blunt, apically bent, or pipette-shaped, based on criteria established in the literature. In addition, missing teeth were recorded applying the tooth agenesis code (TAC). Two previously calibrated specialists analyzed the radiographs visually. Logistic regression with odds ratios (OR) estimated the associations between tooth agenesis and root alterations at a 5% significance level. RESULTS: Patients with any form of tooth agenesis were more likely to have pipette-shaped (i.e., roots with a narrow cervical third and gradual tapering toward the apex; OR = 7.04; 95% confidence interval [CI] 4.23-11.72) or blunt (OR = 5.31; 95% CI 2.62-10.75) roots. Conversely, the agenesis group showed a significantly lower prevalence of normal roots than the group without agenesis (OR = 0.12; 95% CI 0.07-0.20). CONCLUSION: Root morphology alterations are strongly associated with tooth agenesis. This knowledge should be used for customized approaches and multidisciplinary strategies to minimize complications and improve treatment in this group.