Root symmetry between homologous upper incisors in non-orthodontic patients: A cross-sectional study

Introduction: This study aimed to assess the symmetry in length, shape, and root dilaceration between homologous upper incisors of non-orthodontic patients using digital panoramic radiographs (DPR). Methods: This retrospective cross-sectional study evaluated 200 DPR obtained from a private radiology centre in Lima, Peru. All successive patients meeting the eligibility criteria were included from January to August 2024 (86 men and 114 women, 27.84 ± 8.69 years and 28.52 ± 8.38 respectively). Eight hundred upper incisors were examined, divided equally into upper central incisors (UCI) (n = 400) and upper lateral incisors (ULI) (n = 400). The dental imaging software Blue Sky Plan 4.13.35 was utilized to evaluate root length (as a ratio), root shape (using the Albrecht classification), and root dilaceration (according to the Chohayeb classification) while comparing homologous upper incisors. For statistical analysis, weighted Kappa tests and binary logistic regression were employed, with the significance level set at P < 0.05. Results: Among the 200 radiographs, root length symmetry was observed in 192 patients (96%) for UCI and in 185 patients (92.5%) for ULI. Additionally, root shape symmetry was found in 171 patients (85.5%) for UCI and in 124 patients (62%) for ULI. Regarding dilaceration symmetry, 198 patients (99%) showed symmetry for UCI, while 188 patients (94%) did so for ULI. The multivariate analysis indicated that the male sex was more likely to exhibit root shape symmetry in upper lateral incisors (P = 0.033). Conclusions: Most homologous upper incisors display symmetry regarding root length, shape, and dilaceration. However, this symmetry is more prevalent in central than lateral incisors, in which the root shapes may differ between homologous teeth. Orthodontists should consider these findings in their practice.