Patterns of Dental Interventions Across Tooth Position, Age, and Sex: A Retrospective Real-World Clinical Study

Background/Objectives: The lateral symmetry of dental disease and treatment patterns reflects underlying biological, behavioral, and systemic factors. Although clinical experience suggests asymmetric treatment frequencies, large-scale quantitative evidence remains limited. This study aimed to analyze the symmetry and asymmetry of dental interventions-encompassing restorations, extractions, endodontic treatments, and prosthetic procedures-in relation to tooth position, jaw, patient sex, and age group. Methods: A retrospective analysis was conducted on 30,063 dental intervention records from 2738 patients treated at a single private practice between 1999 and 2025. Tooth identification was based on FDI two-digit notation. Chi-square goodness-of-fit tests were applied to assess left-right and upper-lower symmetry, stratified by sex, age group, and tooth position. Bonferroni correction was applied to account for multiple comparisons (adjusted α = 0.0033). Results: Overall left-right symmetry was maintained across the full dataset (χ² = 0.17, p = 0.682). After Bonferroni correction, only the right-side excess at the first premolar position remained statistically robust (p = 0.002), driven predominantly by the lower jaw (tooth 44 vs. 34; p = 0.011). The upper jaw received significantly more interventions than the lower jaw (56.3% vs. 43.7%, p < 0.001). Additional asymmetries observed at the uncorrected threshold-in the lower jaw (p = 0.026), in the 18-30 age group (p = 0.009), and a sex × jaw interaction (p = 0.047)-did not survive correction. Conclusions: Dental treatment patterns are predominantly symmetric at the population level. The most robust site-specific finding was a right-side excess of first premolar interventions, particularly in the lower jaw. These results may inform targeted preventive strategies and population-level oral health planning, with caution warranted in generalizing findings beyond the single-practice setting.