A new tooth size determination method based on the maxillary canine using facial proportions as a reference: the Abay ratio — a retrospective study

Accurate estimation of tooth size is essential for achieving esthetic and functional harmony in orthodontic and restorative treatments. However, traditional analyses like Bolton's do not account for facial proportions, limiting individualized planning. This study investigates the relationship between tooth dimensions and facial measurements-including orbital, nasal, maxillary, and intermolar widths-in the Turkish population, aiming to support clinicians in achieving optimal esthetic outcomes. A retrospective analysis was conducted using dental scans and radiographs of orthodontic patients treated at Ordu University between January 2018 and July 2024. Inclusion criteria required healthy teeth with no restorations, caries, or anomalies, and a balanced facial appearance without prior orthodontic treatment. Digital intraoral scans were performed with the 3Shape TRIOS 3 scanner, and measurements were analyzed using Orthoanalyzer software. Cephalometric and anteroposterior radiographs assessed facial proportions. Statistical analyses, including One-Way ANOVA and Pearson Correlation tests, were performed using NCSS 2007 software, with significance set at p < 0.01. Data from 304 subjects (136 males, 168 females, mean age 18.31 years) were analyzed. Measurements included mandibular width, maxillary width, facial width, intermolar distance, and nasal width. No significant difference in tooth dimensions was found across skeletal classes in males, but trends suggested complex relationships between facial proportions and tooth dimensions. This study enhances understanding of dental-facial relationships in the Turkish population. While facial proportions may influence tooth dimensions, the effects are not uniform across skeletal classifications. These findings provide valuable insights for clinicians in optimizing orthodontic and restorative treatments for improved aesthetic outcomes. The findings of this study highlight that the Abay Ratio provides a simple, reliable, and clinically applicable guideline for determining ideal tooth proportions in harmony with facial dimensions. This novel ratio provides clinicians with a fast and practical system that can be easily applied in daily clinical practice.