# 3D Correspondence Between Maxillary Central Incisor Morphology and Facial Shape in Young Adults

## TL;DR

This study finds that the maxillary central incisor shape is closely but not fully aligned with facial shape in young adults, with differences influenced by age and gender.

## Contribution

The study introduces a 3D volumetric analysis to quantify tooth–face correspondence and its variation with age and gender.

## Key findings

- 82.6% of maxillary central incisor volume corresponds with facial shape.
- Larger tooth volumes correlate with greater incongruence in females and younger participants.
- Men have significantly larger total tooth volumes than women.

## Abstract

Backround: This cross-sectional study aimed to quantify the proportion of 3D tooth–face superimposition in young adults and examine age- and gender-related differences. Methods: In 98 dental students, intraoral MCI and facial scans were acquired under standardized protocols, processed in Mesh Mixer v. 3.5.474and Blender v. 4.3.2., and aligned to reference planes for superimposition. Residual tooth volume, reflecting tooth–face correspondence, was computed via Boolean subtraction. Statistical analyses were performed in IBM SPSS Statistics 25 at α = 0.05. Results: Total tooth volume (1,626,120.79 ± 210,659.56 × 103) exceeded the superimposed volume by 285,052.34 × 103 (17.53%; 95% CI: 15.84–19.22%; p < 0.001), giving a superimposition proportion of 82.6%. Positive correlations between total and remaining tooth volumes were observed overall (ρ = 0.448; p < 0.001), in females (ρ = 0.515; p < 0.001), and in participants < 21 years (ρ = 0.662; p < 0.001). Men had higher total tooth volume than women (1,706,232 ± 151,086 vs. 1,583,561 ± 225,978; p = 0.005). Conclusions: Volumetric analysis revealed high but incomplete dentofacial correspondence. Larger tooth volumes were associated with greater incongruence in females and younger participants, confirming volumetric size as a determinant of morphological congruence. Results highlight clinically meaningful superimposition, supporting the MCI as a reliable reference for restorative planning and esthetic reconstructions, and emphasize the value of 3D analysis for precise dentofacial evaluation and individualized esthetic planning.