Sex Differences in Tooth Wear Evaluated by the Basic Erosive Wear Examination, Simplified Tooth Wear Index, and Tooth Wear Evaluation System 2.0 Using Intraoral Scans

Background: Tooth wear is a chronic, irreversible loss of dental hard tissues caused by abrasion, attrition, and erosion. Biological, chemical, and mechanical factors contribute to its development, and some studies suggest men may exhibit more severe wear than women. Intraoral scans provide high-resolution digital records that can be analyzed efficiently to investigate sex-based differences in tooth wear. Methods: In this retrospective observational study, 246 anonymized intraoral scans from three dental clinics were analyzed. Ethical approval was obtained from the Bioethics Committee at the District Medical Chamber in Kraków, Poland (approval number: XXX/2025), and written permission to use the scans was provided by all participating clinics. Scans were acquired using Medit i500 and iTero 2 scanners. Two calibrated examiners independently assessed tooth wear using the Basic Erosive Wear Examination (BEWE), simplified Tooth Wear Index (sTWI), and Tooth Wear Evaluation System 2.0 (TWES 2.0; screening module). Mixed-effects linear models evaluated associations between sex and tooth wear scores, accounting for repeated measurements and inter-examiner variability. Estimated marginal means for each sex were calculated, and scoring consistency was assessed using confusion matrices and heatmaps. Results: Analysis revealed only minor differences in tooth wear between sexes, with no consistent pattern across indices or tooth regions. For BEWE, males showed slightly higher scores overall (total score 12.80 vs. 12.19 in females), with a significant difference observed only in Sextant 6 (estimate = +0.201; p = 0.038). In sTWI, sex was a significant predictor in a limited number of sites, with small and inconsistent differences. For TWES 2.0, males had significantly higher scores only in Sextant 5 (estimate = +0.237; p = 0.0016). Overall, sex had a limited influence on tooth wear as measured by all three indices. Conclusions: Sex appears to have a minor and inconsistent effect on tooth wear severity. Intraoral scans provide a practical, non-invasive method for assessing tooth wear, but sex alone may not reliably predict severity. These findings suggest preventive strategies and treatment planning should consider multiple factors beyond sex. Clinical trial number: Not applicable.