Comparative Evaluation of Antagonistic Tooth Wear After Placement of Crowns Made From Three Different Materials Using a Digital Intraoral Scanner: An In Vivo Study.

Introduction Antagonistic tooth wear is a significant concern in fixed prosthodontics as it can compromise long-term occlusal stability and natural tooth integrity. Advances in restorative materials have introduced options with varying wear behaviors; however, direct clinical comparisons using digital technologies remain limited. This in vivo study aimed to comparatively evaluate antagonistic tooth wear produced by crowns fabricated by direct metal laser sintering (DMLS), rubellite-layered zirconia, and polyetheretherketone (PEEK) materials using digital intraoral scanning over 12 months. Materials and methods A total of 36 patients (18 males and 18 females; mean age: 30.27 ± 3.45 years) fulfilling the inclusion criteria were enrolled and assigned to three equal groups of 12 patients each. Each group comprised six males and six females. The crowns were fabricated using a fully digital workflow and cemented. Antagonist tooth wear on the opposing mandibular first molars was assessed by superimposing baseline, 6-month, and 12-month digital intraoral scans using dedicated computer-aided design (CAD) software. The linear changes were quantified. Data were analyzed using two-way mixed-design analysis of variance (ANOVA), followed by Tukey's post hoc test. Results All the groups showed a statistically significant increase in antagonist tooth wear between 6 and 12 months. DMLS crowns produced the highest wear at both intervals (6 months: 0.0787 ± 0.0176 mm; 12 months: 0.1018 ± 0.0326 mm), followed by rubellite-layered zirconia crowns (0.0450 ± 0.0238 mm and 0.0605 ± 0.0249 mm). PEEK crowns demonstrated the lowest wear values (0.0288 ± 0.0123 mm at 6 months and 0.0433 ± 0.0129 mm at 12 months). The main effect of material type was highly significant, with DMLS differing markedly from the other two materials, whereas the difference between zirconia and PEEK was not statistically significant. Conclusion Among the study parameters, PEEK crowns exhibited the most favorable wear behavior against natural enamel, followed by rubellite-layered zirconia crowns. Digital scanning has proven to be effective for precise wear quantification. These findings support material-specific selection to minimize iatrogenic enamel loss, while maintaining esthetics and function.