Changes in Maxillary Incisor Inclination Before and After Orthodontic Treatment Across Vertical Skeletal Patterns

Objective: To evaluate changes in maxillary incisor inclination before and after orthodontic treatment in adults with different vertical facial patterns (normodivergent, hypodivergent, hyperdivergent) and to assess the relationship of incisor inclination to facial and growth axes using cephalometric and photographic records. Materials and Methods: This retrospective study included 144 non-growing patients (96 females, 48 males) with available pre- and post-treatment lateral cephalograms and smiling profile photographs. Patients were classified into three groups based on mandibular plane angle (MP/SN): normodivergent (n=66), hypodivergent (n=35), and hyperdivergent (n=43). Angular measurements assessed maxillary incisor inclination and growth/facial axes. Clinical crown angulation (CCA) was evaluated from profile photographs. Statistical analyses included paired t-tests, ANOVA with Bonferroni post hoc tests, and Pearson correlation. Results: No significant changes in maxillary incisor inclination were observed post-treatment in any of the groups. Significant skeletal changes were noted in the hypodivergent group, including increases in MP/SN (p=0.011) and IMPA (p=0.014). Intergroup comparison revealed significant differences in changes in Facial Axis/H (p=0.020) and MP/SN (p=0.025). Correlations between CCA and skeletal axes were more pronounced in normo- and hypodivergent groups, while hyperdivergent patients showed no significant associations. Conclusions: Maxillary incisor inclination remains stable after orthodontic treatment in adults across all vertical patterns. In normo- and hypodivergent cases, skeletal axes can guide esthetic incisor positioning. In hyperdivergent patients, individualized soft tissue and smile analysis is essential due to the weaker skeletal-dental relationship. Personalized treatment planning should balance cephalometric norms with esthetic outcomes.