Objective: To establish normative values for lip prominence relative to the E-line, S-line, and H-line in a Dakshina Kannada skeletal Class I population and to evaluate the relationship between esthetic line measurements and incisor proclination. Interpopulation comparisons with Indian and Caucasian norms were also performed.

Materials and Methods: A cross-sectional cephalometric analysis was conducted on 100 subjects (58 females, 42 males) aged 18–25 years with skeletal Class I relationships. Upper and lower lip prominence relative to the E-line, S-line, and H-line were measured. Upper and lower incisor proclination was assessed in millimeters and degrees. Descriptive statistics were calculated, and gender differences were analyzed using independent t-tests. Pearson correlation and multiple linear regression analyses evaluated associations between incisor proclination and lip prominence. Interpopulation comparisons were performed using one-way ANOVA with Tukey post hoc tests (α = 0.05).

Results: Mean upper and lower lip prominence relative to the E-line were 1.98 ± 2.21 mm and 3.91 ± 2.54 mm, respectively. Similar anterior positioning was observed relative to the S-line and H-line. Males demonstrated significantly greater lip prominence than females (p < 0.05). Strong positive correlations were identified between incisor proclination and corresponding lip prominence (r = 0.58–0.74, p < 0.001). Regression analysis revealed that incisor proclination explained 52% of upper lip and 56% of lower lip projection variability. ANOVA demonstrated significant differences between Dakshina Kannada, Indian, and Caucasian populations (p < 0.001).

Conclusions: The Dakshina Kannada population exhibits a characteristically anterior soft tissue profile distinct from Caucasian standards. Incisor proclination significantly influences lip prominence; however, intrinsic soft tissue morphology also contributes substantially. Region-specific cephalometric norms are essential for culturally appropriate orthodontic treatment planning.