Correlation of Maxillary Central Incisor, Face, and Dental Arch Shape in the Panchkula Population: A Cross-sectional Study

Background: Facial harmony and dental esthetics form the foundation of prosthodontic treatment planning.Classical concepts such as Williams' geometric theory and its modifications suggest that maxillary central incisor (MCI) shape, facial form, and dental arch form follow a harmonious relationship.However, available evidence is inconsistent across populations.This study investigates these correlations and evaluates the coincidence between facial and dental midlines in young adults of the Panchkula population.Aim: To determine the coincidence and correlation between the shape of the MCI, facial form, maxillary dental arch form, and facial-dental midline alignment.Materials and methodology: Ninety subjects aged 18-25 years with complete permanent dentition were included.Standardized extraoral photographs were recorded using a DSLR camera with laser-guided reference lines to determine facial and dental midlines.Facial forms were assessed using acetate tracing sheets, measuring the angle of convergence, classifying them as square (<5°), ovoid (5-12°), or tapering (>13°).Maxillary casts were made from alginate impressions, and the shape of the dental arch and MCI was digitally analyzed using adobe Photoshop CC 23.0.Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 26.0 with Chi-square and Analysis of variance (ANOVA) tests (p < 0.05).Results: Ovoid facial form was most prevalent, followed by tapering and square.Ovoid shapes also predominated in MCIs and dental arch forms.A significant correlation was observed between facial form and dental arch form, supporting the modified Williams theory.No significant relationship was found between facial form and central incisor shape or between incisor shape and arch form.Midline evaluation revealed that facial and maxillary dental midlines coincided in a minority of subjects, with left-sided deviations being more common. Conclusion:The study partially validates the modified Williams principle, demonstrating a strong correlation between facial form and dental arch form, but a limited relation with central incisor shape.Minor midline discrepancies were common yet clinically acceptable.