Assessment of Dental Arch Width in Individuals With Various Growth Patterns: A Cross-Sectional Study

Dental arch width plays a vital role in orthodontic diagnosis, treatment planning, and post-treatment stability. Various skeletal growth patterns, hypodivergent, normodivergent, and hyperdivergent, are known to influence craniofacial morphology and dental arch dimensions. However, limited evidence exists comparing arch widths across these growth types, especially in South Indian populations.

The objectives of this study are to assess maxillary and mandibular arch width measurements in normodivergent, hypodivergent, and hyperdivergent individuals and to compare variations in interpremolar, intermolar, premolar basal, and molar basal arch widths among these growth patterns.

A retrospective cross-sectional study was conducted on 90 orthodontic patients (16-30 years) at RVS Dental College and Hospital using pretreatment casts and radiographs that were obtained from patient records for routine diagnostic and treatment purposes in the Department of Orthodontics and Dentofacial Orthopaedics. Pretreatment dental casts and corresponding lateral cephalograms were screened to identify cases fulfilling the required diagnostic and record quality standards. All data were anonymized prior to evaluation, and no direct patient contact or intervention was involved in the study. Based on cephalometric parameters (FMA, SN-GoGn, Y-axis), subjects were divided into three groups (n=30 each): normodivergent, hypodivergent, and hyperdivergent. Dental arch widths were measured on casts, including interpremolar, intermolar, premolar basal, and molar basal widths in both arches. Statistical analysis was done using IBM SPSS Statistics for Windows, Version 27 (Released 2020; IBM Corp., Armonk, New York, United States). One-way ANOVA with post hoc Tukey tests was applied, and p<0.05 was considered significant.

Hypodivergent subjects consistently exhibited the greatest arch widths, while hyperdivergent subjects showed the narrowest. In the maxilla, the mean interpremolar width was 43.31±0.40 mm (hypodivergent), 42.81±0.39 mm (normodivergent), and 40.94±0.49 mm (hyperdivergent) (p<0.01). A similar trend was observed for intermolar, premolar basal, and molar basal widths. Mandibular arch widths followed the same pattern, with hypodivergent > normodivergent > hyperdivergent (p<0.01 for all parameters). Post hoc tests confirmed statistically significant differences across groups.

Dental arch widths vary significantly with various skeletal growth patterns. Hypodivergent individuals possess the widest arches, hyperdivergent the narrowest, and normodivergent intermediate dimensions. These findings emphasize considering vertical skeletal growth in orthodontic diagnosis, archwire selection, and long-term treatment stability.