Comparison of Palatal Rugae Pattern and Number among Subjects with Different Sagittal Skeletal Relationships Using Extra‐oral Scanning of Dental Study Casts: A Cross‐sectional Prospective Study

Abstract

Introduction: There is growing research interest in determining whether a correlation exists between palatal rugae and skeletal malocclusion. This study aimed to assess and compare the pattern and number of palatal rugae, and the shape of the incisive papilla, among patients with different sagittal skeletal relationships visiting the Department of Orthodontics, Dayananda Sagar College of Dental Sciences, Bengaluru.

Methods: In this cross-sectional prospective study, 159 subjects (age range, 10–22 years) were divided into three equal groups (n = 53 each) based on the ANB angle measured on lateral cephalometric radiographs: Class I (ANB 0°–4°), Class II (ANB > 4°), and Class III (ANB < 0°). Maxillary dental casts were digitized with an intraoral scanner (Prime Scan AC, Connect 5.2 software) and exported as STL files. The shape of the palatal rugae was assessed with the modified Thomas and Kotze classification, and the shape of the incisive papilla was assessed with the Ortman and Tsao classification, using Paint 3D software; the number of palatal rugae (primary and secondary) was assessed with the Lysell classification using Meshmixer software. Chi-square and Kruskal-Wallis tests were used for statistical analysis (α = 0.05).

Results: There were no statistically significant differences among the three sagittal skeletal groups in the number of primary or secondary palatal rugae on either side (P > .05), or in the shape of the incisive papilla (P = .57). Wavy and Curved rugae patterns were the most common primary rugae patterns in all three groups, whereas Annular and Unification patterns were the least common. Pear-shaped incisive papillae were the most common shape in all three groups.

Conclusions: Wavy and Curved rugae patterns predominated in all sagittal skeletal malocclusion groups, and primary rugae outnumbered secondary rugae clinically, although this difference was not statistically significant. Pear-shaped incisive papillae were the most common configuration across groups. No statistically significant association was found between palatal rugae pattern/number or incisive papilla shape and sagittal skeletal malocclusion type, suggesting that palatal rugae are more useful for individual identification than for malocclusion prediction.