Association among geometric configurations of palatal rugae.

BACKGROUND The associations between the length and morphological shape-related characteristics of palatal rugae have not been fully explored. OBJECTIVE We aimed to assess the possible association among various geometric configurations of the palatal rugae in an adult population. MATERIALS AND METHODS The maxillary dental casts of 217 non-growing subjects (95 males, 122 females, mean age 25.5±7.6 years) were scanned (laser scanning system Perceptron ScanWorks® V5) and digitized for linear measurements. The casts were also surveyed for visual categorization into curved, wavy, straight and other topographical forms, along with spatial direction of the rugae and the presence of unification. The rugae were categorized as primary, secondary, and fragmentary based on their lengths (> 5mm, 2-3mm, < 2mm, respectively). Chi square and one-way ANOVA and post-hoc tests were used to compare the palatal rugae groupings. RESULTS Primary and backward-directed rugae prevailed in the total sample (84.7% and 49.3%, respectively). Wavy form was dominant among primary lengths, while straight form was associated with the shorter secondary and fragmentary groups (p=0.0042). Absence of unification was the norm (88.8%). CONCLUSIONS Associations of length and shape characteristics among palatal rugae combine wavy patterns with increased length, and straight forms with shorter folds. These features contribute to the definition of ruga individuality in combination rather than separately.