Palatal rugae morphology is associated with variation in tooth number

Periodic pattern formation during embryonic development

During embryonic development many organs and structures require the formation of series of repeating elements known as periodic patterns. Ranging from the digits of the limb to the feathers of the avian skin, the correct formation of these embryonic patterns is essential for the future form and function of these tissues. However, the mechanisms that produce these patterns are not fully understood due to the existence of several modes of pattern generation which often differ between organs and species. Here, we review the current state of the field and provide a perspective on future approaches to studying this fundamental process of embryonic development.

An Association of Morphological Characteristics of Palatal Rugae and Dental Malocclusion in an Adult Indian Population: A Cross-Sectional Study

Introduction The formation of palatal rugae is completed in the early intrauterine stage, and because of their unique and permanent pattern in each individual, they can be utilized in forensics to identify a person. Objective The primary objective of this study was to determine an association between the rugae pattern and the dental malocclusion system described by Angle. Materials and methods A prospective cross-sectional, observational study was conducted on pretreatment dental casts of 400 subjects in an age range of 18-40 years. The samples were divided according to Angle's system of classification of malocclusion into Class I, Class II, and Class III. The number, length, pattern, and orientation of the three anterior-most primary rugae on both sides of the palatal region were studied. Results Significant differences were noted in the mean number of palatal rugae and mean lengths of rugae 1 and 2 on the right side (p < 0.001) and rugae 3 on the left (p < 0.001) side among the different malocclusion groups. Curved and wavy patterns were predominant, and significant differences were found among the groups (p < 0.05), whereas non-significant differences were observed in the rugae orientation between the groups on the right and left sides. Conclusions The current study showed significant differences in the length, number, and pattern of the palatal rugae among Angle's classes of malocclusion. Clinical implications Palatal rugae can be effectively used to identify dental malocclusion at an early stage and can, therefore, help intercept the developing malocclusion.

Novel method to delineate palatal rugae and assess their complexity using fractal analysis

Palatal rugae constitute significant morphological landmarks, with wide clinical applications in forensics, insertion of mini-screws, and superimposition. Their morphology has been studied mainly with indices relevant to their qualitative characteristics. The present paper aims at presenting a new quantitative method to evaluate their complexity, by means of box-counting fractal dimension analysis, and to investigate its inter- and intra-rater reliability. Twenty maxillary plaster models were scanned for the needs of this study. A sequence of steps, including cropping of the mesh, ball pivoting, distance mapping and fractal dimension analysis, performed with Viewbox 4 software, was followed. Box-counting fractal dimensions were calculated as a measure of rugae's complexity. Inter- and intra-rater reliability were investigated, using Bland-Altman analysis. Fractal dimensions ranged from 1.274 to 1.491 (average: 1.412). Bland-Altman analysis of inter- and intra-examiner reliability demonstrated that the 95% limits of agreement ranged from - 0.012 to 0.011 and from - 0.004 to 0.004, respectively. The method is reliable and can be applied in research and forensics. It offers comprehensive evaluation of the rugae's complexity and a complete set of information about their outlines and height profiles, with minimum user intervention.

Genetic variants in bone morphogenetic proteins signaling pathway might be involved in palatal rugae phenotype in humans

This study investigated, if genetic variants in BMP2, BMP4 and SMAD6 are associated with variations in the palatal rugae pattern in humans. Dental casts and genomic DNA from 75 patients were evaluated. Each patient was classified as follows: total amount of rugae; bilateral symmetry in the amount, length and shape of the palatal rugae; presence of secondary or fragmentary palatal rugae; presence of unifications; predominant shape; and predominant direction of the palatal rugae. The genetic variants in BMP2 (rs1005464 and rs235768), BMP4 (rs17563) and SMAD6 (rs2119261 and rs3934908) were genotyped. Genotype distribution was compared between palatal rugae patterns using the chi-square test (alpha = 0.05). The allele A was associated with the presence of secondary or fragmentary rugae for rs1005464 (OR = 2.5, 95%CI 1.1–6.3; p = 0.014). Secondary or fragmentary rugae were associated with the G allele in rs17563 (OR = 2.1, 95%CI 1.1–3.9; p = 0.017). rs17563 was also associated with rugae unification (p = 0.017 in the additive model). The predominant shape (wavy) was associated with rs2119261 (p = 0.023 in the additive model). The left–right symmetry of the length of primary rugae was associated with rs3934908 in the recessive model (OR = 3.6, 95%CI 1.2–11.7; p = 0.025). In conclusion, genetic variants in the BMP pathway impacted on palatal rugae pattern.