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

• Published in: Scientific reports 2022-12, Vol.12 (1), p.21749-21749, Article 21749
• Main Authors: Makrygiannakis, Miltiadis A., Vastardis, Heleni, Athanasiou, Athanasios E., Halazonetis, Demetrios J.
• Format: Article
• Language: English
• Subjects: 692/700/139; 692/700/3032; 692/700/3032/3124; 692/700/3032/3145; Forensic science; Forensic sciences; Fractals; Humanities and Social Sciences; Maxilla; multidisciplinary; Reproducibility of Results; Science; Science (multidisciplinary); Software
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-25910-y

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.