Evaluation of Mandibular Bone Characteristics in Children with Onychophagy

Background/Objectives: This study aimed to evaluate mandibular bone characteristics in children with onychophagy using fractal analysis (FA) and panoramic radiomorphometric indices. Methods: Ninety children aged 7–11 years were included in this retrospective cross-sectional study and allocated to an onychophagy group (n = 45) or a healthy control group (n = 45). Fractal dimension (FD) was measured in four mandibular regions (condyle, mandibular angle, the interdental trabecular bone of the posterior dentate mandibular region, and the trabecular bone at the level of the tooth apices in the anterior dentate mandibular region) on panoramic radiographs. Radiomorphometric evaluation included the symphysis index (SI), anterior index (AI), molar index (MI), posterior index (PI), panoramic mandibular index (PMI), and mandibular cortical index (MCI). Between-group comparisons were performed using appropriate statistical tests (α = 0.05). Results: Children with onychophagy demonstrated significantly higher FD values than controls in all evaluated mandibular regions (all p < 0.0125 following Bonferroni correction). PMI values were also significantly higher in the onychophagy group (p < 0.001), whereas AI, SI, MI, and PI did not differ significantly between groups after Bonferroni correction. All participants were classified as MCI category C1. Intraobserver reliability was excellent for both FD and radiomorphometric measurements. Conclusions: Onychophagy was associated with differences in mandibular radiographic measurements in children. However, the retrospective cross-sectional design does not establish causality, and the clinical significance of these findings remains uncertain. Further longitudinal studies are needed to clarify these associations.