Work

Anterior arch form-specific analysis of alveolar bone thickness and tooth inclination: associations and clinical relevance in skeletal class II malocclusion

Year: 2025

Type: article

Abstract: BACKGROUND: To evaluate the associations among alveolar bone thickness, labio‑palatal tooth inclination, anterior dental arch form, and vertical skeletal pattern in skeletal Class II malocclusion, and to derive anterior arch form-indicated risk predisposition for orthodontic tooth movement. METHODS: Cone-beam computed tomography (CBCT) scans of 100 skeletal Class II malocclusion patients were grouped into square, ovoid, and tapered arch forms, and were further divided into three vertical skeletal pattern groups. Alveolar bone thickness at three levels (3 mm, 6 mm apical from cementoenamel junction (CEJ), and root apex) on labial and palatal sides of maxillary central incisors, lateral incisors, and canines, as well as labio-palatal inclinations of these teeth, were measured and compared. Two-way analysis of variance (ANOVA) was used to compare the thickness of alveolar bone among nine dental arch form and vertical skeletal pattern groups. Pearson's correlation test assessed the relationships between bone thickness and tooth inclination. RESULTS: Across eighteen measurement sites, two‑way ANOVA identified an arch‑form main effect at eight sites and a vertical‑pattern main effect at seven sites (P < 0.05). The square group exhibited thicker bone than tapered group on the palatal side of central incisors, as well as the labial side of lateral incisors and canines (P < 0.05), while the tapered group had the thickest bone at labial root apex of central incisors (2.33 mm, P < 0.05). Significant differences in thickness were observed among three vertical skeletal pattern groups at 6 mm apical from CEJ and root apex sites of incisors and canines (P < 0.05). Square group had the smallest incisor inclination (103.09° for central incisors and 104.05° for lateral incisors, P < 0.05), and square group had smaller canine inclination (98.80°) than ovoid group (104.58°, P < 0.05). Significant correlations between bone thickness and tooth inclination were observed in three arch form groups (P < 0.05). CONCLUSIONS: Anterior dental arch form associates with alveolar bone thickness and tooth inclination, suggesting its potential to be a rapid, chair‑side preliminary indicator of tooth movement limits in skeletal Class II malocclusion.

Source: BMC Oral Health

DOI: 10.1186/s12903-025-07121-9