CBCT Assessment of Palatal Safe Zones in Adults with Various Skeletal Patterns

Introduction and aims: To investigate the differences in palatal bone thickness among adult patients with different sagittal skeletal patterns using Cone-Beam Computed Tomography (CBCT), and to analyse the safe regions for palatal anchor screw implantation in these patients. Methods: This is a retrospective cross-sectional study. We retrospectively selected preoperative CBCT data from 90 adult patients (age: 26.5 ± 5.8 years) with Angle Class malocclusion treated between 2023 and 2025, divided into skeletal Class I, II, and III groups (30 cases each, 1:1 male-to-female ratio). Bone thickness at 27 points on the left palatal midline was measured using Dolphin software, with 1-way ANOVA and LSD for analysis (α = 0.05). Results: For all skeletal classes, midpalatal bone thickness increased anterior-to-posterior (Class I: η² = 0.42; Class II: η² = 0.40; Class III: η² = 0.35, all P < .05), while lateral/paramedian regions showed the opposite (η² = 0.68-0.82, P<.05). Safe zones (≥6mm) for Class I/II included midpalatal middle/posterior, lateral, and paramedian anterior regions; Class III only had midpalatal posterior (7.59 ± 1.36mm). Conclusion: Palatal safe zones vary by sagittal skeletal pattern, providing critical references for anchor screw placement. Clinical Relevance: Our findings provide evidence-based safe zone maps to guide palatal anchor screw placement, so as to mitigate complications during orthodontic treatment. They also highlight the need to integrate AI-guided planning tools for enhanced accuracy, to inform good clinical practice.