Anterior Alveolar Bone Thickness in Various Sagittal and Vertical Growth Patterns: A Cephalometric Cross-sectional Study

Introduction: Orthodontic diagnosis, treatment planning, and results are significantly influenced by anterior tooth movement. When orthodontic forces shift teeth close to the cortical bone, further tooth movement becomes more difficult, necessitating Orthodontists to evaluate the range of tooth movement prior to starting orthodontic therapy. Aim: To compare the anterior Alveolar Bone Thickness (ABT) in different sagittal and vertical growth patterns using lateral cephalograms. Materials and Methods: The present cross-sectional study included pretreatment lateral cephalograms of patients collected from the Orthodontic departmental archives of SDM College of Dental Sciences and Hospital, Dharwad, Karnataka, India, who had visited between June 2022 to January 2024. Healthy individuals within age group of 18-25 years with no previous history of orthodontic treatment were included in the study. A total of 176 cephalograms were traced manually and categorised as Group 1: Class-I (n=47) (ANB-2-4 degrees), Group 2: Class-II (n=87) (ANB>4 degrees), and Group 3: ClassIII (n=42) (ANB< 2 degrees).The total samples were again divided based on the FMA angle as Group A: Hypodivergent (FMA<22 degrees) (n=60) Group B: Normodivergent (FMA: 22-25 degrees) (n=59) and Group C: Hyperdivergent (FMA>25 degrees) (n=57). Certain cephalometric landmarks (a,b,c,d) were marked and the average ABT was calculated using a caliper/scale, and statistical analysis was done with Two-way Analysis of Variance (ANOVA), and a p-value <0.05 was considered. Results: The measured values of the U1-lab (maxillary labial ABT) showed significantly higher values for Group 3 compared to Group 2 (p-value=0.024). U1-pal (maxillary palatal ABT) (p-value=0.013), U1-lab (p-value=0.001), and (Md-Alv) (total mandibular alveolar thickness) (p-value=0.012) were found significantly higher in Group A compared to C. Conclusion: The study concludes that Class-III individuals have thicker anterior ABT than Class-II individuals, and hyperdivergent individuals possess thinner anterior ABT than other vertical jaw base divergences.