Three-dimensional evaluation of palatal bone thickness for insertion of micro implants in a Portuguese population: a retrospective cone-beam CT study

OBJECTIVE: To examine the palatal bone thickness in a cohort of Portuguese patients representing various age groups to identify optimal insertion sites for enhancing the stability of orthodontic micro implants (MIs). To ascertain whether there are any age- or sex-related variations in palatal bone thickness. DESIGN: Retrospective observational study. METHOD: A total of 50 cone-beam computed tomography (CBCT) scans of patients aged 12-51 years (23 boys/men and 27 girls/women) were analysed. The CBCT scans were grouped according to age and sex. The palatal bone thickness was measured at five points: 4, 8, 12, 16 and 20 mm posterior to the incisive foramen (IF) and at 3, 6 and 9 mm lateral to the midpalatal suture (MPS). A total of 750 regions of interest were evaluated (15 for each of 50 patients). Two-way analysis of variance (ANOVA) and Student's t-tests were employed for data analysis, with a significance level of P < 0.05. RESULTS: The greatest thickness of palatal bone was found to be at 4 mm posterior to the ІF and 9 mm lateral to the MPS in all investigated groups, with a mean thickness of 12.29 ± 2.00 mm for girls/women and 13.59 ± 2.31 mm for boys/men; 13.30 ± 2.38 mm for adolescents and young adults, and 12.27 ± 2.03 mm for adults. Significant statistical differences were identified between male and female individuals and between different age groups (ANOVA, P < 0.05). CONCLUSION: Palatal bone thickness varied with sex and age; thus, these factors must be considered when selecting the appropriate length of MIs. In general, girls/women had a thinner palatal bone than boys/men. The palatal bone was significantly thicker in the adolescent and young adult age group (12-25 years) than in the adult age group (27-51 years). In addition, bone thickness decreased posteriorly within each sagittal section.