Banca de DEFESA: ANNA ELLYSE GRANT DE OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANNA ELLYSE GRANT DE OLIVEIRA
DATE: 29/07/2025
TIME: 14:00
LOCAL: Departamento de Odontologia - AUDITÓRIO
TITLE:

Tomographic evaluation of interradicular distances and palatal thickness for the placement of mini-screws for the C-expander.

KEY WORDS:

Keywords: Palatal Expansion Technique; Cone-Beam Computed Tomography; Miniscrew.

PAGES: 81
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUBÁREA: Ortodontia
SUMMARY:

Introduction: The C-expander is a tissue-bone-borne expander anchored to the maxilla by miniscrews inserted obliquely into the interradicular spaces of the posterior teeth. However, there is still no consensus regarding the ideal sites for miniscrews placement in this appliance. Objective: To evaluate, using cone-beam computed tomography (CBCT), the interradicular distance, alveolar bone thickness, palatal cortical bone thickness, and palatal mucosa thickness in the posterior alveolar region of the maxilla, aiming to suggest the most suitable sites for miniscrew placement in the C-expander appliance. Materials and Methods: The sample consisted of 57 CBCT scans of the maxilla, selected from the database of a dental radiology center. Scans of individuals of both sexes aged 15 years and older were included. The sample was divided into three age groups: Group A (15–30 years), Group B (31–45 years), and Group C (46–59 years). The RadiAnt DICOM Viewer® software was used to measure the shortest interradicular distance distal to the canines (C–PM1), first premolars (PM1–PM2), second premolars (PM2–M1), and between the molars (M1–M2), in axial slices located 4, 6, 8, 10, and 12 mm from the gingival margin (GM). Alveolar bone thickness, palatal cortical bone thickness, and palatal mucosa thickness were measured in coronal slices at insertion angles of 30°, 45°, 60°, and 75° relative to the occlusal plane, at the same interradicular sites and vertical levels from the GM. Measurements were performed on one randomly selected side of the maxilla. Thirty percent of the sample was remeasured after one month to assess method error using the Intraclass Correlation Coefficient (ICC). Intergroup comparisons by sex and age group were conducted using three-way ANOVA followed by Tukey’s post hoc test, with a significance level of 5%. Results: An excellent reproducibility was found for all variables (ICC ≥ 0.777). Interradicular distance increased with vertical height at all sites, with the highest mean at the PM2–M1 region. Bone thickness was greater in anterior sites and in Group A, with significant sex differences across all sites, and decreased progressive with increased height and angulation. Cortical thickness was also greater in Group A, in anterior sites, and at lower heights. Palatal mucosa thickness increased progressively with greater height and angulation. No significant interactions were found between height/angulation and age or sex for any of the variables. Conclusions: The analysis of anatomical parameters enable the identification of the most favorable combinations of insertion height and angulation for each site. The most appropriate insertion angle for miniscrews decreased progressively from anterior to posterior regions. The C–PM1 site showed greater bone and cortical thickness; the PM2–M1 site had the widest interradicular distance; and in the M1–M2 region, more apical and less inclined insertions are recommended.

COMMITTEE MEMBERS:
Presidente - 1378325 - ARTHUR CESAR DE MEDEIROS ALVES
Interna - 3294216 - PATRICIA BITTENCOURT DUTRA DOS SANTOS
Externo à Instituição - ALEXANDRE ANTONIO RIBEIRO