J Dent Oral Biol | Volume 9, Issue 2 | Research Article | Open Access

3D Evaluation of Changes in A Point and Premaxilla after Maxillary Protraction with Rapid Maxillary Expansion by Voxel Superimposition Technique

Hu XY^1*, Cheung GSP¹, Zhang YY², Sun RN³, Fang P¹ and Dong FS⁴

¹Department of Dental Surgery, The University of Hong Kong-Shenzhen Hospital, China ²School of Basic Medical Sciences, Hebei University, China ³Department of Dentistry, Shijiazhuang City Second Hospital, China ⁴College of Stomatology, Hebei Medical University, China

^*Correspondance to: Xiao-Ying Hu 

Abstract

Objective: To evaluate the changes of premaxilla and A point in the midsagittal plane after maxillary protraction with rapid maxillary expansion by voxel superimposition technique in Cone-Beam Computed Tomography (CBCT) in growing patients, and to investigate the possible correlations between premaxillary changes and A point advancement. Materials and Methods: The CBCT records of 46 patients with skeletal Class III malocclusion characterized by maxillary hypoplasia were selected from our CBCT database. 23 patients (14 boys and 9 girls, 8.23 ± 11.46 years old) who underwent Maxillary Protraction with Rapid Maxillary Expansion (RME-MP). The CBCT scan was performed before (T1) and after treatment (T2), the interval is on average 8 to 10 months. 23 patients (11 boys and 12 girls, 8.67 ± 13.31 years old) who did not receive RME-MP served as the control group. Midsagittal slices of the CBCT images were used to evaluate the thickness, labial and palatal aspects, and cross-sectional area of the premaxilla. Paired samples were used for statistical comparison. Correlation between premaxillary changes and A point was analyzed by Pearson correlation coefficient. Results: The PMMT and PMCSA were significantly decreased, and the PMPH was increased after RME-MP. The correlation analysis of the PMBT changes showed negative correlations with the IFA-AA changes (P<0.01). Negative correlations between the PMCSA changes and IFA-AA changes (P<0.05). Conclusion: The changes in the thickness and cross-sectional area of the premaxilla were negatively correlated with the difference of the IF point Advancement (IFA) and the A point Advancement (AA).

Keywords:

Premaxilla; A point; Maxillary protraction; Rapid maxillary expansion; Cone-beam computed tomography

Citation:

Hu XY, Cheung GSP, Zhang YY, Sun RN, Fang P, Dong FS. 3D Evaluation of Changes in A Point and Premaxilla after Maxillary Protraction with Rapid Maxillary Expansion by Voxel Superimposition Technique. J Dent Oral Biol. 2024; 9(2): 1232.