Comparação dos efeitos esqueléticos, alveolares e dentários após expansão rápida da maxila dento-suportada e dento-ósseo suportada em pacientes pós-surto de crescimento puberal: estudo feito a partir de medidas angulares

Abstract

Rapid palatal expansion (RPE) is an auxiliary procedure in orthodontic treatment that aims to increase the transverse maxillary dimension, also providing a rotational movement of zygomaticomaxillary complex. The objective of this study is to evaluate the effects on maxillary base bone, on alveolar process of the maxilla and on upper first molars, through angular measurements, after conventional RPE with hyrax expander and with miniscrew-assisted rapid palatal expansion (MARPE), and identify the fulcrum of rotation after treatment with both techniques. For this purpose, 31 patients were selected (HYRAX group: n = 17, mean age 14.7 + 0.8 years; MARPE group: n = 14, mean age 16.2 + 2 years) with indication for RPE. Cone-beam computed tomography (CBCT) images were taken before treatment (T1), immediately after expansion (T2), and after a 6-month retention period (T3). The CBCT images were oriented and superimposed on the anterior cranial base using Dolphin Imaging software, so that the measurements of interest were randomly performed by the same examiner. The whole process of manipulating and measuring the CBCT images was performed twice in six patients, with an interval of 15 days, to assess method error. For statistical analysis, Jamovi software version 2.3.21 was used. The Intraclass Correlation Coefficient (ICC) was greater than 0.90 for all measures, demonstrating excellent replicability of the method. In the HYRAX group, the fulcrum of rotation was located at or below the frontozygomatic suture (FZS), while in the MARPE group the fulcrum was located at or above the FZS. In the HYRAX group, it was observed that 47% (1.54o) of the response obtained was of dental origin, 20% (0.68o) of alveolar origin and 33% (1.09o) of skeletal origin, while in the MARPE group the skeletal response was 70% (2o), alveolar response was 18% (0.52o) and dental response was 12% (0.34o), with a statistically significant difference between groups in the skeletal (p = 0.005) and dental (p < 0.001) regions. Regarding the retention phase, the HYRAX group had a relapse of 50% in skeletal region, 53% in alveolar region and 32% in dental region, while the MARPE group had a relapse of 41% in skeletal region, 27% in alveolar region and 28% in dental region, with no statistically significant difference between groups. In conclusion, although both techniques were efficient in correcting the initial transverse deficiency, with no difference regarding the stability of the results, the difference found between groups suggests that miniscrew-assisted rapid palatal expansion (MARPE) should be indicated for borderline cases, where minimum compensatory tooth movement is desired.