Evaluación de los cambios esqueléticos verticales post tratamiento ortodóntico de la expansión maxilar rápida con aparato de Haas y Hyrax / Evaluation of the vertical skeletal changes post-orthodontic treatment of the rapid maxillary expansion with Haas and Hyrax appliances

RESUMEN

El propósito del estudio fue determinar si los cambios esqueléticos verticales producidos por la ERM son perjudiciales para el tratamiento de los pacientes dolicofaciales y si existen diferencias entre ambos tipos de aparatos. Material y métodos: Evaluamos las dimensiones esqueléticas verticales en las radiografías cefalométricas laterales pre y post tratamiento ortodóntico de 12 pacientes tratados (Gt) con ERM (aparato de Haas o Hyrax); y, un grupo control (Gc) de 12 pacientes tratados con aparatología fija y con características similares al Gt. Resultados: Las medias iniciales y finales para las medidas lineales (AFAT, AFAI, AFPT, AFPS) aumentan para ambos grupos y en las medidas angulares (SN-PPº, SN-PMº) se observa una disminución en el ángulo SN-PP para el Gt. Al comparar los valores finales encontramos un plano palatino más paralelo al plano SN en el Gt. No se encontraron diferencias significativas al analizar los pacientes tratados por aparato o al comparar los distintos patrones faciales. Conclusiones: No existen diferencias significativas en los efectos esqueléticos verticales producidos por los aparatos de Haas o Hyrax y los efectos indeseados producidos por la EMR son despreciables, por lo que no existen contra indicaciones para realizar este procedimiento en pacientes dolicofaciales.

ABSTRACT

The purpose of this study was to determine if the vertical skeletal changes produced by the rapid maxillary expansion (RME) appliances are harmful for the dolicofacial patients, and if there are differences between both appliances. Material and methods: Vertical skeletal dimensions of the lateral cephalograms pre and post orthodontic treatment of 12 patients treated (Gt) with RME (either Haas or Hyrax expanders) and a control group (Gc) of 12 patients treated with fixed appliances with similar characteristics as the group Gt were evaluated. Results: Initial and final average for the linear measurements (AFAT, AFAI, AFPT, AFPS) increase for both groups. However, when assessing the angular measurements (SN-PPº, SN-PMº) a decrease in the SN-PPº angle is observed for the group Gt. When comparing the initial values of both groups, no significance differences were found; nevertheless the comparison of the final values shows a more parallel palatal plane in the group Gt. No statistical differences were found when evaluating patients with the different appliances or with different facial patterns. Conclusion: There were no statistical significant differences between the patients of the group Gt and the patients of the group Gc. This indicates that the undesirable effects produced by the RME devices were not observed and suggests that no absolute contra indications exist for using this procedure in patients with an increased lower anterior facial height. There were no significant differences observed in the skeletal effects produced by either the Haas or Hyrax appliances.