Rapid maxillary expansion in mouth breathers: a short-term skeletal and soft-tissue effect on the nose.

INTRODUCTION: Rapid maxillary expansion can change the form and function of the nose. The skeletal and soft tissue changes can influence the esthetics and the stability of the results obtained by the procedure. OBJECTIVE: The aim of this retrospective study was to evaluate the short-term effects of rapid maxillary expansion on the skeletal and soft tissue structures of the nose, in mouth-breathing patients, using a reliable and reproducible, but simple methodology, with the aid of computed tomography. METHODS: A total of 55 mouth-breathing patients with maxillary hypoplasia were assessed and were divided into an experimental group treated with rapid maxillary expansion(39 patients, 23 of which were male and 16 female, with an average age of 9.7 years and a standard deviation of 2.28, ranging from 6.5 to 14.7 years) and a control group (16 patients, 9 of which were male and 7 female, with an average age of 8.8 years, standard deviation of 2.17, ranging from 5.11 to 13.7 years). The patients of the experimental group were submitted to multislice computed tomography examinations at two different points in time: (T1) pre-rapid maxillary expansion and (T2) three months after the procedure. The control group underwent to the same exams at the same intervals of time. Four skeletal and soft tissue variables were assessed, comparing the results of T1 and T2. RESULTS: There was in the experimental group a significant increases in all the skeletal and soft tissue variables (p<0.05) but no significant alteration was found in the control group. When comparing the experimental group and the control group, the most important change occurred in the width of the pyriform aperture (p<0.001). CONCLUSION: Rapid maxillary expansion is capable of altering the shape and function of the nose, promoting alterations in skeletal and soft tissue structures. This kind of study may, in the future, permit the proper planning of esthetic procedures at the tip and base of the nose and also the performance of objective measurements in early or late surgical outcomes.