RESUMO
OBJECTIVE: To evaluate the effects of rapid maxillary expansion (RME) on middle ear function before, after, 3 months and one year from expansion procedure. PATIENTS AND METHODS: Eighteen patients with mean age of 8.1 years (±3.7) and posterior cross-bite were followed from pre expansion to one year after RME, regarding their hearing quality and middle ear function. Nine of them presented middle ear dysfunction (MED) and nine presented normal function (NF) before rapid maxillary expansion. Audiometric and tympanometric exams were taken before rapid maxillary expansion, after RME (15 days), 3 months and one year after rapid maxillary expansion. RESULTS: Among those in the MED group, no patient had acoustic reflex (AR) before rapid maxillary expansion; 67% presented type C tympanometric curve, 22% had type A and 11% had As type tympanometric curve. One year after rapid maxillary expansion, all patients presented AR and showed type A tympanometric curves. In NF group, all patients showed AR and type A tympanometric curves in all records. In both groups no audiograms presented significant variations along study. CONCLUSION: Rapid maxillary expansion has no deleterious effect in hearing quality and seems to improve middle ear function in children with posterior cross-bite in a one-year perspective.