Effects of Rapid Maxillary Expansion on Conductive Hearing Loss

Abstract

Objective: To test the null hypothesis that rapid maxillary expansion (RME) with a rigid bonded appliance has no effect on conductive hearing loss (CHL) in growing children. Materials and Methods: Fifteen growing subjects (mean age 13.43 Ϯ 0.86 years) who had narrow maxillary arches and CHL participated in this study. Three pure-tone audiometric and tympanometric records were taken from each subject. The first records were taken before RME (T1), the second after maxillary expansion (T2) (mean ϭ 0.83 months), and the third after retention (mean ϭ 6 months) and fixed appliance treatment (approximately 2 years) periods (T3). The data were analyzed by means of analysis of variance (ANOVA) and least significant difference (LSD) tests. Results: Hearing levels of the patients were improved and air-bone gaps decreased at a statistically significant level (P Ͻ .001) during active expansion (T2-T1) and the retention and fixed appliance treatment (T2-T3) periods. Middle ear volume increased in all observation periods. However, a statistically significant increase was observed only in the T2-T3 period. No significant change was observed in the static compliance value. Conclusions: The hypothesis is rejected. RME treatment has a positive and statistically significant effect on both improvements in hearing and normal function of the eustachian tube in patients having transverse maxillary deficiency and CHL.

Efeitos da expansão rápida de maxila na audição: revisão sistemática da literatura

“…A s t h e r e s u l t o f t h e i n i t i a l s e a r c h , 1 3 s t udies (9,10,11,14,15,16,17,18,19,20,21,22,23) were identified, among which 6 (10,16,19,20,21,22) attended inclusion criteria and were considered relevant for this work's sample. Two (24,25) more were added to them, classified as additional references, found in the bibliographic references of the selected studies.…”

“…The average age of participants in the research was 6 to 8 (10,20,21,24) and 12 to 14 (16,22,25) . The population was equally composed by males and females, but in two researches, there was bigger female participation (16,21) . As for the type of dental procedure for RME, in one study (25) the Haas device was used for expansion.…”

“…However, others used Hyrax (21,22,25) and Butterfly (10) expanders. Three studies did not inform the used device during RME (16,19,20) . As for the activation of the expanding screw, there were differences among the studies.…”

“…In another study (20) , patients were instructed to activate the screw three times a day, for 7 to 14 days, until the necessary expansion for each individual was concluded. Other authors (16) cited that the expander was activated twice a day, once in the morning and at night, until reaching proper expansion. However, in another study (10) , patients were instructed to activate 1/4 of the screw turn, three times a day (morning, afternoon, night), differently from the study conducted in Canada (19) , where the screw was activated 0.3-0.5 mm per day, approximately, for 2 to 4 weeks, until obtaining 4-8 mm expansion.…”

“…Some researchers (10,16,19,21,24,25) also used tympanometry. In all studies, patients were concomitantly examined by an otolaryngologist and/or had their otolaryngology history investigated.…”