Effects of rapid maxillary expansion on the airways and ears

Abstract

The aim of this prospective study remained to describe the morphological and functional changes of the upper airways and the middle ears after rapid maxillary expansion (RME). Thirteen patients comprised the original study sample, of these three patients dropped out. Of the remaining 10 subjects, seven (two females, five males; average age, 8.7 years) underwent orthodontic RME with a Hyrax screw and three (one female, two males; average age, 8.3 years) served as the controls. Inclusion standards for the study group were a uni- or bilateral crossbite with the evidence of a maxillary deficiency. Prohibiting criteria were acute or chronic respiratory disease, allergies, cleft lip and palate, or absence of adenoids. An ear, nose, and throat (ENT) examination, lateral cephalometry, anterior rhinomanometry, tympanometry, and posterior rhinoscopy were carried out for each child at baseline (E1) and after 6 months (E2). Descriptive statistics were calculated for all diagnostic variables and correlations between the study and control group were evaluated.

Rhinomanometry showed a correlation (r = 0.57) between the size of the nasal pharyngeal area and nasal airflow, but only at 150 daPa. The size of the adenoids measured on the lateral cephalograms was correlated with the endoscopic findings. The size of the adenoids remained the same after RME. Patients with maxillary constriction had the largest adenoids and showed a negative pressure in the middle ear. However, this was reduced after RME.

The results suggest a possible impact of maxillary deficiency on otorhinological structures. RME may lead to otorhinological changes. Further interdisciplinary investigations are needed to corroborate these findings.

Introduction

The transverse dimension of the mandible is determined by the inclination of the maxillary bone base and the buccal segment surrounded by the alveolar bone (Solow, 1980). The reduced transverse size of the maxilla and the dental posterior crossbit are usually associated with an increase in nasal resistance (Löfstrand-Tideström et al., 1999). According to Helm (1986), transverse occlusal discrepancies occur in 9.4% of Danish boys and 14.1% of girls.

The increase in nasal resistance has been hypothesized to be related to various aspects of oral respiration and dentofascial development involving teeth and skeleton (Bushey, 1972; Linder-Aronson et al., 1986; Meredith 1987; Usumez et al. , 2003). The term adenoid facies has been used in English literature for at least a century (Proffit and Fields, 2000). Laptook (1981) supported this theory, describing the syndrome in a disease report. Characteristic features of this syndrome of bone development are nasal stenosis, elevation of the nasal tube, oral respiration, bilateral maxillary tooth crossbite, and a decrease in nasal permeability resulting from enlargement of the nasal turbines, along with upper palatal vault. Reducing the volume of the nasal airways.

Linder-Aronson et al. (1993) reported a significant increase in the volume of the sagittal airway and an almost improved nasal airflow, as well as a labial condition of the upper and lower incisors after adenoidectomy. Improvements in nasal airflow may have a positive effect on overall development in childhood (Kurol et al., 1998).