Airway flow and audiologic ability evaluation after rapid maxillary expansion—Case report

1. Introduction 

Maxillary width deficiency is usually manifested in oral breathing patients causing some rhinologic and dentofacial problems such as decrease of nasal permeability, bilateral dental maxillary crossbite and decrease in airway size [1], [2], [3]. Rapid maxillary expansion is an orthopedic procedure commonly used to widen the maxilla and it is generally admitted that this technique is effective to correct palate narrowing due to suture median palatine opening [4]. As soon as the maxilla expands, both walls in nasal cavity move laterally while the floor of the nose drops inferiorly, increasing airway space [5], [6] and consequentially facilitating nasal breathing and air flow [7]. Several studies [2], [6], [8] report R.M.E. is effective when treating patients with auditory and respiratory problems since conductive hearing loss is one of the auditory disorders characterized by elevated air-conduction thresholds. The loss in hearing varies according to the severity and type of the physical change imposed on the mechanical system of the outer or middle ear [7]. Although arch narrowing can to be treated by orthopedics procedures, it is really important to know all advantages rapid maxillary expansion can bring, specifically in the auditory and respiratory apparatus. The purpose of this study was to evaluate through clinical, radiographic and audiologic exams a young oral breathing patient, with signs of nasal constriction, allergic rhinitis and maxillary constriction.

2. Method 

The patient G.B.M, an 8-year-old boy manifested narrowing maxillary and dental posterior crossbite. He was evaluated for allergic rhinitis and oral breathing by an otolaryngologist through airway flow exams performed, and then the subject had standard orthodontics documentation and pure-tone exam done. The orthodontist had planned patient's nonsurgical R.M.E. with a Haas-type palatal expander for narrowing maxillary and dental crossbite correction, following protocol of expansion: after cementation, the expander was turned two times a day, one time in the morning and one time in the night during the following 15 days. Expansion was discontinued when the palatal cusp of either of the maxillary molars was about to go into buccal crossbite [9], [10], [12]. At that time, the expansion screw was fused with a dab of acrylic for stabilization. Pretreatment pure-tone records (T1) preceded the start of treatment and the post-treatment records (T2) were taken 18 days after the first activation. A Vitratace 130SL espirometry device measured the air that entered and left the lung after maximum effort in aspiratory and expiratory processes before and after R.M.E., at same day pure-tone was performed, where the obtained volume took a form in relation to expiratory time. The expander was removed after 90 days of stabilization following orthodontics treatment.

3. Results and discussion 

Pretreatment espirometry record was 350ml while post-treatment record was 400ml. Rapid maxillary expansion increased significantly airway flow by 50ml [11]. Interacoustics AC 33 pure-tone audiogram measurement device was performed by the speech therapist for audiometric witch was done before and after R.M.E. to determinate patient́s hearing level. The results before R.M.E. (T1) were considered normal but there was an improvement in hearing ability after treatment (T2) (Table 1).

Table 1. Pretreatment (T1) and post-treatment (T2) audiometric evaluation.

	Frequency (Hz)	250Hz		500Hz		1000Hz		2000Hz
		T1	T2	T1	T2	T1	T2	T1	T2
	Right ear	15	10	20	15	20	15	15	10
	Left ear	15	15	15	10	20	15	20	10

Based on findings [7], [12], [13] it may be said that the hearing ability in patients with conductive hearing loss and maxillary narrowing should be corrected through rapid maxillary expansion. The skeletal changes occurred after R.M.E. procedure in the mouth, nasal cavity, oropharynx, and nasopharynx will modify the soft-tissue architecture overlying the bony structures of the nasomaxillary complex [14], [15]. It is known conductive hearing loss is often caused by upper respiratory infections, so when improving airway flow, auditory function will be consequentially beneficed. Although orthodontics treatment is conducted to correct dental and skeletal discrepancies, treatment outcomes of R.M.E. may also be effective on naso-respiratory and auditory of the growing children [2], [7], [12], [14], so those benefits could be applied specially in oral breathing patients who often manifest maxillary width deficiency.

4. Conclusion 

Positive effects on auditory and respiratory systems are possible with additional benefits of R.M.E. treatment in an oral breathing growing patient.