Long-term effects of orthodontic therapy on the maxillary dental arch and nasal cavity

Results of nose breathing evaluation during orthodontic treatment in children

Relevance. In the modern practice of an orthodontist, distal occlusion caused by respiratory dysfunction is increasingly more common. It is especially evident in early mixed dentition, i.e., in 6-8-year-old children with diagnosed pathology of ENT organs, namely, adenoids.Objective. The study aimed to evaluate the relationship between respiratory dysfunction and distal occlusion in children with early mixed dentition.Materials and methods. The study performed conventional anterior and posterior rhinoscopy, endoscopic examination of ENT organs, anterior active rhinomanometry, and masticatory muscles’ electromyography. The orthodontic examination included an oral examination, impression-taking, occlusion assessment, morphometric analysis of the jaw models and lateral cephalometric image measurements.Conclusion. In modern medical practice, the pathology of ENT organs and maxillofacial anomalies are closely related. Therefore, the collaboration between an orthodontist and an ENT specialist is the key to the effective treatment of distal occlusion in early mixed dentition.

The role of rapid maxillary expansion in pediatric obstructive sleep apnea: Efficacy, mechanism and multidisciplinary collaboration

This review aims to provide current knowledge about the efficacy, mechanism, and multidisciplinary collaboration of rapid maxillary expansion (RME) treatment in pediatric obstructive sleep apnea (OSA). OSA is a chronic disease characterized by progressively increasing upper airway resistance, with various symptoms and signs. Increasingly the evidence indicates that RME is a non-invasive and effective therapy option for children with OSA. Besides, the therapeutic mechanism of RME includes increasing upper airway volume, reducing nasal resistance, and changing tongue posture. Recent clinical researches and case reports also show that a multidisciplinary approach improves sleep-disordered breathing in children. Applied with adenotonsillectomy, mandibular advancement, continuous positive airway pressure, and comprehensive orthodontic treatment, RME can be more effective in recurrent or residual OSA.

Successful treatment of a child with Schwartz-Jampel syndrome using rapid maxillary expansion and CPAP

STUDY OBJECTIVES

We reported an 8-year-old male patient with Schwartz-Jampel syndrome, severe obstructive sleep apnea, constricted maxilla and moderate tonsillar hypertrophy. The syndrome is characterized by myotonia, skeletal dysplasia, and facial dysmorphism.

METHODS

CPAP was initially prescribed, but he was not able to tolerate due to a high pressure setting. Rapid maxillary expansion alone reduced AHI to 10.4 events/h.

RESULTS

When combined with CPAP, AHI is further reduced to 2.4 events/h. The patient has a better compliance with CPAP following rapid maxillary expansion therapy as the pressure setting decreased.

CONCLUSIONS

This is the first report utilizing a combination of rapid maxillary expansion and CPAP therapy to successfully treat severe pediatric OSA.

Evaluation of effects of a modified asymmetric rapid maxillary expansion appliance on the upper airway volume by cone beam computed tomography

BACKGROUND/PURPOSE

The rapid maxillary expansion is accepted as the gold standard for the treatment of unilateral posterior crossbite in growing children. This study used cone beam computed tomography (CBCT) to evaluate the effects of a modified asymmetric rapid maxillary expansion (ARME) appliance on the upper airway volumes.

MATERIALS AND METHODS

A modified ARME appliance was used on 12 adolescent male patients (mean age: 13.92 ± 0.82 years) with a class I skeletal relationship and posterior unilateral crossbite. Lateral cephalometric measurements and upper airway volume were evaluated using CBCT images. The posterior airway volumes of the oropharyngeal and nasopharyngeal airways were measured.

RESULTS

Cephalometric measurements showed significant (P < 0.05) posterior rotation of the mandible. There was no significant movement of the maxilla according to the cranial base on the sagittal plane. Nasopharyngeal and oropharyngeal airway volumes increased significantly (P < 0.05).

CONCLUSION

The results of this study demonstrate that treatment with the modified ARME has no significant effect on the maxilla but may increase the upper airway volume.

Relationship between olfaction and maxillofacial morphology in children with malocclusion

OBJECTIVES

Functional problems, including nasal flow problems, are associated with specific skeletal and dental features. Further, maxillary expansion has been associated with nasal airway resistance alterations. This study aimed to investigate whether there is a correlation between skeletal features and nasal airflow- and olfaction-related problems.

MATERIALS AND METHODS

This prospective study included 68 patients (30 boys, 38 girls; mean age 9 ± 2 years) examined at the Ohu University Hospital. We classified patients into three skeletal Classes (Class I, II, and III) based on the ANB angle. Olfactory disorder history was collected from the guardians. Maxillofacial measurements, nasal airflow assessments, and olfactory tests were performed using cephalometric analysis, rhinomanometry, and T&T olfactometer, respectively.

RESULTS

Malocclusion, resulting from skeletal mandibular protrusion and smaller maxilla, was associated with reduced olfaction in children. The detection and recognition thresholds of skeletal Class III were significantly higher than those of Classes I (p = .01) and II (p = .01). Significant correlations were observed between SNA and the detection threshold (r = -.50) as well as between nasion perpendicular-point A and the recognition threshold (r = -.53). The detection and recognition thresholds were significantly higher in Class III than in Classes I (r = .3) and II (r = -.1).

CONCLUSIONS

Maxillary growth and development may be associated with olfaction in children. Changing the maxillofacial morphology may improve olfactory function. In the future, we will investigate how malocclusion treatment affects olfactory function.

Efficacy of different designs of mandibular expanders: A 3-dimensional finite element study

INTRODUCTION

Nonsurgical mandibular expansion has been increasingly performed in recent years because it can effectively expand the mandibular dental arch. However, many types of mandibular expanders have been used in previous studies. No relevant studies have compared the biomechanical responses of different designs of mandibular expansion appliances with screws. Therefore, the purpose of this study was to analyze the stress distribution and displacement of the dentoalveolar structures according to different designs of mandibular screw expanders.

METHODS

Cone-beam computed tomography scans were used for 3-dimensional reconstruction of the mandibular finite element model. Four different designs of mandibular expanders, 1 removable expander (type A) and 3 fixed expanders (types B, C, and D), were added to the finite element models. Expanders were activated transversely for 0.2 mm. The initial tooth displacement and von Mises stress distribution were evaluated.

RESULTS

All the expanders enlarged the arch dimensions. In types A and B, the stress was mainly concentrated in the region of the anterior teeth, along with greater tooth displacement, whereas in types C and D, greater stress and displacement occurred in the region of the posterior teeth. Type A showed the greatest amount of transverse displacement. Type D was more efficient in the region of the posterior teeth.

CONCLUSIONS

Types A and B should be used with great caution in the clinic because of their incompatible expansion pattern. Type D is the recommended mandibular expansion appliance because of its appropriate expansion pattern.

Effects on nasal airflow and resistance using two different RME appliances: a randomized controlled trial

Objectives

To evaluate and compare the effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion (RME) on nasal airflow and resistance.

Material and methods

Fifty-four consecutive patients who met the eligibility criteria were recruited from September 2010 to December 2015. Of these 54 subjects, 40 agreed to participate in the part of the study involving evaluation of nasal flow and resistance. The 40 subjects were allocated to either the TB group, mean age 9.7 years (SD 1.5), or the TBB group, mean age 10.2 years (SD 1.4). All subjects performed rhinomanometric registration at baseline (T0), but only 30 attended the post-expansion registration (T1), of whom 16 had been randomized to the TB group and 14 to the TBB group. The study outcomes, nasal airflow and nasal airway resistance, were evaluated with linear regression adjusted for baseline variable of the outcome to compare the study groups with complete cases strategy as well as after multiple imputation (MI).

Randomization

Participants were randomly allocated in blocks of different sizes, using the concealed allocation principle in a 1:1 ratio. The randomization list was computer generated to ensure homogeneity between groups.

Blinding

Blinding was done only for outcome assessor due to clinical limitations. The care providers at the ENT unit who conducted all the rhinomanometry examinations were blinded to which group the patients were allocated to.

Results

Complete case analysis showed significantly higher post-expansion nasal airflow values for the TBB group compared with the TB group, mean difference 51.0 cm3/s (P = 0.018). The evaluation after MI showed a similar significant mean difference, 52.7 cm3/s (P = 0.020) in favour of the TBB group when taking into account the missing values from the T1 examination. Even reduction in nasal airway resistance showed similar pattern in favour of the TBB group.

Limitations

Our results represent the short-term effects. A longer follow-up period would have been preferable.

Conclusions

The TBB RME induced significantly higher nasal airway flow and lower nasal resistance values than TB RME. It might be wiser to use TBB RME in cases with constricted maxilla and upper airway obstruction.

Registration

This trial was not registered in any external sites.

Protocol

The protocol was not published before trial commencement.

Skeletal effects of RME in the transverse and vertical dimensions of the nasal cavity in mouth-breathing growing children

Introduction:

Maxillary constriction is a dentoskeletal deformity characterized by discrepancy in maxilla/mandible relationship in the transverse plane, which may be associated with respiratory dysfunction.

Objective:

The objective of this study was to evaluate the skeletal effects of RME on maxillary and nasal transverse dimensions and compare the differences between males and females.

Methods:

Sixty-one mouth-breathers patients with skeletal maxillary constriction (35 males and 26 females, mean age 9.6 years) were included in the study. Posteroanterior (PA) radiographs were taken before expansion (T1) and 3 months after expansion (T2). Data obtained from the evaluation of T1 and T2 cephalograms were tested for normality with the Kolmogorov-Smirnov method. The Student's t-test was performed for each measurement to determine sex differences.

Results:

RME produced a significant increase in all linear measurements of maxillary and nasal transverse dimensions.

Conclusions:

No significant differences were associated regarding sex. The RME produced significant width increases in the maxilla and nasal cavity, which are important for treatment stability, improving respiratory function and craniofacial development.

Short-term evaluation of tegumentary changes of the nose in oral breathers undergoing rapid maxillary expansion

Introduction

Rapid maxillary expansion is an orthodontic and orthopedic procedure that can change the form and function of the nose. The soft tissue of the nose and its changes can influence the esthetics and the stability of the results obtained by this procedure.

Objective

The objective of this study was to assess the changes in nose dimensions after rapid maxillary expansion in oral breathers with maxillary atresia, using a reliable and reproducible methodology through computed tomography.

Methods

A total of 30 mouth-breathing patients with maxillary atresia were analyzed and divided into a treatment group who underwent rapid maxillary expansion (20 patients, 10 of which were male and 10 female, with a MA of 8.9 years and a SD of 2.16, ranging from 6.5 to 12.5 years) and a Control Group (10 patients, 5 of which were male and 5 female, with a MA of 9.2 years, SD of 2.17, ranging from 6.11 to 13.7 years). In the treatment group, multislice computed tomography scans were obtained at the start of the treatment (T1) and 3 months after expansion (T2). The patients of the control group were submitted to the same exams at the same intervals of time. Four variables related to soft tissue structures of the nose were analyzed (alar base width, alar width, height of soft tissue of the nose and length of soft tissue of the nose), and the outcomes between T1 and T2 were compared using Osirix MD software.

Results

In the TG, the soft tissues of the nose exhibited significant increases in all variables studied (p < 0.05), whereas, changes did not occur in the control group (p > 0.05). In the treatment group, mean alar base width increased by 4.87% (p = 0.004), mean alar width increased by 4.04% (p = 0.004), mean height of the soft tissues of the nose increased by 4.84% (p = 0.003) and mean length of the soft tissues of the nose increased by 4.29% (p = 0.012).

Conclusion

In short-term, rapid maxillary expansion provided a statistically significant increase in the dimensions of the soft tissues of the nose.

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.

Airway compartments volume and oxygen saturation changes after rapid maxillary expansion: a longitudinal correlation study

OBJECTIVE

To evaluate changes in airway volumes and respiratory performance in patients undergoing rapid maxillary expansion and determine whether any correlations exist between the morphological and respiratory functional modifications induced by rapid maxillary expansion and pretreatment airway stenosis.

MATERIALS AND METHODS

Fifteen patients (11 females and 4 males; mean age, 7.5 ± 0.3 years) were enrolled in the study. Each patient underwent cone beam computed tomography and polysomnography examination before rapid maxillary expansion and after the removal of the maxillary expander 12 months later. The airway regions were segmented and the volumes were computed.

RESULTS

The upper, middle, and lower airway volumes were significantly increased 2305 mm(3), 1144 mm(3), and 1915 mm(3), respectively. Similarly, oxygen saturation was increased (+5.3%) and the apnea/hypopnea index was improved (-4.2 events). All the observed modifications were statistically significant (P < .05). Baseline middle and lower airway volume showed a significant negative correlation with the oxygen saturation modification.

CONCLUSIONS

The results of this study showed that when rapid maxillary expansion is performed in subjects having posterior crossbite, oxygen saturation is improved. The improvement is greater in subjects having more reduced middle and lower airway volumes.

The role of rapid maxillary expansion in the promotion of oral and general health

Rapid maxillary expansion (RME) is an effective orthopedic procedure that can be used to address problems concerned with the growth of the midface. This procedure also may produce positive side effects on the general health of the patient. The aim of the present consensus paper was to identify and evaluate studies on the changes in airway dimensions and muscular function produced by RME in growing patients. A total of 331 references were retrieved from a database search (PubMed). The widening of the nasal cavity base after midpalatal suture opening in growing patients allows the reduction in nasal airway resistance with an improvement of the respiratory pattern. The effects of RME on the upper airway, however, have been described as limited and local, and these effects become diminished farther down the airway, possibly as a result of soft-tissue adaptation. Moreover, limited information is available about the long-term stability of the airway changes produced by RME. Several studies have shown that maxillary constriction may play a role in the etiology of more severe breathing disorders such as obstructive sleep apnea (OSA) in growing subjects. Early orthodontic treatment with RME is able to reduce the symptoms of OSA and improve polysomnographic variables. Finally, early orthopedic treatment with RME also is beneficial to avoid the development of facial skeletal asymmetry resulting from functional crossbites that otherwise may lead to functional and structural disorders of the stomatognathic system later in life.

Orthodontics treatments for managing obstructive sleep apnea syndrome in children: A systematic review and meta-analysis

A small maxilla and/or mandible may predispose children to sleep-disordered breathing, which is a continuum of severity from snoring to obstructive sleep apnea. Preliminary studies have suggested that orthodontic treatments, such as orthopedic mandibular advancement or rapid maxillary expansion, may be effective treatments. The aim is to investigate the efficacy of orthopedic mandibular advancement and/or rapid maxillary expansion in the treatment of pediatric obstructive sleep apnea. Pubmed, Medline, Embase, and Internet were searched for eligible studies published until April 2014. Articles with adequate data were selected for the meta-analysis; other articles were reported in the qualitative assessment. Data extraction was conducted by two independent authors. A total of 58 studies were identified. Only eight studies were included in the review; of these, six were included in the meta-analysis. The research yielded only a small number of studies. Consequently, any conclusions from the pooled diagnostic parameters and their interpretation should be treated carefully. Although the included studies were limited, these orthodontic treatments may be effective in managing pediatric snoring and obstructive sleep apnea. Other related health outcomes, such as neurocognitive and cardiovascular functions have not yet been systematically addressed. More studies are needed with larger sample size, specific inclusion and exclusion criteria and standardized data reporting to help establish guidelines for the orthodontic treatment of pediatric obstructive sleep apnea.

Nasal airway changes in bone-borne and tooth-borne rapid maxillary expansion treatments

INTRODUCTION

Our aim was to determine the presence of a correlation between the nasal airway skeletal transverse dimension and air intake changes in rapid maxillary expansion treatments.

METHODS

Sixty-one patients with maxillary transverse deficiency (11-17 years old) were randomly allocated into three groups (two treatment groups - tooth- [hyrax] or bone-borne [miniscrew-implant-based] expander - and one control group). Cone-beam computed tomography scans (CBCT) were obtained from each patient as well as acoustic rhinometry (AR) readings. Specifically, in AR, airway volume up to minimum cross-sectional areas (Vol. 1&2) and minimum cross-sectional areas (Min. 1&2) in the nasal cavity were measured. Records were obtained at two time points (initial T1 and at removal of appliance at 6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on the nasal base. Descriptive statistics were compiled and student's t-test was used.

RESULTS

Of the 480 pairings measured, only 9 showed statistically significant positive correlations between T1 and T2. Correlation data were highly variable in all categories, showing no clear tendencies. No statistical difference was found when comparing all groups in terms of airway changes.

CONCLUSION

With very few positive correlations observed and otherwise highly variable data, no really conclusive finding was obtained to suggest any realistic correlation between changes in the skeletal dimensions and changes in the nasal airway.

Model of oronasal rehabilitation in children with obstructive sleep apnea syndrome undergoing rapid maxillary expansion: Research review

Rapid maxillary expansion (RME) is a widely used practice in orthodontics. Scientific evidence shows that RME can be helpful in modifying the breathing pattern in mouth-breathing patients. In order to promote the restoration of physiological breathing we have developed a rehabilitation program associated with RME in children. The aim of the study was a literature review and a model of orofacial rehabilitation in children with obstructive sleep apnea undergoing treatment with rapid maxillary expansion. Muscular training (local exercises and general ones) is the key factor of the program. It also includes hygienic and behavior instructions as well as other therapeutic procedures such as rhinosinusal washes, a postural re-education (Alexander technique) and, if necessary, a pharmacological treatment aimed to improve nasal obstruction. The program should be customized for each patient. If RME is supported by an adequate functional rehabilitation, the possibility to change the breathing pattern is considerably amplified. Awareness, motivation and collaboration of the child and their parents, as well as the cooperation among specialists, such as orthodontist, speech therapist, pediatrician and otolaryngologist, are necessary conditions to achieve the goal.

N-butanol olfactory threshold and nasal patency before and after palatal expansion in children. A preliminary study

OBJECTIVES

Olfaction is based on the function of the nasal olfactory receptors. Children can well detect and respond to odors in order to have information about food and environment. Rapid maxillary expansion seems to improve dental class and increase nasal patency correcting oral respiration in children. Nevertheless, there are no studies demonstrating that expansion in pediatric patients could influence olfactory sensitivity. The aim of this study was to evaluate olfactory threshold and nasal patency in children aged from 6 to 12 years before and after rapid maxillary expansion.

METHOD

N-butanol olfactory thresholds, anterior active rhinomanometry, and peak nasal inspiratory flow were measured in 12 children (6-12 years) before (T0), 20 days (T1), and 6 months after rapid maxillary expansion application (T2).

RESULTS

A significant lower olfactory threshold was found comparing T2 and T0 N-butanol olfactory threshold values (p=0.038). Peak nasal inspiratory flow showed a significant improvement both at T1 and T2, with respect to T0 values (p=0.043 and p=0.0001, respectively). T2 nasal resistances showed a trend towards a significant reduction when compared with T1 values (p=0.15).

CONCLUSION

This pilot study suggested that rapid maxillary expansion may lead to improved N-butanol olfactory thresholds, at least 6 months after palatal expansion. Furthermore, rapid maxillary expansion seems to improve peak nasal inspiratory flow values, and finally although with lower sensitivity, reduce nasal resistances as measured by rhinomanometry.

Role of mandibular displacement and airway size in improving breathing after rapid maxillary expansion

BACKGROUND

Oral breathing and maxillary deficiency are often associated with steep mandibular plane angle, and retrognathic mandible compared with the faces of healthy controls. Some studies suggested that after rapid maxillary expansion, improvement in nasal breathing and repositioning of mandible with transitory increasing of facial height and, in some cases, spontaneous forward repositioning might occur. The above-mentioned mandibular effects could contribute to enlarge oropharynx volume with repositioning of tongue and soft palate with an improvement of upper airway volume after treatment. The aim of this study was to investigate by cone beam computed tomography the role of oropharyngeal volume and mandibular position changes after rapid maxillary expansion in patients showing improved breathing pattern confirmed by polysomnography exam.

METHODS

The final sample of this retrospective study comprised 14 Caucasian patients (mean age 7.6 years) who undergone rapid maxillary expansion with Haas-type expander banded on second deciduous upper molars. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). Mandibular landmarks localization and airway semiautomatic segmentation on cone beam computed tomography scans allowed airway volume computing and measurements.

RESULTS

No significant differences were found between oropharyngeal airway changes and mandibular displacement after rapid maxillary expansion in growing patients.

CONCLUSIONS

The suggested improvement in upper airway and breathing after rapid maxillary expansion should be further related to different compartments of airway such as rhinopharynx and nasal cavity.

Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study

INTRODUCTION

Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction. However, the effect of RME on tongue posture and pharyngeal airway volume in children with nasal airway obstruction is not clear. In this study, we evaluated these effects using cone-beam computed tomography.

METHODS

Twenty-eight treatment subjects (mean age 9.96 ± 1.21 years) who required RME treatment had cone-beam computed tomography images taken before and after RME. Twenty control subjects (mean age 9.68 ± 1.02 years) received regular orthodontic treatment. Nasal airway ventilation was analyzed by using computational fluid dynamics, and intraoral airway (the low tongue space between tongue and palate) and pharyngeal airway volumes were measured.

RESULTS

Intraoral airway volume decreased significantly in the RME group from 1212.9 ± 1370.9 mm(3) before RME to 279.7 ± 472.0 mm(3) after RME. Nasal airway ventilation was significantly correlated with intraoral airway volume. The increase of pharyngeal airway volume in the control group (1226.3 ± 1782.5 mm(3)) was only 41% that of the RME group (3015.4 ± 1297.6 mm(3)).

CONCLUSIONS

In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway.

Changes in nasal air flow and school grades after rapid maxillary expansion in oral breathing children

Objective: To analyse the changes in nasal air flow and school grades after rapid maxillary expansion (RME) in oral breathing children with maxillary constriction. Material and Methods: Forty-four oral breathing children (mean age 10.57 y) underwent orthodontic RME with a Hyrax screw. Forty-four age-matched children (mean age 10.64 y) with nasal physiological breathing and adequate transverse maxillary dimensions served as the control group. The maxillary widths, nasal air flow assessed via peak nasal inspiratory flow (PNIF), and school grades were recorded at baseline, and 6 months and one year following RME. Results: After RME, there were significant increases in all the maxillary widths in the study group. PNIF was reduced in the study group (60.91 ± 13.13 l/min) compared to the control group (94.50 ± 9.89 l/min) (P < 0.000) at the beginning of the study. Six months after RME, a significant improvement of PNIF was observed in the study group (36.43 ± 22.61). School grades were lower in the study group (85.52 ± 5.74) than in the control group (89.77 ± 4.44) (P < 0.05) at the baseline, but it increased six months after RME (2.77 ± 3.90) (P < 0.001) and one year later (5.02 ± 15.23) (P < 0.05). Conclusions: Nasal air flow improved in oral breathing children six months and one year after RME. School grades also improved, but not high enough to be academically significant.

Key words:Maxillary constriction, oral breathing, nasal air flow, rapid maxillary expansion, school grades.

Does rapid maxillary expansion have long-term effects on airway dimensions and breathing?

INTRODUCTION

In this systematic review, we identified and qualified the evidence of long-term reports on the effects of rapid maxillary expansion (RME) on airway dimensions and functions.

METHODS

Electronic databases (Ovid, Scirus, Scopus, Virtual Health Library, and Cochrane Library) were searched from 1900 to September 2010. Clinical trials that assessed airway changes at least 6 months after RME in growing children with rhinomanometry, acoustic rhinometry, computed tomography, or posteroanterior and lateral radiographs were selected. Studies that used surgically assisted RME and evaluated other simultaneous treatments during expansion, systemically compromised subjects, or cleft patients were excluded. A methodologic-quality scoring process was used to identify which studies would be most valuable.

RESULTS

Fifteen articles fulfilled the inclusion criteria, and full texts were assessed. Three were excluded, and 12 were assessed for eligibility. Four articles with low methodologic quality were not considered. The remaining 8 were qualified as moderate. The posteroanterior radiographs showed that nasal cavity width increases; in the lateral radiographs, decreased craniocervical angulation was associated with increases of posterior nasal space. Cone-beam computed tomography did not show significant increases of nasal cavity volume. Rhinomanometry showed reduction of nasal airway resistance and increase of total nasal flow, and acoustic rhinometry detected increases of minimal cross-sectional area and nasal cavity volume.

CONCLUSIONS

There is moderate evidence that changes after RME in growing children improve the conditions for nasal breathing and the results can be expected to be stable for at least 11 months after therapy.