Rapid Maxillary Expansion In Children Research Articles

Mandibular response after rapid maxillary expansion in mixed dentition children with different vertical growth patterns: a retrospective study.

This study evaluated the mandibular development induced by rapid maxillary expansion (RME) therapy in mixed dentition patients with different vertical growth patterns through long-term observation. The research utilized a retrospective design that included two cohorts: a control group consisting of pediatric subjects with individualized malocclusions, and an experimental group received RME therapy. A total of 60 subjects were included; 37 in the RME group (17 males and 20 females) and 23 in the control group (13 males and 10 females). Based on mandibular plane angles, 19 pertinent cephalometric variables were quantified with Dolphin Imaging software, and participants were subclassified into high-angle and normal-angle subgroups. Changes in the groups during the observation period were statistically analyzed with a t-test. Compared to the control group, both sagittal parameters tended to decrease after treatment in the RME group (p < 0.05), and none of the vertical correlations were statistically different (p > 0.05). Within the normal-angle experimental subgroup, sagittal parameters markedly decreased when contrasted with their normal-angle control group (p < 0.05). Notably, a substantive decrease in overjet was solely observable in the sagittal dimension among the high-angle expansion subgroup when compared to the high-angle control subgroup (p < 0.05). In the vertical dimension, neither the normal-angle nor high-angle subgroups exhibited any statistically significant differences from their respective control cohorts (p > 0.05). Based on long-term observation, RME therapy promotes mandible sagittal growth of the mandible in subjects with normal-angle vertical growth patterns. A similar tendency was not observed in subjects with high-angle vertical growth patterns. In addition, the mandibular plane angle did not increase after RME in children with high-angles.

Oral health-related quality of life after rapid maxillary expansion in children:

Oral health-related quality of life after rapid maxillary expansion in children:

Changes in behavioral and cognitive abilities after rapid maxillary expansion in children affected by persistent snoring after long-term adenotonsillectomy: A noncontrolled study

The objective of this study was to verify changes in behavioral abilities and cognitive functions after rapid maxillary expansion (RME) in children with refractory sleep-disordered breathing (SDB) in the long term after adenotonsillectomy. A prospective clinical trial study using RME therapy was conducted. Participant inclusion criteria were children who had adenotonsillectomy with maxillary transverse deficiency and persistent SDB (obstructive apnea-hypopnea index ≥1). The study included 24 children aged 5-12 years, and of these 24 children, 13 had primary snoring and 11 had obstructive sleep apnea. The patients underwent laryngeal nasofibroscopy and a complete polysomnography. In addition, patients completed the Obstructive Pediatric Sleep Questionnaire and Obstructive Sleep Apnea 18-Item Quality-of-Life Questionnaire. Behavioral and neurocognitive tests were also completed before and after RME. The Obstructive Pediatric Sleep Questionnaire and Obstructive Sleep Apnea 18-Item Quality-of-Life scores showed a statistically significant decrease in both groups (P<0.001) after RME. The results showed that neurocognitive and behavioral parameters (Child Behavior Checklist scale) were similar in primary snoring and obstructive sleep apnea (OSA) groups before RME. In the OSA group, the mean scores of the "Somatic" and "Aggressiveness" domains decreased significantly (P<0.05). The cognitive functions did not register significant differences pre- and post-RME in any of the cognitive functions, except for visuospatial function in the OSA group. The noncontrolled design was a major limitation of our study. The need for treatment for SDB should consider the association of symptoms and behavioral disturbances with the child's obstructive apnea-hypopnea index. RME might prove to be an alternative treatment for children with SDB refractory to adenotonsillectomy, improving quality of life and behavioral aspects. However, a larger sample size with a control group is needed to substantiate these claims.

Effects of rapid maxillary expansion on sleep disturbance scale for children: A longitudinal CASE-series study.

To evaluate the effects of rapid maxillary expansion (RME) on Sleep Disturbance Scale for Children (SDSC) with maxillary atresia. The sample consisted of 27 paediatric patients evaluated through a Brazilian version of the SDSC, answered by their guardians at the following experimental time points: T0 (before installing the Hyrax expander), T1 (on the day of expander stabilization), T2 (3 months after expander stabilization), T3 (immediately after expander removal, following 6 months of retention), and T4 (3 months post-retention). Multilevel Poisson analysis adjusted for repeated measures was performed to compare outcomes across the assessment time points. The mean age of patients was 9.1 years (SD = 1.46). The total SDSC scores decreased and were statistically significant from T2 onwards (P < .01), with a decrease of 24% at T4 compared with T1 (IRR 0.76; 95% CI 0.69-0.84). The mean scores at T4 were already lower than the cutoff point for risk of sleep disorders. Regarding the specific domains, there was a significant reduction in sleep breathing disorders, sleep-wake transition disorders, and disorders of excessive somnolence as of T2 (P < .01), T3 (P < .05) and T4 (P < .05), respectively. RME in children with maxillary atresia had a positive effect on the reduction of total SDSC scores after 3 months of expander stabilization, sustained over 6 and 9 months and significant reduction in sleep breathing disorders domain, sleep-wake transition disorders domain, and disorders of excessive somnolence domain over time points.

Morphological Changes of the Epipharynx as a Result of Rapid Maxillary Expansion in Children

Rapid maxillary expansion（RME）is a technique used to treat dental malalignment. Consensus has yet to be reached changes in the epipharyngeal region associated with RME. The objective of this study was to ascertain the morphological changes that occur in the epipharyngeal region as a result of RME. In the present study, a comparative investigation of the pharyngeal tonsils and the epipharyngeal airway on lateral cephalograms scanned before and after RME was therefore performed. Fourteen patients who underwent orthodontic treatment for dental malalignment by RME were included. The mean length of pharyngeal tonsil（A）was 114.65 pixels before RME and 108.64 pixels after RME. The mean value of epipharyngeal space（N）was 210.72 pixels before RME and 233.95 pixels after RME. The mean A/N ratio was 0.547 before RME and 0.466 after RME. The mean pharyngeal tonsil（Pt）area was 16181.14 pixels before RME and 16407.71 pixels after RME. The mean airway（Air）area was 12488.96 pixels before RME and 16040.64 pixels after RME. The mean Pt / Ep（Ep = Pt + Air）area was 0.570 before RME and 0.502 after RME. In this study showed that the A/N and Pt/Ep ratios decreased significantly after RME. The N and Air area values also increased significantly, but there were no significant changes in the A and Pt area values. It was concluded that the decrease in the A/N and Pt/Ep ratios were due to the changes in the N and Air area values.

Advantages of Interceptive Orthodontic Treatment; Rapid Maxillary Expansion in Children with Malocclusion Resulting from Mouth Breathing Habits

Background: One of the causes of malocclusion in developing children is the practice of mouth breathing. Morphological disturbances may occur during the growth phase in children with chronic mouth breathing. This resulting in the unfavorable development of dentofacial and craniofacial complexes. Mouth breathing in children as a condition has come to the attention of health care professionals. Malocclusion incidence will be decreased and eventually eliminated with the early identification and treatment of these poor oral habits. Purpose: The study determines the benefits of interceptive orthodontics Rapid Maxillary Expansion treatment in children with malocclusion caused by the habit of mouth breathing. Methods: Data were gathered by searching and analyzing literature from electronic databases PubMed, Wiley, and Science Direct in the 2012 and 2022 publication period. Interceptive orthodontics; rapid maxillary expansion; mouth breathing; malocclusion and children keywords were used to conduct the systematic search of the data. Results: One of the most frequent malocclusions is caused by the practice of mouth breathing which narrows the maxillary arch. Some of the characteristic features are decreased distance between nasal cavity’s lateral walls, bilateral or unilateral posterior crossbite, crowding of the anterior teeth, and deep palate.

Age-dependent interactions of maxillary sutures during RME and their effects on palatal morphology : CBCT and dental cast analysis.

PurposeThe effects of rapid maxillary expansion (RME) on the transverse palatine and midfacial sutures have been extensively scrutinized. Unlike the dentition stage, age-dependency was not yet regarded when investigating morphological changes of the tooth-bearing palate. Therefore, the first aim of the present study was to analyse age-dependent sutural and morphological changes of the palate in selected patients by cone-beam computed tomography (CBCT) and dental cast analysis. Secondly, age-dependent effects of RME on width, height, and depth of the palate in the region of the maxillary palatine processes were investigated by a comprehensive dental cast study, so that the combination of results could be used to provide a biomechanical explanation of the occurring changes.MethodsCBCT datasets of 9 patients (between 7.3 and 13.8 years) were measured around the median palatal suture and compared with the results of an individualised dental cast analysis. In addition, possible effects on other maxillary sutures were investigated. In the dental cast study, changes after RME in the tooth-bearing palate were analysed three-dimensionally in 60 children and adolescents. It was possible to divide those into three equally sized, age-dependant groups (PG1: < 10 years, n = 20; PG2: ≥ 10 < 12 years, n = 20; PG3: ≥ 12 years, n = 20).ResultsThe CBCT analysis reveals age-related differences in sutural responses. The opening width of the median palatine suture decreases cranially (frontal) and dorsally (horizontal). The opening mode thus changes from parallel to triangular in both planes. The transverse palatine suture completely opens in younger patients only (PG1 and PG2). The width increases are always significant in all patients. While in PG1 the width increase is greater posteriorly than anteriorly, this is always reversed in PG2 and PG3. The palatal height always increases significantly anteriorly, but posteriorly only in the youngest patients (PG 1) median and paramedian. In PG 2 and PG 3, the posterior height change is very small. That is the reason why the anteroposterior comparison reveals a much more pronounced height increase anteriorly than posteriorly.ConclusionThe comparison of selected CBCT data with a dental cast analysis allows the conclusion that the maxillary expansion after RME in children up to 10 years is rather parallel, whereas it occurs V‑shaped (anterior > posterior transversal, inferior > superior vertical) with increasing age, especially in adolescents from the age of 12. In addition to an age-progressive rigidity of the pterygopalatomaxillary junction, morphological changes of the transverse palatine suture during growth seem to be causal. Thus, age-dependent effects of palatal expansion occur due to a positional change of maxillary centres of rotation and resistance. From dental cast measurements, especially at the skeletal–basal level, conclusions can be drawn about the median palatal suture opening mode.

Rapid Maxillary Expansion (RME): An Otolaryngologic Perspective.

Background. To evaluate the possible effects of Rapid Maxillary Expansion (RME), such as nasal breathing problems, middle ear function, Obstructive Sleep Apnea (OSA) in the otolaryngology field. RME has already been introduced in orthodontics to expand the maxilla of young patients affected by transversal maxillary constriction. Methods. A literature search was performed using different databases (Medline/PubMed, EMBASE, and CINAHL), from May 2005 to November 2021, according to the PRISMA guidelines. Results. The application of RME in children has shown good results on nasal function, reducing nasal resistances, independently from a previous adenotonsillectomy. These results are not only related to the increasing of nasal transverse diameters and volume, but also to the stiffening of airway muscles, enabling the nasal filtrum function and avoiding mouth opening, thereby decreasing respiratory infections. Positive effects have also been reported for the treatment of conductive hearing loss and of OSA, with the reduction of Apnea Hypopnea Index (AHI), possibly due to (i) an increased pharyngeal dimensions, (ii) a new tongue posture, and (iii) reduced nasal respiratory problems. Conclusions. Otolaryngologists should be aware of the indications and benefits of the RME treatment, considering its possible multiple beneficial effects.

Changes in the Mandible Following Rapid Maxillary Expansion in Children with Class II Malocclusion: A Systematic Review.

Objective: The aim of this systematic review was to determine whether rapid maxillary expansion (RME) allows favorable changes in the mandible during the treatment of class II malocclusion before the growth spurt. Methods: A search of Pubmed/Medline, the Science Direct, and the Google Scholar database was performed. The keywords used were: orthodontics, rapid maxillary expansion, class II, and growing patients. Relevant articles were assessed for quality according to Cochrane guidelines, and then changes in SNA, SNB, ANB, NL-NSL (or SN-SNP.SNA), and ML-NSL (or SN-Go-Gn) relationships were analyzed. Results: The selection process brought forth five articles, including 162 patients (91 females, 71 males) for detailed analysis. The quality of the evidence (GRADE) for comparisons and outcomes was assessed as moderate for SNB and ANB and as low or very low for other variables. Conclusions: The results of this systematic review showed that there is a small body of moderate-quality evidence for statistically and clinically favorable changes in SNB and ANB angles and a small body of low-quality evidence for changes in vertical parameters after RME.

A clinical trial on 3D CT scan and polysomnographyc changes after rapid maxillary expansion in children with snoring

ObjectiveThe present prospective clinical study aimed to investigate the effects of rapid maxillary expansion on the airway, correlating airway volumes obtained on multi-slice computed tomography and polysomnography assessment of oxygen saturation and apnea/hypopnea index. MethodsTwenty-four patients (11 with obstructive sleep apnea and 13 with residual snoring, mean age 10.0 (1.8), were enrolled in the study. Each patient underwent multislice computed tomography and nocturnal polysomnography before rapid maxillary expansion and after removal of maxillary expansion after six months. Airway regions were segmented, and volumes were computed. ResultsThe increase in oropharyngeal volume was significant in both groups. Oxygen saturation and apnea/hypopnea index were not statistically significant. No correlation was found between total airway volume, oxygen saturation, and apnea/hypopnea index changes between the time points examined. ConclusionsThis study showed that when rapid maxillary expansion is performed in individuals with sleep-disordered breathing, there were statistically significant differences in oropharyngeal volume between pre- and post-rapid maxillary expansion, but there was no correlation between oxygen saturation values and oropharyngeal volume increase. Level of evidenceThe article is classified as Evidence Level 3 (Three).

Rapid maxillary expansion in children, an update

Introduction: Rapid maxillary expansion (RME) increases oxygen saturation in children with Obstructive Sleep Apnea (OSA) in the short and long term. Objective: To analyze the current literature about rapid maxillary expansion, its effects on anatomical structures, midpalatal suture opening (MPS) and obstructive sleep apnea. Methodology: Articles published at MEDLINE/PubMed and Science Direct were analyzed, with an emphasis on the last 5 years. Articles were evaluated with the PRISMA and AMSTAR guidelines. The search was carried out using the words

Perceived pain during rapid maxillary expansion in children with different expanders.

To evaluate and compare the intensity of pain caused by rapid maxillary expansion (RME) with two expanders: Hyrax and Haas type, in growing patients. Thirty-nine patients (23 girls and 16 boys) with an average age of 9.3 years (SD = 1.39 years) were randomized into two groups and treated with Hyrax- and Haas-type expanders. In both groups, initial activation of the expander screw was one full turn on the first day followed by 2/4 of a turn two times a day (morning and night) for 7 days. Inclusion criteria were patients presenting with a posterior crossbite or maxillary atresia between 7 and 12 years old. To evaluate the intensity of pain during the active phase of the treatment, a combination of the Numerical Rating Scale and Wong-Baker Faces Pain Scale was used. Mann-Whitney test was used to compare the two treatment groups. There was significant inverse correlation between days following insertion and pain. During the expansion period, 100% of the children reported some pain. Hyrax expander subjects reported greater pain than those treated with the Haas-type expander only on the first day. The level of pain remained greater in girls throughout treatment. Pain was reported regardless of the type of expander and was higher in the Hyrax group only on the first day of activation.

The effect of rapid maxillary expansion in children: a meta-analysis

IntroductionCraniofacial growth is modified by chronic mouth breathing. Rapid maxillary expansion leads to separation of the mid-palatal suture, improving the occlusion and the upper airway size. AimSystematically evaluate scientific articles on the effects of rapid maxillary expansion on airway dimensions and classify the quality of the evidence of the information. MethodsSearches on PUBMED, LILACS, EMBASE, SCOPUS, WEB OF SCIENCE and COCHRANE, as well as in the grey literature were performed. The articles found were selected and evaluated both for the risk of bias (ROBINS-I) and for the quality of evidence (GRADE). ResultsOf the 309 works found, 26 papers were selected for full reading, of which 22 were excluded. Data compilation and analysis were performed in four papers, two being controlled non-randomized clinical trials and two non-randomized and uncontrolled clinical trials. No randomized clinical trial was found. ConclusionsThe meta-analysis found an increase in the internasal and inter-zygomatic distances and oropharyngeal volume after rapid maxillary expansion, which, together with clinical findings, makes the recommendation favorable to the intervention. The quality of the evidence for each outcome was considered very low.

Effects of rapid maxillary expansion on temporomandibular joints.

To evaluate the impact of rapid maxillary expansion (RME) on the condylar position, disc joint, joint space, and interarticular relationship in growing patients. A systematic search was performed in nine databases. The clinical studies selected included those with pre- and post-magnetic resonance, conventional computed tomography or cone beam tomography in growing patients. Risk of bias assessment was performed using the Cochrane Collaboration tool for controlled clinical studies and National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment for Before-After Studies With No Control Group. Initially, 4303 records were identified. Only eight studies fulfilled the criteria and were included in the qualitative analysis. Of those, two were controlled clinical studies with a risk of uncertain to high bias. The remaining papers had a low to moderate risk of bias. Results showed that RME in children and adolescents promoted the following: remodeling in the head and or condylar branch, changes in condylar position and joint space, maintenance of improved symmetry between the condyles, and no ability to modify the position or shape of the articular disc. RME in growing patients is able, in the short term, to modify the condyle-fossa relationship but does not change the position or shape of the articular disc. The intercondylar symmetric relationship is maintained or improved. Although the NHLBI score shows low to moderate risk of bias, the clinical relevance of these review findings is limited by Cochrane and Grades of Recommendation, Assessment, Development and Evaluation scores.

Oropharyngeal Airway Changes after Rapid Maxillary Expansion in Children with Bilateral left Lip and Palate

Purpose: To assess the effect of rapid palatal expansion (RPE) on the oropharynx in individuals (age range from 9 to 14) with complete bilateral cleft lip and palate (BCLP). Methods: Forty CBCT scans of 20 twenty complete BCLP individuals who had undergone rapid maxillary expansion maxillary before alveolar cleft grafting. Sample was divided into 2 groups according to the type of expander used. Scans were examined before expansion, and 3 months after expansion. Oropharyngeal 3D`volume was measured at both times for each study group. Results: All post scans showed statistically significant increase in volume when compared to the pre scans using ANOVA variance test. However, no difference was detected between both groups. Conclusion: RME increases the volume of the oropharyngeal airway regardless of the type of fixed expander.

Nasal Chamber Changes Following Rapid Maxillary Expansion in Children with Bilateral Cleft Lip and Palate

Purpose: The aim was to study the skeletal effect of rapid palatal expansion (RPE) on the anterior and posterior nasal width in a sample of Egyptian children (age range 9.4-14.3 years, mean 11.16 years) with bilateral cleft lip and palate (BCLP). Methods: Twenty Egyptian children with complete BCLP exhibiting maxillary transverse deficiency were divided randomly into; Group 1 received a fixed fan expander and Group 2 a hyrax expander. Cone-beam computed tomography (CBCT) images were taken before T1 and 3 months after expansion T2, just before the alveolar cleft grafting (ACG) surgical procedure. Linear and angular measurements were assessed to measure the degree of change on the anterior and posterior nasal chamber widths, dentition, and dental arch. Results: Repeated measure ANOVA with a between variable analysis was used to examine the effect of the two expanders on the dental arch and anterior nasal width as well as posterior nasal width. Statistically significant increase in dentoalveolar measurements were found in each group, nasal widths showed no statistically significant differences before and after expansion. Conclusion: increase in nasal width were found to be statistically insignificant following RME.

Change in Nasal Airflow, Associated with the Treatment of Rapid Maxillary Expansion in Children with Maxillary Compression

Maxillary compression malocclusion in horizontal or transverse plane, is in early age, of multifactorial origin, due to the lack of development of the maxilla. It is one of the most common malformations in orthodontics

Rapid maxillary expansion in children with nocturnal enuresis: A randomized placebo-controlled trial.

To investigate whether rapid maxillary expansion (RME) is a useful treatment method for nocturnal enuresis (NE) and whether the treatment effect is due to placebo. The study also aimed to identify prognostic variables in patients responding to treatment. Thirty-eight children with therapy-resistant NE were recruited and randomized into two groups: the intervention group or placebo group. Both groups were treated with RME, but the placebo group received treatment with a sham appliance for 2 weeks before having the actual treatment. A medical history focused on micturition habits, previous treatment, heredity, and sleep disorders was taken. Daytime voided volumes and nocturnal urine production during wet nights were recorded before the intervention. Of the 38 patients recruited, two dropped out as one patient was unable to take dental impressions and one refused to have the appliance fitted. There was a statistically significant reduction of wet nights after the RME treatment (P < .001). No significant reduction was found after the placebo treatment (P < .40). Eleven patients (35%) had their enuresis frequency reduced by >50%. Large voiding volume and a wide maxilla at baseline had a strong association with positive treatment outcome. RME has a modest effect on children with therapy-resistant NE. The treatment outcome does not seem to be due to a placebo effect of the appliance. A wide maxillary width and large voiding volume at baseline seem to be positive predictors regarding response to treatment.

Skeletal changes after rapid maxillary expansion in children with obstructive sleep apnea evaluated by low-dose multi-slice computed tomography

ObjectiveThe objective of this study was to evaluate the skeletal effects of rapid maxillary expansion (RME) therapy performed using teeth as anchors, in obstructive sleep apnea (OSA) children, by low-dose computed tomography (CT) of the midpalatal suture opening, maxillary base width, nasal cavities width, first molar angulation and, unlike most studies in the literature, on the pterygoid processes distance. MethodsFourteen children (mean age 8.68 years) with OSA presenting a malocclusion characterized by upper-jaw contraction had 16-Multislice CT (MSCT) scans taken before (T0) and after (T1) RME. All exams were performed using a rigid protocol to ensure reproducibility of image collection over time, with a 16-row MSCT scanner equipped with a Dentascan reconstruction program. Scanning parameters were as follows: scout view in the anteroposterior (AP) and laterolateral (LL); 1.25-mm slice thickness with 0.6-mm collimation from the dentoalveolar and basal areas of the maxilla up to the nasal cavity, parallel to the palatal plane; 80 kV, 100 mA with an 11.25-mm table speed/rotation, rotation time 0.6 s. Matrix size was 512 × 512. ResultsOpening of the midpalatal suture was demonstrated in all cases. The results showed statistically significant T0 to T1 increments in all treated cases and clear imaging findings. ConclusionUse of three-dimensional (3D)-CT for follow-up studies requires a very rigid protocol to maintain reproducible positions in the scanner over time. The images confirm the real remodeling of craniofacial structure. However, to be valid such an imaging approach needs great attention to reproducibility of anatomic images over time. The changes in volume of the UA, even with a rigid protocol, cannot be affirmed with 3D-CT. There is a need to improve the definition of markers using this imaging approach when performing longitudinal studies; currently this issue is unresolved.

Nasal function before and after rapid maxillary expansion in children: A randomized, prospective, controlled study

ObjectivesChildren can well detect and respond to odours in order to have information about food and environment.Rapid Maxillary Expansion seems to improve dental and skeletal crossbite and increase nasal patency correcting oral respiration in children. A previous pilot study suggested that Rapid Maxillary Expansion may lead to improved N-Butanol olfactory thresholds, and peak nasal inspiratory flow values (PNIF). The aim of the present study was to prospectively evaluate olfactory threshold, nasal flows and nasal resistances in children aged from 6 to 11 years before and after Rapid Maxillary Expansion, comparing treated children with a control group of similar age, growth stage (prepubertal) and transversal skeletal deficiency. MethodsN-butanol olfactory thresholds, anterior active rhinomanometry (AAR) and PNIF were measured in 11 children (6–11 years) before (T0), immediately and 6 months after Rapid Maxillary Expansion application (T1 and T2 respectively), and in a control group of 11 children (6–11 years) whose members remained under observation for the period of the study. ResultsConsidering the study group, PNIF values improved at T1 respect to the T0 values (p = 0.003), while T2 values were significantly higher than T0 ones (p = 0.0002). N-Butanol Olfactory Threshold significantly improved at each control (p = 0.01, p = 0,01 and p = 0.0003, for T1 vs T0, T2 vs T1, T2 vs T0 respectively). No differences on AAR values were found during the six months follow-up in this group.Considering the control group, no significant differences were found for any of the considered variables during the time of the study.Comparing the two groups, there was a significant increase of PNIF values in the study group compared to the control group (p = 0.003) at T1, which was even more evident six months after Rapid Maxillary Expansion (p = 0.0005). This improvement was not shown by AAR values. N-Butanol Olfactory Threshold showed a significant improvement at T2 respect to T1 (p = 0.002) and T0 (p = 0.0005). ConclusionRapid Maxillary Expansion seems to significantly improve the respiratory capacity of treated patients, at least in terms of PNIF, and their olfactory function, measured by N-Butanol Olfactory Threshold Test. Further studies should be performed to evaluate if also changes in nasal resistances, measured by AAR, could occur, maybe considering a larger group of subjects and possibly using 4-phase rhinomanometry in order to evaluate the effective resistances during the entire breath.