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.     

Photographic assessment of nasal morphology following rapid maxillary expansion in children

Objective

The aim of the present study was to use facial analysis to determine the effects of rapid maxillary expansion (RME) on nasal morphology in children in the stages of primary and mixed dentition, with posterior cross-bite.

Material and Methods

Facial photographs (front view and profile) of 60 patients in the pre-expansion period, immediate post-expansion period and one year following rapid maxillary expansion with a Haas appliance were evaluated on 2 occasions by 3 experienced orthodontists independently, with a 2-week interval between evaluations. The examiners were instructed to assess nasal morphology and had no knowledge regarding the content of the study. Intraexaminer and interexaminer agreement (assessed using the Kappa statistic) was acceptable.

Results

From the analysis of the mode of the examiners'' findings, no alterations in nasal morphology occurred regarding the following aspects: dorsum of nose, alar base, nasal width of middle third and nasal base. Alterations were only detected in the nasolabial angle in 1.64% of the patients between the pre-expansion and immediate post-expansion photographs. In 4.92% of the patients between the immediate post-expansion period and 1 year following expansion; and in 6.56% of the patients between the pre-expansion period and one year following expansion.

Conclusion

RME performed on children in stages of primary and mixed dentition did not have any impact on nasal morphology, as assessed using facial analysis.     

Rapid maxillary expansion and surgically assisted rapid maxillary expansion effects on nasal volume

The purpose of this study was to compare the effects of rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME) on nasal volume using acoustic rhinometric methods. Two groups of subjects were used in the study. Group 1 consisted of 10 subjects (mean age 12.30 +/- 0.82 years) who were treated with RME, and group 2 consisted of 10 subjects (mean age 18.70 +/- 2.54 years) who were treated by SARME. In both groups, all cases had a maxillary width deficiency with bilateral crossbites. Nasal volume records were taken by the same otorhinolaryngologist with an AR device. AR recordings were performed for each patient with and without the use of a decongestant. The first record was taken before expansion, and the second record was taken at the end of retention. The data for both groups were evaluated using Wilcoxon signed rank test and Mann-Whitney U-test. The nasal volume showed a significant increase in both the RME and the SARME groups (P < .05). The measurement with the use of decongestant was similar to that without use of decongestant on the both groups (P < .05), but the different increments in nasal volume between the RME and the SARME groups were not statistically significant. Although the mean ages between the RME and the SARME groups were different, the increase in nasal volume was similar in both groups.     

手术辅助上颌快速扩弓对鼻气道形态和鼻阻力的影响

目的: 评价手术辅助上颌快速扩弓（surgically assisted rapid maxillary expansion, SARME）对成人鼻腔容积及鼻阻力的影响。方法: 16例上颌横向发育不足,伴一侧或双侧后牙反牙合成人患者进行手术辅助上颌快速扩弓。所有研究对象均在治疗前（T1）、扩弓保持3个月后（T2）拍摄螺旋CT,测量鼻腔宽度及鼻腔容积变化,并采用鼻声反射测量（AR）检查鼻腔最小横截面积及鼻阻力的改变。应用SPSS 16.0 软件包中的配对t检验比较治疗前（T1）、扩弓保持3个月后（T2）鼻腔宽度、鼻腔最小横截面积、鼻腔容积和鼻阻力的改变。结果: 上颌快速扩弓后,鼻腔上部及中部宽度无显著变化（P>0.05）,而鼻底宽度显著增加（P<0.01）。鼻腔容积及鼻腔最小横截面积显著增加（P<0.05）,而鼻阻力显著减小（P<0.01）。结论: 手术辅助上颌快速扩弓可对成人鼻气道形态产生影响,使鼻阻力降低。     

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 abovementioned 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.     

Changes in soft tissue nasal widths associated with rapid maxillary expansion in prepubertal and postpubertal subjects

Objective:To evaluate changes in the soft tissue width of the nose induced by rapid maxillary expansion (RME). Data on greater alar cartilage (GAC) and alar base (AB) widths were compared with a normative sample within the same age range.Materials and Methods:This prospective study consisted of an RME sample of 79 patients treated with an RME protocol. Mean age at the start of RME treatment was 13.5 years; average duration of treatment was 6.7 months. Patients were grouped into prepubertal and postpubertal groups based on their cervical vertebral maturation (CVM) stage. AB and GAC widths were determined at three separate time points. The normative sample consisted of 437 orthodontically untreated whites, aged 10–16 years. A repeated measures analysis of variance (ANOVA) was used to determine group differences. In addition, independent sample t-tests were used to compare posttreatment nasal width values vs the untreated normative sample.Results:Increases in AB and GAC widths of the nose in the RME sample were less than 1.5 mm. No significant differences were noted in width changes between the prepubertal and postpubertal subgroups. Comparisons of T3 values showed that on average nasal width increases were greater in the RME group than in untreated norms by 1.7 mm for the GAC measure (statistically significant), and by less than 1 mm for the AB measure.Conclusions:RME has no significant clinical effects on the widths of the apical base and the greater alar cartilage of the nose; no differences were observed between the two maturational subgroups.     

Effects of rapid maxillary expansion on nasal mucociliary clearance

Objective:To evaluate the changes in nasal mucociliary clearance in orthodontic patients after rapid maxillary expansion (RME) therapy.Materials and Methods:Forty-two children (25 boys and 17 girls) participated in this study. The RME group consisted of 21 patients (mean age, 13.8 years), who had undergone RME at the initiation of orthodontic treatment. The control group consisted of 21 subjects (mean age, 13.6 years), who were attending the department of orthodontics for active orthodontic treatment. The nasal mucociliary clearance was assessed by the saccharin test. Saccharin transit times (STTs) were measured for each treated subject before expansion (T1), after RME (T2), and after a 3-month retention period (T3). Records were obtained at the same time intervals for each group.Results:The STT decreased significantly in the RME group after expansion and retention (P < .05). A statistically significant difference was found when the STTs of the control and RME groups were compared after expansion and retention (P < .05).Conclusions:The STTs of young orthodontic patients with maxillary narrowness and without any history of nasal or systemic disease were within normal limits. However, RME increased the mucociliary clearance in patients who had maxillary narrowness, having positive effects on nasal physiology and increasing nasal cavity volume.     

Changes in natural head position observed immediately and one year after rapid maxillary expansion

Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A number of studies have examined the relationship between RME and the change in airway resistance, or the relationship between airway resistance and natural head position (NHP). Few studies, to date, have examined the relationship between RME and the change in NHP resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni- or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion, and one year after RME. No significant changes in the craniofacial angles were observed immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14 degrees (P < 0.01), OPT/HOR by 2.13 degrees (P < 0.05), and CVT/HOR by 2.55 degrees (P < 0.05). The results of this study suggest an ongoing change in head posture possibly due to a change in the mode of breathing from oral to nasal as a result of RME, thereby contributing to a change in craniofacial development, supporting and adding to the soft tissue stretching hypothesis.     

The effect of rapid maxillary expansion on nasal airway resistance

There has been a long-standing controversy over the efficacy of rapid maxillary expansion to relieve nasal obstruction and improve respiration. Recently rhinomanometry has provided a discipline for the investigation into nasal airway physiology with quantifiable parameters for evaluation and comparable studies. In this trial, a sample of 26 patients (13 male and 13 female, age range 10.10 to 19.6 years), receiving rapid maxillary expansion as part of their orthodontic mechano-therapy, were appraised for nasal airway resistance before and after expansion. The posterior rhinomanometric technique was used, measuring the respiratory flow between pharynx and the nostrils at a preset pressure difference between these two points. The formula for calculating the resistance is derived from the electrical Ohm's Law and requires that the pressure difference be divided by the flow. Reductions were recorded in all cases with an average of 36.2 per cent (range 11.6-58.6). The correlation between the resistance reductions and the delivered expansions (increases in trans-palatal widths) was weak (r = 0.32). In view of the probable significance of the liminal valve in nasal resistance, expansions in this area were assessed by changes in the trans-alar widths. The correlation between trans-alar increases and the trans-palatal expansions was weak (r = 0.115), as it was between the trans-alar increases and the reductions in nasal airway resistance (r = 0.30).     

The effect of rapid maxillary expansion on nasal airway resistance

The purpose of this study was to evaluate changes in nasal resistance to airflow in persons undergoing rapid maxillary expansion and to reevaluate the responses at a 1-year follow-up. Nasal resistance measurements, assessed in four modes (natural state, anterior nares dilation with Tygon tubing, following administration of decongestant, and nares dilation with tubing and decongestant), were taken on a group of 38 patients receiving rapid maxillary expansion and compared with a control group not receiving expansion. Thirty-three of the patients were reevaluated 9 to 12 months after expansion was completed. Eighteen subjects in the control group were also reevaluated. Oral/nasal airflow rates (percent nasality) were recorded for the control group and for some of the expansion patients. Results indicated that some subjects receiving rapid maxillary expansion had a significantly higher nasal resistance than the control group. There was a significant median reduction in nasal resistance following rapid maxillary expansion, measured in the natural state only, and this appeared to be stable up to 1 year after maximum expansion was obtained. Rapid maxillary expansion appeared to effect an expansion at the anterior nares, which contributes to nasal resistance reduction. Individual variation in nasal resistance values was considerable and hence the median response for the group was not a reliable estimate of individual response. Due to the high individual response variability, rapid maxillary expansion is not a predictable means of decreasing nasal resistance.     

Changes in pharyngeal aerobic microflora in oral breathers after palatal rapid expansion

Background  

The purpose of this study was to investigate in oral breathing children the qualitative and quantitative effects on aerobic and facultatively anaerobic oropharyngeal microflora of respiratory function improved by rapid palatal expansion (RPE).     

Assessment of changes in the nasal airway after nonsurgical miniscrew-assisted rapid maxillary expansion in young adults

Objectives:To evaluate changes in the volume and cross-sectional area of the nasal airway before and 1 year after nonsurgical miniscrew-assisted rapid maxillary expansion (MARME) in young adults.Materials and Methods:Fourteen patients (mean age, 22.7 years; 10 women, four men) with a transverse discrepancy who underwent cone beam computed tomography before (T0), immediately after (T1), and 1 year after (T2) expansion were retrospectively included in this study. The volume of the nasal cavity and nasopharynx and the cross-sectional area of the anterior, middle, and posterior segments of the nasal airway were measured and compared among the three timepoints using paired t-tests.Results:The volume of the nasal cavity showed a significant increase at T1 and T2 (P < .05), while that of the nasopharynx increased only at T2 (P < .05). The anterior and middle cross-sectional areas significantly increased at T1 and T2 (P < .05), while the posterior cross-sectional area showed no significant change throughout the observation period (P > .05).Conclusions:The results demonstrate that the volume and cross-sectional area of the nasal cavity increased after MARME and were maintained at 1 year after expansion. Therefore, MARME may be helpful in expanding the nasal airway.     

Stability of surgically assisted rapid maxillary expansion and orthopedic maxillary expansion after 3 years' follow-up

Objective:To evaluate the stability of surgically assisted rapid palatal expansion (SARME) and orthopedic maxillary expansion (OME) after 3 years of follow-up, and compare these changes with a control group.Materials and Methods:The subjects of the study were divided into three groups. Group 1 was composed of 10 patients (6 males, 4 females) with a mean age of 15.51 years (range: 13.33–17.58 years) and treated with OME, Group 2 comprised 10 patients (7 males, 3 females) with a mean age of 19.01 years (range: 16.25–25.58 years) and treated with SARME. Group 3 was the control group, consisting of 10 untreated, skeletal Class 1 subjects (6 males, 4 females) with a mean age of 15.27 years (range: 13.42–17.00 years) and matched to the OME group for sex and age. Lateral cephalometric and posteroantererior films were taken before expansion (T1), postexpansion (T2), and 3 years after the retention period (T3).Results:After OME and SARME, significant increases were observed for both dental and skeletal transverse widths (P < .01). After 3 years of follow-up, maxillary basal width decreased 1.35 ± 0.44 mm in the SARME group and 1.19 ± 0.41 mm in the OME group, while upper molar width decreased 2.23 ± 1.24 mm in the SARME group and 2.79 ± 1.01 mm in the OME group.Conclusions:Both the OME and SARME procedures remained stable after 3 years of follow-up with some amount of postretention relapse, compared with the control group.