A 25-year evaluation of pharyngeal airways dimensional changes after headgear orthopedic treatment

Residents' journal review

Orthodontic treatment, particularly involving premolar extractions, has been a subject of ongoing debate within the orthodontic community. The impact of such interventions on the pharyngeal airway, a critical component of the respiratory system, remains a topic of exploration. This retrospective cephalometric study aims to investigate changes in pharyngeal airway dimensions following orthodontic treatment involving either all four or all five premolar extractions. A sample of 68 participants, extracted from orthodontic records, underwent cephalometric analysis to quantify changes in pharyngeal airway dimensions. The study compared two groups: those treated with all four premolar extractions (n=34) and those treated with all five premolar extractions (n=34). Cephalometric radiographs taken before and after treatment were analyzed, focusing on airway width, length, and volume. Preliminary findings indicate significant changes in airway dimensions within each group. In the all four premolar extraction group, there was a statistically significant decrease in airway width (p=0.02) and volume (p=0.04). Similarly, the all five premolar extraction group exhibited significant reductions in airway width (p=0.03) and volume (p=0.02). However, the between-group comparisons revealed no significant differences in changes between the two groups. This study sheds light on the intricate relationship between orthodontic interventions, specifically premolar extractions, and changes in pharyngeal airway dimensions. While significant changes were observed within each group, the lack of significant differences between the all fourand all five premolar extraction groups raises intriguing questions about the specific impact of premolar extraction patterns on the upper airway.

Background: Objective of the study was to determine linear and volumetric changes in pharyngeal airway dimensions in class III patients treated by different modalities of orthognathic surgery and to compare the results of different orthognathic surgical modalities, and determine the change at the position of the hyoid bone. Methods: Pre and post-treatment lateral cephalogram of 53 class III adult patients who were treated by different modalities of orthognathic surgery studied to assess the changes in pharyngeal airway dimensions and hyoid bone position after orthognathic surgery. 28 patients were treated with mandibular set back, and 25 patients were treated with Bijaw surgery. Lateral cephalogram records were taken before treatment (T1), after surgery (T2), the end of the fixed treatment (T3) and 1 year after debonding (T4). Results: Interception of both surgical modalities has significant impact on various skeletal and pharyngeal parameters i.e., BMeH (0.00), PNS (0.009), MPS (0.13), GOP (0.001), IPS (0.007), SAS (0.006), and MAS (0.00). OJ (overjet) and OB (overbite) was significant especially after time interval of one year. In Bijaw groups, PPST4 parameter was significantly increased (0.0000), SPST4 (0.000), GOP (0.000), EPS (0.000) and IPS parameter was significantly decreased (0.045). Significant difference was observed in T4 time interval in superior pharyngeal airway space, posterior airway space and middle airway space with (p<0.05). Conclusions: Pharyngeal airway is significantly altered following orthognathic surgery in class III patients and it depends on the type of surgical modality employed were Bijaw surgery has significant impact on oropharyngeal and hypopharyngeal airway space.

The goal of this study was to understand the changes to the head and neck musculoskeleton and the pharyngeal airway after surgery. We tested the correlation between the changes in the skeleton and pharyngeal airway and the apnea-hypopnea index (AHI). Prospective, noncontrolled study. In a pilot study, 12 consecutive subjects (3 women, body mass index: 22.4 Kg/m(2) ± 2.7, AHI: 35.9/sec ± 18.0) with Class II dentoskeletal malocclusion and high mandibular plane underwent segmental maxillomandibular rotational advancement (SMMRA). Subjects underwent overnight polysomnography and three-dimensional computed tomography scanning of the head and neck before and 3 months after surgery. Linear, angular, and area measurements were obtained from skeletal images placed in the Frankfort horizontal position and from horizontal cross-sectional tomograms derived from the upright pharyngeal airway. Skeletal movements, dimensional changes of the airway, and correlations between measurements and AHI were calculated. A linear regression model was generated using significant bivariate correlations. The AHI was significantly reduced to 4.6/sec ± 4.1 with improvement in the nadir oxygen saturation from 83.0% ± 7.2 to 90.6% ± 3.6 after SMMRA. Following skeletal advancement, the hyoid bone was advanced and elevated by 7.5 mm ± 2.9 and 6.7 mm ± 5.5, respectively; the cervical spine was rotated forward by 4.6° ± 2.8; and the airway length was shortened by 6.8 mm ± 4.0 (all P < .01). Variable improvement of airway dimensions was noted at each horizontal level. A quadratic regression model was derived using the measurements of the Sella-Nasion-B point angle and AHI (Rsq = 0.557, sig = 0.000). Dimensions of pharyngeal airway were correlated with dimensions of craniofacial skeleton. Sella-Nasion-B point angle could be used as a guidance in achieving normalized AHI after surgery.

Background: It was essential to evaluate respiratory function when diagnosing and planning orthodontic treatment. Based on the correlation between pharyngeal airway space and craniofacial structure, airway width was hypothesized to be an indicator of airway patency in different groups of skeletal malocclusion. Aim: The purpose of this study was to investigate age and gender related changes in pharyngeal airway dimensions in different sagittal skeletal relationships Materials and Method: Sixty lateral cephalograms of patients aged 10-30 years with no pharyngeal pathology or nasal obstruction were retrospectively selected and categorized into skeletal Class I (n = 20), Class II (n = 20), and Class III (n = 20) malocclusion based on ANB angle. McNamara's airway analysis was used to quantify upper- and lower-airway dimensions. The analyses of intergroup differences were performed using a one-way ANOVA, an independent t-test, and Tukey's test as a post-hoc test. Results: Participants in the study ranged in age from 20.57 ± 5.41 years (males) and 20.03 ± 4.58 years (females) were included in the study. The upper pharyngeal airway (UPA) dimensions demonstrated a positive correlation with age. In both genders, the mean upper pharyngeal airway (UPA) size exceeded the lower pharyngeal airway (LPA) size, but neither age nor gender was associated with statistically significant differences in skeletal malocclusion. Conclusion: It was shown that skeletal malocclusions of different types have no effect on the upper and lower pharyngeal airways and that the upper and lower pharyngeal airways are not influenced by age or gender.

To evaluate two-dimensional changes in pharyngeal airway dimensions in pre-pubertal children with a Class II malocclusion treated with a Fr&#228;nkel-2 appliance compared to a matched non-treated control sample. Lateral cephalograms obtained from 28 consecutively treated pre-pubertal children before (T0) and after (T1) a one-year Fr&#228;nkel-2 treatment were analysed. Fr&#228;nkel-2 appliance was used for at least 18 hr/day during 12 months. The control group was matched as closely as possible. All the cases presented normal facial growth pattern. Sagittal and vertical cephalometric measurements assessing maxillary and mandibular skeletal positions, as well as sagittal pharyngeal airway dimensions, were calculated. Intraclass correlation coefficient was calculated in order to determine reliability. Differences based on age for all the outcome variables at T0 were compared with an independent t-test. A MANOVA was used thereafter to determine if any factors and their interactions were associated with changes in the outcome variables. Differences between T1 and T0 were evaluated with either a t-student test or a Mann Whitney U test. At T0 differences between groups were noted for several variables. These differences were considered during the follow-up statistical analysis. Changes between groups after treatment (T1-T0) were noted for SNB, PNS to Ba, McNamara Low and Middle to S (increase in treatment group), and ANB and AD1 to Ba (decrease in treatment group). Some pharyngeal two-dimensional airway dimensions changed in Class II malocclusion pre-pubertal patients during a one-year treatment with Fr&#228;nkel-2 appliances.

The effects of sex, skeletal age, and sagittal skeletal pattern on pharyngeal airway dimensions and related structures in growing Thai orthodontic patients

Three-dimensional assessment of pharyngeal airway in nasal- and mouth-breathing children

The purpose of this study was to analyze airway volume and minimum cross-sectional area (CSA) in a postsurgical follow-up period of at least 12 months in patients after mandibular advancement surgery with minimal maxillary displacement compared with nonsurgical patients with Class I malocclusions (control group). The study sample included 14 patients in the surgical group and 14 patients in the control group. Linear, angular, area, and volume measurements were obtained to characterize the sample and assess the outcomes. Comparisons were made among measurements taken before treatment, at least 1 month after surgery, and at follow-up at least 12 months after surgery. Substantial anteroposterior changes in the mandible and hyoid bones, with minor maxillary movement, were observed. Pharyngeal airway volume increased considerably after surgery, maintaining stability, yet there were no substantial changes observed in the velopharynx and oropharynx. The minimum CSA increased in the postsurgery period and was maintained in the follow-up. Results of correlation analysis revealed negative associations between hyoid displacement and changes in pharyngeal airway volume and CSA. This suggested that when the hyoid bone shifted forward in the anteroposterior direction, it was correlated with an enlargement in pharyngeal airway dimensions. The greatest increase was seen in pharyngeal airway total volume and CSA, and these changes were stable in the follow-up period. Mandibular advancement surgery with minimal maxillary displacement may lead to significant and stable increases in pharyngeal airway dimensions, benefitting patients with narrower pharyngeal airways and potentially higher risk of breathing disorders.

The function of respiration is highly relevant to orthodontic diagnosis and treatment planning. Significant relationships between pharyngeal, craniofacial as well as dentofacial structures have been reported in several studies. Many authors have emphasized that mouth breathing is concomitantly associated with constricted airway causing obstructive sleep apnoea. Associated symptoms can be cured with correction of either skeletal or dental problems or both. Therefore it would be very intriguing to understand and interpret the airway during diagnosis and treatment planning for a clear view of changes in the airway dimensions during the course of orthodontic treatment using various treatment modalities. Therefore a complete understanding of the concept of airway should be considered as an important one. This chapter gives us an insight to the intricate detailing on how the various orthodontic and dentofacial orthopedic treatment signifies the changes in the dimensions of pharyngeal airway.

BackgroundMandibular advancement surgery may positively affect pharyngeal airways and therefore potentially beneficial to obstructive sleep apnea (OSA).ObjectiveTo collect evidence from published systematic reviews that have evaluated pharyngeal airway changes related to mandibular advancement with or without maxillary procedures.MethodologyPubMed, EMBASE, Web of Science, and Cochrane Library were searched without limiting language or timeline. Eligible systematic reviews evaluating changes in pharyngeal airway dimensions and respiratory parameters after mandibular advancement with or without maxillary surgery were identified and included.ResultsThis overview has included eleven systematic reviews. Maxillomandibular advancement (MMA) increases linear, cross-sectional plane and volumetric measurements of pharyngeal airways significantly (p<0.0001), while reducing the apnea-hypopnea index (AHI) and the respiratory disturbance index (RDI) significantly (p<0.0001). Two systematic reviews included primary studies that have evaluated single-jaw mandibular advancement, but did not discuss their effect onto pharyngeal airways. Based on the included primary studies of those systematic reviews, single-jaw mandibular advancement was reported to significantly increase pharyngeal airway dimensions (p<0.05); however, conclusive long-term results were lacking.ConclusionMMA increases pharyngeal airway dimensions and is beneficial to patients suffering from OSA. However, more evidence is still needed to draw definite conclusion related to the effect of single-jaw mandibular advancement osteotomies on pharyngeal airways.

The objective of this study was to examine if chin cup therapy have any adverse effect on the sagittal pharyngeal dimensions in Class III malocclusion patients. Twenty patients (10 girls and 10 boys; mean age 10.31 +/- 1.15 years) with skeletal Class III malocclusion, and an untreated control group (8 girls and 10 boys, mean age 9.89 +/- 1.55 years) were evaluated. The chin cup appliance and an occlusal bite plate with 600 grams totally was used for 9.78 +/- 0.93 months. Linear, angular and area measurements were evaluated on the cephalometric radiographs taken before and after observation and treatment periods. Treatment changes showed significant increases in maxillary forward position, effective length of the maxilla and the mandible, and vertical facial height measurements. The mandible showed a clockwise rotation revealed by the decrease in SNB and the increase in mandibular plane angles. Significant increase in the nasopharyngeal area was found when the treatment and control groups were compared. The nasopharyngeal airway area was affected by chin cup treatment, without any adverse effect on the pharyngeal airway dimensions in the short term.

To assess changes in pharyngeal airway dimensions, head posture and hyoid position after maxillary expansion and face mask (FM) treatment compared to untreated classIII patients. This study examined 24classIII patients (10girls, 14boys, mean age: 10.97 ± 0.88years) treated with expansion and apetit-type FM appliance and 24untreated classIII patients (16girls, 8boys, mean age: 10.50 ± 1.06years). Pre- and posttreatment cephalometric radiographs were digitally analysed. Parametric data were analysed with paired and independent-samples t‑tests, nonparametric data were analysed with Wilcoxon signed-rank and Mann-WhitneyU tests. Spearman's correlation analysis was used to examine the relationship between dental/skeletal treatment changes and those of craniocervical postural position, pharyngeal airway dimension and hyoid position. With respect to the hypopharyngeal airway dimension, the hypopharyngeal sagittal length (CV3'-LPW), velar angle (HRL/U-PNS) and velar length (U-PNS) significantly increased in the treatment group. All the parameters describing head posture and those describing the distances of the hyoid bone to the HRL changed significantly after treatment, but these changes were not significantly different from the control group. In the treatment group, there also occurred asignificant increase in the sagittal growth of the maxilla (SNA, Co‑A, Na-PerpA, Wits), vertical growth of the maxillomandibular complex (SN-GoGN, N‑ANS, N‑Me), counterclockwise rotation of the maxilla (SN-PP) and overjet, while aclockwise rotation (y-axis) and anonsignificant inhibition of the sagittal growth (Co-Gn) of the mandible were observed. The treatment induced increases of hypopharyngeal sagittal length (CV3'-LPW), soft palate thickness and anteroposterior movement of hyoid bone (H-CV3) demonstrated apositive correlation with changes of craniocervical angles (NSL/OPT, NSL/CVT) and anegative correlation with craniohorizontal angles (OPT/HOR, CVT/HOR). The change of the anteroposterior movement of hyoid bone (H-CV3) was also positively correlated with oropharyngeal sagittal length (CV2'-MPW), the hypopharyngeal sagittal length (CV3'-LPW) and the minimal dimension of the pharyngeal airway space (PASmin). While expansion and FM treatment did not affect the head posture and hyoid bone position, positive effects were observed in the hypopharyngeal airway region.

Long-term effects of symphyseal distraction and rapid maxillary expansion on pharyngeal airway dimensions, tongue, and hyoid position

Pharyngeal airway evaluation after isolated mandibular setback surgery using cone-beam computed tomography.