Oropharyngeal Airway Dimensions Research Articles

Changes in airway dimensions and hyoid bone position following class II correction with forsus fatigue resistant device

The objective of this study was to investigate the effects of fixed functional therapy on oropharyngeal airway dimensions and hyoid bone positions in Class II patients and make comparison with an untreated Class II group. Eighteen patients (8 girls, 10 boys; mean age 13.62±1.92years) who were treated with Forsus Fatique Resistant Device (FFRD) and 19 patients (11 girls, 8 boys; mean age 12.74±0.91years) who served as control were enrolled. Cephalograms were used to assess linear, angular, and area measurements. Intragroup comparisons were made by paired t and Wilcoxon tests and intergroup comparisons were performed by independent t test. With respect to controls, FFRD group showed increased airway dimensions at soft palate (P<0.05) and more forward positioning of the hyoid bone (P<0.05). Dentoalveolar changes exhibited mesial movement of lower incisors and molars and reduction in overjet (P<0.001) in FFRD group. Positive effects in oropharyngeal airway dimensions and increased values of hyoid bone displacement to a more forward position were found after fixed functional therapy. Treatment with fixed functional appliances is mostly based on mesial movement of mandibular dentition, which might influence changes in tongue posture. The present results might indicate that oropharyngeal airway dimensions may be affected by postural changes of the hyoid bone in consequence of dentoalveolar changes. Clinically, these may be considered especially in Class II cases with reduced airway dimensions.

Upper airway changes after Xbow appliance therapy evaluated with cone beam computed tomography

To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients. The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1). Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars. Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.

Assessment of oropharyngeal airway dimensions in skeletal class II cases treated with twin block appliance

Assessment of oropharyngeal airway dimensions in skeletal class II cases treated with twin block appliance

Influence of myofunctional therapy on oropharyngeal airway dimensions in skeletal class II cases - a cephalometric study

Skeletal Class II malocclusion is associated with a multitude of functional problems one of which is reduced oropharyngeal airway dimension. The airway is receiving renewed attention in recent literature regarding snoring and obstructive sleep apnoea syndrome especially as a retrognathic mandible is often implicated as its cause. The study was undertaken to investigate the myofunctional appliance (TWIN BLOCK) effects on the oropharyngeal airway dimensions in Skeletal Class II individuals in the average age of 11-13 years. This study also expresses the existence of any correlation between airway dimension and craniofacial morphology.

Sagittal airway changes: rapid palatal expansion versus Le Fort I osteotomy during maxillary protraction

The purpose of the present study was to evaluate upper airway changes related to craniofacial changes induced by a facemask (FM) combined with Le Fort I osteotomy without down-fracture in Class III maxillary retrusion subjects (group 1) when compared with a similar group of subjects treated with traditional rapid palatal expansion and FM therapy. Pre- (T1) and post- (T2) protraction cephalometric radiographs of group 1 (10 females and 6 males; mean age 12.75 ± 1.91 years) and group 2 (7 females and 9 males; mean age 12 ± 1.7 years) were traced. The treatment duration was 149 ± 14 days (approximately 5 months) and 270 ± 46 days (approximately 9 months) for groups 1 and 2, respectively. A paired t-test for intergroup comparisons of values at T1, an independent samples t-test for intragroup comparisons of values at T1 and T2, and a non-parametric Mann-Whitney U-test for intergroup comparisons were used. To evaluate the relationship between changes in upper airway dimension and craniofacial morphology, a multiple-regression analysis was performed. Significant maxillary protraction along with clockwise rotation of the mandible was achieved in both groups. Counter-clockwise maxillary rotation was significant in group 1 (P < 0.05) but not in group 2. While nasopharyngeal measurements (PNS-ad1, PNS-ad2) showed significant increases (P < 0.05) as a result of treatment in both groups, oropharyngeal measurements did not change. Maxillary protraction, which was achieved in both groups but in a shorter period of time in group 2, improved nasopharyngeal but not oropharyngeal airway dimensions.

Oropharyngeal airway dimensions after treatment with functional appliances in class II retrognathic children

Class II skeletal malocclusion and respiratory disorders owing to the obstruction of the upper airway at early growth stages have been correlated. The retro/micrognathism can be treated with functional appliances. However, the effects of an early functional orthopedic treatment on the airway dimensions have not been evaluated before the growth peak. Therefore, the objective of this study was to evaluate the changes in the airway dimensions of class II retrognathic children who received treatment with either Klammt or Bionator on a pre-pubertal stage. The sample consisted of 50 lateral cephalograms of class II retrognathic patients in a pre-puberal stage, before and after the use of a Klammt or Bionator II treatment for 1 year. The data were evaluated by Student's t-test or Mann-Whitney test, and significance was set at 5% (P < 0·05). When the measurements before and after treatment were compared, a statistically significant increase in the airway dimensions was found at the space where the adenoid tissue was located. The only airway dimensions that increased after treatment with functional appliances were the ones located at the nasopharynx. The adenoid tissue is still in the peak of growing at the ages of the subjects included in this study. However, the measurements along the nasopharynx increased when compared with the initial ones. Still, similar retrospective and prospective studies are needed at older stages.

Treatment and post-treatment effects of facemask therapy on the sagittal pharyngeal dimensions in Class III subjects

The purpose of this cephalometric study was to analyse the treatment and post-treatment craniofacial effects of a facemask (FM) combined with a bite block (BB) with specific regard to the sagittal pharyngeal dimensions in subjects with a Class III malocclusion when compared with an untreated Class III control group. The FM/BB group (22 subjects, 12 females and 10 males) had a mean age pre-treatment (T1) of 8.9 +/- 1.5 years, at the end of active treatment (T2) of 10.5 +/- 1.3 years, and post-treatment (T3) of 12.6 +/- 1.9 years. The treated group was compared with a control group of 14 subjects (6 females and 8 males) with untreated Class III malocclusions that matched the FM/BB group as to age at T1, T2, and T3, observation periods and skeletal maturation. Comparisons of the T2-T1 and T3-T1 changes between the two groups were analysed with the Mann-Whitney test. Significant favourable skeletal changes in the maxilla and mandible were observed in the treated group both after Ts2 and T3. No significant short- or long-term changes in the sagittal oropharyngeal and nasopharyngeal airway dimensions were induced by maxillary protraction in subjects with a Class III malocclusion when compared with untreated controls.

Effects on the sagittal pharyngeal dimensions of protraction and rapid palatal expansion in Class III malocclusion subjects

This study examined the effects of rapid palatal expansion (RPE) and maxillary protraction headgear therapy in 18 patients with a skeletal Class III malocclusion (11 girls and seven boys; mean age 10.9 years) on upper airway dimensions compared with an untreated control group (nine girls and eight boys; mean age 10.9 years). Pre- and post-treatment cephalometric radiographs were traced and analysed at similar time intervals. The average treatment time was 6.94 +/- 0.56 months. Wilcoxon's test was used for intragroup comparisons and the Mann-Whitney U-test for intergroup comparisons. A significant increase occurred in the maxillary forward position. Mandibular forward movement and downward and backward rotation were inhibited. In addition, the upper incisors were proclined (P < 0.001), and the lower incisors were significantly retroclined (P < 0.05). When the treatment and control groups were compared, the upper airway linear measurements (pns-ad1, pns-ad2, APW-PPW, APW'-PPW') and the nasopharyngeal area had increased in the treatment group. These results demonstrated that maxillary expansion together with protraction of the maxilla improved naso- and oropharyngeal airway dimensions in the short term.

Postsurgical Stability of Oropharyngeal Airway Changes Following Counter-Clockwise Maxillo-Mandibular Advancement Surgery

This study evaluated oropharyngeal airway changes and stability following surgical counter-clockwise rotation and advancement of the maxillo-mandibular complex. Fifty-six adults (48 females, 8 males), between 15 and 51 years of age, were treated with Le Fort I osteotomies and bilateral mandibular ramus sagittal split osteotomies to advance the maxillo-mandibular complex with a counter-clockwise rotation. The average postsurgical follow-up was 34 months. Each patient's lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and postsurgical changes (T3-T2). During surgery, the occlusal plane angle decreased significantly (8.6 +/- 5.8 degrees ) and the maxillo-mandibular complex advanced and rotated counter-clockwise. The maxilla moved forward (2.4 +/- 2.7 mm) at ANS and the mandible was advanced 13.1 +/- 5.1 mm at menton, 10 +/- 4.4 mm at point B, and 6.9 +/- 3.7 mm at lower incisor edge. Postsurgical hard tissue changes were not statistically significant. While the upper oropharyngeal airway decreased significantly (4.2 +/- 3.4 mm) immediately after surgery, the narrowest retropalatal, lowest retropalatal airway, and the narrowest retroglossal airway measurements increased 2.9 +/- 2.7, 3.7 +/- 3.2, and 4.4 +/- 4.4 mm, respectively. Over the average 34 months postsurgical period, upper retropalatal airway increased 3.9 +/- 3.7 mm, while narrowest retropalatal, lowest retropalatal airway, and narrowest retroglossal airway remained stable. Head posture showed flexure immediately after surgery (4.8 +/- 5.9 degrees ) and extension postsurgically (1.6 +/- 5.6 degrees ). Maxillo-mandibular advancement with counter-clockwise rotation produces immediate increases in middle and lower oropharyngeal airway dimensions, which were constrained by changes in head posture but remain stable over the postsurgical period. The upper oropharyngeal airway space increased only on the longest follow-up.

Sagittal airway dimensions following maxillary protraction: a pilot study

The relationship between changes in the position of the maxillary structures caused by maxillary protraction therapy and airway dimensions have not been investigated as comprehensively as the accompanying skeletal changes. The purpose of this study was to examine the effects of rapid palatal expansion (RPE) used in conjunction with maxillary protraction headgear on the sagittal dimension of the airway. The treatment sample consisted of 19 Class III patients (12 girls, 7 boys) with a mean age of 10.51 +/- 1.15 years, presenting with maxillary retrognathism. A cap splint type rapid palatal expander that had hooks between the upper lateral and canine teeth was used intraorally, and a Petit type facemask device extraorally, for an average of 6.78 +/- 0.93 months. Pre- and post-treatment cephalometric radiographs were evaluated. The results of the study revealed that point A moved anteriorly. The palatal plane showed a counter-clockwise rotation matched by the clockwise rotation of the mandible and an accompanying decrease in SNB angle. The vertical parameters showed a statistically significant increase. The head was in a more extensive position in relation to the cervical vertebrae. The nasopharyngeal airway measurements (PNS-ad1, PNS-ad2) showed an increase of 2.71 +/- 3.35 and 3.03 +/- 2.37 mm, respectively. These results demonstrated that limited maxillary widening together with protraction of the maxilla, improve nasopharyngeal but not oropharyngeal airway dimensions in the short term.

A method of studying adaptive changes of the oropharynx to variation in mandibular position in patients with obstructive sleep apnoea.

The aim of this study was to develop a method of studying the effects of mandibular advancement on oropharyngeal airway dimensions in the sagittal plane in conscious, supine patients. Six white, dentate, male patients with proven obstructive sleep apnoea had sagittal fluoroscopic recordings taken in the resting supine position. Images were recorded at four frames per second as the mandible was advanced with the teeth in contact to maximum protrusion and then opened. Software in the fluoroscopic imaging system permitted measurement of the change in mandibular position together with oropharyngeal airway dimensions expressed as the narrowest dimension observable in the post-palatal and post-lingual sites. Plotting of airway dimensions during mandibular advancement enabled estimation of the degree of protrusion associated with maximal airway benefits. Progressive mandibular advancement produced variable adaptive changes in the post-palatal and post-lingual regions of the oropharynx. The amount of airway opening appeared to be related to the horizontal and vertical relationships of the face and to the dimensions of the soft palate. The changes in post-palatal and post-lingual airway dimensions were not always identical, despite the observation that both tongue and soft palate were seen to move in unison, with close contact being maintained between the two structures. Jaw opening resulted in synchronous posterior movement of both tongue and soft palate, with consequent narrowing of oropharyngeal airspace. Fluoroscopy is a simple method of assessing upper airway changes with mandibular advancement in the conscious patient. The technique should facilitate the selection of subjects for whom mandibular advancement would seem advantageous. The nature of the adaptive response is dependent on individual structural variation. It is suggested that, where artificial mandibular advancement with dental devices is considered beneficial, jaw opening should be kept to a minimum.