Effects of an anteriorly titrated mandibular position on awake airway and obstructive sleep apnea severity

doi:10.1016/j.ajodo.2003.05.006

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 125, Issue 5, May 2004, Pages 548-555

https://doi.org/10.1016/j.ajodo.2003.05.006 Get rights and content

Abstract

The objective of this study was to investigate whether a reduction of obstructive sleep apnea (OSA) severity was associated with significant upper airway (UA) changes after an anterior titration of the mandibular position. Eighteen OSA patients with a mean (SD) apnea hypopnea index (AHI) of 32.5 (12.3) were recruited. Baseline supine cephalometry was obtained before the initial insertion, and follow-up supine cephalometry was undertaken after titration with a titratable oral appliance in place. The mean AHI before treatment was significantly reduced to 9.7 (7.4) (P < .001) after titration. In 13 responders with AHI reduced to ≤15/h, a significant forward displacement of the anterior wall of the velopharynx (P < .05) was observed. In addition, there was a significant forward displacement of the posterior wall of the oropharynx and the hypopharynx (P < .05). In the 5 nonresponders, no significant changes in the position of the anterior and posterior wall were observed. There was no significant difference in the total amount of mandibular advancement between responders and nonresponders. We conclude that treatment success with oral appliance therapy appears to depend not only on anterior titration of the mandibular position to enlarge the UA, but also on the amount of change in the size of the UA in response to mandibular advancement.

Section snippets

Material and methods

A total of 18 OSA patients (15 men, 3 women) were recruited for this study. All were diagnosed with OSA based on polysomnographic sleep studies at the Sleep Disorders Clinic of the Vancouver Hospital and Health Sciences Centre. The mean (SD) age of the patients was 45.9 (9.9) years (range, 24 to 69) and the mean body mass index (BMI) was 27.7 (5.4) kg/m² (range, 21.3 to 42.3). Each patient gave written informed consent. Patients were excluded if they had a history of temporomandibular joint

Results

In 18 patients, the forward titration of the mandibular position from the initial two-thirds protrusion was commenced after a median and interquartile range adaptation period of 21 (14-28) days after the initial placement of the OA (Fig 3). The titration period was 131 (97-206) days. Both the mean apnea index and the AHI before treatment were significantly reduced after titration of the mandibular position (apnea index, 9.2/hour [9.8] to 1.2/hour [2.5], P = .03; AHI: 32.4/hour [13.1] to

Discussion

The results of this study demonstrated that, in responders, the AHI and the minimum SaO₂ were successfully improved after titration of the mandibular position. The anterior wall of the velopharynx was repositioned forward, and forward repositioning of the posterior oropharyngeal and hypopharyngeal walls also occurred.

The enlargement of the velopharynx in response to an anteriorly titrated mandibular position was achieved by forward repositioning of the soft palate (Fig 4). The connection

Conclusions

The velopharynx was significantly enlarged in conjunction with repositioning of the soft palate after the gradual anterior titration of the mandibular position during wakefulness; this resulted in a reduction of OSA severity in the responders. No significant changes in the UA were observed in the nonresponders. Treatment success in OA therapy appears to depend not only on the anterior titration of the mandibular position, which might maximize the treatment efficacy for each patient, but also on

Acknowledgements

We thank M. Wong for her expertise in software and data management and I. Ellis for her editorial assistance.

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Long-term influence of mandibular advancement on the volume of the posterior airway in skeletal Class II-patients: a retrospective analysis
2017, British Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
The gain in posterior airway space may be of particular benefit to patients with sleep apnoea. Many can be treated with orthodontic appliances that secure the mandible in an anterior position and prevent collapse of the posterior airway.24 Orthognathic surgery has been described as the therapeutic option in patients with obstructive sleep apnoea, particularly those who also have maxillomandibular deficiency.6,25
In the past, maxillomandibular advancement has resulted in considerable improvement in the volume of the posterior airway space. The objective of the present study was to find out how mandibular advancement without maxillary involvement would affect the posterior airway space in patients with mandibular retrognathism. Cone-beam computed tomographic (CT) scans were done for 20 patients before, and six months after, mandibular advancement. Cephalometric analysis at both time points included 2-dimensional and 3-dimensional assessment of the upper airway. Eight men and 12 women presented a preoperative mean (SD) Wits value of 7.4 (1.54) mm, with an airway area of 7.11 (1.88) cm² and a volume of 14.92 (4.46) cm³. Six months postoperatively they showed a Wits value of 2.7 (0.41) mm, an airway area of 11.33 (3.49) cm², and a volume of 25.7 (6.10) cm³. There was a mean (range) enlargement of 59 (22-82) % of the area and 73 (29-108) % of the volume. A preoperative Wits value of 8 mm or more correlated significantly with a larger increase of the posterior airway space (p = 0.002). At the same time, an improvement in the Wits value of 4.5 mm or more correlated significantly with an increase in volume (p = 0.016). The effect of mandibular advancement on the posterior airway space was significant, and the volumetric effect seems to be even more relevant than the two-dimensional changes.
Do mandibular advancement devices influence patients' snoring and obstructive sleep apnea? a cone-beam computed tomography analysis of the upper airway volume
2015, Journal of Oral and Maxillofacial Surgery
The upper airway volume is central to the development and treatment of snoring and obstructive sleep apnea, and mandibular advancement devices (MADs) have increasingly been used as an effective alternative to continuous positive airway pressure for these 2 conditions. We investigated the changes in breathing patterns and upper airway volume parameters measured on cone-beam computed tomography (CBCT) scans of patients with and without the use of custom-made MADs.
We performed a prospective study at the Department of Oral and Maxillofacial Surgery, Odense University Hospital, on consecutively treated patients. CBCT scans were performed with and without the MAD to measure the changes in the upper airway volume. The patients underwent diagnostic cardiorespiratory monitoring before and after 3 months of MAD therapy. Measurements with and without MAD were compared using Student's t test and the Wilcoxon signed rank test, and mixed-model analyses were performed adjusting for sleep apnea severity, type 2 diabetes, body mass index, gender, and age.
A total of 44 patients (31 men and 13 women, age 50 ± 13 years, body mass index 31 ± 5.6 kg/m²) completed the trial. MAD therapy was associated with an increase in the total upper airway volume from 22.9 ± 8.7 cm³ before treatment to 26.7 ± 10.7 cm³ after treatment (P < .001). MAD therapy reduced the apnea-hypopnea index (AHI) from 15.8 ± 17.4 events/hour before treatment to 6.2 ± 9.8 events/hour after treatment (P < .001).
The results of the present study indicate that MAD therapy appears to produce significant changes in the upper airway volume that correlate with a decrease in the AHI.
Selection of response criteria affects the success rate of oral appliance treatment for obstructive sleep apnea
2014, Sleep Medicine
Citation Excerpt :
The most common definitions of treatment success include a reduction in the apnea–hypopnea index (AHI) to <5 events per hour or <10 events per hour in addition to a >50% reduction in baseline AHI [2–28]. A >50% reduction in baseline AHI alone, posttreatment AHI <15 events per hour, and a reduction in AHI to <20 events per hour also have been used [2–28]. Among these, the most stringent definition of success is a reduction in the AHI to less than 5 events per hour in conjunction with a >50% reduction in AHI at baseline, which generally can be achieved by nasal continuous positive airway pressure.
In oral appliance therapy for obstructive sleep apnea (OSA), treatment success is arbitrarily defined. We investigated if the selection of response criteria affected the success rate of oral appliance treatment.
The effects of an oral appliance on apnea–hypopnea index (AHI) and nadir percutaneous oxygen saturation (SpO₂) were investigated in 224 OSA patients. Treatment success was defined as a reduction in AHI to <5 events per hour with a >50% reduction in baseline AHI (criterion 1), a follow-up AHI of <10 events per hour with a >50% reduction in baseline AHI (criterion 2), a >50% reduction in baseline AHI alone (criterion 3), or a >50% reduction in baseline AHI with the nadir SpO₂ above 90% (criterion 4).
The baseline AHI was reduced with an oral appliance in place compared with the follow-up value (23 ± 11–8.5 ± 8.7 events/h; P < .05) in all of the participants. In every OSA subgroup, the success rate under criterion 3 (75% [mild], 71% [moderate], and 70% [severe]) was greater than that under criterion 1 (53%, 40%, and 24%, respectively). However, responders under criterion 3 in the severe OSA subgroup were still hypoxemic with a nadir SpO₂ of 87 ± 8% even after treatment. This situation was improved by the use of criterion 4, in which a satisfactory improvement in AHI (from 38 ± 11 to 1 ± 1 events/h; P < .01) was associated with a sufficient increase in the nadir SpO₂ (93 ± 2%).
We conclude that the selection of response criteria influences the success rate of oral appliance treatment. To avoid adverse health outcomes, an adjunct definition of treatment success using SpO₂ may be effective for patients who have more severe OSA.
Cephalometric and three-dimensional assessment of superior posterior airway space after maxillomandibular advancement
2012, International Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
For the movements of advancement, special attention is given to the treatment of obstructive sleep apnea disturbances.22 Clinically, the use of orthodontic appliances that protect the mandible anteriorly show satisfactory results for the treatment of these disturbances.23 According to Goodday,7 patients with OSAS and a maxillomandibular deficiency must be advised to undergo maxillomandibular advancement surgery as the first choice of treatment.
The purpose of this study was to quantify cephalometric and three-dimensional alterations of the posterior airway space of patients who underwent maxillomandibular advancement surgery. 20 patients treated by maxillomandibular advancement were selected. The minimal postoperative period was 6 months. The treated patients underwent cone-beam computed tomography at 3 distinct time intervals, preoperative (T1), immediate postoperative period up to 15 days after surgery (T2), and late postoperative period at least 6 months after surgery. The results showed that the maxillomandibular advancement promoted an increase in the posterior airway space in each patient in all the analyses performed, with a statistically significant difference between T2 and T1, and between T3 and T1, p < 0.05. There was a statistical difference between T2 and T3 in the analysis of area and volume, which means that the airway space became narrower after 6 months compared with the immediate postoperative period. The maxillomandibular advancement procedure allowed great linear area and volume increase in posterior airway space in the immediate and late postoperative periods, but there was partial loss of the increased space after 6 months. The linear analysis of airway space has limited results when compared with analysis of area and volume.
The effect of mandibular advancement on upper airway structure in obstructive sleep apnoea
2010, Thorax
Citation Excerpt :
However, the mechanisms by which MAS improve OSA are not well understood. Limited studies have identified an effect of mandibular advancement on aspects of the structure and function of the upper airway.9–16 Importantly, these predominantly used cephalometric x-rays which are limited by their two-dimensional nature.
The mechanisms by which mandibular advancement splints (MAS) improve obstructive sleep apnoea (OSA) are not well understood. This study aimed to evaluate the mechanism of action of MAS by assessing their effect on upper airway structure in patients with OSA.
Patients were recruited from a sleep disorders clinic for treatment with a custom-made MAS. MRI of the upper airway was performed during wakefulness in the supine position, with and without the MAS.
Sixty-nine patients with OSA were recruited. Treatment with the MAS reduced the apnoea–hypopnoea index (AHI) from 27.0±14.7 events/h to 12.2±12.5 events/h (p<0.001). There was an increase in the total airway volume with mandibular advancement (16.5±0.7 cm³ vs 18.1±0.8 cm³; p<0.01) that occurred predominantly because of an increase in the volume of the velopharynx (5.7±0.3 cm³ vs 6.5±0.3 cm³; p<0.001). This increase in airway calibre was associated with an increase in the lower anterior facial height (6.8±0.1 cm vs 7.5±0.1 cm; p<0.001), reduction in the distance between the hyoid and posterior nasal spine (7.4±0.1 cm vs 7.2±0.1 cm; p<0.001), lateral displacement of the parapharyngeal fat pads away from the airway (right parapharyngeal fat pad 0.17±0.02 cm; left parapharyngeal fat pad 0.22±0.02 cm) and anterior movement of the tongue base muscles (0.33±0.03 cm). Subanalyses in responders and non-responders to MAS treatment showed that the increase in upper airway calibre with mandibular advancement occurred only in responders.
These results suggest that the mechanism of action of MAS is to increase the volume of the upper airway, predominantly by increasing the volume of the velopharynx, and this increased volume is associated with changes in the surrounding bony and soft tissue structures.

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Dr Alan Lowe invented the Klearway appliance; the University of British Columbia holds the patent, and specific licencees are assigned the rights to manufacture and distribute it.

Submitted, March 2002; revised and accepted, May 2003.

View full text

Original articleEffects of an anteriorly titrated mandibular position on awake airway and obstructive sleep apnea severity☆

Abstract

Section snippets

Material and methods

Results

Discussion

Conclusions

Acknowledgements

Chest

Am J Orthod Dentofacial Orthop

Respir Physiol

Lancet

Sleep Med Rev

Pathogenesis of upper airway obstruction during sleep

J Appl Physiol

Oral appliances for sleep breathing disorders

Effect of mandibular and tongue protrusion on upper airway size during wakefulness

Am J Respir Crit Care Med

Effects of a titratable oral appliance on supine airway size in awake non-apneic individuals

Sleep

Mandibular advancement modulates respiratory-related genioglossus electromyographic activity

Sleep Breath

Treatment, airway and compliance effects of a titratable oral appliance

Sleep

Recent developments in oral appliance therapy of sleep disordered breathing

Sleep Breath

Original article
Effects of an anteriorly titrated mandibular position on awake airway and obstructive sleep apnea severity☆