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

https://doi.org/10.1016/j.ajodo.2003.05.006Get 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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    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.

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