The impact of oral appliance therapy with moderate mandibular advancement on obstructive sleep apnea and upper airway volume

Abstract

Purpose To find out if a moderate protrusion with a mandibular advancement device (MAD) can significantly increase the upper airway volume and, further, what signs and symptoms of obstructive sleep apnea (OSA) can be improved by this maneuver. Methods There were 58 adults diagnosed with OSA who were referred for MAD therapy. The mean apnea-hypopnea index (AHI) was 19.2 (SD 8.6). Five indicators of signs and symptoms of OSA (AHI, oxygen saturation, snoring, daytime sleepiness, and health-related quality of life) were evaluated at the baseline and after 6 months of MAD therapy. Nasal resistance and airway volume and cross-sectional areas with and without the MAD in situ were recorded. Based on AHI reduction, the treatment response was classified as complete, partial, or non-complete. Statistical analyses included the chi-square, t tests, Mann-Whitney U tests, and regression analyses (linear and logistic). Results Twenty-three patients attained a complete response (residual AHI < 5 events/h) to MAD therapy. In 13 subjects, the response was partial, and in 9 patients, it was non-complete. The complete responders were significantly younger, and they had a deeper overbite than partial/non-complete responders. A convex profile associated positively, but a vertically restricted throat and increased lower facial height associated negatively with the increase in airway volume. Conclusions Excellent MAD therapy outcomes were achieved in most patients. Only age and deep bite had some influence on AHI reduction, indicating multifactorial nature in the response to MAD therapy.

Dimensional analysis of the upper airway in obstructive sleep apnoea syndrome patients treated with mandibular advancement device: A bi‐ and three‐dimensional evaluation

“…The soft tissue connections between the target organs within the palatoglossal and palatopharyngeal arches are tightened by the advanced projection of the mandible, resulting in an enlargement of this area, the oropharynx, justifying the major improvement of the oropharynx compared to the other regions, once the MAD is placed. Interestingly, the reduction of the AHI Pahkala et al 48 obtained in their sample was quite similar to the one of the present study, from 19.9 ± 8.7 to 6.4 ± 5.2. According to Shete et al, 49 the increased upper airway volume favours an increased airflow, which is responsible for the improved patient's symptoms and increased oxygen saturation level.…”

“…This augmentation was at the expense of mainly the oropharynx, which significantly augmented from 10.9 ± 4.8 to 12.7 ± 5.4 cm 3 . Several studies have observed similar results 48‐50 . Our results are parallel to the findings observed in Pahkala et al, 48 where with a similar design and under a CBCT diagnosis, they observed a significant increased oropharynx volume after the placement of the MAD, which significantly augmented the total volume of the upper airway.…”

Correlation between Polysomnographic Parameters and Tridimensional Changes in the Upper Airway of Obstructive Sleep Apnea Patients Treated with Mandibular Advancement Devices

“…In the present study, 44% of the patients completed treatment with less than five events/hour. Similar findings have been published by other authors [31,32].…”

Acoustic pharyngometry ‐ A new method to facilitate oral appliance therapy

“…The total increase of vertical interincisal dimension of the OAs ranged from 4 to 12 mm, with a mean of 5.6 mm. A recent study identified patients with larger overbite as significantly more likely to achieve complete response of OA treatment, hypothesising that increased vertical dimensions for these patients normalises the intermaxillary space for the tongue in the oral cavity 44 . However, a general conclusion should not be drawn that increased vertical dimension improves the effect of OA treatment.…”