Original article
A comparison of responders and nonresponders to oral appliance therapy for the treatment of obstructive sleep apnea

https://doi.org/10.1016/j.ajodo.2004.06.035Get rights and content

Introduction: This retrospective study compared cephalometric variables between responders and nonresponders to a titratable oral appliance (OA) in a group of subjects matched for sex, pretreatment age, and body mass index (BMI). Methods: Nine nonresponders as defined by an improvement in the apnea hypopnea index (AHI; <20%) and their individually matched responders were selected for this study. The difference in age for each matched pair was ±5 years, and, for BMI, the difference was ±15%. The pretreatment AHI was matched to the same category (moderate, >15 to ≤30; severe I, >30 to ≤45; and severe II, >45 AHI). Results: Middle and inferior airway space and oropharyngeal airway cross-sectional area were significantly larger in the nonresponders. Position of the mandible relative to the cervical spine was the only significant skeletal variable and was larger in nonresponders. Changes in BMI between the groups were statistically significant; the averages were a 2.9% increase in the nonresponders and a 0.5% decrease in responders. The wider airway in nonresponders might reflect an enhanced neuromuscular compensation while awake. The weight gain in nonresponders was relatively small, but it might have reduced the effectiveness of the OA. Conclusion: When treating OSA patients with OA therapy, clinicians should pay particular attention to airway size and weight changes.

Section snippets

Subject selection

In this retrospective study, we tracked the database of patients who had been treated with adjustable and titratable OAs at the Sleep Apnea Dental Clinic at the University of British Columbia or the orthodontic practice of Dr Alan A. Lowe. All patients had been diagnosed by overnight polysomnography (PSG) with the methodology previously described.14, 15, 16 They also met our patient selection criteria, including at least 10 healthy teeth in each arch, no evidence or past history of

Results

From the database, 9 of 134 patients were found to be nonresponders according to our criteria—5 moderate, 3 severe I, and 1 severe II. Table II shows demographic data, pretreatment and posttitration AHI, and improvement in AHI for each nonresponder-responder pair. All subjects were male. Their ages, pretreatment BMIs, posttitration BMIs, and pretreatment AHIs were not statistically significantly different in the 2 groups overall. The posttitration AHI and improvement in AHI were statistically

Discussion

The etiology of OSA is still controversial, but the interaction of anatomic and neuromuscular factors appears to determine pharyngeal patency.19, 20 Many anatomic alterations in OSA patients have been previously reported with lateral cephalometric analyses. Lowe et al,16 with a principal component analysis, documented several alterations including posteriorly positioned maxilla and mandible, steep occlusal plane, overerupted maxillary and mandibular teeth, proclined incisors, steep mandibular

Conclusions

A comparison of responders and nonresponders showed that nonresponders had wider upper airways and an average increase of 2.9% in BMI during treatment. These results suggest that practitioners should be cautious when treating patients with an OA if they have a wide anteroposterior airway and a weight change during treatment.

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  • Cited by (0)

    The Klearway appliance was invented by Alan A. Lowe at the University of British Columbia, which has obtained international patents, and specific licensees have been assigned the rights to manufacture and distribute the appliance worldwide. Royalties from the sale of the Klearway appliance are paid to the University of British Columbia.

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