Mandibular advancement splints (MAS) have a role in the management of obstructive sleep apnoea (OSA) in some patients, but dentists warn of an “unacceptably high” failure rate if not done by a well-trained multidisciplinary team.
An Adelaide study also found that just which patients will benefit remains unclear. Dental surgeons reviewed 82 patients with diagnostic and MAS-in-situ sleep study results from 304 patients who had been referred by a respiratory physician and received a custom-made splint at the South Australian Oral and Maxillofacial Surgery Unit between 2008 and 2014.
Overall the mean Apnea Hypopnea Index (AHI) reduced by eight events per hour and Respiratory Disturbance Index (RDI) by 13 events per hour with the splints.
On the basis of objective AHI/RDI data, the study found a subgroup of patients (33%) improved with the devices but almost half the patients (49%) had no change and some patients (18%) experienced worsening OSA.
Using the more subjective Epworth Sleepiness Scale, 58% of patients were “better”, 36% were stable and 5% were worse with a splint.
The researchers said the poor correlation between objective and subjective measures of improvement suggested clinicians should always follow-up with a MAS-in-situ sleep study to confirm the device was effective for their patients.
They noted that one in four patients did not attend an outpatient visit for the opportunity to have their device adjusted for fit or titrated for optimal mandibular protrusion.
This may have contributed to an overall response rate below that of other published studies, the researchers suggested.
“Follow-up clinics allow clinicians to identify splints that fit poorly or are poorly tolerated, enabling either adjustment of splint design or for treatment to be reasonably abandoned and alternatives to be discussed,” they said.
The researchers were unable to identify predictors of improvement.
“A complex interaction between baseline OSA severity, age and BMI was identified in this dataset, which was best modelled with a randomForest model. Unfortunately, there were no clear features to guide patient selection.”
They concluded that mandibular advancement splint therapy was a viable treatment for a subset of patients with OSA who are unable to tolerate CPAP therapy, but with some caveats.
“It is imperative that people who work in this area are well trained and have access to a multi-disciplinary team of relevant specialists.
“Detailed protocols should be developed so that standard data sets are available and auditing of results is possible using objective measures. In the absence of these commitments, the treatment has an unacceptably high risk of suboptimal results.”