Oral appliances: A successful treatment modality for obstructive sleep apnea category

Sir,

I have read two articles published in your esteemed journal (obstructive sleep apnea [OSA] and metabolic disorders. 2006;8:51-52 and OSA: Diagnosis and Treatment in an Endocrine Clinic. 2006;8:53-55) with great interest. Both of them are very informative and provide immense knowledge about OSA. It is very true that OSA has implications beyond disturbed sleep and yet this disorder remains undiagnosed in a substantial portion of the population especially in developing countries like India. Sir, I would like to bring to your kind notice that although continuous positive airway pressure (CPAP) remains to the gold standard treatment modality for OSA, oral appliances are now gaining popularity.

The role of dentists, especially orthodontists and prosthodontists, as part of a multidisciplinary team, in the management of obstructive sleep apnoea is being increasingly recognized. Oral appliances have emerged as a successful modality that modifies the position of tongue or jaw, altering the posterior pharyngeal space. The most-common oral appliance is mandibular advancement device (MAD). MADs came into the market for OSA treatment almost two decades ago. These appliances dilate or open the airway by anterior repositioning of mandible during sleep to relieve snoring and OSA. These devices are especially helpful to patients who are intolerant to their CPAP mask, or for snoring only.

The basic mode of function of MAD is related to the mechanical influence of mandibular advancement on pharyngeal patency. Because tongue is connected to mandible, the forward displacement of mandible improves the airway patency of retroglossal space by reducing folds and compression in upper-airway. The retropalatal space and retrolingual space are widened.[1] Lateral wall of the soft palate anatomically connects to the base of the tongue through the palatoglossal arch, so the mandibular advancement stretches the soft palate through the mechanical correction, stiffening the velopharyngeal segment as evidenced by Gakwaya et al. using phrenic nerve magnetic stimulation.[2]

Besides dilating the upper-airway and preventing upper-airway obstruction during sleep by holding the mandible in the forced protruded position, MAD sometimes causes undesirable consequences such as dryness of mouth, tooth discomfort or pain, hypersalivation, jaw pain, stiffness or pain of masticatory muscles, occlusal change of tooth position and loosening of teeth. But these are short term, and disappear on removal of appliance. Moreover, jaw pain and stiffness or pains in masticatory muscles are frequently associated with the amount of protrusion of mandible.[3] Usually, MAD is given at 75% of maximum mandibular protrusion but significant decrease in apnea hypopnea index has been found with 50% of maximum mandibular protrusion in mild to moderate OSA cases.[4]

Overall advantages of oral appliances over CPAP are:

• Better-patient compliance than with CPAP

• Ease of fabrication and good success rate in mild to moderate cases

• Robust and cost effective therapy

• Economical for poor patients

• Easy to handle, care and use.