By Kent Moore, DDS, MD
The 11th annual Academy of Dental Sleep Medicine meeting featured some of the field's most well-known researchers who presented the latest findings in oral appliance therapy.
Support is growing within scientific publications for the use of oral appliance therapy in patients with mild to moderate obstructive sleep apnea, according to Wolfgang Schmidt-Nowara, MD, who presented an annual review course titled, "Update in Sleep Medicine: New Developments." In addition, he pointed out that several medical specialties (sleep, oral and maxillofacial surgery, and orthodontics) now are recognizing the value of oral appliance therapy for OSA. Dr. Schmidt-Nowara has served as both president of the American Board of Sleep Medicine and as president of the American Sleep Disorders Association.
INFLUENCES ON EFFECTIVENESS
The relative success of oral appliance therapy may be affected by some sleep medications, which relax the airway muscles and/or reduce respiratory drive, according to Mary Susan Esther, MD, medical director of Carolinas Sleep Services in Charlotte, N.C. However, newer sedatives such as zolpidem tartrate (AmbienŽ, Searle) and zaleplon (SonataŽ, Wyeth-Ayerst) don't appear to worsen upper airway obstruction. In fact, these medications have been prescribed for patients beginning oral appliance therapy.
Dr. Esther also mentioned in her presentation titled, "Sleep Medication and their Effect on Oral Appliance Therapy," that most anti-depressants suppress REM sleep (during which apneas tend to be higher). However, the effects of estrogen-containing drugs, melatonin and sedative drugs on sleep physiology are more varied.
Another factor that may influence the effectiveness of oral appliance therapy is sleep posture. Without attention to the sleep position or posture, one could easily mistakenly assess treatment as falsely ineffective based on changes in the apnea-hypopnea index, said Kazuya Yoshida, DDS, PhD, a research fellow in the department of oral and maxillofacial surgery at the Graduate School of Medicine, Kyoto University, Japan. Apnea and hypopneas are influenced strongly by sleep posture, and this factor should be assessed in all sleep studies, according to his research.
ADDRESSING CONCERNS
Tom Abrahamsen, DDS, an associate professor of dentistry and director of the clinical preceptor program at Case Western Reserve University, Cleveland, Ohio, addressed concerns regarding temporomandibular joint (TMJ) problems associated with oral appliance therapy. Oral appliances affect upper airway volumetric expansion via forward translation of the mandibular condyle and disc. In some predisposed individuals, this may exert unfavorable forces on the joint, causing problems with the disc.
Dr. Abrahamsen presented a practical method for minimizing TMJ complications in this group of patients using a silastic shem (bite-guard material). After the patient takes the oral appliance out of his mouth each morning, he places the shem between his front teeth and bites down for approximately 10 minutes. Due to the shem's angle, the resultant vector of force acts to reseat the condyle and disc within the fossa and to dissipate any degree of joint edema that may have developed overnight with use of the appliance.
A session titled, "Updates in Sleep Medicine" by Alan Lowe, DMD, PhD, FRCD, FACD, of University of British Columbia, Vancouver, also dealt with complications surrounding oral appliance therapy. Immediate complications include excessive saliva, which is generated because the body thinks the appliance is food; this usually resolves in eight weeks. Another potential complication is the sense of the jaw being stretched to a forward mandibular posture; this also usually resolves in the first eight weeks. On occasion, some patients complain of specific or generalized tooth discomfort, which often can be relieved by the dentist grinding the acrylic or adjusting the clasps.
After long-term use (three to five years), tooth or occlusal change (usually tipping forward of the lower front teeth or tipping of the upper front teeth backward) sometimes can be seen. This can be managed with a simple orthodontic therapy including springs and acrylic incorporated directly into the oral appliance.
Dr. Lowe said clinicians shouldn't be afraid of occlusal problems seen with oral appliance therapy, but they should learn to monitor and to manage these problems. He also noted that oral appliances should be evaluated and possibly replaced every two years. Long-term wear of the oral appliance needs to be monitored by a dentist to identify possible occlusal changes and to initiate appropriate therapy if required.
Back by popular demand this year was Chris Robertson, BDS, MDS, an orthodontist from Dunedin, New Zealand, who combined his incredible knowledge of long-term use of oral appliance therapy with wit and humor. Dr. Robertson presented his data on the extent, time frame, and course of dental and occlusal changes occurring during mandibular advancement splint therapy in sleep-disordered breathing. He found orthodontic tipping of the maxillary and mandibular anterior teeth upwards of two years into active oral appliance therapy.
INVENTIVE MINDS
Dr. Robertson also discussed the use of tongue-stabilizing appliances, which hold the tongue in an anterior position and prevent posterior movement of the tongue base, in the treatment of sleep-disordered breathing. While the tongue-stabilizer he invented hasn't undergone multicenter study, Dr. Robertson is very optimistic that this is an option that should be offered to more patients.
Jack Gerschman, BDSc, PhD, of Australia, gave his results on a prospective trial of another invention, an adjustable mandibular positioner, which advances the mandible and tongue base. Dr. Gerschman found that the appliance was very beneficial in the management of OSA.
All the speakers were impressive, and the meeting had arguably the largest and finest group of international speakers ever assembled in one place to discuss the latest cutting-edge issues in dental sleep medicine. Next year's meeting, again in conjunction with the Associated Professional Sleep Societies Annual Meeting, will be in Chicago.
Dr. Moore served as the program chair of the Academy of Dental Sleep Medicine's annual meeting and has a private oral and maxillofacial practice in Charlotte, N.C.
This issue of Sleep Tracks is produced in conjunction with the American Sleep Apnea Association. The ASAA can help you help your patients. For brochures, newsletter reprints, articles and other materials, write to the staff at: 1424 K Street, N.W., Suite 302, Washington, D.C. 20005, call (202) 293-3650 or visit www.sleepapnea.org.
Sleep Tracks, Advance for Managers of Respiratory Care, September, 2002.
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