Nasal CPAP may alter facial structure in adults with obstructive sleep apnea
Last Updated: 2010-10-15 12:51:02 -0400 (Reuters Health)
By Karla Gale
NEW YORK (Reuters Health) - Just three years' use of nasal continuous positive airway pressure (nCPAP) can cause changes in the position of the jaws and teeth, according to a study of Japanese adults treated for obstructive sleep apnea (OSA).
While none of the patients noticed these changes, they are likely to become more pronounced over time because OSA treatment continues for a lifetime.
Therefore, Dr. Harry L. Legan, spokesperson for the American Association of Orthodontists, told Reuters Health, "The sharp sleep doctor will consider having the patient evaluated by an orthodontist to see if they should wear an intraoral retention device to prevent untoward movements of the teeth while using nCPAP." Dr. Legan was not involved in the research.
The prospective study included 46 OSA patients who had used a nasal mask to deliver nCPAP for > 4 h/d and > 5 d/wk for 25 to 46 months (mean 35 months). Forty-one were men, and ages ranged from 28 to 84.
Lead author Dr. Hiroko Tsuda, from Kyushu University Hospital, Fukuoka, Japan, and associates analyzed lateral digital cephalometric radiographs taken prior to starting nCPAP and at follow-up.
"The whole front area of the maxilla was pushed back and the maxillary incisor became retroinclined," the authors report in the October issue of Chest. As a compensatory response, the mandible rotated downward and backward. All these changes were statistically significant, the authors note, as was the decrease in facial convexity.
nCPAP is known to cause midface hypoplasia and malocclusion in children, the authors note, but this is the first study to find similar changes in adults. Because they aren't growing, the severity of changes is likely to be less in adults, but "these changes may affect the profile, tongue space, and OSA symptoms," they write.
Dr. Tsuda's group concludes that "the use of an nCPAP machine for > 2 years could be associated with change in the craniofacial form by reducing maxillary and mandibular prominence, the interrelationship of the two dental arches, and the prominence of the upper incisors."
These short-term changes, though statistically significant, aren't clinically relevant since there was "almost no trouble such as eating difficulty or serious esthetic impairment," Dr. Tsuda told Reuters Health in an email. And he wouldn't advise these observations to keep anyone from using CPAP, because of the serious consequences of untreated OSA.
Still, he said, "Patients should be informed of this possible side effect prior to starting CPAP therapy."
Dr. Legan noted that "anything we do to push facial structures back is not beneficial in patients with sleep apnea. I think it could be problem, even in the shorter term, because there's not a lot of tolerance in how some people's bite fits together -- the front teeth could potentially end up behind the back teeth."
"Then for people who use nCPAP long term," he added, "surely some significant dental and even bony changes are possible, and we'd like to try to reduce or eliminate those bad side effects."
Dr. Legan is past chair of the orthodontic department at Vanderbilt University, and is currently in private practice in Franklin, Tennessee.
SOURCE:http://link.reuters.com/neq58p
Chest 2010;138:870-874.
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