If the muscles of the region of the uvula – that little lobe at the back of the throat – get more flaccid and the tonsils bigger, breathing during sleep is complicated. The air has difficulty in getting in, and when the person forces his breathing, the result is snoring, that disagreeable noise that everyone knows. Besides disturbing those who are nearby, it is a sign of poor quality sleep. When the effort is made to breathe and the air does not pass, because the air passageway is closed, apnea intervenes, in events that last more than 10 seconds and are considered abnormal when they exceed a frequency of five occurrences an hour. “Snoring is, at the least, one symptom of sleep apnea”, explains dentist Eduardo Rollo Duarte. In his doctoral project at the University of São Paulo (USP), he developed a kind of intraoral plate to be placed inside the mouth at night, to reduce the apnea and the snoring.
Sleep disorders cause a series of problems, such as daytime drowsiness, difficulties in memorizing and headaches. And a milder apnea can often be easily controlled. Obstruction in the region of the pharynx can be caused by various factors, from anatomical abnormalities and genetic factors, hypothyroidism, aging, that leaves the muscles flaccid, obesity, to the use of cigarettes, alcoholic beverages and sedatives that leave the muscles excessively relaxed, preventing the passage of the air.
The function of the intraoral plate, made from acrylic resin, is to clear this passage. Having been produced, it was tested on 15 patients with an average of 49 years old who showed moderate and light apnea (from 5 to 30 interruptions per hour of sleep). Before the treatment, the patients did a polysomnography, an examination for a complete evaluation of the patients? sleep, carried out at the Sleep Disorders Clinic, in Bauru. The test was repeated after one year’s use of the plate and showed that 93% of the patients had a reduction, averaging 77%, in the frequency of apnea. Digitalized X-rays also indicated an increase in the dimensions of the upper airway, and the patients themselves reported that daytime drowsiness had decreased. “One of the advantages of the appliance is that it controls the problem and prevents a surgical intervention”, say a professor from USP’s Faculty of Dentistry, Maria Luiza Arantes Frigerio, who is supervising Duarte.
The use of intraoral plates is already a well disseminated practice abroad. Around the 1980s, the first plates produced in the United States did not allow adjustments, and for that reason they could cause problems in the mandibular joint. Today, the agency responsible for analyzing and approving medicines in the USA, the FDA, now has about 20 types of plate approved for use. The first Brazilian one is going to be cheaper than the imported one. The simplicity of the design and the acrylic resin allow it to be made by a dental surgeon specialized in dental prostheses. Another advantage is that, being adjustable, like other more modern models, the plate has a lock that controls the opening, or the advance of the mandible. Despite the facilities, Duarte emphasizes that it does not make sense to think of the material developed in isolation. “The use of the plate is only effective when associated with a treatment for the sleep disorder, which should be carried out by a multidisciplinary team made up of doctors and dentists from the sleep area.”
Treatment of the syndrome of obstructive sleep apnea and hypopnea and snoring with a plate to reposition the mandible
Regular Line of Research Grants
Maria Luiza Moreira Arantes Frigerio – USP
R$ 11,841.25 (FAPESP)