Nowadays MAD, the mandibular advancement device, seems to be delivered from almost every dental office in an effort to assist the medical profession fighting sleep apnea, a major problem for many of our patients. The device is supposed to direct the mandible forward and inferiorly in order to increase the air flow through the mouth. However, a standardized method in making the device seems lacking and many patients suffer discomfort or pain after wearing the device after various lengths of time. Dentists regularly also register changes of occlusion, most often posterior open bites.
As the device shall position the mandible forwards the most often clinically achieved index accompanying the impressions to the laboratory must be taken in a protruded mandibular position. But how much protrusion seems to be left at random. There are studies concluding that it does not matter whether the protrusion is 75% of maximum protrusion or only 25%. Nevertheless it seems accepted to allow a rather large amount of protrusion as additional protrusion as adjustment of the device often is recommended in the cases where the originally designed device has not given the expected relief.
At a vertical temporomandibular joint condylar asymmetry an excessive and prolonged protrusion definitely puts the comfort of the patient and a harm free function of the stomatognathic system at risk. At a vertical condylar asymmetry most likely the clinically taken index does not register the mandible in a symmetrically protruded mandibular position. Most likely the mandible is deviating towards the ” shorter ” condyle side. To then have this position maintained during six to eight hours of sleep with thus an awkward and asymmetrical muscle function and temporomandibular joint condylar positions may be one reason for discomfort or facial pain at awakening.
One way to avoid the problem is to use the Maaxloc ( following the analysis of the vertical condylar heights in the panoramic x-ray ) in constructing the index which is to be used in the mounting of the models in the articulator. It is then easy to bilaterally just set the amount of individually determined protrusion to be applied in the fabrication of the device. A symmetrical protrusion is thereby achieved resulting in a more comfortable device.
A good friend of mine, Dr Staffan Lindholm, Stockholm, Sweden, is probably one of the most experienced dentists in Scandinavia when it concerns oral devices in fighting sleep apnea. His expertise and unusual self criticism already several years ago motivated him to compare the outcome of 59 conventionally and from just clinically taken indices oral devices with another 59 devices constructed from articulator set protrusion of the models mounted with the Maaxloc registration. Six patients of the first group suffered pain and discomfort from their devices while only 1 patient of the second group showed a minor dissatisfaction, but tolerated the splint. The 6 not successful devices in the first group of patients were later adjusted according to a Maaxloc registration resulting in patient satisfaction.
In many discussions with fellow dentists and dental technicians Dr. Lindholm proclaims the superiority of the Maaxloc instrument in constructing a more comfortable and successful oral device. He is happy to generally tell about his continuing success with a 80-90% reduction of the risk to develop discomfort or pain in the patients who are forced to wear an oral device fighting sleep apnea by using the Maaxloc registration in mounting the models before its fabrication in the laboratory . In conclusion, please do consider a correct index in protrusion for the construction of any anti sleep apnea device at your choice and thereby enjoy a major increase of clinical success!
Tore L. Hansson 