Why do complications occur?
Why do TMJ symptoms occur?
- Inflammation in the TMJ
- Referred pain from the muscles of mastication
Why do occlusal changes occur?
- Proliferation (thickening) of the posterior attachment in the TMJs that will not allow condyle to fully seat in the fossa
- Muscles of mastication lengthen and adapt to foward Jaw position
- Tooth movement related to use of appliance.
Occlusal Maintenance
- Start within 1/2 hour of removing appliance
- Gently clench molars together and hold for 2-3 seconds
- Repeat 4 times per minute for 10 minutes or until bite returns to normal.
Complications of oral appliance therapy
Occlusal changes and temporomandibular symptoms occur in a percentage of patients who wear oral appliances for the treatment of snoring and sleep apnea.
In a recent study, Robertson found that overall, 26% of patients in this study exhibited some form of occlusal changes which were radiographically detectable. Only 10% of the sample however, showed changes that were clinically detectable. Nearly all patients with occlusal changes exhibited a degree of retroclination of the upper anteriors, a proclination of the lower anteriors with associated decreases in both overbite and overjet. Small increases in lower face height were also observed.
No intrusion of teeth was found in either the molar or premolar regions, but a posterior open bite seen in some patients was found to be due to a repositioning of the head of the mandibular condyle in the glenoid fossa.
Case 1:
In case one, a 40-year-old non-apneic snorer with bruxism was treated with a mandibular advancement splint .The patient was also diagnosed with gastric reflux. Following 3 years of appliance wear, severe incisal wear was observed which was also associated with a non-occlusion ofthe buccal occlusion.The degree of mandibular advancement of the appliance was 6.4mm.
When taken in centric occlusion transcranial temporomandibular radiographs demonstrated a posterior-superior increase in joint space between the head of the mandibular condyle and the glenoid fossa. Treatment with mandibular advancement was discontinued, with the patient’s symptoms being subsequently well controlled with the use of a tongue-stabiliser. Corrective orthodontic treatment was then undertaken to re-establish the anterior relationship. Contact of the posterior occlusion was only established however, after treatment had been discontinued for nine months. Extensive restorative procedures were then undertaken to re‹establish the occlusion.
Case 2:
The patient is a 40-year-old male apneic was treated with a mandibular repositioner with 9.9mm of mandibular advancement.
Following 3 years of appliance wear, a 15° retroclination of the upper anteriors was associated with a 12° proclination of the lower anteriors, and these changes were associated with a 6mm reduction in overiet. A Case picturevertical repositioning of the condylar- head was also observed. None of the above changes were attributed to growth modification. Treatment with mandibular advancement was subsequently continued, as this patient now much preferred his physical appearance and occlusal changes.
When taken in centric occlusion transcranial temporomandibular radiographs demonstrated a posterior-superior increase in joint space between the head of the mandibular condyle and the glenoid fossa.
Treatment with mandibular advancement was discontinued. Tongue-stabiliser inserted. Corrective orthodontic treatment to re-establish the anterior relationship. Contact of the posterior occlusion was established after treatment had been discontinued for nine months. Extensive restorative procedures to re-establish the occlusion.
Case 3:
The patient is a 57-year-old male apneic with a Skeletal III facial pattern.The patient was treated with a mandibular advancement appliance with 3mm of protrusion. Treatment duration was 3 years.Although mandibular advancement was minimal, a permanent anterior crossbite occurred. This patient declined any remedial treatment and is continuing to use his mandibular advancement appliance.
CONCLUSIONS
Occlusal changes can occur with mandibular repositioning appliances. Most changes appear to be of a minor nature, and of little concern to the patients, however some patients can exhibit changes that are detrimental to their occlusion. These changes do not appear to be directly correlated to the degree of protrusion, age, gender or skeletal type. To date cephalometric predictors for at-risk patients are unknown. It is strongly advised that informed consent be given to all patients prior to treatment with mandibular repositioning appliances, this should be combined with routine regular dental reviews with ongoing treatment.
Courtesy of Christopher Robertson, BDS MDS
Robertson CJ Dental and skeletal changes associated with long-term mandibular advancement.
In: Sleep (2001 Aug 1) 24(5):531-7
