Wednesday, December 16, 2009

Current Evidence Providing Clarity in Management of Temporomandibular Disorders

James Fricton, DDS, MS:Current Evidence Providing Clarity in Management of Temporomandibular Disorders: Summary of a Systematic Review of Randomized Clinical Trials for Intra-oral Appliances and Occlusal Therapies. J Evid Base Dent Pract 2006;6:48-52.

From the University of Minessota, School of Dentistry, Minneapolis, MN


The Guidelines Committee for the American Academy of Orofacial Pain conducted an evidence-based literature review to systematically search and review the literature for all randomized clinical trials for TMJD treatment using methods derived from the Cochrane Collaboration (http://www.cochrane.org/); the Oxford Centre for Evidence-based Medicine, (http://www.cebm.net/); and the Centre for Reviews and Dissemination, University of York, United Kingdom (www.york.ac.uk/ inst/crd/index.htm). Trials in which placebo, no treatment, or other treatments were used in the control group were included as were trials in which postrandomization exclusions occurred since there was no evidence that these occurred preferentially in one or other arm of the trials. This presentation reviews the results of this review for intraoral splints and occlusal therapies for temporomandibular disorders. This paper only provides a summary of the methods and results. The full results can be found in the subsequent journal publication.7

Methods of the Review
One hundred sixty-eight trials that were identified by the methods described in the search strategy were evaluated by the reviewers. Trials that proved on closer examination not to be true randomized trials were excluded. However, it is recognized that many nonrandomized studies that evaluate the efficacy of TMJD treatments including level II cohort studies, level III case-control studies and case series, and level
IV reviews of expert opinion have contributed significantly to our understanding of the treatment of TMJD. However, they were not included because of their high numbers, diversity of results, and their lower power in answering the question posed.  The knowledge gained by these studies in pilot data, study design, outcome measures, subject selection, and statistical analysis have contributed significantly in the
development of studies with more strength and conclusive results.

The results of randomized clinical trials were captured using both a qualitative and a quantitative method that could be conveyed to treating clinicians and patients. The quantitative evaluation included the NNT (number needed to treat).

For the purpose of this review, the treatments for TMJD were divided into 6 general treatment types:
1. Physical medicine treatments
2. Intraoral orthopedic appliances
3. Pharmacological therapy
4. Behavioral and psychological therapy
5. Temporomandibular joint surgery and arthrocentesis
6. Occlusal treatments

The questions to be answered for each treatment were:
1. Does the specific treatment effectively reduce TMJD pain compared to a placebo control?
2. Does the specific treatment more effectively reduce TMJD pain compared to no treatment or other treatments?

An assessment of the methodological quality of each RCT was also conducted to determine reasons for diversity of results for similar treatments and the potential for type I and type II errors. The criteria for this review and the percentage of each criterion met by the studies is presented in other papers as part of this review. The quality review was not intended to criticize the authors for the selected study designs, but rather to objectively identify source bias that may contribute to diverse or inconclusive results. The authors of these studies must be applauded for their use of an RCT, the highest level of evidence, to demonstrate efficacy of a treatment....

It was the intent of this review to conduct a meta-analysis of the data from the studies. However, in conducting the review, it was determined that the heterogeneity of studies, the varying quality, and the spareness of the similar outcomes data made it difficult to be sensibly combined....

Thirty-nine RCT studies involving intraoral splints were reviewed.9-47 In general, splints showed modest active therapeutic effects in reducing TMJD pain compared to a placebo control in more severe patients and comparable results to other treatments. In general, methodological issues in most of these studies make the results inconclusive and support the need for more well-controlled studies with improved methods. The mean quality score (0-1) of the studies was low at 0.53. Conclusions that can be drawn from this evidence-based review include the following:

1. Stabilization splints can reduce TMJD pain compared to nonoccluding splints in those subjects with more severe TMJD pain. There were no studies that demonstrated that splints work better in muscle pain, joint pain, or headache disorders, and in most studies, a mixed diagnosis of muscle and joint pain were present.
2. Stabilization splints in the short term were equally effective in reducing TMJD pain compared to physical
medicine, behavioral medicine, and acupuncture treatment for TMJD. However, the long-term effects of
behavioral therapy may be better than splints in reducing symptoms in more severe patients where psychosocial problems may be present but definitive studies have not been done. In one study, stabilization appliance therapy was more effective than pharmacological treatment for headache pain suggesting more research is needed in headache patients.
3. Anterior positioning and soft splints have some evidence to suggest that they are effective in reducing TMD pain compared to placebo controls.
4. Anterior positioning splints are at least equal to or more effective in treating TMJ clicking and locking than
stabilization splints.
5. Anterior bite planes have modest evidence of its efficacy for headaches and inconclusive evidence of effectiveness compared to a stabilization splint for TMJD pain. There is concern that partial coverage splints may contribute to tooth pain and/or occlusal changes and, thus, further study is needed before widespread use. More research is needed to study the efficacy of different types of splints for TMJD subtypes and severity and particularly, with types of headaches. Splints also need to be studied compared to placebo medications as well as other treatments including pharmacological treatment, behavioral treatment, and physical medicine procedures. The efficacy of appliance therapy for TMJDs does not only depend on appliance selection but also how well it is adjusted to facilitate patient comfort and compliance. It is
important to note that complications can occur from excessive, or incorrect use of appliances. Gingival inflammation, mouth odors, speech difficulties, and occlusal changes from these appliance can occur. Long-term, full-time use of partial coverage appliances and repositioning splints, in particular, can cause reversible changes to occlusal and functional jaw relationships. Some clinicians view orthopedic appliances as the definitive therapy for TMJD, but it is recommended that these appliances only be viewed as only part of a TMJD rehabilitation treatment program to encourage healing and normal function.

Dental treatment of malocclusion including occlusal adjustment, restorative dentistry, orthodontics, and orthognathic surgery have been advocated for treatment and prevention of TMD to improve the biomechanical efficiency, chewing ability and, in some cases, signs and symptoms of TMD. Seventy-nine studies involving occlusal treatment were reviewed.27,37,48-54 The results of these studies are equivocal
and few conclusions can be arrived at from the studies. The studies had a mean quality score of 0.50 and, thus, may be prone to bias influencing the results. One placebo-controlled RCT studied occlusal adjustment as a treatment of TMJD with a quality score of 0.51 and an NNT of 7. Two placebo controlled RCTs studied occlusal adjustment as a preventive treatment with a quality score of 0.53 and an NNT of 25.

Conclusions that can be drawn from this evidence-based review include;
1. There is insufficient evidence to suggest that any occlusal treatment as reviewed here is more or less effective than placebo in treating TMJD pain.
2. There is also insufficient evidence to suggest that any occlusal treatment is as or more effective than other
rehabilitation treatments in treating TMJD pain.
3. There is also insufficient evidence to support the generalized preventive influence of occlusal adjustment
and orthodontic correction of malocclusion on TMJD development. Since occlusal treatments are typically irreversible treatments and the evidence on its therapeutic or preventive effects on TMJD is insufficient, it is recommended that reversible treatment such as self-care, splints, physical therapy, and cognitive-behavioral therapy be used to initially manage signs and symptoms of TMJD. It is also acknowledged that these occlusal dental treatments can be used successfully to correct a malocclusion or uncomfortable occlusion in a patient with or without TMJD. For example, a patient who reports an uncomfortably high restoration or occlusal prematurities is often treated with an occlusal adjustment as the primary treatment. A patient who develops an open bite from rheumatoid the occlusion. However, since occlusal stability can be affected by
problems in the muscles or joints, it is important to stabilize TMJD signs and symptoms as well as jaw position with reversible treatments prior to considering any irreversible treatments to correct the malocclusion. A jaw position can be evaluated for stability using several methods, including improvement in the signs and symptoms; splint adjustments have not changed in past 2 to 3 months; no changes in TMJ
computed tomography scans in past 6 months; and no increase in incisal edge to incisal edge measurements. Failure to ensure jaw position is stable may result in continued occlusal dysfunction. However, once the muscles, joints, and jaw position are stable, occlusal treatment can proceed with improved confidence that occlusal changes will not occur after the occlusal treatment is completed.

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