Based on: Kim M-R, Graber TM, et al: Orthodontics and Temporomandibular Disorder: A Meta-analysis. Am J Orthod Dentofacial Orthop 2002; 121 (May): 438-446
Objective: The purpose of this study was to perform a meta-analysis to evaluate the relationship between orthodontic treatment and temporomandibular disorder (TMD). A MEDLINE search identified 960 articles of which 31 met the inclusion criteria for the meta-analysis. 18 of these 31 articles were cross-sectional studies or surveys and 13 were longitudinal studies. Because of the severe heterogeneity of the studies the authors were not able to perform a true meta-analysis. Based on their review of the articles they concluded that the data did not indicate that traditional orthodontic treatment increased the prevalence of TMD. One of the things that severely hampered this study was the lack of a reliable and valid diagnostic classification system for TMD.
Conclusions: Because of the unknown cause of TMD, methodologic shortcomings, and lack of a widely accepted classification scheme, definitive conclusions about the relationship of orthodontic treatment and temperomandibular disorder could not be reached.
Reviewer's Comments: To me the results of this study were not very surprising. Temporomandibular disorder has long been a catch-all diagnosis for a wide-ranging number of symptoms and problems for which a specific diagnosis cannot be identified. If we cannot clearly define TMD, it should be no surprise that it would be difficult to find a strong relationship with any form of treatment. Because of this lack of standardization and the tremendously high number of articles published on this topic, it is possible to find some article to support your view no matter what that might be.