TMD and occlusion part I. Damned if we do? Occlusion: the interface of dentistry and orthodontics.
OBJECTIVE
To review how occlusion, facial growth, TM disc position and malocclusion may relate to TMD; to review clinical studies investigating TMD pre- and post-orthodontic treatment as well as other studies linking occlusal features with TMD highlighting their limitations; and to make suggestions for improved study designs in the future in order to provide an evidence-base for clinical practice.


METHODS
Review article.


METHODS
Electronic databases (MEDLINE and the Cochrane Database of Systematic Reviews) were used to select relevant and frequently cited studies (mean: 28 citations). Citation rate was confirmed using the Web of Science. Study designs are reviewed and weaknesses discussed.


RESULTS
Evidence is lacking to suggest static occlusal factors cause TMD.


CONCLUSIONS
Poor study designs have led to much of the controversy over whether occlusal factors (including orthodontics) 'cause' TMD. In order to provide an evidence-base for future clinical practice, suggestions to improve study designs are made.
Luther
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Department of Orthodontics, Child Dental Health, Leeds Dental Institute, Clarendon Way, Leeds, UK. f.luther@leeds.ac.uk
D018865:Dental Research; D006801:Humans; D008310:Malocclusion / Q000150:complications*; D008445:Maxillofacial Development; D009971:Orthodontics, Corrective / Q000009:adverse effects*; D012107:Research Design; D019224:Temporomandibular Joint Disc / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000209:etiology*