Scientists conducted a systematic review published in the Journal of Oral Rehabilitation which looked at whether or not there is a relationship between TMD and head and cervical posture. The following is a summary:
"The objective of this systematic review was to find sufficient evidence to deny or accept the association between the head and cervical posture and Temporomandibular Disorders (TMDs), and thus assist health professionals in the evaluation and treatment of patients with TMDs.
A search was conducted through all publications written in English about this topic using the databases from Medline, ISI Web of Science, EMBASE, PubMed and Lilacs. The abstracts that fulfilled the initial guideline were retrieved and evaluated to ensure they met the inclusion criteria. To assess the methodological quality of the studies, a questionnaire was developed considering the following criteria: participant's eligibility, control group, diagnosis of TMDs, posture diagnosis and randomization. Twenty-two studies were selected based on their abstracts. Only seventeen studies actually fulfilled the inclusion criteria.
The search provided information about the quality of the studies, in which several methodological defects were found. The evidence presented in this systematic review shows that the relation between TMDs and the head and neck posture is still controversial and unclear. The insufficient number of articles considered of excellent methodological quality is a factor that hinders the acceptance or denial of this association."
Source: Rocha, C. P., Croci, C. S. and Caria, P. H. F. (2013), Is there relationship between temporomandibular disorders and head and cervical posture? A systematic review. Journal of Oral Rehabilitation, 40: 875-881. doi: 10.1111/joor.12104