Neck disability is associated with masticatory myofascial pain and regional muscle sensitivity.
OBJECTIVE
The primary aims of this study are to compare neck disability in masticatory myofascial pain subjects versus asymptomatic controls, and to evaluate the correlation between neck disability and muscle pain.


METHODS
Two groups composed this case-control study: a symptomatic group comprised of 27 subjects diagnosed with masticatory myofascial pain, as determined by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), and a control group comprised of 28 asymptomatic subjects. The collected variables were pain intensity (visual analogue scale), pressure pain threshold of the temporomandibular joint, anterior temporalis, masseter, sternocleidomastoid muscle, upper trapezius and Achilles tendon (digital dynamometer, kgf/cm(2)), and neck disability (Neck Disability Index). Statistical analysis included Student's t-test and the Pearson product-moment correlation coefficient (5% significance level and 95% confidence interval).


RESULTS
The symptomatic group showed greater neck disability with a mean (SD) of 11.8 (7), as compared with 2.8 (2.4) for the asymptomatic group (p<0.05). A negative correlation was found between neck disability and pressure pain threshold of the anterior temporalis (r=-0.4, 95% CI -0.6 to -0.15, p=0.002), the sternocleidomastoid (r=-0.35, 95% CI -0.56 to -0.09, p=0.007) and the upper trapezius (r=-0.37, 95% CI -0.58 to -0.12, p=0.005).


CONCLUSIONS
Our results reinforced the clinical interconnection between masticatory and cervical structures, insofar as subjects with masticatory myofascial pain reported greater neck disability, which, in turn, was correlated with regional muscle sensitivity.
Department of Physiotherapy, Federal University of Sergipe, Sergipe, Brazil.
Dayse Regina Alves
DR
da Costa
Department of Physiotherapy, Federal University of Sergipe, Sergipe, Brazil.
Ana Paula
AP
de Lima Ferreira
Department of Physiotherapy, Federal University of Sergipe, Sergipe, Brazil.
Thaís Alves Barreto
TA
Pereira
Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
André Luís
AL
Porporatti
Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
Paulo César Rodrigues
PC
Conti
Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil. Electronic address: yurimartinscosta@yahoo.com.br.
Yuri Martins
YM
Costa
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
Leonardo Rigoldi
LR
Bonjardim
D000293:Adolescent; D000328:Adult; D001938:Brazil; D016022:Case-Control Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008410:Masticatory Muscles / Q000503:physiopathology*; D009209:Myofascial Pain Syndromes / Q000503:physiopathology*; D009334:Neck Muscles / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D053591:Referred Pain / Q000503:physiopathology*
Cervical disorders; Myofascial pain; Neck disability; Pressure pain threshold; Temporomandibular disorders