Funcion masticatoria

Journal of Oral Rehabilitation 2009 36; 391–402

Masticatory function in subacute TMD patients before and after treatment
L . J . P E R E I R A * , M . H . S T E E N K S †, ‡, A . D E W I J E R †, ‡, C . M . S P E K S N I J D E R † & ˆ ¸˜ A . V A N D E R B I L T † *Department of Clinical Dentistry, Vale do Rio Verde University, UNINCOR, Tres Coracoes ⁄ MG,
†

Brazil,

Department ofOral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Center Utrecht, Utrecht, The

Netherlands and ‡Department of Oral Function and Prosthetic Dentistry, College of Dental Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands

SUMMARY Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investigated whethertreatment of subacute nonspecific TMD patients may influence oral function and clinical outcome measures. Fifteen patients with subacute TMD participated in the study. We quantified masticatory performance, maximum voluntary bite force, muscle activity and chewing cycle duration before and after treatment. Masticatory performance and bite force of patients were compared with the results obtained foran age- and gender-matched group of subjects without TMD complaints. Furthermore, we determined possible changes in anamnestic and clinical scores from questionnaires (mandibular function impairment questionnaire; MFIQ), pain scores and clinical outcome measures. Maximum bite force significantly increased, although the values after treatment were still significantly lower than those of the subjectswithout TMD complaints. The corresponding

electromyography values did not show significant change after treatment. The masticatory performance of the patients remained unaltered; patients chewed significantly less efficient than controls. The average duration of chewing cycles significantly decreased after treatment. We observed a significant improvement in MFIQ scores. During the clenching andchewing tasks, the visual analogue scale scores were significantly higher than before these tasks. We may conclude that subacute temporomandibular joint disorders negatively influence chewing behaviour. Bite force, chewing cycle duration and also perceived mandibular function significantly improved after treatment, although the masticatory performance remained unaltered. KEYWORDS: bite force,masticatory performance, muscle activity, temporomandibular joint disorder, treatment Accepted for publication 27 August 2008

Introduction
The term ‘temporomandibular disorders’ (TMDs) embraces a number of clinical problems that involve the masticatory musculature, the temporomandibular joint (TMJ) and associated structures or both (1). Main TMD subgroups are classified as muscle-related and TMJ-relatedconditions. These conditions are specific in case of systemic involvement, or when other aetiologies like neoplasms, growth disturbances and ⁄ or inflammation are involved (2). When specific TMDs are

excluded, these conditions are classified as non-specific TMD, thus without an underlying pathology (2). Mastication is one of the main functions of the stomatognathic system and it may be hampered byTMDs (3–5). As a result, limited masticatory function is one of the problems that patients with TMDs encounter. Rehabilitation in order to improve the masticatory function is therefore one of the goals in the treatment of TMD (6). Most of the TMD studies deal with masticatory ability (subjective measure obtained from questionnaires), whereas only a limited number of
doi:10.1111/j.1365-2842.2008.01920.x

ª 2009 The Authors. Journal compilation ª 2009 Blackwell Publishing Ltd

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L . J . P E R E I R A et al.
studies on masticatory performance (objective measure obtained from chewing tests) have been performed. Using questionnaires and clinical examination, the three most frequent jaw disabilities were found to be: eating hard foods (77Æ6%), yawning (75Æ7%) and chewing (64Æ5%)...