Test-retest reliability of the isometric contraction test (IC test) of the masticatory muscles in subjects with and without temporomandibular muscle disorders.

OBJECTIVE: Recently, the DC/TMD has become an essential tool for the diagnosis of temporomandibular disorders (TMD). However, as they fail to include functional activities, new assessment proposals have emerged, such as the isometric contraction test (IC test) of the masticatory muscles, which uses muscle contractions to identify muscular TMD. This study aimed to determine the test-retest reliability of the IC test. METHODS: A total of 64 participants (40 women and 24 men) completed the IC test administered by two different physical therapists on two non-consecutive days. Cohen's kappa (k), PABAK, and percent agreement (PA) between days were estimated. RESULTS: The IC test showed good to excellent test-retest reliability values (k>0.77; PABAK>0.90), both globally and individually for the muscles evaluated, and PA>90%, therefore above the thresholds for clinical applicability. However, the global assessment of myofascial pain and the evaluation of the medial pterygoid muscle showed slightly lower reliability values. CONCLUSION: The IC test is reliable for the assessment of subjects with muscular TMD, both in terms of the global assessment and the evaluation of each muscle, which supports its clinical applicability. Care should be taken when assessing myofascial pain globally and when evaluating the medial pterygoid in all types of pain.

Test-retest reliability of the isometric contraction test (IC test) of the masticatory muscles in subjects with and without temporomandibular muscle disorders

Abstract Recently, the DC/TMD has become an essential tool for the diagnosis of temporomandibular disorders (TMD). However, as they fail to include functional activities, new assessment proposals have emerged, such as the isometric contraction test (IC test) of the masticatory muscles, which uses muscle contractions to identify muscular TMD. Objective This study aimed to determine the test-retest reliability of the IC test. Methods A total of 64 participants (40 women and 24 men) completed the IC test administered by two different physical therapists on two non-consecutive days. Cohen's kappa (k), PABAK, and percent agreement (PA) between days were estimated. Results The IC test showed good to excellent test-retest reliability values (k>0.77; PABAK>0.90), both globally and individually for the muscles evaluated, and PA>90%, therefore above the thresholds for clinical applicability. However, the global assessment of myofascial pain and the evaluation of the medial pterygoid muscle showed slightly lower reliability values. Conclusion The IC test is reliable for the assessment of subjects with muscular TMD, both in terms of the global assessment and the evaluation of each muscle, which supports its clinical applicability. Care should be taken when assessing myofascial pain globally and when evaluating the medial pterygoid in all types of pain.

Validity of the Isometric Contraction Test of the Masticatory Muscles for Diagnosis of Muscular Temporomandibular Disorders.

In recent years, the Diagnostic Criteria for Temporomandibular Pain Disorders (DC/TMD) has been questioned, mainly because of the dependence on the muscular pressure needed to be applied during the clinical examination. Therefore, it is necessary to establish improvements in diagnostic strategies for DC/TMD of axis I. The aim of this study was to determine the validity of the Isometric Contraction Test of the masticatory muscles (ICTest) to diagnose DC/TMD of axis I. Forty (n = 40) patients with muscular TMD (myalgia in any of its subtypes), as well as forty age and sex matched controls, participated. They were diagnosed according to DC/TMD of axis I and performed the ICTest in a single session. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and positive (LR+) and negative likelihood ratios (LR-) of the ICTest compared with the DC/TMD of axis I were calculated. The ICTest showed a specificity of 95% for the diagnosis of myalgia, and between 94.9% and 96.8% for all subtypes in relation to the DC/TMD of axis I. For sensitivity, lower values were obtained, that is, 90.0% for myalgia, and losing sensitivity depending on the type of myalgia. The LR+ was over 10 for all diagnoses, with the exception of myofascial pain with referral, which was lower. When addressing the LR-, the myofascial diagnosis was the only one below 0.2. According to the results, the ICTest could be considered a valid procedure to diagnose subjects with muscular TMD in a clinical setting.