Neurobiology of Temporomandibular Joint Pain: Therapeutic Implications

Portuguese translation, cultural adaptation and psychometric properties of the temporomandibular joint scale: a cross-sectional study

BACKGROUND

The temporomandibular joint (TMJ) scale assesses the severity of temporomandibular joint disorders (TMD), yet a European Portuguese translation is lacking.

OBJECTIVES

To translate, cross-culturally adapt and to examine the psychometric properties (construct validity and reliability) of the TMJ scale.

METHODS

Translation and cultural adaptation were carried out according to international recommendations, including initial translation, evaluation of this translation and cultural adaptation by a panel of experts, and back translation. The final Portuguese version was used to examine the reliability and validity, and participants with TMD were recruited from a Portuguese outpatient clinic. Reliability measures included internal consistency with Cronbach's alpha and test-retest reliability with the intraclass correlation coefficient (ICC2,1). The Spearman correlation comparing the TMJ scale with the Fonseca and Helkimo indexes was used to assess the construct validity.

RESULTS

A total of 63 participants (23 ± 2 years; 61,9% female) were included. Similar internal consistency was observed between the two moments of application (0.921 and 0.918), and test-retest reliability was excellent, with an ICC2,1 = 0.998 (95%CI: 0.988-0.999). Robust positive correlations (rho 0.554-0.611, p < 0.001) were found between the TMJ scale and Fonseca and Helkimo indexes.

CONCLUSION

The European Portuguese version of TMJ scale is now available to improve the assessment of severity of TMD in routine clinical practice. This version is also reliable and valid.

Temporal Summation and Aftersensations of Second Pain in Women with Myofascial Temporomandibular Disorder Differ by Presence of Temporomandibular Joint Pain

Purpose

Mechanisms underlying myofascial temporomandibular disorder (mTMD) are poorly understood. One theory is dysfunction in the central mediation of pain, specifically in enhanced facilitatory pain modulation. Because mechanisms leading to central sensitization may differ for joint and muscle pain, this study of mTMD addressed phenotypic heterogeneity by temporomandibular (TM) joint pain in the examination of quantitative sensory testing (QST).

Patients and Methods

The stimulus dependent increase in second pain (temporal summation (TS)) and associated aftersensations (AS) were examined across groups of women with mTMD with TM joint pain and without, and a demographically matched control group.

Results

TS was slightly more evident in mTMD without joint pain vs with (p = 0.035), but AS were most robustly persistent in the group with joint pain vs without (p < 0.002).

Conclusion

While both subgroups demonstrated evidence of central sensitization relative to controls on one of two measures, differences in QST results, if replicated, may point to possible differences in the mechanisms that yield central sensitization. Alternatively, it may represent methodological artifacts that need to be addressed. Therefore, greater consideration should be given to symptom-based phenotypes in studies examining TS and AS.