Effect of transcutaneous electrical nerve stimulation on jaw movement-evoked pain in patients with TMJ disc displacement without reduction and healthy controls

Abstract

Objective: Transcutaneous electrical nerve stimulation (TENS) may serve as non-invasive intervention for painful temporomandibular disorders (TMD) to improve jaw motor function, but its efficacy is still debated. This parallel study evaluated the effect of TENS on pain and movement patterns after repeated jaw movements in patients with painful temporomandibular joints (TMJ) and disc displacement without reduction (DDwoR), and compared with healthy controls.

Material and Methods: 20 patients with TMJ pain and DDwoR and 20 age- and gender-matched healthy volunteers were randomly assigned to TENS/sham TENS (sTENS) intervention groups in a block design (10 in each group). Participants performed 20 repeated jaw movements (4 x 5 sessions), and reported pain intensity on a 0–10 Numerical Rating Scale (NRS) subsequently both before and after the intervention. Data were tested by repeated measures analysis of variance (ANOVA).

Results: Significant increase of pain intensity and reduction of opening range were shown within repeated jaw movements in TMJ pain patients in contrast to healthy participants (p ≤ .001). Pain was significantly reduced during repeated open-close (p = .007), fast open-close (p = .016) and horizontal movements (p = .023), accompanied with increased opening range (p = .033) and open-close velocity (p = .019) with TENS intervention when compared with sTENS group (p > .05) in TMJ pain patients.

Conclusions: This study indicated that movement-evoked pain was reduced either spontaneously or by sTENS in TMJ pain patients with DDwoR, and interestingly, that TENS could attenuate movement-evoked pain and improve jaw motor function during repeated jaw movements. The findings may have implications for TENS treatment in TMJ pain patients with DDwoR.

Keywords:

• Temporomandibular Disorders
• Disc displacement without reduction
• Facial pain
• Mandibular movements
• Transcutaneous electrical nerve stimulation

Acknowledgments

The authors thank all the staff of Orofacial Pain and TMD Research Unit, Institute of Stomatology, Affiliated Hospital of Stomatology, Nanjing Medical University for their selfless help. Author contributions: Lin Wang and Jinglu Zhang contributed equally to this work and should be considered co-corresponding authors.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [81830031, 81570959]; and the Priority Academic Programme Development of Jiangsu Higher Education Institutions [PAPD-2018-87]; and the Natural Science Foundation of Jiangsu Province [BL2014073 and 15KJA320002 to Lin Wang]; and Six Distinguished Talent [2016-WSW-008] and the Jiangsu Provincial Key Medical Discipline [zdxka2016026]; and State Scholarship Fund from China Scholar Council [201708320348].