Acupoints for the treatment of temporomandibular disorders: a literature review

Aim: Acupuncture is successfully used for the treatment of Temporomandibular Disorders (TMDs), especially for pain of articular or muscular origin. The scientific literature shows a great number of usable acupoints and techniques of stimulation. This review aims to analyze the acupoints and the techniques most used in the treatment of TMDs symptoms and compare its effectiveness. Methods: Computer retrieval was performed with Medline, PubMed, Scopus. The dates of the articles surveyed ranged from 2009 to February 2019. Terms used for the search were "Acupuncture points" AND "TMD” OR “TMJ”. The inclusion criteria were: (1) publications in English; (2) controlled clinical trials; (3) patients with TMD of muscular or articular origin; and (4) studies that used acupuncture only for treatment. Results: Out of 83 titles retrieved, 41 abstracts were read and 21 full articles were selected and categorized according to the following classes: TMDs, acupoints location, techniques of stimulation, effectiveness of therapy. TMDs of muscle origin are absolutely the most treated diseases (18 papers: 85.7%). Out of a total of 49 selected acupoints, the most used were: “Hegu” (LI4) (16 papers: 76,2%); “Jiache” (ST6) (13 papers: 62%); “Xiaguan” (ST7) (10 papers: 47,6%); “Fengchi” (GB20) (8 papers: 38%); “Quanjiao” SI18 (6 papers: 28,6%) and Ashi points (6 papers: 28,6%). According to points location, the combination of local and distal points was used in most cases (11 papers: 50%). Distal points only were used in some cases (5 papers: 23.8%), while local points only were never used. Other locations (ashi/trigger points, microsystems) were used in 28,6% of cases (6 papers). Concerning the techniques of stimulation, the somatic acupuncture was the most used (12 papers: 57,1%), followed by dry needling and laser acupuncture (4 papers: 19%). Acupuncture therapies were effective in 90,5% of cases, regardless of the technique used. Conclusion: Acupuncture treatments for TMDs are effective, regardless of the technique of stimulation used, but extremely varied. In the clinical practice there are some acupoints most used but there is no evidence of standardized protocols. The acupoints selection based on the diagnosis of TMD is not clear in literature. There is a need for well-designed randomized controlled trials (RCT) including the use of acupuncture points on a diagnostic basis. This could allow a better evaluation of the additional benefit of acupuncture for managing TMD.