Effectiveness of Laser Acupuncture for Reducing Pain and Increasing Mouth Opening Range in Individuals with Temporomandibular Disorder: A Systematic Review and Network Meta-Analysis.

PURPOSE OF REVIEW: Laser acupuncture (LA) demonstrates promising results in the treatment of musculoskeletal disorders. However, its effects on temporomandibular disorder (TMD) are not yet fully understood. Thus, the aim of this systematic review and network meta-analysis was to assess the effectiveness of LA on pain intensity and maximum mouth opening range (MMO) related to TMD. A search was carried out in 11 electronic databases and references of included studies to locate randomized clinical trials (RCTs) that evaluated LA as a primary treatment for TMD. The risk of bias was assessed using the RoB 2 tool. Network meta-analysis was conducted on the MetaInsight platform, considering the pain intensity and counseling (C) as the outcome of reference. The GRADE system was used to assess the certainty of the evidence. RECENT FINDINGS: Five studies evaluated pain intensity, four with a high risk of bias and one with a low risk. Two studies evaluated pain intensity on palpation (one with high and one with low risk of bias), and one study with high risk of bias evaluated MMO. Laser parameters were: 690-810 nm, 40-150 mW, and 7.5-112.5 J/cm2. Occlusal splint (OS) [- 2.47; CI 95% - 3.64, - 1.30] and Physiotherapy (PT) [-2.64; CI 95% - 3.94, - 1.34] reduced pain intensity compared to C. The ranking of treatments in order of effectiveness was PT > OS > LA > C > CR (craniopuncture). The certainty of the evidence was very low or low. The data do not support the indication of LA for the treatment of TMDs and new placebo-controlled RCTs must be conducted to demonstrate its effectiveness more precisely.

Photobiostimulation activity of different low-level laser dosage on masticatory muscles and temporomandibular joint in an induced arthritis rat model.

This study aimed to investigate the anti-inflammatory effects of different dosage of low-level laser therapy (LLLT) in an experimental model of temporomandibular joint (TMJ) arthritis. One hundred male Wistar rats were used and divided into the following groups: CG, control group; AG, animals group with left TMJ arthritis induced by intra-articular injection of Complete Freund's adjuvant - CFA; LG5, LG10 and LG20 - animals with arthritis and treated with LLLT at doses 5, 10, and 20 J/cm2, respectively. Morphological analysis was performed by TMJ histological sections stained with hematoxylin-eosin (HE), picrosirius (PSR), and toluidine blue (TB), as well as histomorphometric evaluation of cartilage, articular disc, and masticatory muscles. The amount of feed consumed within 3 weeks was evaluated, and biochemical analysis of TMJ tissues included measurement of sulfated glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) 2 and 9 zymography, and ELISA for cytokines IL-6, TNF-α, and IL-1ß. Only the 20 J/cm2 dose promoted higher feed intake compared to AG. On the other hand, all LLLT doses promoted better organization of articular disc collagen fibers, greater number of proteoglycans in articular cartilage, increased area and diameter of left lateral pterygoid fibers, reduced latent and active MMP 9 and 2 activity, and lower IL-1ß concentration compared to AG. Considering the study limitations, it was observed that LLLT treatments were effective in protecting and tissue cleansing joint structures, accelerating tissue repair, especially at lower doses.

Temporomandibular disorders: knowledge, competency, and attitudes of predoctoral dental students.

OBJECTIVE: To evaluate knowledge, competency, and attitudes related to temporomandibular disorders (TMD) among predoctoral dental students, and to investigate the curricular organization of contents related to TMD and occlusion. METHODS: Predoctoral dental students (n = 147) answered a questionnaire with topics related to TMD. Another questionnaire evaluated the organization of TMD and occlusion courses. RESULTS: Contents related to TMD and occlusion were taught in the same course in all dental schools. The students' responses showed low agreement with the current gold standards pertaining to TMD. Most students declared that they did not feel confident to treat patients with TMD (62.6%), were not satisfied with the content pertaining to TMD (55.8%), and considered a lack of clinical practice to be the primary limitation in their training (59.2%). DISCUSSION: Students' knowledge of basic concepts related to TMD was limited, highlighting the need for readjustment of the dental curriculum to increase clinical experience.

Experimental model of temporomandibular joint arthritis: Evaluation of contralateral joint and masticatory muscles.

OBJECTIVE: To investigate morphological and biochemical changes in an experimental model of temporomandibular joint (TMJ) arthritis, as well as examine contralateral joint involvement and morphometric aspects of masticatory muscles in affected animals. DESIGN: Forty Wistar rats were allocated into three groups, as follows: a healthy control group (HG); and a group with arthritis induced in the left TMJ (IG); and a contralateral group with noninflamed right TMJ (CG). Arthritis was induced by intra-articular injection of 50 µL of Complete Freund's Adjuvant (CFA). Morphological analysis was performed using histological sections of TMJs stained with hematoxylin-eosin, picrosirius and toluidine blue. In addition, histomorphometric analyses of the articular cartilage, articular disc and masticatory muscles, were performed. Biochemical analysis of TMJ tissues included dosage of sulfated glycosaminoglycans (GAGs), zymography of the Matrix Metalloproteinases (MMPs) 2 and 9 and ELISA for the cytokines IL-6, TNF-α and IL-1ß. The data were analyzed by paired and unpaired t-tests, with a p < 0.05. RESULTS: IG animals presented morphological and biochemical changes in their TMJ, including synovial membrane hyperplasia; chronic inflammatory infiltrate; collagen fiber disorganization in the disc; reduced proteoglycans in the cartilage; greater disc thickness; lower cartilage thickness; lower feed intake; higher activity of MMP-9 and MMP-2, and higher concentration of IL-6, TNF-α, and IL-1ß, as compared to HG. CG animals showed posterior disc thickening; reduced proteoglycans in the cartilage; lower collagen fiber organization of the disc; active MMP-9, and higher concentration of IL-6 and TNF-α compared to HG animals. Articular inflammation reduced the area and diameter of fibers of the temporal (right), medial pterygoid (left), and lateral pterygoid (right and left) muscles as compared to HG animals. CONCLUSION: TMJ arthritis reduced the area and diameter of masticatory muscle fibers and caused morphological and molecular changes in the contralateral joint.