Efficacy of acupuncture and laser acupuncture in temporomandibular disorders: a systematic review and meta-analysis of randomized controlled trials

Temporomandibular disorders, known as TMDs, represent a complex set of conditions that affect the temporomandibular joint (TMJ), the masticatory muscles, and adjacent tissues. This joint, located near the ear, is responsible for the movements of opening and closing the mouth, chewing, and speaking. When there are problems in this region, patients may experience facial pain, difficulty opening the mouth, clicking, or jaw locking. The pain may be of muscular, articular, or mixed origin, with 90% to 95% of cases presenting facial pain of muscular origin without identifiable structural causes.

Treatment traditionally involves conservative approaches such as occlusal splints, medications, physical therapy, and self-management techniques, but the search for effective therapeutic alternatives continues to be a priority in the medical field.

Acupuncture has gained increasing interest as a therapeutic option for pain management in various conditions, including TMDs. In parallel, laser acupuncture emerges as a modern alternative that uses low-level laser light to stimulate traditional acupuncture points, eliminating the need for needle insertion. This technique offers potential advantages by being noninvasive, painless, and inherently safer than traditional acupuncture. Despite the theoretical benefits, scientific evidence on the efficacy of these therapeutic modalities for TMDs remained fragmented and required systematic analysis to adequately guide clinical practice.

The objective of this research was to perform a comprehensive qualitative and quantitative analysis of the scientific literature on the use of acupuncture and laser acupuncture in the treatment of pain associated with temporomandibular disorders. The researchers conducted a systematic review with meta-analysis, following rigorous methodologic criteria established by the PRISMA guidelines and the Cochrane Handbook. The search was performed in three important electronic databases — PubMed, EMBASE, and SCOPUS — covering publications through July 2023, with no language restrictions. Only randomized controlled trials that compared acupuncture or laser acupuncture with other treatments in patients with TMD were included.

Inclusion criteria specified studies with adult patients diagnosed with TMD, adequate description of the acupuncture techniques used, presence of control groups, and validated outcome measures such as pain scales and mouth opening. The methodologic quality of the studies was assessed using the Cochrane risk-of-bias assessment tool (RoB 2), and a meta-analysis was conducted to quantitatively investigate the efficacy of the interventions compared with placebo.

The analysis identified 11 randomized controlled trials that met the inclusion criteria, involving participants with different types of TMD. Of the analyzed studies, seven investigated TMD of muscular origin, four addressed combined types (muscular and articular), and none focused exclusively on articular problems. Six studies tested traditional needle acupuncture, while three investigated laser acupuncture, comparing these interventions with control groups that received sham acupuncture, sham laser, drug therapy, or decompression splints. Session duration ranged between 15 and 30 minutes, with different treatment protocols.

The results demonstrated that acupuncture offers short-term benefits for reducing pain intensity in TMDs of muscular origin. The meta-analysis revealed that both the acupuncture group and the laser acupuncture group showed significantly higher efficacy rates than the placebo group. In particular, laser acupuncture showed high efficacy in the treatment of temporomandibular disorders, with some studies demonstrating statistically significant differences on the visual analog pain scale. In addition to pain reduction, some studies reported improvements in mouth opening and masticatory function in patients with TMD of muscular origin.

The clinical implications of these findings are relevant for both patients and health care professionals dealing with TMDs. For patients, the results suggest that acupuncture and especially laser acupuncture may represent valid therapeutic options, particularly when conventional conservative methods do not provide adequate relief. Laser acupuncture, in particular, offers practical advantages by being noninvasive, painless, and free of significant side effects — aspects especially important for patients who fear needles or have contraindications to other treatments. For professionals, these data provide scientific evidence that can guide therapeutic decisions and the incorporation of these modalities into multidisciplinary treatment protocols.

The demonstrated efficacy, especially for TMDs of muscular origin, suggests that these therapies can be integrated as part of an initial conservative approach, potentially reducing the need for more invasive interventions or prolonged use of medications.

However, the study has important limitations that should be considered when interpreting the results. The methodologic quality of the included studies was variable, with only four of the 11 trials presenting low risk of bias. Many studies had small samples, which can limit generalization of the findings. In addition, there was heterogeneity in the diagnostic methods used, the pain assessment scales, and the treatment protocols, making direct comparisons among studies difficult.

Most research evaluated only short-term effects, with few studies investigating long-term benefits. The authors acknowledge that evidence for acupuncture as a symptomatic treatment of TMD remains limited and emphasize the need for more rigorous studies, with larger samples and prolonged follow-up, to definitively establish the therapeutic value of these interventions. Despite these limitations, the results provide encouraging evidence, particularly for laser acupuncture, pointing to a promising direction in research and treatment of temporomandibular disorders, with the potential to significantly improve the quality of life of patients affected by these painful conditions.