The Efficacy Of Photobiomodulation Therapy For Painful Temporomandibular Disorders:Meta-analysis

Objective:Meta-analysis of the results of randomized controlled trials of photobiomodulation in the treatment of temporomandibular disorders(TMD)was conducted to evaluate the effectiveness of photobiomodulation in improving pain in patients with TMD,with a view to providing a reference for the selection of clinical diagnosis and treatment methods for TMD.Methods:Databases of PubMed,EMbase,Cochrane Library,CNKI,WanFang,WeiPu and other databases were systematically searched.The limit of searching time was from inception until October 2019.Randomized controlled trials addressing photobiomodulation(experimental group)versus placebo(control group)for the treatment of painful TMD were collected.Two researchers independently screened the literature,extracted the literature,and all the included studies used the Cochrane Risk Assessment Scale for quality evaluation.The primary outcome of interest includes the change in pain intensity and pressure pain threshold from baseline to endpoint.The secondary outcome indicators are maximum mouth opening after treatment,lateral movement of the left and right sides,and range of forward movement.All outcome indicators were analyzed using Revman 5.3 software.Results:?A total of 7 randomized controlled trials were included,with a total of 274 patients.Statistical results found that photobiomodulation can significantly improve changes in visual analog scale scores compared with placebo control group(MD=-1.11,95%CI[-1.46,-0.77],P=0.02),changes in pressure pain threshold(SMD=-0.74,95%CI[-1.23,-0.25],P=0.003)and also can improve the painful TMD(MD=-1.10,95%CI[-2.06,-0.14],P=0.02).However,maximum mouth opening(MD=0.30,95%CI[-1.21,1.81],P=0.70),left lateral movement(MD=-0.42,95%CI[-0.99,0.15],P=0.15),right side motion(MD=-0.14,95%CI[-1.04,0.76],P=0.76),and forward motion range(MD=0.65,95%CI[-0.68,1.97],P=0.34)from photobiomodulation therapy not different from those of placebo.?Five trials of chronic painful TMD showed changes in visual analog scale scores for pain improvement of 1.10(MD=-1.10,95%CI[-2.06,-0.14],P=0.02)of photobiomodulation.Conclusion:Photobiomodulation therapy can significantly improve the pain intensity and pain sensitivity of patients with painful TMD,and shows same effectivity for patients with chronic pain.However,there may be no difference in improving the function of the temporomandibular joint.