Efficacy Evaluation Of Photobiomodulation In The Treatment Of Painful Temporomandibular Joint Disorders

PartⅠApplication of mechanical sensitivity mapping technique in temporomandibular disordersObjective To explore the difference of mechanical sensitivity function in the orofacial regions of temporomandibular disorders patients and normal subjects.Methods Eighty patients suffering from pain in the unilateral masseter muscle or temporomandibular joint(TMJ)and 40 healthy controls were recruited into the study.After palpated with a quantitative palpometer,numerical rating scale(NRS)was used to evaluate the mechanical pain sensitivity of subjects in the test points.Shannon Entropy and Center of gravity(COG)were calculated to explore the difference of mechanical sensitivity function in TMD patients and healthy individuals.Data were analyzed with Three-way analysis of variance(ANOVA)to analyze the difference of NRS scores over test site,test point and gender within groups.Two-way ANOVA was used to find the difference of Entropy and COG coordinated over gender and test site.Results TMD patients tend to have significant difference in entropy values on their pain side and healthy side(masseter muscle: pain side:1.11±0.35,healthy side:0.66±0.56;P<0.001;TMJ: pain side: 0.70±0.52,healthy side: 0.38±0.48;P=0.006),and significant higher NRS scores was found on their pain side(masseter: 44.4±5.2,TMJ: 34.3±3.6)compared to the healthy side(masseter: 30.3±3.1,P<0.001;TMJ:24.2±1.4,P<0.001),while no significant difference of entropy values or NRS scores was found on the left and right sides of healthy control(entropy: masseter: P=0.071,TMJ: P=0.117;NRS scores: masseter: P=0.941,TMJ: P=0.303).Conclusion Mechanical sensitivity mapping technique can help the professionals distinguish TMD patients from healthy individuals and it can be used as an auxiliary method to evaluate the efficacy of TMD treatment.Part ⅡEffect of photobiomodulation therapy on painful temporomandibular disordersObjective To investigate the effect of photobiomodulation therapy(PBMT)on painful temporomandibular disorders(TMD)patients.Methods A randomized,placebo controlled and double-blinded experiment was conducted to evaluate the effect of PBMT on TMD patients.One hundred TMD patients suffering from unilateral masseter myalgia(n=50)or temporomandibulat joint(TMJ)arthralgia(n=50)were randomly divided into a photobiomodulation(PBM)group and a placebo group.The PBMT was applied with a gallium-aluminum-arsenide(Ga Al As)laser(wavelength=810nm)at pre-determined points in the masseter muscle(three points,6J/cm2,60s)or TMJ region(five points,6J/cm2,30s)according to their most painful site.Both groups were treated once a day for one week.The placebo treatment was done exactly in the same manner as the PBMT but without power output.Pain intensity,jaw movement(including pain free jaw opening,maximum unassisted jaw opening,maximum assisted jaw opening,protrusion,left and right lateral excursion),pressure pain thresholds(PPT)of bilateral masseter muscle and TMJ regions,and mechanical sensitivity mapping were measured before and after the treatment on Day 1 and Day 7.Data were analyzed with Two-way Repeated Measures analysis of variance(ANOVA).Results Pain intensity,mechanical sensory function and PPT were improved after both PBMT and placebo treatment(P<0.001).Although no significant intervention difference was found in the pain intensity of masseter myalgia patients(P=0.074),PBMT was associated with better improvements in range of jaw movement compared to placebo in TMD patients and caused greater reduction in pain intensity(P=0.014)and improvement of sensory function(P=0.041)in TMJ arthralgia patients.Conclusion Both PBMT and placebo treatment are effective in reducing pain intensity and promoting recovery of sensory function in TMD patients,but PBMT showed better effectiveness in improving jaw movement and reducing pain intensity in TMJ arthralgia patients compared to placebo.