Quantitative Sensory And Motor Function Research On Patients With Masticatory Muscle Pain Treated With Low-energy Laser

Part ⅠStudy on somatosensory and motor funtion in patients with unilateral orofacial painObjective To explore the difference of somatosensory and motor function between patients with unilateral masseter pain and normal subjects.Methods 20 patients suffering from unilateral masseter pain and 20 healthy controls were recruited.The cold/warm detection threshold（CDT/WDT）,cold/hot pain threshold（CPT/HPT）,pressure pain threshold（PPT）were measured at three sites:the center of bilateral masseter muscles and the surface overlying the dorsum of the homolateral hand.In addition,pain-free maximum opening（PMO）and numerical rating scale（NRS）were also tested.Data were analyzed with T test.Results There was no significant difference in CDT/WDT/CPT/HPT/PPT between the two groups in hand(P_handCDT=0.251,P_handWDT=0.997,P_handCPT=0.883,P_handHPT=0.737,P_handPPT=0.513).There was no significant difference in CDT/WDT betweenthepatientandcontrolgroups(P_painCDT=0.206,P_nopainCDT=0.472,P_painWDT=0.411,P_nopainWDT=0.965).HPTs of both side masseter in pain patients were more sensitive than in controls(P_painHPT=0.014,P_nopainHPT=0.026,P_nopainCPT=0.004,P_painCPT=0.001).PPTs of pain side masseter in pain patients were lower than in controls（P=0.001）,PPTs of pain side masseter were also lower than contralateral side in patient group（P=0.011）.The PMO was much smaller（P<0.001）while NRS was higher（P<0.001）in patient group.Conclusion Patients with masseter pain showed more high sensitivities to thermo and mechanical noxious thresholds.Part Ⅱ The effect of low level laser therapy on masticatory muscle painObjective To investigate the clinical efficacy of low level laser therapy in patients with masticatory muscle pain.Methods The experiment was performed in a randomized,placebo controlled and double-blinded manner.Twenty patients（age: 40.6±17.5years）suffering from unilateral masseter pain were randomly divided into a laser group（LG）or a placebo group（PG）.LG received Low Level Laser Therapy（LLLT）and PG received a similar but inactive treatment on both sides of masseter.Both groups were treated for 5minutes once a day for one week.PMO/NRS and PPT of both sides were measured and analyzed before and after treatment.Results Before treatment,there was no significant difference in PMO,NRS and bilateral PPT between the two groups(P_PMO = 0.717,P_NRS= 0.278,P_{Pain PPT} = 0.838,Pnon-pain_PPT= 0.846).In laser group,PMO（P=0.003）,PPT of pain side（P<0.001）and NRS（P=0.002）were significant improved after treatment.There was no significant difference in PPT on non-pain side（P=0.628）.In control group,PPT of pain side（P=0.039）was also improved after treatment,PMO（P=0.501）,NRS（P=0.066）and PPT of non-pain side（P=0.670）had no difference between before and after treatment.After treatment,The PMO in the laser group significantly increased(P_PMO = 0.005)compared to placebo group.However,NRS and bilateral PPT didn’t show significant difference between two groups(P_NRS=0.145,P_{Pain PPT}=0.312,P_{non-pain PPT}=0.488).Conclusion LLLT can effectively improve the mandibular movement range and help to release the masticatory muscle pain symptoms of patients.