Effectiveness of low level laser therapy in the treatment of TMD myalgia: two case reports / Eficácia do laser de baixa potência no tratamento da DTM: dois relatos de casos

Objective: To report two cases of low level laser therapy used in the treatment of muscle pain caused by temporomandibular disorders (TMDs). Methods: Two patients were selected and subjected to eight applications of low level laser therapy (diode - wavelength of 795 nm, energy density of 8 J/cm2, power of 120 mW, 66 se per point). Laser was punctually applie on masseter and temporalis muscles bilaterally. Three methods were used to evaluate the effectiveness of treatment: pressure algometer, visual analog scale (VAS) and maximal mouth opening. Each measurement was performed before and after the laser therapy session. The results were subjected to statistical analysis (ANOVA two factors and Tukey’s test, α = 0.05). Results: For both patients, no significant difference was found between the results obtained with the algometer, before and after laser application, within each session. VAS results showed a tendency to lower values after laser application. In both cases, the highest values obtained by the pressure algometer were found between the days 9 (fourth application) and 16 (sixth application). Both patients had an improvement on mouth opening. Conclusions: The assessment methods used were quite practical to register the pain before and after treatment. Therapy with low level laser seems to have a beneficial effect for the masticatory muscles pain.

Objetivo: relatar dois casos do uso do laser de baixo potência no tratamento da dor muscular causada pela disfunção temporomandibular (DTM). Métodos: Dois pacientes foram selecionados e submetidos a oito aplicações de laser de baixa potência (diodo - comprimento de onda de 795 nm, densidade de energia de 8 J/cm2, potência de 120 mW, 66 segundos por ponto). O laser foi aplicado pontualmente nos músculos masseter e temporal bilateralmente. Três métodos foram utilizados para avaliar a eficácia do tratamento: algômetro de pressão, escala visual analógica (VAS) e abertura máxima da boca. Cada medição foi realizada antes e após a sessão de terapia com laser. Os resultados foram submetidos à análise estatística (ANOVA dois fatores e teste de Tukey, α= 0,05). Resultados: Em ambos os casos, não foi encontrada diferença significativa entre os resultados obtidos com o algômetro antes e depois da aplicação do laser dentro de cada sessão. Os resultados com o VAS mostraram uma tendência a reduzir os valores após a aplicação do laser. Foram encontrados os maiores valores obtidos pelo algômetro de pressão entre os dias 9 (quarta aplicação) e 16 (sexta aplicativo), em ambos os casos. Ambos os pacientes tiveram uma melhora na abertura da boca. Conclusões: Os métodos de avaliação utilizados foram bastante prático para registrar a dor antes e após o tratamento. A terapia com laser de baixa potência parece ter um efeito benéfico para a dor músculos mastigatórios

Reliability and Usefulness of the Pressure Pain Threshold Measurement in Patients with Myofascial Pain

OBJECTIVE: To assess the usefulness of a pressure algometer to measure pressure pain threshold (PPT) for diagnosis of myofascial pain syndrome (MPS) in the upper extremity and trunk muscles. METHOD: A group of 221 desk workers complaining of upper body pain participated in this study. Five physiatrists made the diagnosis of MPS using physical examination and PPT measurements. PPT measurements were determined for several muscles in the back and upper extremities. Mean PPT data for gender, side, and dominant hand groups were analyzed. Sensitivity and specificity of Fischer's standard method were evaluated. PPT cut-off values for each muscle group were determined using an ROC curve. RESULTS: Cronbach's alpha for each muscle was very high. The PPT in men was higher than in females, and the PPT in the left side was higher than in the right side for all muscles tested (p<0.05). There was no significant difference in PPT for all muscles between dominant and non-dominant hand groups. Diagnosis of MPS based on Fischer's standard showed relatively high specificity and poor sensitivity. CONCLUSION: The digital pressure algometer showed high reliability. PPT might be a useful parameter for assessing a treatment's effect, but not for use in diagnosis or even as a screening method.

Usefulness of Electronic Pressure Algometer in Evaluation of Pressure Pain Threshold in Normal Korean Adults

OBJECTIVE: To examine pressure pain threshold (PPT) on several skeletal muscles in upper extremity, trunk, and lower extremity by using electronic pressure algometer and to evaluate it's interrater reliability, reproducibility, difference between gender and dominance, correlation with body mass index, and comparison among each muscles. METHOD: Forty healthy adults (male 27, female 13) were examined by two raters and reexamined in the same order after a rest of 10 minute. PPT at the splenius capitis, upper trapezius, infraspinatus, lumbar paraspinal muscle, extensor carpi radialis, vastus medialis, and gluteus medius muscles of both side was measured by medical electronic algometer. Rate of force application was approximately 2 lb/sec. Body mass index (BMI) was estimated from the individual's body weight by the square of their height. RESULTS: There were no statistical differences of PPTs at all muscles between two raters, between two test with time interval, and between dominant and nondominant side, respectively. PPT in man was higher than female at all muscles. There was significant correlation between BMI and PPT at lumbar paraspinal muscle, vastus medialis, and gluteus medius only in male. PPT was highest at lumbar paraspinal muscle and lowest at splenius capitis. CONCLUSION: Electronic pressure algometer is a reliable tool for evaluation of PPT which has high interrater reliability and high reproducibility and is not affected by dominance and location of muscles. Therefore, it is a useful clinical tool to compare PPT before and after treatment and to study the mechanism of musculoskeletal pain research program.