The patients in the laser group received irradiation from an 810 nm low-level laser ( Peak power 80 W , average power 50 mW , 1500 Hz , 1 micro s pulse width , 120 seconds , 6 J , 3.4 J/cm ( 2 ) per point ) , which was applied on four points around the TMJs and on painful muscles three times a week for 4 weeks .