Abstract: Objective: To assess the impact of mandibular protrusion on joint vibration recorded from the temporomandibular joint (TMJ) reducible disc displacement. Methods: The vibrations of the TMJ were recorded bilaterally from 30 subjects with reducible disc displacement by joint vibration analysis (JVA) in two movement patterns (1.open/close cycle from the intercuspal position; 2. open/close cycle from edge-to-edge position). Mandibular opening and its pattens were recorded and analyzed by Joint-3D technique. Results: The values of total integral and peak amplitude (P<0.01) in movement 2 were lower than that in movement 1. The wave patterns of the power-frequency spectra for all participants were qualitatively similar unimodal spectrum in two types of movement but with lower amplitude in movement 2. There was no significant difference between 2 movement patterns for peak frequency (P=0.705) and the ratio of >300 Hz/<300 Hz (P=0.386). Conclusion: Edge-to-edge open/close movement can reduce the intensity of joint vibration compared to the open/close cycle from the intercuspal position. The electronic recording of vibrations in TMJ can provide a quantitatively analysis and reliable evidence for repositioning splint through mandibular protrusion.