Vibrating-traction method for mechanical joint distraction

Mechanical static traction has been adopted as one of the treatment procedu res for joint diseases and fractures. The effect of mechanical vibration on the mechanical traction of the temporomandibular joint was studied in six human subjects. A mechanical traction force of 2000 gf was applied as a dyn amic traction force with mechanical vibration or as a static traction force . The dynamic traction force with vibration was applied for 5 min to the ri ght temporomandibular joint using a vibratingtraction apparatus which gener ated mechanical vibrations of 1000, 3000 or 4000 Hz. Application of a stati c traction force for 5 min was used as a control condition. Vertical condyl ar displacement was mathematically evaluated from the deviation of the mand ible using Eddy current displacement sensors which were attached to the max illary dental arch. Among the three vibration frequencies, 3000 Hz resulted in the maximum vertical condylar displacement for all six subjects, showin g the mean condylar displacement of 668 +/- 242 mu m. In contrast, vibratio ns of 1000 and 4000 Hz showed a smaller traction effect. Application of the static traction force for 5 min resulted in a mean vertical condylar displ acement of 5.7 +/- 4.9 mu m, showing almost no traction effect to the joint . From the results of this study, it was revealed that vibrating traction c ould distract a joint more effectively than could static traction and that the traction force necessary for effective vibrating traction was less than that for static traction.