THE FRACTAL ANALYSIS OF TEMPOROMANDIBULAR JOINT SOUNDS
Liu Zhenzhai, Xu Rui, Zhang Hongmei, Li Jiantao (Department of Biomedical Engineering, Tianjin Medical University, Tianjin, 300070) Zhang Yuwei (Stomatological Medical College, Tianjin Medical University, Tianjin, 300070)
Temporomandibular joint (TMJ) is one of the most complicated joints in human body. It performs complicated physiological function. Temporomandibular joint sounds (the sounds produced by TMJ when mandible open close) contain copious information concerned with states of TMJ. This paper analyzed the sound signal produced by TMJ of the normal and the temporomandibular joint internal derangement (TMJID) patient using theory of chaos and fractal in nonlinear dynamics. The results showed: the vibration produced by TMJ when mandible open close is a complicated chaotic vibration; temporomandibular joint sound signal produced has fractal framework; its correlation dimension is fraction; and the value of the correlation dimension of the TMJ sound signal of the normal is significantly higher than that of the TMJID patient.