| 3033 Ploughing Forces On the Surface of the TMJ Disc | ||
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L.E. ROTHE, L.R. IWASAKI, J.C. NICKEL, and M.W. BEATTY, University of Nebraska Medical Center College of Dentistry, Lincoln, USA In humans, the movement of the condyle over the TMJ disc produces tractional forces due to friction and cartilage deformation (ploughing). The coefficient of static friction ( mstatic) is reported to be less than 0.005. Data describing the ploughing coefficient ( mploughing) are lacking. Objective:To test the hypothesis that mploughing is significantly greater than mstatic . Methods: 56 porcine TMJ discs were used in a laboratory apparatus to measure the ploughing forces on the disc surface. Each disc was statically loaded with 11 N for a specified period, after which a pseudo-condyle was moved over the surface of the disc at peak velocities of 117 ± 2.6 mm/s. Each experiment was performed twice per disc (T1,T2). Results: Measured mploughing were on average two orders of magnitude greater than published data of mstatic (p < 0.001). Duration of loading affected ploughing. Static loading for 60 s (T1=0.50 ± 0.08, T2=0.55 ± 0.08) increased mploughing by 23% compared to loading for 10 s (T1=0.39 ± 0.06, T2=0.43 ± 0.05,p < 0.001). Conclusions: Ploughing forces are the most significant source of tractional forces on the TMJ disc surface. Supported by a UNMC College of Dentistry Student Research Scholarship. | ||
| Seq #275 - TMJ - Structure and Function II 3:45 PM-5:00 PM, Friday, 8 March 2002 San Diego Convention Center Exhibit Hall C | ||
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