Longitudinal study on torque transmitted from denture base to an abutment tooth of lower distal-extension removable...

The purpose of this study was to make a longitudinal analysis of torque transmitted to a direct abutment tooth of a lower distal-extension removable partial dentures constructed with the conus crown telescopic system. Torque around the vertical and lateral axes of the tooth were measured during chewing of food at the time of insertion of the new dentures to about three months after. The maximal mean value of torque (Max.MT) was calculated from the peak level of all chewing strokes at the minimum of the interocclusal distance. The integration values of torque (I) and time (T) from initiation of chewing to swallowing were obtained, then the average value of torque (Ave.T) was calculated (Ave.T = I/T). The results are summarized as follows: (a) There were no remarkable changes of Max.MT around the both axes; (b) Max.MT around the lateral axis was 7-47 x 10(-3) kgm (mean: 25 x 10(-3) kgm) (1 kgm = 9.8 Nm) in the downward direction and Ave.T around the lateral axis was 6-14 x 10(-3) kgm ss-1 (mean: 10 x 10(-3) kgm ss-1) in the downward direction; (c) There were marked differences of Max.MT and Ave.T around the vertical axis between subjects. Max.MT around the vertical axis was less than 24 x 10(-3) kgm and Ave.T around the vertical axis was less than 6 x 10(-3) kgm ss-1.