Recently conical telescopic denture has been used in many clinical treatments, but it has many problems with retentive force of conical double-crown that need to be solved. The purpose of this study was to elucidate the correlation between retentive force and various factors of conical telescopic double-crown. Various factors such as fabricating material, taper angle, height of cone and load were considered as problems in report 1. In this experiment, retentive force related to the diameter of the cone was examined.
The results were as follows:
1. Retentive force was greater as the diameter was decreased compared with retentive forces for two diameters of cone. This effect was greater as the height of the cone and load were increased and the taper angle was decreased.
2. Retentive force decreased as the taper angle of any diameter of cone was increased and this effect was greater as the height of the cone and load were increased. Retentive force depends on the taper angle strongly in any diameter.
3. Retentive force had a tendency to increase slightly as the height of the cone of any diameter of cone was increased and it was greater as the taper angle was decreased and the load was increased. But the increasing rate was less compared with any other factors.
4. Retentive force increased in proportion to the load on any diameter of cone, and this effect was greater as the diameter and taper angle were decreased and the height of the cone was increased.