Abstract
For investigating material influences on the retentive force of Konus·Krone, the outer crown of Konus·Krone was prepared using the alloys with different hardness (gold-platinum alloy : Degulor M, and Co-Cr alloy containing titanium : Dentitan) with varied thickness (0.4, 0.6, 0.8 mm). Using these outer crowns, the influences of combinations of varied Konus angles (4, 6, 8°), inner crown heights (2, 4, 6, 8, 10 mm) and loads (5, 10, 15 kgf) on Konus·Krone were investigated basically. Under all the Konus angle and load conditions tested, Degulor M showed the tendency that the retentive force decreased as the outer crown became thicker, and the rate of these decreases became constant as the load increased at any Konus angle. In addition, at any outer crown thickness, the mean retentive force and its standard deviation tended to decrease as Konus angle became larger, and increased as the load increased. The retentive force of Dentitan tended to increase as Konus angle decreased and as the inner crown height increased in a manner similar to Degulor M. However, the decreases in retentive force due to changes in Konus angles and inner crown heights were small, and the retentive force was kept high even at low inner crown heights and large Konus angles. All the outer crowns tested showed positive load dependence; the heavier the load, the greater the retentive force. Dentitan showed strong load dependence at all the inner crown heights tested, compared with Degulor M. Different alloys showed different onset trends in retentive force, that is, Dentitan was largely affected by the load which is relating to strains themselves, but not so directly influenced by such factors as Konus angle and inner crown height, compared with Degulor M.
