チタン鋳造冠の適合に関する研究

抄録

Standardized forms cast in titanium and 2 types (shoulder and chamfer) of titanium crowns were fabricated, and their fit was evaluated. Chamfer type Ag-Pd alloy crowns were also fabricated and their fit was compared with that of the titanium crowns. In addition, the castability was investigated using wedgeshaped casts of gold alloy and titanium. In the latter, 2 different spruing methods were used. The results obtained were considered as a baseline during the examination of titanium crowns. The titanium samples were fabricated using a casting machine (pressure difference type) and Al₂O₃/MgO based investment.
The results were as follows:
1. Accuracy of the standardized forms depended on heating conditions of the mold.
2. The fit of titanium crowns surpassed that of the Ag-Pd alloy crowns.
3. The fit of the shoulder type crowns was superior to that of the chamfer type crowns.
4. The spruing method influenced the accuracy of the edge in the titanium wedges.
The marginal fit of titanium crowns is influenced by titanium castability. The heating condition and spruing method should be chosen carefully and crown margins should be given an appropriate thickness to improve marginal fit.