Investigation of repeat casting for dental pure titanium

Objectives: Precise titanium casting depends on the ideal casting system and good mold refractory materials. It is rare to discuss of repeatedly used pure titanium. The aim of this study was to investigate the possibility of the pure titanium repeat casting under appropriately controlled condition.

Methods: Commercially pure titanium (Ohara, Japan) was used. An automatic argon casting machine (Castimatic-S, Japan) was used to cast pure titanium. A modified magnesia-based mold material was used. A 3D measuring machine (CE503, Taiwan) was used to measure marginal fit. A microhardness tester (MXT-50, Japan) was used to measure VH. The level of chemical reactivity of titanium was evaluated by XRD (Rigaku, Japan). The mechanical properties of titanium were measured by an Instron testing machine (Instron, USA). Data was analyzed with Wilcoxon test (p < 0.05) and ANOVA. Results: The success rate of complete casting reached 100 % in both groups. The marginal fit and VHN showed no significant difference (p > 0.05) in both groups. The tensile strength showed significant difference (p < 0.05) in both groups. The higher of interfacial reactivity was found in recasting titanium.

Conclusion: under appropriately controlled the casting conditions, the repeated use of the pure titanium may be produced an acceptable restoration.