Marginal accuracy and geometry of cast titanium copings

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Metallurgical Engineering

Background:

• Titanium (Ti) is a biocompatible metal with established use in medical implants.
• Its application as a substitute for traditional alloys in dental crown restorations requires further investigation.
• Understanding Ti casting properties is crucial for its successful integration into restorative dentistry.

Purpose of the Study:

• To evaluate the geometric accuracy and marginal fit of dental coping margins cast from pure titanium (99.5%).
• To compare the casting accuracy between 45-degree facial and 90-degree palatal margin configurations.
• To assess the suitability of titanium for use in crown restorations based on casting precision.

Main Methods:

• Twenty castings of coping margins (45-degree facial, 90-degree palatal) were fabricated using a commercial indirect casting technique with pure titanium.
• Castings were cemented with zinc phosphate cement.
• Coping and die assemblies were embedded in resin, sectioned longitudinally, and analyzed microscopically at 50x magnification to measure geometry and marginal discrepancy.

Main Results:

• Characteristic casting shrinkage was observed in titanium, particularly along the horizontal axis on the shoulder surface.
• Horizontal linear shrinkage was more pronounced in the 45-degree margin configurations compared to the 90-degree margins.
• The 90-degree margin configuration exhibited the greatest surface area of marginal discrepancy.

Conclusions:

• Pure titanium exhibits casting shrinkage, impacting the marginal accuracy of dental restorations.
• The 90-degree margin design is associated with a higher degree of marginal discrepancy in titanium castings.
• Further research is needed to optimize titanium casting techniques for precise dental crown fabrication.