Abstract:

BACKGROUND: In recent years, development of zirconia abutments has become a hotspot. The zirconia all-ceramic crowns and zirconia abutments restoration are recognized by many clinicians and patients because of their excellent aesthetic restoration effects, and the fit accuracy between them is a key factor for the implant restoration.
OBJECTIVE: To develop the zirconia abutments and to study the fitness of the interface between the zirconia abutments and zirconia crowns.
METHODS: Nanometer zirconia powder was used to manufacture zirconia abutments by injection molding. Five zirconia abutments and five titanium abutments were divided into two groups: Zirconia abutments-zirconia crowns group and titanium abutments-Co-Cr alloy based PFM crowns group. In the zirconia abutments-zirconia crowns group, five zirconia crowns were made upon the zirconia abutments by computer aided design and computer aided manufacturing. While in titanium abutments- Co-Cr alloy based PFM crowns group, five Co-Cr alloy based PFM crowns were made upon the titanium abutments by finished plastic cap casting. The finished crowns were inserted onto the abutments respectively to observe whether the crowns were inserted onto the abutments completely. Then the microgap models of the interface between abutments and crowns were made using silicone rubber impression, afterwards, to repair and cut these models. Microgap pictures were observed and collected by scanning electron microscope, and the microgap was tested by Digora Optime.
RESULTS AND CONCLUSION: The insertion rate of the two groups was both 100%. The microgaps in the axial surface and cervical part of zirconia abutments-zirconia crowns group were significantly lower than those of titanium abutments-Co-Cr alloy based PFM crowns group (P < 0.05). The interface between zirconia abutments and zirconia crowns shows a good fitness and provides a reliable scientific basis for the clinical application.