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Effects of preparation and luting system on all-ceramic computer-generated crowns
W H Mörmann1, A Bindl, H Lüthy
1Department of Preventive Dentistry, University of Zurich, Switzerland. moermann@zzmk.unizh.ch
The International Journal of Prosthodontics
|October 6, 1998
Summary
Bonded all-ceramic crowns made with CAD/CIM technology and custom inside shapes demonstrated superior fracture strength. This defect-oriented internal morphology significantly enhances the performance of cemented and bonded crowns.
Area of Science:
- Dental materials science
- Biomaterials engineering
- Prosthodontics
Background:
- Computer-aided design/computer-integrated machining (CAD/CIM) enables precise customization of internal crown surfaces.
- Understanding the impact of internal crown morphology on fracture strength is crucial for all-ceramic restorations.
Purpose of the Study:
- To investigate how the internal shape of all-ceramic crowns influences their fracture strength.
- To compare the performance of cemented versus bonded CAD/CIM crowns.
Main Methods:
- Four distinct preparation types were used to create CAD/CIM all-ceramic crowns.
- Crowns were tested in uncemented, zinc phosphate-cemented, and bonded states.
- Fracture load was measured by applying force until failure.
Main Results:
- Cemented crowns exhibited significantly higher fracture loads than uncemented controls.
- Bonded crowns showed significantly greater fracture loads compared to cemented crowns.
- Bonded crowns with increased occlusal dimensions demonstrated the highest fracture resistance.
Conclusions:
- Bonded all-ceramic CAD/CIM crowns with defect-oriented internal morphology and enhanced occlusal dimensions achieve high fracture strength.
- Custom internal shaping and bonding are key factors in improving the mechanical integrity of all-ceramic restorations.