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Wear behavior of different double-crown systems
Jörg Engels1, Oliver Schubert, Jan-Frederik Güth
1Department of Prosthodontics, Ludwig-Maximilians University, Goethestr. 70, 80336 Munich, Germany. Joerg.engels@med.uni-muenchen.de
Clinical Oral Investigations
|May 11, 2012
Summary
Wear affects retentive forces (RFs) in double-crown systems. Conventionally cast systems offer higher RFs, while electroformed systems provide more predictable results, especially with limited abutment teeth.
Area of Science:
- Dental Materials Science
- Prosthodontics
- Biomaterials Engineering
Background:
- Dental restorations often utilize double-crown (DC) systems for retention.
- Understanding the long-term stability and retentive forces (RFs) of different DC materials and designs is crucial for clinical success.
- Factors like material composition, abutment height, taper angle, and aging significantly influence the performance of DCs.
Purpose of the Study:
- To evaluate the impact of artificial aging on the retentive forces (RFs) of various double-crown (DC) systems.
- To analyze the influence of abutment height, inner crown (IC) material, outer crown (OC) material, taper angle, and artificial aging on DC retentive forces.
Main Methods:
- Four groups of 240 inner (IC) and outer crowns (OC) were fabricated with varying IC/OC materials (zirconia, non-precious alloy, precious alloy, electroformed, conventionally cast).
- Specimens were subjected to 10,000 separation cycles in artificial saliva to simulate aging.
- Retentive forces (RFs) were measured at baseline, 5,000, and 10,000 cycles, with data analyzed using multivariate ANOVA.
Main Results:
- All groups experienced a loss of RFs after aging. Group D (precious alloy IC, conventionally cast OC) exhibited the highest baseline and sustained RFs (approx. 4.0 N).
- Material significantly influenced RFs (p < 0.001). Groups A, B, and C (electroformed OCs) showed RF dependency on abutment height, taper angle, and aging (p < 0.001).
- Group D demonstrated no correlation between RF and abutment height (p = 0.550), suggesting material and fabrication method are key.
Conclusions:
- Artificial aging leads to retentive force loss in all tested double-crown systems.
- Conventionally cast double-crowns (DCs) generally provide higher retentive forces compared to electroformed DCs.
- Electroformed DCs offer more predictable retentive force outcomes, making them suitable for cases with few and short abutment teeth.
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