Evaluation of mechanical cycling fatigue for full thickness and layered CAD/CAM-designed and machined all-ceramic crowns
Date
2004
DOI
Authors
Al-Gergawi, Khaled
Version
OA Version
Citation
Abstract
Objective: The objective of this study was to evaluate the effect of cyclic loading of CAD/CAM full thickness (monolithic) and layered (veneers bonded to different copings) crowns.
Materials: Monolithic crowns were made of 3M/ESPE MZ100 (MZ), VITA Alpha 3 porcelain (AL), VITA ln-Ceram Spinell (IN-S), VITA Mark II (MK). Copings for the layered crowns were made of VITA glass-infused ln-Ceram Alumina (GIN-A), VITA resin-infused In-Ceram Alumina (RIN-A), VITA resin infused feldspathic porcelain (RIP), and 3M/ESPE MZ100 (MZ).
Methods: A correlation program of the CEREC II machine was used to design and mill fullthickness crowns with 1.5 to 2.0 mm occlusal and 1.0 to 1.5 mm axial thickness, and layering veneers of 1.0 to 1.5 mm occlusal and 0.5 to 1.0 mm axial thickness. An In-Lab CEREC machine was used to make 0.5 mm uniformly thick copings. A polyether (3M/ESPE lmpregum Penta) mold was used to duplicate positive dies by using 3M Scotch-Weld epoxy resin. Resin bonding cement (3M/ESPE RelyX ARC) was used to bond the fabricated full-thickness crowns to dies, layered veneers to copings and the bonded crowns to dies. Layered veneer/coping crowns (AL(gb)/GIN-A) were bonded to the copings by using glass, and Vitadur/GIN-A ceramics was directly bonded to the copings. All crowns were polished by using Axis Dental Cera Glaze porcelain polishing kit (NTI-Kahla GmbH. Germany) from coarse to fine with the use of a Revolution micro motor (Buffalo Dental MFG. Co. INC. Syosset, NY) at 20,000 RPM, and maintained wet in plastic holders. Four assemblies for full-thickness crowns were tested: MZ 100 composite crowns, Alpha 3 porcelain crowns, ln-Ceram Spinell ceramic crowns, and Mark II porcelain crowns. For the layered veneer/coping crowns 13 combinations were tested: AL veneer/MZ coping crowns, MZ veneer/MZ coping crowns, MK veneer/MZ coping crowns, AL veneer/RIP coping crowns, MZ veneer/RIP coping crowns, MK veneer/RIP coping crowns, AL (resin bonded} veneer/GIN-A coping, AL(glass bonded) veneer/GIN-A coping crowns, Vitadur (directly infused) veneer/GIN-A coping crowns, MZ veneer/GIN-A coping veneer crowns, MK veneer/GIN-A coping crowns, MZ veneer/RIN-A coping crowns, and MK veneer/RIN-A coping crowns. Cyclic loading was accomplished with a 450-N dead weight load on an 8 mm contact sphere, at 1.6 Hz. A sample of at least 6 specimens of each combination was tested at various numbers of cycles: baseline (no cycles), 5,000; 15,000; 50,000; and 100,000. Load at failure was determined by using compression loading at 0.5 mm/min.
Results: A 2-way ANOVA indicated a statistically significant difference for Vita Alpha 3 fullthickness crowns between baseline and 30,000 cycles (P= 0.03), for MZ 100 full thickness crowns between 100,000 cycles and baseline (P[less than]0.0001), 5,000 cycles (P[less than]0.0001 ), 15,000 cycles (P=0.0002), and 50,000 cycles (P= 0.015). For the layered veneer/coping group, a significant difference was found for the glass infused In-Ceram alumina copings between Vitadur/GIN-A baseline and 5,000 cycles (P= 0.04), between AL(gb)/GIN-A baseline and 15,000 cycles (P= 003) and 50,000 cycles (P= 0.002), also AL(rb)/GIN-A baseline and 15,000 cycles (P= 0.04), as well as between MZ/GIN-A baseline and 100,000 cycles (P= 0.16). Resin-infused ln-Ceram Alumina copings had a significant difference between baseline and 50,000 cycles of MK/RIN-A (P= 0.03), MZ 100 copings group showed a significant difference between AL/MZ baseline and 5,000 cycles (P=0.0007) and 15,000 cycles (P[less than]0.0001). The differences between MK/MZ baseline and 5,000 cycles (p=0.013), 50,000 cycles (P= 0.0003), and 15,000 cycles and 50,000 cycles (P= 0003), MZ/MZ baseline and 15,000 cycles (P= 0.0003) and 50,000 cycles (P[less than]0.0001), 15,000 cycles, and 50,000 cycles (P[less than]0.0001) were significantly different. For resin-infused porcelain copings a significant difference was found between AL/RIP baseline and 5,000 cycles (P=0.006), MK/RIP baseline and 50,000 cycles (P= 0.004) and 15,000 cycles and 50,000 cycles (P= 0.01), MZ/RIP baseline and 5,000 cycles (P=0.02) and 50,000 cycles (P= 0.0001), 5,000 cycles and 15,000 cycles (P=0.0008), 15,000 cycles and 50,000 cycles (P[less than]0.0001).
Conclusions: Under the test conditions, all full-thickness crowns demonstrated decreased load at failure after 100,000 cycles. In-Ceram Spinell full-thickness crowns demonstrated the least percentage loss of load at failure. Paradigm MZ 100 crowns demonstrated the highest load at failure values . All layered veneer/coping combination crowns recorded decreased load at failure after 50,000 cycles. AL/RP combinations were the least resistant to strength degradation. MZ/MZ combinations demonstrated the highest failure-load values for the layered crowns.
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Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2004 (Prosthodontics).
Includes bibliography (leaves 158-165).
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2004 (Prosthodontics).
Includes bibliography (leaves 158-165).
License
This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.