TY - JOUR
T1 - Fatigue life and failure modes of crowns systems with a modified framework design
AU - Lorenzoni, Fabio C.
AU - Martins, Leandro M.
AU - Silva, Nelson R.F.A.
AU - Coelho, Paulo G.
AU - Guess, Petra C.
AU - Bonfante, Estevam A.
AU - Thompson, Van P.
AU - Bonfante, Gerson
N1 - Funding Information:
We thank Dr. André Inácio Lorenzoni for schematics support; to the dental technician José Carlos Romanini for his contribution to the preparation, in part, of the specimens. This study was supported, in part, by grants 4695/06-2 and CNPq PEC-PG 133202-2007-3. The authors acknowledge Hitachi S3500N SEM imaging that was made possible by the New York University College of Dentistry's cooperative agreement with the NIH/NIDCR.
PY - 2010/8
Y1 - 2010/8
N2 - Objectives: To evaluate the effect of framework design on the fatigue life and failure modes of metal ceramic (MC, Ni-Cr alloy core, VMK 95 porcelain veneer), glass-infiltrated alumina (ICA, In-Ceram Alumina/VM7), and veneered yttria-stabilized tetragonal zirconia polycrystals (Y-TZP, IPSe.max ZirCAD/IPS e.max,) crowns. Methods: Sixty composite resin tooth replicas of a prepared maxillary first molar were produced to receive crowns systems of a standard (MCs, ICAs, and Y-TZPs, n = 10 each) or a modified framework design (MCm, ICAm, and Y-TZPm, n = 10 each). Fatigue loading was delivered with a spherical steel indenter (3.18 mm radius) on the center of the occlusal surface using r-ratio fatigue (30-300 N) until completion of 106 cycles or failure. Fatigue was interrupted every 125,000 cycles for damage evaluation. Weibull distribution fits and contour plots were used for examining differences between groups. Failure mode was evaluated by light polarized and SEM microscopy. Results: Weibull analysis showed the highest fatigue life for MC crowns regardless of framework design. No significant difference (confidence bound overlaps) was observed between ICA and Y-TZP with or without framework design modification. Y-TZPm crowns presented fatigue life in the range of MC crowns. No porcelain veneer fracture was observed in the MC groups, whereas ICAs presented bulk fracture and ICAm failed mainly through the veneer. Y-TZP crowns failed through chipping within the veneer, without core fractures. Conclusions: Framework design modification did not improve the fatigue life of the crown systems investigated. Y-TZPm crowns showed comparable fatigue life to MC groups. Failure mode varied according to crown system.
AB - Objectives: To evaluate the effect of framework design on the fatigue life and failure modes of metal ceramic (MC, Ni-Cr alloy core, VMK 95 porcelain veneer), glass-infiltrated alumina (ICA, In-Ceram Alumina/VM7), and veneered yttria-stabilized tetragonal zirconia polycrystals (Y-TZP, IPSe.max ZirCAD/IPS e.max,) crowns. Methods: Sixty composite resin tooth replicas of a prepared maxillary first molar were produced to receive crowns systems of a standard (MCs, ICAs, and Y-TZPs, n = 10 each) or a modified framework design (MCm, ICAm, and Y-TZPm, n = 10 each). Fatigue loading was delivered with a spherical steel indenter (3.18 mm radius) on the center of the occlusal surface using r-ratio fatigue (30-300 N) until completion of 106 cycles or failure. Fatigue was interrupted every 125,000 cycles for damage evaluation. Weibull distribution fits and contour plots were used for examining differences between groups. Failure mode was evaluated by light polarized and SEM microscopy. Results: Weibull analysis showed the highest fatigue life for MC crowns regardless of framework design. No significant difference (confidence bound overlaps) was observed between ICA and Y-TZP with or without framework design modification. Y-TZPm crowns presented fatigue life in the range of MC crowns. No porcelain veneer fracture was observed in the MC groups, whereas ICAs presented bulk fracture and ICAm failed mainly through the veneer. Y-TZP crowns failed through chipping within the veneer, without core fractures. Conclusions: Framework design modification did not improve the fatigue life of the crown systems investigated. Y-TZPm crowns showed comparable fatigue life to MC groups. Failure mode varied according to crown system.
KW - All-ceramic
KW - Crown
KW - Fatigue life
KW - Framework design
KW - Glass-infiltrated
KW - Metal ceramic
KW - Y-TZP
UR - http://www.scopus.com/inward/record.url?scp=77953702890&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77953702890&partnerID=8YFLogxK
U2 - 10.1016/j.jdent.2010.04.011
DO - 10.1016/j.jdent.2010.04.011
M3 - Article
C2 - 20450952
AN - SCOPUS:77953702890
SN - 0300-5712
VL - 38
SP - 626
EP - 634
JO - Journal of Dentistry
JF - Journal of Dentistry
IS - 8
ER -