Fracture Strength of Zirconia and Alumina Ceramic Crowns Supported by Implants.
Due to the brittleness and limited tensile strength of the veneering glass-ceramic materials, the methods that combine strong core material (as zirconia or alumina) are still under debate. The present study aims to evaluate the fracture strength and the mechanism of failure through fractographic analysis of single all-ceramic crowns supported by implants. Forty premolar cores were fabricated with CAD/CAM technology using alumina (n = 20) and zirconia (n = 20). The specimens were veneered with glass-ceramic, cemented on titanium abutments, and subjected to loading test until fracture. SEM fractographic analysis was also performed. The fracture load was 1165 (±509) N for alumina and 1638 (±662) N for zirconia with a statistically significant difference between the two groups (P = 0.026). Fractographic analysis of alumina-glass-ceramic crowns, showed the presence of catastrophic cracks through the entire thickness of the alumina core; for the zirconia-glass-ceramic crowns, the cracks involved mainly the thickness of the ceramic veneering layer. The sandblast procedure of the zirconia core influenced crack path deflection. Few samples (n = 3) showed limited microcracks of the zirconia core. Zirconia showed a significantly higher fracture strength value in implant-supported restorations, indicating the role played by the high resistant cores for premolar crowns.
1  Department of Dentistry, Vita Salute University, San Raffaele Hospital, Milan, Italy.|2  Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Italy.
Tonino
T
Traini
3  Department of Fixed Prosthodontics, School of Dentistry, University "Federico II," Naples, Italy.
Roberto
R
Sorrentino
1  Department of Dentistry, Vita Salute University, San Raffaele Hospital, Milan, Italy.
Enrico
E
Gherlone
4  Post-Graduate School of Oral Surgery, Università Sapienza, Rome, Italy.
Federico
F
Perfetti
Patrizio
P
Bollero
2  Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Italy.
Ferdinando
F
Zarone
D000537:Aluminum Oxide / Q000737:chemistry*; D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry*; D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
D003764:Dental Materials; D019279:Resin Cements; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; C023506:Glass ceramics; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; C028541:zirconium oxide
alumina; fracture; implant-supported prostheses; strength; zirconia