title: Polymer infiltrated ceramic network structures for resistance to fatigue fracture and wear.
abstract: To investigate fatigue fracture resistance and wear behavior of a polymer infiltrated ceramic network (PICN) material (ENAMIC, Vita Zahnfabrik).
  
  
  
  Anatomically shaped ENAMIC monolithic crowns were milled using a CAD/CAM system. The crowns were cemented on aged dentin-like composite abutments (Z100, 3M ESPE) with resin-based cement (Vita DUO Cement, Vita). The specimens were subjected to 2 types of fatigue and wear tests: (1) accelerated sliding-contact mouth-motion step-stress fatigue test (n=24) in water; and (2) long-term sliding-contact mouth-motion fatigue/wear test using a clinically relevant load (P=200N, n=8) in water. Failure was designated as chip-off or bulk fracture. Optical and scanning electron microscopes were used to examine the occlusal surface and subsurface damage, as well as to reveal the material's microstructure. In addition, wear volume and depth were measured by X-ray micro-computed tomography.
  
  
  
  For accelerated mouth-motion step-stress fatigue testing, 3 out of the 24 ENAMIC crowns fractured following cyclic loading up to 1700N. Minor occlusal damage and contact-induced cone cracks were observed in all surviving specimens, but no flexural radial cracks were seen. For long-term mouth-motion fatigue/wear testing under a 200N load in water, a small wear scar without significant cracks was observed in all 8 tested ENAMIC crowns.
  
  
  
  Monolithic CAD/CAM ENAMIC crowns showed superior resistance to sliding-contact fatigue fracture and wear.
authors: Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA.
authors: Haifa
authors: H
authors: El Zhawi
authors: Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA; School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
authors: Marina R
authors: MR
authors: Kaizer
authors: Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA.
authors: Asima
authors: A
authors: Chughtai
authors: School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
authors: Rafael R
authors: RR
authors: Moraes
authors: Department of Biomaterials and Biomimetics, New York University College of Dentistry, 433 First Avenue, New York, NY 10010, USA. Electronic address: yz21@nyu.edu.
authors: Yu
authors: Y
authors: Zhang
mesh_terms: D002516:Ceramics; D017076:Computer-Aided Design; D003442:Crowns; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D011108:Polymers; D055114:X-Ray Microtomography
chemical_list: D011108:Polymers; D003776:Dental Porcelain
keywords: CAD/CAM crowns; Damage modes; Fatigue fracture; Polymer infiltrated ceramic network; Wear