title: Fracture Resistance and Mode of Failure of Ceramic versus Titanium Implant Abutments and Single Implant-Supported Restorations.
abstract: BACKGROUND
  The material of choice for implant-supported restorations is affected by esthetic requirements and type of abutment.
  
  
  OBJECTIVE
  This study compares the fracture resistance of different types of implant abutments and implant-supported restorations and their mode of failure.
  
  
  METHODS
  Forty-five Oraltronics Pitt-Easy implants (Oraltronics Dental Implant Technology GmbH, Bremen, Germany) (4 mm diameter, 10 mm length) were embedded in clear autopolymerizing acrylic resin. The implants were randomly divided into three groups, A, B and C, of 15 implants each. In group A, titanium abutments and metal-ceramic crowns were used. In group B, zirconia ceramic abutments and In-Ceram Alumina crowns were used. In group C, zirconia ceramic abutments and IPS Empress Esthetic crowns were used. Specimens were tested to failure by applying load at 130° from horizontal plane using an Instron Universal Testing Machine. Subsequently, the mode of failure of each specimen was identified.
  
  
  RESULTS
  Fracture resistance was significantly different between groups (p < .05). The highest fracture loads were associated with metal-ceramic crowns supported by titanium abutments (p = .000). IPS Empress crowns supported by zirconia abutments had the lowest fracture loads (p = .000). Fracture modes of metal-ceramic crowns supported by titanium abutments included screw fracture and screw bending. Fracture of both crown and abutment was the dominant mode of failure of In-Ceram/IPS Empress crowns supported by zirconia abutments.
  
  
  CONCLUSIONS
  Metal-ceramic crowns supported by titanium abutments were more resistant to fracture than In-Ceram crowns supported by zirconia abutments, which in turn were more resistant to fracture than IPS Empress crowns supported by zirconia abutments. In addition, failure modes of restorations supported by zirconia abutments were more catastrophic than those for restorations supported by titanium abutments.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Al-Jouf University, Sakaka, Saudi Arabia.
authors.forename: Mohd G
authors.initials: MG
authors.lastname: Sghaireen
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D066298:In Vitro Techniques; D008422:Materials Testing; D014025:Titanium / Q000737:chemistry*
chemical_list: C483026:In-Ceram Alumina; D003776:Dental Porcelain; D014025:Titanium
keywords: IPS Empress Esthetic; In-Ceram Alumina; dental implant; fracture resistance; implant abutment; zirconia