title: Load fatigue performance of implant-ceramic abutment combinations.
abstract: OBJECTIVE
  The mechanical properties and functional load performance of implant restorations coupled with metal abutments have been studied widely. However, the fatigue performance of the newly introduced ceramic implant abutments has not been reported. This study investigated the load fatigue performance of four implant systems and their corresponding zirconia ceramic abutments at the manufacturers' recommended torque levels.
  
  
  METHODS
  Three different diameters (narrow, regular, and wide) of the Replace Select and Branemark systems and two different diameters (4.1 mm and 5.0 mm) of the Osseotite NT and Osseotite NT Certain systems provided 10 implant-abutment test groups. The abutments tested were Procera zirconia, Zireal posts, and Certain ZiReal posts. Each group had a sample size of five. A rotational load fatigue machine applied a 21-N load to the specimens at an angle of 45 degrees to produce an effective bending moment of 35 Ncm at a test frequency of 10 Hz. The number of cycles to failure was recorded.
  
  
  RESULTS
  Twenty-nine of the 50 implant-abutment combinations tested failed. Eighteen abutments fractured. Seven implant fractures and 16 abutment screw fractures were seen, along with some damage to the implant platform in some specimens. No significant difference was seen between the implant systems, but significant differences were observed between the implant diameters. A subsequent one-way analysis of variance revealed statistically significant differences between the 10 implant-abutment test groups.
  
  
  CONCLUSIONS
  Rotational load fatigue testing performance of zirconia abutments is dependent on the abutment diameter. Failure modes varied according to system design characteristics.
authors.affiliation: Dental Department, Alexandra Hospital, Singapore.
authors.forename: Huong Q
authors.initials: HQ
authors.lastname: Nguyen
authors.forename: Keson B
authors.initials: KB
authors.lastname: Tan
authors.forename: Jack I
authors.initials: JI
authors.lastname: Nicholls
mesh_terms: D017076:Computer-Aided Design; D000044:Dental Abutments; D015921:Dental Implants; D019250:Dental Implants, Single-Tooth; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D012399:Rotation; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019415:Torque; D015040:Zirconium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D016876:Metal Ceramic Alloys; C077451:Procera; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide