title: Reliability and failure modes of narrow implant systems.
abstract: OBJECTIVE
  Narrow implants are indicated in areas of limited bone width or when grafting is nonviable. However, the reduction of implant diameter may compromise their performance. This study evaluated the reliability of several narrow implant systems under fatigue, after restored with single-unit crowns.
  
  
  METHODS
  Narrow implant systems were divided (n = 18 each), as follows: Astra (ASC); BioHorizons (BSC); Straumann Roxolid (SNC), Intra-Lock (IMC), and Intra-Lock one-piece abutment (ILO). Maxillary central incisor crowns were cemented and subjected to step-stress accelerated life testing in water. Use level probability Weibull curves and reliability for a mission of 100,000 cycles at 130- and 180-N loads (90 % two-sided confidence intervals) were calculated. Scanning electron microscopy was used for fractography.
  
  
  RESULTS
  Reliability for 100,000 cycles at 130 N was ∼99 % in group ASC, ∼99 % in BSC, ∼96 % in SNC, ∼99 % in IMC, and ∼100 % in ILO. At 180 N, reliability of ∼34 % resulted for the ASC group, ∼91 % for BSC, ∼53 % for SNC, ∼70 % for IMC, and ∼99 % for ILO. Abutment screw fracture was the main failure mode for all groups.
  
  
  CONCLUSIONS
  Reliability was not different between systems for 100,000 cycles at the 130-N load. A significant decrease was observed at the 180-N load for ASC, SNC, and IMC, whereas it was maintained for BSC and ILO.
  
  
  CONCLUSIONS
  The investigated narrow implants presented mechanical performance under fatigue that suggests their safe use as single crowns in the anterior region.
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Ronaldo
authors.initials: R
authors.lastname: Hirata
authors.affiliation: Department of Prosthodontics, Bauru College of Dentistry, University of São Paulo, Alameda Otávio Pinheiro Brisola 9-75, Bauru, SP, 17.012-901, Brazil. estevamab@gmail.com.
authors.forename: Estevam A
authors.initials: EA
authors.lastname: Bonfante
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.|Universidade do Norte Paulista-UNORP, São José do Rio Preto, SP, Brazil.|Department of Operative Dentistry, São Paulo State University, Araçatuba, SP, Brazil.
authors.forename: Rodolfo B
authors.initials: RB
authors.lastname: Anchieta
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.|Department of Operative Dentistry, São Paulo State University, Araçatuba, SP, Brazil.
authors.forename: Lucas S
authors.initials: LS
authors.lastname: Machado
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.|Department of Dental Surgery and Traumatology, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Gileade
authors.initials: G
authors.lastname: Freitas
authors.affiliation: Department of Prosthodontics, Bauru College of Dentistry, University of São Paulo, Alameda Otávio Pinheiro Brisola 9-75, Bauru, SP, 17.012-901, Brazil.
authors.forename: Vinicius P
authors.initials: VP
authors.lastname: Fardin
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Nick
authors.initials: N
authors.lastname: Tovar
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.|Department of Periodontology and Implant Dentistry, New York University College of Dentistry, New York, NY, USA.|Division of Engineering, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D003442:Crowns; D000044:Dental Abutments; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015203:Reproducibility of Results; D013499:Surface Properties; D014025:Titanium
chemical_list: D015921:Dental Implants; D014025:Titanium
keywords: Biomechanics; Dental implants; Fatigue; Reliability; Weibull