title: Evaluation of the effect of tumor necrosis factor-alpha gene polymorphism on the risk of peri-implantitis: a case-control study.
abstract: OBJECTIVE
  Tumor necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine, which promotes bone resorption and mediates the inflammatory response to infection. Because implant failures appear to cluster in subsets of individuals, this phenomenon may be related to gene polymorphisms. Therefore, the aim of this study was to investigate the relationship between a specific polymorphism in the TNFalpha gene (allele 2 of TNFalpha(-308)) and peri-implantitis.
  
  
  METHODS
  This case-control study included Caucasian nonsmoking Brazilian patients with implant-supported restorations. Oral epithelial cells were taken from patients with and without peri-implantitis to evaluate the frequencies of different alleles of the TNFalpha(-308) gene by polymerase chain reaction.
  
  
  RESULTS
  Ninety patients (49 with peri-implantitis and 41 with healthy implants) were enrolled in this study. Polymorphism in allele 2 of TNFalpha(-308) was not associated with an increased risk for peri-implantitis (P = .8171), although 14.63% of the subjects in the control group carried allele 2 and 19.39% in the peri-implantitis group carried allele 2 (chi-squared = 0.708; P = .5202).
  
  
  CONCLUSIONS
  Polymorphism of the TNFalpha(-308) gene was not associated with an increased risk of peri-implantitis in the population evaluated in this study.
authors.affiliation: Department of Periodontology and Implantology, School of Dentistry, University of Santo Amaro, Santo Amaro, Brazil.
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Cury
authors.forename: Veronica V
authors.initials: VV
authors.lastname: Horewicz
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Ferrari
authors.forename: Rui
authors.initials: R
authors.lastname: Brito
authors.forename: Wilson R
authors.initials: WR
authors.lastname: Sendyk
authors.forename: Poliana M
authors.initials: PM
authors.lastname: Duarte
authors.forename: Jamil A
authors.initials: JA
authors.lastname: Shibli
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015921:Dental Implants / Q000009:adverse effects*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000209:etiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012016:Reference Values; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*; D055815:Young Adult
chemical_list: D015921:Dental Implants; D014409:Tumor Necrosis Factor-alpha