title: Peri-implant disease and chronic periodontitis: is interleukin-6 gene promoter polymorphism the common risk factor in a Brazilian population?
abstract: OBJECTIVE
  To investigate the association between interleukin-6 (IL-6) G174C polymorphism and susceptibility to peri-implant disease (PID) and/or chronic periodontitis (CP), in Brazilian subjects.
  
  
  METHODS
  A total of 103 Brazilian patients were submitted to peri-implant and periodontal examination. According to their peri-implant characteristics, patients were divided into: group A (healthy, n = 52), group B (peri-implant mucositis, n = 20), and group C (peri-implantitis, n = 31). All patients (n = 103) were also characterized as healthy periodontium patients without CP (HP, n = 60) or CP patients (CP, n = 43). DNA was extracted from buccal cells, and the IL-6 G174C polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism. Differences in the prevalence of genotypes and alleles between healthy and ill patients were analyzed by chi-square test (P < .05), considering PID, CP, and PID+CP.
  
  
  RESULTS
  Results considered the presence of PID and/or CP in all patients. The CC genotype was the least common in all groups. The chi-square test showed no significant correlation between genotypes. However, the odds ratio showed that individuals with GG genotype and allele G were 1.53 and 1.43 times more susceptible to PID, respectively. The risk of presenting CP was increased in patients with GG genotype and allele G 1.35 and 1.24 times, respectively. When both diseases were evaluated together, patients with GG genotypes and allele G were 1.75 and 1.50 times more likely to present PID and CP together. When PID was evaluated without CP, patients with allele G were 2.08 times more susceptible to PID.
  
  
  CONCLUSIONS
  The frequency of the genotype IL-6 174GG and allele G was different between healthy and ill groups. Therefore, this genotype may be a common risk factor for both CP and PID in Brazilian populations.
authors: Research Department, National Institute of Traumatology and Orthopaedics, Rio de Janeiro, Brazil. pcasado@into.saude.gov.br
authors: Priscila Ladeira
authors: PL
authors: Casado
authors: Ricardo
authors: R
authors: Villas-Boas
authors: Wallace
authors: W
authors: de Mello
authors: Maria Eugenia Leite
authors: ME
authors: Duarte
authors: José Mauro
authors: JM
authors: Granjeiro
mesh_terms: D000328:Adult; D000483:Alleles; D001938:Brazil; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D055113:Chronic Periodontitis / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D057873:Peri-Implantitis / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D013280:Stomatitis / Q000235:genetics
chemical_list: D015850:Interleukin-6