title: Association between tumor necrosis factor-alpha G-308A polymorphism and dental peri-implant disease risk: A meta-analysis.
abstract: BACKGROUND
  Tumor necrosis factor-alpha (TNF-α) is a potent immune-inflammatory mediator involved in the regulation of bone resorption. The single nucleotide polymorphism G-308A in the TNF-α gene increases the level of this cytokine. This phenomenon is also related to several diseases. Although the association between TNF-α (G-308A) polymorphism and dental peri-implant disease has been investigated, results have remained controversial. Hence, we performed this meta-analysis to provide a comprehensive and systematic conclusion on this topic.
  
  
  METHODS
  We performed a systematic literature search in PubMed, Embase, ISI Web of Science, Cochrane Library, and Chinese National Knowledge Infrastructure until July 2015. A fixed-effect model was established to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). The calculated values were then used to assess the strength of the association between the TNF-α (G-308A) polymorphism and the dental peri-implant disease risk. The heterogeneity between included studies was evaluated with Cochran Q and I statistics. Interstudy publication bias was investigated with a funnel plot.
  
  
  RESULTS
  Six eligible studies were included in this meta-analysis. The pooled ORs did not reveal a significant relationship between the TNF-α (G-308A) polymorphism and the disease susceptibility. Subgroup analyses in terms of ethnicity and disease type yielded similar results.
  
  
  CONCLUSIONS
  Our meta-analysis revealed that TNF-α (G-308A) polymorphism was not significantly associated with the risk of dental peri-implant disease. However, further studies with large sample sizes should be performed to verify these results.
authors: Department of Stomatology, Daping Hospital and Research Institute of Surgery, Third Military Medical University, Chongqing Center for Evidence-Based and Translational Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
authors: Yuan-Yuan
authors: YY
authors: Mo
authors: Xian-Tao
authors: XT
authors: Zeng
authors: Hong
authors: H
authors: Weng
authors: Ying
authors: Y
authors: Cen
authors: Qian
authors: Q
authors: Zhao
authors: Xiujie
authors: X
authors: Wen
mesh_terms: D003758:Dental Implantation, Endosseous / Q000009:adverse effects; D015921:Dental Implants / Q000009:adverse effects*; D019232:Dental Restoration Failure; D006801:Humans; D057873:Peri-Implantitis / Q000209:etiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D015921:Dental Implants; D014409:Tumor Necrosis Factor-alpha