title: Surface contamination of dental implants assessed by gene expression analysis in a whole-blood in vitro assay: a preliminary study.
abstract: OBJECTIVE
  We aimed at evaluating pyrogen contamination of dental implants made of titanium and zirconia by using gene expression analysis in a whole-blood in vitro assay.
  
  
  METHODS
  Titanium and zirconia implants (five each) were incubated in human whole blood. Samples were assayed for gene expression levels of toll-like receptor 4 (TLR4), TLR9, interleukin (IL)-1β, nuclear factor 'kappa-light-chain-enhancer' of activated B-cells (NF-kB), tumour necrosis factor (TNF)-α, and Fas-associated protein with death domain (FADD) as indicators of surface contamination resulting in lipopolysaccharides (LPS)-stimulated TLR- or TNF-mediated immune responses. Gene expression was assayed using real-time quantitative polymerase chain reaction (RT-qPCR). Non-stimulated blood from the same donor served as a negative control, and blood stimulated with LPS served as a positive control. After dry-heat treatment with dry heat, all implants were re-analysed as described above.
  
  
  RESULTS
  Both implant systems contained surface contaminants evoking a pro-inflammatory response similar to that induced by LPS. After dry-heat treatment, gene expression was significantly decreased to levels similar to those of negative control samples.
  
  
  CONCLUSIONS
  The results demonstrated LPS-like surface-bound contaminants in both tested implant systems. Depyrogenation with dry heat seems to be an effective means of reducing such contamination in dental implants.
authors.affiliation: Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University, Kiel, Germany. sharder@proth.uni-kiel.de
authors.forename: Sönke
authors.initials: S
authors.lastname: Harder
authors.forename: Elgar S
authors.initials: ES
authors.lastname: Quabius
authors.forename: Lars
authors.initials: L
authors.lastname: Ossenkop
authors.forename: Christian
authors.initials: C
authors.lastname: Mehl
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D001773:Blood Cells / Q000276:immunology* / Q000378:metabolism; D046508:Culture Techniques; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D003666:Decontamination / Q000379:methods; D015921:Dental Implants; D003764:Dental Materials; D004866:Equipment Contamination / Q000517:prevention & control*; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D010865:Pilot Projects; D011749:Pyrogens / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D013499:Surface Properties; D014025:Titanium; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D051217:Toll-Like Receptor 9 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015040:Zirconium
chemical_list: D016207:Cytokines; D015921:Dental Implants; D003764:Dental Materials; D053200:Fas-Associated Death Domain Protein; D053583:Interleukin-1beta; D016328:NF-kappa B; D011749:Pyrogens; D051197:Toll-Like Receptor 4; D051217:Toll-Like Receptor 9; D014409:Tumor Necrosis Factor-alpha; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide