title: Expression of interleukin 6 and tumor necrosis factor alpha in soft tissue over ceramic and metal implant materials before uncovering: a clinical pilot study.
abstract: OBJECTIVE
  To compare the effect of ceramic and metal implant materials on the expression pattern of inflammatory cytokines in peri-implant soft tissue.
  
  
  METHODS
  This split-mouth study included patients who received dental implants. In each patient, four different materials were used for the implant cover screws: the ceramic material titanium niobium oxynitride ([Ti,Nb]ON) with plasma-chemical oxidation treatment, (Ti,Nb)ON, a titanium-tantalum alloy, and tantalum. Biopsy specimens of peri-implant tissue were harvested at reentry, 4 months after the initial surgery. Immunohistochemical staining was performed for tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6).
  
  
  RESULTS
  Six patients received a total of 24 dental implants with the four different types of implant cover screws. Quantitative analysis of TNF-α; and IL-6 expression showed the lowest expression of IL-6 (1.5; interquartile range, 0 to 8.5) and TNF-α (4.8; interquartile range, 3.5 to 7.5) in tissue adjacent to the (Ti,Nb)ON layer. In comparison to the metal surfaces, the expression of both cytokines was significantly lower (P = .01 and P = .03).
  
  
  CONCLUSIONS
  The lowest levels of cytokine expression were observed in tissue adjacent to the ceramic (Ti,Nb)ON coating with plasma-chemical oxidation. Based on the results of this study, this ceramic layer shows promise as a biocompatible material, and further study is warranted.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Cologne, Cologne, Germany. Dr.A.Nickenig@t-online.de
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Nickenig
authors.forename: Karl Andreas
authors.initials: KA
authors.lastname: Schlegel
authors.forename: Manfred
authors.initials: M
authors.lastname: Wichmann
authors.forename: Stephan
authors.initials: S
authors.lastname: Eitner
mesh_terms: D000328:Adult; D001672:Biocompatible Materials; D002516:Ceramics; D003722:Dental Alloys; D015921:Dental Implants; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism*; D009556:Niobium; D010084:Oxidation-Reduction; D010865:Pilot Projects; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013635:Tantalum; D014025:Titanium; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D001672:Biocompatible Materials; D003722:Dental Alloys; D015921:Dental Implants; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D009556:Niobium; D013635:Tantalum; C041500:titanium nitride; D014025:Titanium