title: Adherent endotoxin on dental implant surfaces: a reappraisal.
abstract: Osteoimmunology is the crosstalk between cells from the immune and skeletal systems, suggesting a role of pro-inflammatory cytokines in the stimulation of osteoclast activity. Endotoxin or bacterial challenges to inflammatory cells are directly relevant to dental implant pathologies involving bone resorption, such as osseointegration failure and peri-implantitis. While the endotoxin amount on implant devices is regulated by standards, it is unknown whether commercially available dental implants elicit different levels of adherent-endotoxin stimulated cytokines. The objective of this work is to develop a model system and evaluate endotoxin-induced expression of pro-inflammatory cytokine genes relevant to osteoclast activation on commercially available dental implants. Murine J774-A1 macrophages were cultured on Ti disks with different level of lipopolysaccharide (LPS) contamination to define the time-course of the inflammatory response to endotoxin, as evaluated by reverse transcription polymerase chain reaction analysis. The developed protocol was then used to measure adherent endotoxin on commercially available packaged and sterile dental implants in the "as-implanted" condition. Results show that tested dental implants induce variable expression of endotoxin-stimulated genes, sometimes above the level expected to promote bone resorption in vivo. Results are unaffected by the specific surface treatment; rather, they likely reflect care in cleaning and packaging protocols. In conclusion, expression of genes that enhance osteoclast activity through endotoxin stimulation of inflammatory cells is widely different on commercially available dental implants. A reappraisal of the clinical impact of adherent endotoxins on dental (and bone) implant devices is required in light of increasing knowledge on crosstalk between cells from the immune and skeletal systems.
authors.affiliation: Nobil Bio Ricerche, Portacomaro, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Morra
authors.forename: Clara
authors.initials: C
authors.lastname: Cassinelli
authors.forename: Daniele
authors.initials: D
authors.lastname: Bollati
authors.forename: Giovanna
authors.initials: G
authors.lastname: Cascardo
authors.forename: Marco
authors.initials: M
authors.lastname: Bellanda
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D001862:Bone Resorption / Q000276:immunology; D002460:Cell Line; D018932:Chemokine CCL2 / Q000032:analysis; D051546:Cyclooxygenase 2 / Q000032:analysis; D016207:Cytokines / Q000276:immunology; D045662:Dental Etching / Q000379:methods; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D004731:Endotoxins / Q000276:immunology*; D018836:Inflammation Mediators / Q000276:immunology; D007375:Interleukin-1 / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis; D008070:Lipopolysaccharides / Q000276:immunology; D016173:Macrophage Colony-Stimulating Factor / Q000032:analysis; D008264:Macrophages / Q000276:immunology; D051379:Mice; D010010:Osteoclasts / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D016207:Cytokines; D015921:Dental Implants; D003764:Dental Materials; D004731:Endotoxins; D018836:Inflammation Mediators; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor; D014025:Titanium; D051546:Cyclooxygenase 2
keywords: Dental implants; endotoxin; implant surface; inflammatory response; osteoimmunology