title: Long-term dose- and time-dependent effects of endodontic sealers in human in vitro osteoclastogenesis.
abstract: BACKGROUND
  This study evaluates the concentration and time-dependent effects of endodontic sealers' extracts (AH Plus [Dentsply DeTrey, Konstanz, Germany], GuttaFlow [Roeko, Colténe/Whaledent, Germany], Tubliseal [Kerr/Sybron, Romulus, MI], Sealapex [Kerr/Sybron, Romulus, MI], and RealSeal [SybronEndo, Orange, CA]) in the differentiation and function of both unstimulated and stimulated osteoclast precursors, simulating, respectively, immature/undifferentiated precursors and cells undergoing osteoclastogenesis.
  
  
  METHODS
  The sealers were mixed according to the manufacturers' instructions, freshly extracted with culture medium (1.3 cm(2)/mL, 24 hours, 37°C, 5% CO2/air), and diluted (1:20, 1:100, 1:500, and 1:2500). Human peripheral blood mononuclear cells were used as osteoclast precursor cells. After overnight attachment, peripheral blood mononuclear cell cultures were exposed to the sealers' extracts during 21 days in the absence (unstimulated) or presence (stimulated) of recombinant macrophage colony-stimulating factor and receptor for the activation of nuclear factor-κB ligand. Cultures performed in the absence of the extracts were used as the control. Cultures were characterized for osteoclastic differentiation and function.
  
  
  RESULTS
  Extracts caused mostly inhibitory effects on osteoclastic cells, both in unstimulated and stimulated conditions, which were reflected by a decrease in tartrate-resistant acid phosphatase activity, the presence of actin rings, vitronectin and calcitonin receptors, the calcium phosphate resorbing ability, and the expression of osteoclastic genes. Also, the extracts induced alterations in the relative contribution of some intracellular signaling pathways involved in osteoclastogenic events. The sealers differed in the dose- and time-dependent profile. An adaptive cell response was noticed for the inhibitory effects after long-term exposure.
  
  
  CONCLUSIONS
  Endodontic sealers affect the osteoclastic differentiation and activity, which is followed by an adaptive cell response. Our results suggest that the deleterious effect in the bone periapical tissues observed with the root canal sealers might involve, at least partially, a direct effect on the osteoclastic cells.
authors.affiliation: Serviço de Endodontia, Faculdade de Medicina Dentária, Universidade do Porto, Porto, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Rodrigues
authors.forename: João
authors.initials: J
authors.lastname: Costa-Rodrigues
authors.forename: José António
authors.initials: JA
authors.lastname: Capelas
authors.forename: Maria Helena
authors.initials: MH
authors.lastname: Fernandes
mesh_terms: D000135:Acid Phosphatase / Q000187:drug effects; D000199:Actins / Q000187:drug effects; D000328:Adult; D002126:Calcium Hydroxide / Q000737:chemistry / Q000494:pharmacology; D002130:Calcium Phosphates / Q000737:chemistry; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003188:Composite Resins / Q000737:chemistry / Q000494:pharmacology; D004129:Dimethylpolysiloxanes / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004853:Epoxy Resins / Q000737:chemistry / Q000494:pharmacology; D006171:Gutta-Percha / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000187:drug effects; D007527:Isoenzymes / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008297:Male; D016328:NF-kappa B / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects*; D011493:Protein Kinase C / Q000187:drug effects; D053245:RANK Ligand / Q000494:pharmacology; D018003:Receptors, Calcitonin / Q000187:drug effects; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000494:pharmacology*; D012459:Salicylates / Q000737:chemistry / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects
chemical_list: D000199:Actins; D002130:Calcium Phosphates; D003188:Composite Resins; D004129:Dimethylpolysiloxanes; D004338:Drug Combinations; D004853:Epoxy Resins; C515718:GuttaFlow; D039302:Integrin alphaVbeta3; D007527:Isoenzymes; D016328:NF-kappa B; D053245:RANK Ligand; C511498:Real Seal composite resin; D018003:Receptors, Calcitonin; D012387:Root Canal Filling Materials; D012459:Salicylates; C505688:TNFSF11 protein, human; D015035:Zinc Oxide-Eugenol Cement; C534916:epoxy resin-based root canal sealer; C055601:Sealapex; C048769:tubliseal; D016173:Macrophage Colony-Stimulating Factor; D006171:Gutta-Percha; C020243:calcium phosphate; D011493:Protein Kinase C; D048051:p38 Mitogen-Activated Protein Kinases; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002126:Calcium Hydroxide