title: The effect of curing light intensity on the cytotoxicity of a dentin-bonding agent.
abstract: Various dentin-bonding agents (DBAs) have been widely used to improve the bonding strength of dental resins and to prevent microleakage at the resin-dentin interface, although DBA may exert potentially detrimental effects upon dental pulp. In this study, a DBA (Scotchbond Multi-purpose) cured at different light intensities (100, 200 and 300-mW/cm2) for 10 seconds was extracted with Dulbecco's modified Eagle's medium (DMEM) for 24 hours. Thereafter, pulp cells (1 x 10(4) cells/well) were exposed to DMEM with or without DBA extract for 12 hours, 24 hours and five days. Pulp-cell cytotoxicity was measured with a modified 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. No significant cytotoxicity of DBA eluents on pulp cells was found for the 12-hour exposure group. Following 24-hour exposure of cells to DBA cured at 100-mW/cm2, pulp cells became rounder, more retracted and lost some cellular processes as compared to controls. Five-day exposure of pulp cells to DBA extract cured by light at levels of 100, 200 and 300 mW/cm2, respectively, led to a growth retardation of 26%, 48% and 70% as analyzed by the inhibition of mitochondrial dehydrogenase activity. These results indicate that DBA may exert some cytotoxic effects upon dental pulp, especially when DBA-curing is insufficiently complete, as may occur at a low light intensity.
authors.affiliation: Laboratory of Dental Pharmacology & Toxicology, Graduate Institute of Clinical Dental Science, College of Medicine and National Taiwan University Hospital, Taipei.
authors.forename: R S
authors.initials: RS
authors.lastname: Chen
authors.forename: C C
authors.initials: CC
authors.lastname: Liuïw
authors.forename: W Y
authors.initials: WY
authors.lastname: Tseng
authors.forename: C Y
authors.initials: CY
authors.lastname: Hong
authors.forename: C C
authors.initials: CC
authors.lastname: Hsieh
authors.forename: J H
authors.initials: JH
authors.lastname: Jeng
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000528:radiation effects / Q000633:toxicity*; D006801:Humans; D008027:Light; D019279:Resin Cements / Q000528:radiation effects / Q000633:toxicity*
chemical_list: D017220:Dentin-Bonding Agents; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose