Cytotoxicity of dentine bonding agents on human pulp cells is related to intracellular glutathione levels.
OBJECTIVE
To evaluate ex vivo the mechanisms of cytotoxicity of dentine bonding agents in human pulp cells in vitro.


METHODS
Human pulp cells were obtained from impacted third molars with informed consent and then cultured using an explant technique. Set specimens from Clearfil SE Bond (CB), Prime & Bond 2.1 (PB), and Single Bond (SB) were eluted with culture medium. Cytotoxicity was judged using an assay of tetrazolium bromide reduction. To determine whether glutathione (GSH) levels were important in the cytotoxicity of dentine bonding agents, cells were pretreated with 2-oxothiazolidine-4-carboxylic acid (OTZ) to boost GSH levels or buthionine sulfoximine (BSO) to deplete GSH. Three replicates of each dentine bonding agents were performed in each test. All assays were repeated three times to ensure reproducibility. Statistical analysis was by one-way analysis of variance (anova). Tests of differences of the treatments were analysed by Duncan's test.


RESULTS
Clearfil SE Bond, PB, and SB were cytotoxic to pulp cells in a concentration-dependent manner (P<0.05). The cytotoxicity was upregulated by dentine bonding agents in the following order: PB>SB>CB. Addition of OTZ extracellularly protected the pulp cells from dentine bonding agents-induced cytotoxicity (P<0.05). Addition of BSO enhanced pulp cell death on dentine bonding agents-induced cytotoxicity (P<0.05).


CONCLUSIONS
Dentine bonding agents have significant potential for pulpal toxicity. GSH depletion could be the mechanism for dentine bonding agents-induced cytotoxicity.
Huang
F-M
FM
Department of Dentistry, Chung Shan Medical University Hospital School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
Li
Y-C
YC
Lee
S-S
SS
Chang
Y-C
YC
D000096:Acetone / Q000633:toxicity; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000633:toxicity; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002478:Cells, Cultured; D003764:Dental Materials / Q000633:toxicity*; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017220:Dentin-Bonding Agents / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D011109:Polymethacrylic Acids / Q000633:toxicity; D011761:Pyrrolidonecarboxylic Acid / Q000494:pharmacology; D019279:Resin Cements / Q000633:toxicity; D053778:Thiazolidines / Q000494:pharmacology
C438313:Clearfil SE Bond; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D004791:Enzyme Inhibitors; D011109:Polymethacrylic Acids; D019279:Resin Cements; D053778:Thiazolidines; C444444:prime and bond 2.1; C115612:single bond; D000096:Acetone; D017438:Bisphenol A-Glycidyl Methacrylate; D019328:Buthionine Sulfoximine; D005978:Glutathione; D011761:Pyrrolidonecarboxylic Acid; C029536:2-oxothiazolidine-4-carboxylic acid