Toxic effects of daily applications of 10% carbamide peroxide on odontoblast-like MDPC-23 cells.
BACKGROUND
bleaching has been widely studied, mainly due to the possible undesirable effects that can be caused by this esthetic procedure. The cytotoxicity of the bleaching agents and its components to pulp cells has been demonstrated in several researches. The aim of this study was to evaluate the toxic effects of successive applications of 10% carbamide peroxide (CP) gel on odontoblast-like cells.


METHODS
Enamel-dentin discs obtained from bovine incisors were adapted to artificial pulp chambers (APCs). The groups were formed as follows: G1: Without treatment (control group); G2: 10% carbamide peroxide, CP (five applications/one per day); G3: 10% CP (one unique application); and G4: 35% hydrogen peroxide, HP (three applications of 15 min each). After treatment, cell metabolism (MTT), alkaline phosphatase (ALP) activity and plasma membrane damage (flow cytometry) were analyzed.


RESULTS
Reductions in cell metabolism and alkaline phosphatase activity along with severe damage of the cytoplasmic membrane were noted in G2. In G3, no damage was observed, compared to the control group. Intermediary values of toxicity were obtained after 35% HP application.


CONCLUSIONS
It can be concluded that one application of 10% CP did not cause toxic effects in odontoblast-like cells, but the successive application of this product promoted severe cytotoxic effects. The daily application of the bleaching agents, such as used in the at-home bleaching technique, can increase the damages caused by this treatment to the dental pulp cells.
Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil.
Adriano Fonseca
AF
Lima
Ana Paula Dias
AP
Ribeiro
Diana Gabriela Sousa
DG
Soares
Nancy Tomoko
NT
Sacono
Josimeri
J
Hebling
Carlos Alberto
CA
de Souza Costa
D000469:Alkaline Phosphatase / Q000378:metabolism; D000077463:Carbamide Peroxide; D002460:Cell Line; D006801:Humans; D009804:Odontoblasts / Q000187:drug effects* / Q000201:enzymology; D010545:Peroxides / Q000008:administration & dosage / Q000633:toxicity*; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity
D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D000469:Alkaline Phosphatase