Cytotoxic effect of a 35% hydrogen peroxide bleaching gel on odontoblast-like MDPC-23 cells.
OBJECTIVE
This study evaluated transenamel and transdentinal cytotoxic effects of a bleaching gel on the MDPC-23 cell line.


METHODS
Discs obtained from bovine incisors were placed in a metallic device to simulate an in vivo pulp chamber. Groups were formed according to the enamel surface treatment: G1: 35% H(2)O(2) bleaching gel; G2: 35% H(2)O(2) bleaching gel + halogen light; G3: halogen light; and G4: control. Cell metabolism was evaluated by the methyltetrazolium assay and cell morphology by scanning electron microscopy.


RESULTS
Cell metabolism decreased by 31.7%, 41.6%, and 11.5% in G1, G2, and G3, respectively. Cytotoxic effects observed in G2 were significantly more severe compared with G3 and G4. In G1 and G2, a smaller number of viable cells with major morphologic alterations remained adhered to dentin.


CONCLUSIONS
The bleaching gel associated with light presented transenamel and transdentinal cytotoxic effects characterised by direct damage to odontoblasts and decrease of their metabolic activity.
Dias Ribeiro
Ana Paula
AP
Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, São Paulo State University, Araraquara, Brazil.
Sacono
Nancy Tomoko
NT
Lessa
Fernanda Campos Rosetti
FC
Nogueira
Indri
I
Coldebella
Cármen Regina
CR
Hebling
Josimeri
J
de Souza Costa
Carlos Alberto
CA
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004396:Coloring Agents; D003743:Dental Enamel / Q000187:drug effects; D003804:Dentin / Q000187:drug effects; D004058:Diffusion; D005782:Gels; D006861:Hydrogen Peroxide / Q000633:toxicity*; D008027:Light; D008855:Microscopy, Electron, Scanning; D009804:Odontoblasts / Q000187:drug effects*; D016877:Oxidants / Q000633:toxicity*; D011897:Random Allocation; D013778:Tetrazolium Salts; D013844:Thiazoles; D014073:Tooth Bleaching
D004396:Coloring Agents; D005782:Gels; D016877:Oxidants; D013778:Tetrazolium Salts; D013844:Thiazoles; D006861:Hydrogen Peroxide; C022616:thiazolyl blue