Cytotoxic effect of a 35% hydrogen peroxide bleaching gel on odontoblast-like MDPC-23 cells

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Sep;108(3):458-64. doi: 10.1016/j.tripleo.2009.05.006.


Objective: This study evaluated transenamel and transdentinal cytotoxic effects of a bleaching gel on the MDPC-23 cell line.

Study design: 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.

Conclusion: The bleaching gel associated with light presented transenamel and transdentinal cytotoxic effects characterised by direct damage to odontoblasts and decrease of their metabolic activity.

MeSH terms

  • Animals
  • Cattle
  • Cell Line
  • Cell Survival / drug effects
  • Cells, Cultured
  • Coloring Agents
  • Dental Enamel / drug effects
  • Dentin / drug effects
  • Diffusion
  • Gels
  • Hydrogen Peroxide / toxicity*
  • Light
  • Microscopy, Electron, Scanning
  • Odontoblasts / drug effects*
  • Oxidants / toxicity*
  • Random Allocation
  • Tetrazolium Salts
  • Thiazoles
  • Tooth Bleaching*


  • Coloring Agents
  • Gels
  • Oxidants
  • Tetrazolium Salts
  • Thiazoles
  • Hydrogen Peroxide
  • thiazolyl blue