Low toxic effects of a whitening strip to cultured pulp cells.
OBJECTIVE
To assess the trans-enamel and trans-dentin toxicity of a 10% hydrogen peroxide (HP) whitening strip to odontoblast-like cells (MDPC-23).


METHODS
Enamel surfaces of enamel/dentin discs adapted to artificial pulp chambers were subjected to two 30-minute whitening strip applications to obtain indirect extracts (DMEM + bleaching components that diffused across enamel and dentin). The extracts were applied for 1 hour to the cells for 1 or 5 days. A bleaching gel with 35% HP was used as the positive control. Cell viability (MTT assay) and morphology (SEM) as well as the quantity of HP in the extracts were assessed.


RESULTS
Discrete cell viability reduction (21.9%) associated with slight alterations in cell morphology occurred after application of the extracts for 5 days to the MDPC-23 cells (Tukey's test; P < 0.05). Lower enamel/dentin diffusion of HP was observed after the use of the whitening strip compared with the bleaching gel (Mann-Whitney; P < 0.05).
Department of Dental Materials and Prosthodontics, Univ. Estadual Paulista, Araraquara School of Dentistry, Araraquara, SP, Brazil.
Diana Gabriela
DG
Soares
Department of Dental Materials and Prosthodontics, Univ. Estadual Paulista, Araraquara School of Dentistry, Araraquara, SP, Brazil.
Elaine Cristina Voltoline
EC
Pontes
Department of Dentistry, Federal University of Brasilia, Brasilia, DF, Brazil.
Ana Paula Dias
AP
Ribeiro
Department of Orthodontics and Pediatric Dentistry, Univ. Estadual Paulista, Araraquara School of Dentistry, Araraquara, SP, Brazil.
Fernanda Gonçalves
FG
Basso
Department of Orthodontics and Pediatric Dentistry, Univ. Estadual Paulista, Araraquara School of Dentistry, Araraquara, SP, Brazil.
Josimeri
J
Hebling
Department of Physiology and Pathology, Univ. Estadual Paulista, Araraquara School of Dentistry, Araraquara, SP, Brazil.
Carlos Alberto de Souza
CA
Costa
D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D003745:Dental Enamel Permeability / Q000187:drug effects; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D003806:Dentin Permeability / Q000187:drug effects; D004058:Diffusion; D006861:Hydrogen Peroxide / Q000493:pharmacokinetics / Q000633:toxicity*; D008855:Microscopy, Electron, Scanning; D009804:Odontoblasts / Q000187:drug effects*; D012464:Saliva, Artificial / Q000008:administration & dosage; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors; D046509:Tissue Culture Techniques; D014073:Tooth Bleaching / Q000295:instrumentation; D058205:Tooth Bleaching Agents / Q000493:pharmacokinetics / Q000633:toxicity*
D004396:Coloring Agents; D012464:Saliva, Artificial; D013778:Tetrazolium Salts; D013844:Thiazoles; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide; C022616:thiazolyl blue