Effects of a bleaching agent on human gingival fibroblasts
The purpose of the present study was to determine the effects of a carbamide peroxide-containing at-home bleaching agent on gingival fibroblasts in vitro, assessing functions of the cells necessary for their role in maintaining the health of the gingival tissue: viability/morphology, proliferation, and the production of fibronectin and collagen types I, III, and V. Fibroblasts were obtained from healthy patients and exposed to control or solutions for 24 hours. Thymidine incorporation into cellular DNA was used to measure cell proliferation. The production of collagen types I, III, and V by fibroblasts in the presence or absence of the bleaching agents was determined by enzyme-linked immunosorbent assay (ELISA) specific for each collagen type.
Results showed that the bleaching agent is cytotoxic to these cells at some concentrations, having significant effects on viability/morphology, proliferation, and functional activities that are important for the maintenance of the tissue and in healing. Bleaching agents caused death or significant morphological changes in the cells at concentrations greater than or equal to 0.0125%. Proliferation of the fibroblasts was significantly reduced by the bleaching agent at concentrations of greater than or equal to 0.006%. Bleaching agents at concentrations of less than 0.0125%, however, had no apparent effect on the cellular viability and morphology. The production of fibronectin and collagen types I and III was significantly reduced by bleaching agents at concentration > 0.017% or 0.0125% respectively. The conclusion of this study is that particular care should be taken in administering bleaching agents to patients with gingivitis, periodontal disease, or preexisting gingival lesions, and to those using alcohol and tobacco. [P.W.]
Tipton, D., S. Braxton, and M. Dabbous, J Periodont, 66:7, 1995