NAC prevents pulpal toxicity without affecting esthetic effects of bleaching

Objective: Tooth whitening procedures was previously shown to adversely affect both the hard and soft tissues. In this study we report the establishment of novel strategies and procedures to prevent damage induced by bleaching agents on dental pulp and gingival cells using in vivo model system.

Methods: We used 8 week old rats to study the effect of both chair side and over the counter bleaching agents on dental pulp stromal cells (DPSCs) and gingival cells. Cell death was determined by staining of the cells with Annexin V and Propidium iodide. Tissue topography was determined by scanning electron microscope, and Alkaline Phosphatase staining was used to determine the function of the cells.

Results: Both chair side and over the counter bleaching agents induce significant cell death in DPSCs and gingival cells. Growth inhibition, cell death and loss of cellular function in DPSCs and gingival cells were completely prevented when N-acetyl cysteine (NAC) was applied before bleaching of the tooth. NAC also preserved tissue integrity when determined by SEM. In addition, NAC did not affect the whitening capacity of the bleaching agents.

Conclusions: NAC protected the pulp and oral tissues from toxicity induced by bleaching agents without interfering with their whitening capacity. Therefore, application of NAC prior to the bleaching of the teeth should be beneficial for oral health and safety of the patients.