Objective:
Adverse effect of smoking has been widely reported. However effect of smoking cessation has not entirely clear. The Objective of this study was to investigate that gingival fibroblast cells (HGF) and human epithelial cells’ (HE) smoking inflammatory response and changes in repair period during smoking cessations by time-dependently.

Methods:
This study was approved by the Institutional Ethics Review Committee of The Nippon Dental University. Both cells were obtained from normal human gingival tissue. When cells were cultured until confluence, medium was replaced 1ug/ml nicotine contained medium for 24 hours. Then there were replaced non-nicotine fresh medium. IL-6 level was detected by ELISA. The results of smoking group were significantly decreased cell number time-dependently. The migration of both cell types in response to smoking cessation over period of 3 days was investigated in an in vitro wound healing model. The cell cultures were analyzed by morphologically examination under TEM and SEM.

Results:
It was detected that ability of cell migration of smoking cessation group was significantly increased comparing with smoking group (p<0.001). Smoking group were significantly decreased comparing control and smoking cessation group (p<0.001). Following 24 hours nicotine stimulation, there were observed a lot of vacuolization in cytoplasm by phase-contrast microscope, TEM and SEM.

Conclusions:
Our study demonstrated the cell damaging effect of smoking. On the other hand, actually damage of smoking was still remained in cells, we also indicated ability of the cell repairing effect of smoking cessation.