Vascular dysfunction may also reduce oxygen delivery to gingival tissue. Pocket oxygen tension was reported to be significantly lower in smokers than non-smokers providing support for the negative effects of smoking on vascular system (Hanioka et al. 2000). Evidence from both human and experimental studies suggests that smoking has a long-term chronic effect, and its effect is not simply a vasoconstriction. Its suppressive effects on the vascular system of gingiva can be observed through less gi