Hi AT! You might have a point. From the article I got:
"Nicotine is a vasoconstrictor compound, which means that it has the tendency to stimulate the contraction of the muscular wall of the blood vessels, resulting in reduced blood flow. Based on research, the extended decrease of nutrient and oxygen supply to the gum increases the probability of periodontal disease development. Restriction of blood flow also affects the mouths natural inhibitory function of cleaning and fighting bacteria, as well as reduces the body’s innate ability to heal and generate new cells."
Nicotine constricting blood flow is the problem. I figured nicotine has this constricting effect overall and equally in the body. Are you saying because the nicotine is taken up by blood vessels in the mouth they are being affected more then if the nicotine came in though your arm? I figured there would be reduced blood flow throughout all your body equally over time and it really doesn't matter how it entered the body. But I am interested in learning about PG, VG and Nicotine in finer and finer details - so share what you know.
I am not aware of any direct research on constricting effects of nicotine directly on blood vessels in a mouth. So, I can only say that constriction of vessels should be (more or less) proportional to concentration of nic in blood. Mouth (and lungs) digest nic from vapor and later it redistributes throughout a body, but during vaping it concentration will be always higher in the mouth, so - more adverse effect on blood vessels.