I can think of one complication from vaping. It's that it dries out your mouth.
Which will mean more bacteria build up and possibly more staining etc. depending on what you eat and drink.
Chewing gum would probably solve this. It's the only way I can keep my mouth not dry.
Drink lots of water as this will also help keep you from becoming dehydrated. I have always drank the amount your suppose to drink but have found that I need to drink more than before. There is a thread on this,here in the forum too. Happy vaping!!