I don't know what kind of study you're doing, and I'm not clicking the link to find out about a few subjective or bias questions which will likely lead to zero conclusions (other than "vaping is bad", which is the go-to for the medical/dental community).
As a former researcher, I can tell you the only honest study you can do, will take at least 500 test subjects and 10-20 years to conduct properly. You'll need 100 each of non-smokers/non-vapers for control group...100 each current smokers, former smokers who don't vape or use any other nicotine diversion, former smokers who vape, and non-smokers who vape. You'll have to also eliminate/mitigate environmental factors, excessive drinkers, caffeine addicts, and those who consume sugar (drinks/candy), or any other known oral-health damage causing factors.
I'd wish you luck on your endeavor, but we both know you're probably not going to be investigating this thoroughly (long-term) or seriously... because next semester you'll have a new pet-project to complete for your indoctrination officials (a.k.a professors)... rather than learning real dentistry....
Sorry for the cynicism, but I've been around long enough in the medical field to know smoke-and-mirrors faux-research attempts when I see it....