Short answer: NO.
Details? Read on.
The smoke from a traditional analog cigarette is dry and contains toxins and, more specifically, tar, which act as agents that bond to not only the surface of your teeth but to practically everything else in your life and surroundings: walls, ceilings, car upholstery, other people, etc.
The “smoke” from an electronic cigarette, however, is merely a water vapor that disintegrates into the air within seconds. Unlike regular smoke, the water vapor is moist and doesn’t contain the toxins and tar that cling to smokers’ teeth and cause them to discolor. The e liquid is comprised of just a few ingredients, many of which are flavorants to emulate a specific flavor.
As a fun “science” project, you can try the old paper towel trick. First, blow cigarette smoke through a sheet of paper towel. Second, blow e cigarette vapor through a new paper towel. Last, observe results: the first paper towel will show some staining and the second will not. To further elaborate on this little project, you can even stick two separate sheets of paper towel in two jars, blow smoke in one and vapor in the other, and place the lid on both. Give it some time to allow the smoke and vapor to really “soak” into the towel’s fibers. Results?
There are some e liquids that come in a wide array of bright colors, including red, purple, and green. If e liquid did indeed stain teeth, then it’s safe to assume users of this type of e liquid would have colorful teeth. This, however, is not the case.
The effect of using e cigarettes has quite the opposite effect as cigarettes do, and many vapers have reported cleaner and whiter teeth.