Saliva doesn't produce the acid that causes cavities, bacteria that feed on the food in your mouth do.
Look, go see a dentist or don't; but suggesting that dental care is unnecessary is reckless.
Saliva doesn't produce acid directly, but it combines with other things to contribute to the environment that produces the acid. I couldn't find the exact study, but a fair few studies founds links between genes, saliva, bacteria and cavity rates.
Look, I didn't suggest dental care is unnecessary. Quite the opposite: brush your teeth folks, and if you're lucky like many other people, you won't have to go to the dentist and won't suffer debilitating consequences. Treat it like a finger: look after it, clean it, don't hurt it, but you don't need to waste time and money on a yearly checkup of it (unless you've got a good reason to).