I removed white sugar/corn syrup from my diet and my teeth have rarely had issues for many years. Even when I skipped regular teeth brushing in the past.
Note: It can take several decades for the damage to accumulate, even for completely absurd diets. It is very difficult to observe results from changes to lifestyle or routine and correctly attribute them.
Most will start seeing dental issues with untreated tooth decay in the beginning or during their 30's, which equates roughly 2 decades of mistreatment. If accelerated, in your 20's after 1 decade.
Assuming you're not predisposed to other issues and that you still brush your teeth at least once a day most of the time, that's the speed of decay you should expect and the timelines you're working with. The daily, monthly or even yearly progression is miniscule, making it difficult to observe if it has been slowed or halted, especially in messy anecdotal tests.
The exception being tooth grinding, which can go faster and is easy to measure.
I want to do that too but it’s a hellish nightmare because sugar is in nearly everything sold at grocery stores, and living in a big city there are also endless temptations. I did manage to kick the habit of putting sugar in tea and coffee though, which is good because I drink those nearly everyday.
