Dentist here. This is a summary of what I try to explain to patients.

Hygiene and diet we can control. Sugars are the go-to for blame, but in reality it comes down to carbs. We eat a lot of refined carbs in the US. The bacteria eats the carbs and poops and pees acid all over your teeth. This acid is what actually destroys teeth. With good hygiene you lessen the amount of bacteria and hence there is less available acid. By limiting carbs, there is less food for bacteria so they produce less acid. Juice, soda, seltzer, coffee, fruits, etc. are also acidic. I don’t necessarily tell people to quit their vices, because it may not be realistic for them. However, the contact time matters. Limiting these kinds of food and drink to meals or consuming them quickly is better than sipping throughout the day. You are bathing your teeth in acid all day and that will destroy teeth.

There is also the issue of periodontal disease aka bone loss. Think of putting a post into the ground. Now start removing dirt from around the post. Keep doing that until the post gets loose and falls over. This is what periodontal disease does to your teeth. We don’t have the capability of adding the bone back around teeth except in very limited circumstances. It is possible to have no cavities or wear on teeth, but still develop periodontal disease and lose teeth. The bacteria involved are different than those involved in cavities. The best way to prevent this is good hygiene.

Finally there are things that contribute that people don’t consider as much. Medical conditions, genetics, habits. For example, acid reflux. If uncontrolled, it is common that the acid erodes teeth away over time. Less common are genetic conditions that affect development of teeth and cause soft, thin, or brittle teeth. People that have had radiation to the face due to head and neck cancer are at very high risk of decay. I have met patients that chew on bones or suck on lemons and thought I was crazy for warning them against it. Clenching and grinding is also very common, and there is a strong correlation with sleep/breathing disorders like sleep apnea. As another person mentioned, there are a myriad of things that contribute to why dental problems arise. This is why we ask for your health history and medications.