placed on the tooth. An untreated cavity and dead or dying nerve could also lead to an infection of the jaw or sinuses, which in turn could lead to draining infections and even to infection of the brain. Death could follow if no treatment is available.
Very small lesions found in middle aged persons sometimes may be left alone if the person has good dental hygiene otherwise. This is a matter for you to bring to the attention of your dentist and ask for his/her opinion. Every person is different, so you need the opinion of the dentist after he/she makes a diagnosis.
So to answer your question – you don’t have to get them filled – you can ignore the bad breathe the bacteria causes and wait until the decay hits the nerve and causes pain or until the tooth breaks off. Hopefully, the bacteria in your mouth, that all your food and drink passes, won’t go elsewhere in your body. Hopefully, it won’t go directly into the arteries that pass through your neck and go elsewhere – but you cannot get rid of the decay on your own, you need a dentist to remove the decay and fill the remaining hole so it does not get food and more bacteria in it.
There is an old saying you only need to take care of the teeth you want to keep.