What happens when a tooth that already has a filling gets another cavity in a different spot? i have a molar on the lower left side of my mouth got a filling last year, and now has another cavity in a different spot. can a tooth have more than one filling

Yes : Yes it can. There are different surfaces on the tooth and sometimes you can have a cavity on one surface, and then get a cavity on a different surface at a later date. We call the surfaces buccal, lingual, mesial, distal, and occlusal. You would refer to the surfaces as outside, inside, front, back and top. Hope this info helps.

Yes : Yes you can have more than one filling in a tooth. However, the is a limit to how much of the tooth can be filled with a successful long term result. I like to use the analogy of a used tire. When tire becomes worn, you can patch, plug, or even retread; however, at some point it is best and safest to have it replaced. The dentist may recommend treatment other than adding more filling to the tooth, such as an inlay, onlay, 3/4 crown or full crown.

Teeth : Teeth often get a "patchwork" of fillings, but there comes a point where too much is too much. One factor is the size of the fillings, as pin hole sized fillings don't weaken the tooth as much as fillings that take up half of the tooth. As more and more tooth structure is lost, a crown should be considered.

Yes you can have: more than 1 cavity in a tooth.