If your wisdom teeth decay you have few options: remove them, or restore them if they are in a fully functional occlusion ( bite also called bite).
Your dentist will recommend whatever is best for you.
Hope this helps.
Sorry to hear about your wisdom tooth. The options for wisdom teeth that have decay in them are pretty much the same as the options for any other tooth with decay (extraction, filling, crown). It is our opinion on which one of these options is best and that opinion is based on the circumstances. If you have a nice straight wisdom tooth not causing any problems, or a wisdom tooth that has its roots near a nerve that we want to avoid; then we might consider doing a simple filling (possibly a crown if decay is large enough, I have even seen some with bridges on it). If your wisdom tooth is not straight and you don't use it to chew then we may think it is better to extract the decayed wisdom tooth so you don't have to deal with it in the future.
Best of luck to you!
William F. Scott IV, DMD