Not sure if we have the full information here. How do you know the teeth are dead? Has this been diagnosed by your dentist and/or endodontist? Are the teeth starting to discolor? Did you have an accident that effected that area? It is odd that both of those teeth should just 'die' on their own. Before you seek any treatment, make sure you understand what happened / is happening and why.
If both teeth are truly dead, you can wait for a problem to happen to do something about them. Unfortunately, no one has a crystal ball that can tell them when that may be AND, according to Murphy's Law, the problems will happen when you least want it to (just before a vacation, holiday, wedding, family illness, etc.) You are in control of the problem now, so I recommend you do something about before it controls you.
Root canal treatment is usually the treatment of choice for a dead tooth. Whether you follow that up with a crown or a filling will depend on the philosophy of your treating dentist and on other factors... is the tooth discolored, how heavy is your bite in that area, what is going on with the other teeth, what are your aesthetic preferences, etc.)
Hope this helps.