Planning is very imperative for cases like this. Your dentist and orthodontist should work as a team during the course of your treatment. Smile analysis is important so your dentist can tell the orthodontist how much space he/she will need for your crown in order to make your smile proportional. Best of luck!
It is hard to answer without evaluating you both clinically and radiographically. If it is an active cavity, and depending on its size, some sort of intervention should take place. Sometimes very small cavities can be remineralized other times they need to be removed and replaced with a filling. There are a number of variables to take into consideration and your best bet is to consult with your dentist regarding your specific circumstances. Best of luck!
