First off, don't forget you're still a DDS/DMD. You can still work as a dentist, either full or part time.
There are lots of additional options out there. In the private sector: dental chains, dental material companies, dental insurances companies, companies not directly related to dentisty; in the public sector: healthcare administrator, dental school administrator, or some combination of above.
It also might stimulate the entrepreneurial bug in you as well.