In dentistry we rely on a number of mission critical systems. If these critical systems fail we cannot do dentistry. This includes the air compressor, the central vac and maybe even the curing light. Most dentists have an emergency plan to back up a failure in a mission critical system. You may have a small emergency compressor or have an arrangement with Henry Schein to bring you a loaner.
You need to have exactly the same type of arrangement with your IT provider. That is an emergency plan to get the office up and running within a few hours or a day at most in the unlikely event of a major computer system failure. Having a disaster recovery plan is not only good policy it is part of the updated HIPAA omnibus rule.