The modern dental practice not only relies on dental equipment, but is also driven by computers and a server.
It's a well recognized and acknowledged practice to have regular back-ups of all your software and data. There is lots of debate over cloud-based vs. physical back-ups, how many generations of back-up one might want, but much of that is subjective and opening a debate is not what we want to accomplish. What is important is that your back-up be functional and effective. The best way to make this determination is to restore your back-up on a regular basis.
The time to find out there is a problem with the data or the methods of restoring it is not after a catastrophic event, but when you have time to deal with it (i.e. under test conditions). This is why it is very important to periodically test your back-up by running a restoration. If you're concerned about over-writing good data, restore to another system. It's important not only to confirm the back-up is effective and complete, but that you know how to restore it and are comfortable doing so. The best way to accomplish this is to perform regular restorations yourself.
Setting up a duplicate system at home (for example) can be a "safe" way to restore without affecting your existing data and it provides you with an easily accessed and implemented duplicate in the event of a system failure.