I have long advocated a dental office have a RAID 1 array. This article from PC Magazine explains the various RAID configurations and even gives directions to set up your own system if you are technically inclined.
To build a RAID 1 array, all you need is two identical drives (if they’re the same brand, model, and capacity, so much the better) and a RAID controller. Most modern PCs have RAID built into the motherboard; if yours doesn’t, you can add a PCI or PCI Express controller for about $50. With 500GB drives going for about $100 these days, there’s little reason not to add some redundancy to your data storage, not to mention some peace of mind