I have seen quite a few badly wired dental suites, one of my pet hates is all the loose cables under the units these often get pulled out of appliances because they get entangled on equipment.
The new regulations for the decontamination and control of hepititus means that very few dentists have dirty and clean rooms, and when they have they are never installed to spec, because the electricians have no idea about the equipment to use.
However your pictures just shows me that no electrician has been anywhere near this dentist, so looks like another DIY jobbie, or a very sadistic qualified sparkie