Considering canon 90d to replace old rebel xsi

I use a dslr every day in my dental practice to take macro photos of teeth. My current set up is a rebel xsi with a canon 60mm macro lens and canon mr14ex ring flash. Even with an old entry level camera, the macro lens and ring flash can clearly show every crack and cavity when displayed on the flat screen in front of the patient.

Unfortunately, my camera is literally falling apart and needs to be replaced. I'm kind of locked into the ef SLR because replacing the macro lens and ring flash would be prohibitively expensive.

I'm considering the 90d as a replacement it should be a big step up from the xsi, but even an sl3 would be better. What do you guys think?