Dental Prophylaxis commonly referred to "floating teeth", is designed to reduce the sharp edges (enamel points) from the teeth, correct small hooks, waves and transverse ridges - basically to balance the upper and lower teeth so your horse will be able to chew/eat properly (mastication), comfortably and teeth will wear evenly.

Performance Dentistry in addition to dental prophylaxis it includes removal of wolf teeth, reduction and smoothing of canine teeth,  creation of bit seats to make using a bit more comfortable and effective for the horse.

Corrective Dentistry here you are dealing with dental overgrowths that need correction.  It may be a portion of a tooth (hooks, excessive or accentuated transverse ridges), the entire tooth (protruding, step or ramp), several teeth (wave) or an entire arcade (row of teeth). Also correcting the molar and incisor table heights and angles for proper occlusion (surface to surface contact of opposing teeth).

Oral Dental Surgery, Orthodontics and Endodontics

definitions By Jack Easley, DVM, MS, Diplomat ABVP (Equine), Equine Veterinary Practice