All dental procedures are performed under general anesthesia. Not all types of problems are readily visible in an awake patient. The teeth are cleaned by ultrasonic scaling, the gingiva and roots are probed to check for attachment loss, pockets, fractures, and root exposure. If there is significant disease present and the tooth can not be saved, then extraction will be recommended. It is very difficult and time consuming to remove a healthy tooth, therefore, we only remove the ones that are causing, or will cause a significant problem. It is not the number of teeth that determine the quality of life for a pet, it's whether there is underlying disease or oral pain.
Common procedures include: Dental scaling and polishing, dental extractions, oral mass removals.
This is an informative article regarding veterinary dentistry: http://vetharmony.org/2016/01/19/how-to-beat-your-pets-dental-disease-without-getting-ripped-off/