Veterinarians clean and extract teeth, but to keep pet's teeth in their best shape you can brush their teeth. I would recommend a soft toothbrush and rub the outside surface of all the teeth daily. Then as the pet is accustomed to having it's teeth brushed add toothpaste specially made for pets. DO NOT USE HUMAN TOOTHPASTE Obviously some animals are not going to tollerate brushing. They may do ok on oral treats, chews, or washes etc.
The combination of saliva, bacteria and food deposits on the teeth are the leading cause to a buildup of plaque. Plaque has billions of bacteria that cause the gums to become inflammed, later the tooth ligament loosens and teeth may fall out. The end results are bad breath, pain, gum diseaes and eventually loose and lost teeth.
We should intervene with teeth cleaning and brushing at home.
When brushing is not enough the plaque has to be remove manually with scrapers and cleaning. Your pet will object to this cleaning, therefore we must place them under a safe anesthesia and this allows us to examine, clean and polish their teeth. We can perform radiographs of the teeth roots exposing disease not seen on the surface. Teeth can be saved with root canals and caps the same as humans, however we would need refer this to a specialist.