The great majority of people brush their own teeth. Infants and toddlers usually have a parent to brush the teeth. Very old people usually have an orderly or nursing aide brush their teeth.
Dentist.
A guardian takes care of his/her ward.
Called "floating". Basically teeth that has worn unevenly are ground smooth.
They are called a Menagerie Man.
a tree doctor
Having your horses teeth taken care of is called having the horses teeth floated.
It is called a social worker
The person who takes care of pets would be called a veterinarian (a.k.a vet)
a stablehand
The Purser and his staff, including Stewards
A person who takes care of fish is called an "aquarist" or a "fishkeeper." They are responsible for maintaining the health and well-being of the fish in their care by ensuring they have a suitable environment, feeding them properly, and monitoring their behavior.
a dentist is a docter that takes care of your dental health. (Teeth, like if you have a cavity, that's the person you would go to and etc.)