dentisto

A clean build, and one of the easiest in the language to justify: dento is a tooth, -ist- is the professional suffix, so dentisto is a teeth professional. The coincidence that English arrived at the same string by a different route through French dentiste is a bonus, not the reason. The suffix is doing real work here, and you can watch it work across the whole profession list: instruisto, kuracisto, ĵurnalisto, pentristo, artisto, maristo. The article on the people-making affixes sets out the family.

Note what -ist- actually claims. It marks someone defined by an occupation or a committed adherence, not merely someone who does the thing once. A person with a mouthful of teeth is not a dentisto. And Esperanto uses the same suffix for adherents of a doctrine, so komunisto and esperantisto are formed identically to dentisto. That double duty occasionally raises eyebrows and is entirely regular.

Beside it, kuracisto is a doctor, from kuraci, to treat medically, and it is a verb root taking -ist- where dentisto is a noun root taking -ist-. Both are allowed. Dentkuracisto also exists and is the more precise word for a dental surgeon, though dentisto is what anyone says out loud.