Many people only go to the dentist when they have dentalgia,which is a:

A) cavity.
B) broken tooth.
C) toothache.
D) loose tooth.

Dentalgia is another term for toothache, which is a common symptom of various dental issues. While a cavity or broken tooth can also cause dental pain, the term dentalgia specifically refers to the sensation of a toothache. A loose tooth may sometimes cause discomfort but is not necessarily a toothache or dentalgia. Therefore, choice C is the most accurate answer.