Maryland Code, Insurance § 14-402

(1) a dentist or professional dental corporation that accepts payment on a fee-for-service basis for providing specific dental services to individual patients for whom the services have been prediagnosed;

(2) an authorized insurer whose activities are authorized and regulated under other provisions of this article;

(3) a nonprofit health service plan that is subject to Subtitle 1 of this title;

(4) a health maintenance organization that is authorized by and subject to Title 19, Subtitle 7 of the Health-General Article; or

(5) a dental plan whose regulation by the State is preempted by federal law.