(a) All children of school age, in the Commonwealth, (i) upon original entry into the school, (ii) while in the third grade, and (iii) while in the seventh grade, shall be given a dental examination by a school dentist: Provided, however, That this requirement shall not apply to those school districts or joint school boards which have instituted a program of dental hygiene services as provided in subsection (b) of this section.

(b) Any school district or joint school board may institute a program of dental hygiene services for children of school age, which program shall be approved by the Secretary of Health, and for that purpose may employ dental hygienists.