State law addresses dental screening.
GUIDELINES FOR THE SCHOOL DENTAL HEALTH PROGRAM FOR PENNSYLVANIA’S SCHOOL AGE CHILDREN AND ADOLESCENTS
"All children of school age in the Commonwealth, upon original entry into school, third grade and in seventh grade to be given a dental examination by a school dentist"
Pennsylvania Unconsolidated Statutes Article XIV Section 1403. Dental Examinations and Dental Hygiene Services.
(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
The Pennsylvania Code § 23.3. Dental examinations.
(a) Dental examinations shall be required on original entry into school and in grades three and seven. In instances where there are kindergartens in some schools of a district and not in others, the board or joint board may decide whether medical and dental examinations shall begin in the first grade or in the kindergarten.