The Board of Education in any school district or independent school district may, in its discretion, establish and maintain dental clinics or courses for teaching mouth hygiene; and may provide for and furnish treatment, if requested by the parent or guardian or deemed necessary by the board of Education, of children who have defective teeth or mouth conditions, and who shall be found by such Board of Education, or persons deputized for that purpose, to be unable otherwise to procure such treatment. Any expense incurred in connection therewith shall be paid out of the maintenance building fund of said district.