It is unlawful for any person, except a dental service plan corporation chartered in accordance with the provisions of this Act and operating in accordance with authority from the Director, to establish, maintain or operate a dental service plan, or to solicit subscribers to or enter into contracts with respect to a dental service plan. This prohibition, however, shall not be construed as preventing the organization, establishment and operation of corporations organized in accordance with the provisions of the Voluntary Health Services Plans Act nor shall it be construed as preventing a person from furnishing dental services for the prevention of disease among his employees or from furnishing such dental service as is required under the workers’ compensation laws and related legislation, when the employee is not charged for such services; nor shall it be construed to prohibit an insurance company, or other corporation or society which is subject to the supervision of the Director, from operating in accordance with the laws governing insurance companies, or such corporations or societies; nor shall it be construed to prohibit the continued operation of any dental, medical, or health service plan in existence and functioning upon the effective date of this Act.