Washington Revised Code Title 48. Insurance § 48.44.495. Dental services that are not subject to contract or provider agreement

(a) Require, directly or indirectly, that a dentist who is a participating provider provide services to an enrolled participant at a fee set by, or at a fee subject to the approval of, the health care service contractor unless the dental services are covered services, including services that would be reimbursable but for the application of contractual limitations such as benefit maximums, deductibles, coinsurance, waiting periods, or frequency limitations, under the applicable group contract or individual contract; nor

(b) Prohibit, directly or indirectly, a dentist who is a participating provider from offering or providing to an enrolled participant dental services that are not covered services on any terms or conditions acceptable to the dentist and the enrolled participant.