215 ILCS 5/356q
On or after the effective date of this Section, every insurer which delivers or issues for delivery in this State a group accident and health policy providing coverage for hospital, medical, or surgical treatment on an expense-incurred basis shall offer, for an additional premium and subject to the insurer's standard of insurability, optional coverage for the reasonable and necessary medical treatment of temporomandibular joint disorder and craniomandibular disorder. The group policyholder shall accept or reject the coverage in writing on the application or an amendment thereto for the master group policy. Benefits may be subject to the same pre-existing conditions, limitations, deductibles, co-payments and co-insurance that generally apply to any other sickness. The maximum lifetime benefits for temporomandibular joint disorder and craniomandibular treatment shall be no less than $2,500. Nothing herein shall prevent an insurer from including such coverage for temporomandibular joint disorder and craniomandibular disorder as part of a policy's basic coverage, in lieu of offering optional coverage.
215 ILCS 5/356q