(1) Unless the context clearly requires otherwise, in this section "dental care assistance plan" means any plan of dental insurance offered by an insurer as defined by chapter 48.01 RCW and any agreement for dental care benefits entered into or renewed after January 1, 1989, provided by a health care service contractor as defined by chapter 48.44 RCW.

(2) Each employer, public or private, that offers its employees a dental care assistance plan and each employee benefits fund that offers its members a dental care assistance plan limiting the provider of dental care to designated providers or group of providers, shall make available to and inform its employees or members of the option of enrolling in an alternative dental care assistance plan that permits the employees or members to obtain dental care services from any licensed dental care provider of their choice. The portion of the premium paid by the employer for the limiting plan shall be comparable to, but in no case greater than, the portion of the premium paid by the employer for the other plan. If employees are members of a bona fide bargaining unit covered by a labor-management collective bargaining agreement, the selection of the options required by this section may be specified in the agreement. The provisions of this section are not mandatory if the employees are covered by Taft-Hartley health care trust, except that the labor-management trustees may contract with a dental care assistance plan if a feasibility study determines it is to the advantage of the members: PROVIDED, That this section shall only apply to employers with greater than twenty-five employees under coverage.