In addition to practices authorized in Section 1925, a registered dental hygienist in alternative practice may perform the duties authorized pursuant to subdivision (a) of Section 1907, subdivision (a) of Section 1908, and subdivisions (a) and (b) of Section 1910 in the following settings:

shortage areas, as certified by the Department of Health Care Access and Information in accordance with existing office guidelines. If the dental health professional shortage area certification is removed, a registered dental hygienist in alternative practice with an existing practice in the area may continue to provide dental hygiene services, and shall annually provide patients treated at an existing practice with a list of dentists in the previous dental health professional shortage area who may be able to see the patient for comprehensive services.