Regardless if box 85 is complete on your T4, you may be able to use your employee paid premiums for private medical (EHC) benefits and/or dental benefits on your personal tax return.
From the CRA website: "Employee-paid premiums to a private health services plan are considered qualifying medical expenses and can be claimed by the employee on his or her income tax and benefit return. The figure may be completed on box 85 of your T4, and if not, the value of the deductions for EHC (Extended Health Care), and/or Dental will show on your final paystub for the year." Box 85 is not mandatory to be completed.
The extent to which you can use these amount will depend upon your personal situation.
Please reference the CRA website at this link: Paid Private health services plan premiums
