You may be able to. You can choose any 12 month-period that ends in the tax year to claim your receipts. So next year, depending on what expenses you have for 2020, you can claim some or all of your 2019 dental expenses. The FAQ has more information on claiming prior year medical expenses: https://turbotax.community.intuit.ca/community/family-health/help/can-i-claim-prior-year-medical-exp...

If you have TurboTax Live Assist & Review, here is how to talk to a Tax Expert: https://turbotax.community.intuit.ca/community/navigating-turbotax/help/i-m-using-turbotax-live-assi...