You may try calling around and asking dentists/endodontists if they discount services for cash/self pay. When I didn’t have insurance my dentist charged me the insurance reimbursement rate which is like half of the price they normally charge.

Someone else recommended care credit, which is also a good option. If you can’t pay it off before the zero interest period expires, make sure you have a plan to do a balance transfer to another card bc the default rates are high and the interest from the whole promotional period will hit retroactively if you don’t pay it!