Some credit cards have promotions that give a low rate of interest for purchases over the first few (12?) months. This would be your best option but only if you can resist the temptations to take fuller advantage of the pomotion by going on a shopping spree. Use the credit card comparison tool to look for credit cards with "0% purchase" promotions. It will take at least a week between applying and receiving the credit card.
Some dental surgeries also offer finance deals that are worth comparing with other options.