Yes, it might. Depending on the kind of work your dentist does and how s/he does it, if the shape of the new tooth or teeth is different from your retainer, it could adversely affect your retainer fit. Be sure to let your dentist know that you wear a retainer and bring it to your appointment. That way your dentist can make sure to test the retainer on your new dental work, and make any adjustments to your dental work, if necessary.