My bridge on the upper right side is 20 years old. My dentist says it could break at any time. One of the teeth it is attached to has had root canal treatment and my dentist has filled it for now. Should I go ahead and replace it before it breaks? I am 72 years old and have several jaw teeth missing and several fillings in the remaining teeth. I have 3 teeth on the bridge and 4 single crowns. My two upper front teeth have large fillings and will eventually need crowns. I am a diabetic and have had lung cancer with a lobectomy last year to remove a tumor. Thank you.