Should I replace my 30-year-old bridge with dental implant ?

If the bridge is in good shape with no decay there is no reason to replace it.  The research equates bridges and implant over time.  If there was no bridge you could chose either restoration and would have made a good choice.  Implants are not 100% successful.  Bone loss is minimal after 30 years and bone grafting is becoming better every year.  

From what you are describing, it would be a good idea to plan out replacing that bridge with dental implants. This would be a great idea to help take the forces off of the teeth anchoring the bridge.  This should help with the longevity of those teeth.  Find an experienced cosmetic dentist and surgeon to consult with. Good luck.   

Bone loss will continue overtime due to atrophy. If the bone is not stimulated it will continue to shrink along with the gums and more gap between bridge and gums. Depending on surrounding anatomical areas, you might be able to bone graft at the same time of the implant surgery. Other times you need to graft first and then return and place the implant 2-3 months later. Replacing the missing tooth with an implant will also prolong the life of the anchor teeth by distributing masticatory forces. You'll be very happy you did it. Dental Implants are the best treatment to replace missing teeth. If done properly they can last a lifetime.

If you have been wearing a bridge for 30 years, there is definitely bone loss in the area, which will continue as you get older. What I suggest is to look into dental implants sooner than later, because if the bridge does start to fail or becomes painful, your best option would be to get implants. Better to get them now and improve your quality of life. Look into getting a 3-tooth implant-supported bridge, which will look, feel and function as close to natural teeth as possible. You will need bone grafting before the implants are placed. Once the bone heals, then two implants will be placed and a 3-tooth crown bridge will attach. The implants will fuse to the bone and actually promote bone growth.

If you've had the bridge in place for 30 years, the bone loss has already taken place.  While it can continue over time, it more than likely will not change more at this point.  Because you can feel the defect or missing bone with your finger, a bone graft is probably needed to make the implant successful.  I usually tell patients to leave well enough alone and wait to make the decision until the bridge needs to be replaced.  If the bridge is in excellent condition, do not replace it until necessary.