E. Drew Moore, DDS, MS

This is a difficult situation for certain. The first thing is that your surgeon or restorative dentist should try everything to remove the broken screw. It is not easy and he or she might have to buy some special instruments, but this should be tried first and foremost. A new bridge could be placed over these implants. The implant bodies look stable, from your radiograph. A second option, but one that is much more aggressive is if the screw cannot be removed, the implant can be removed by a special reverse torque instrument. This might not work. A third and really aggressive course is to remove the implatn by trephining it out. This is a special drill that would go over the implant. However, if the bony ridge is thin, there is a risk of so much bone destruction that the area might not be able to receive a new bone graft or a new implant. I would NOT remove your canine to place an implant. The canine teeth are the ones on which we function. If a person has stable canines, it is better not to replace them with implants. So, if the broken screw cannot be removed and the implant cannot be reversed out, I think the new implant bridge with a cantilever is an okay option. But, the bite has to be very light and the new implant crowns/bridge cannot have excursive interferences. There were probably interferences in your original implant bridge, causing the wear and the forces that broke the screw. You are fortunate to still have that molar to help in the bite. Even if the screw can be removed and these implants can get a new bridge, there cannot be interferences in the new bridge. Implants cannot handle the same kind of forces that natural teeth can. 

You do have uneven gums/uneven gingival contours. That middle left incisor should be longer than the tooth to its/your left. So, it is called Crown Lengthening, which actually involves some gum and bone shortening/removal. From your pictures, the existing crowns appear poorly shaped and bulky. If you were planning on redoing the front six teeth, then crown lengthening done by a periodontist, is definitely the way to go. The resulting crowns will be at the proper heights and lengths and the gums will look right. If one of the teeth is loose, and you decided to replace with an implant, you would want to have that tooth extracted and the socket grafted with bone. This should heal for a few months. Once the graft site heals, your periodontist and general dentist will have a better idea of the bone level in which the implant will be placed. At this time, the implant can be placed and if the bone support is good, a temporary crown may be placed on the implant right away, or you can wear a temporary partial. Once the implant has had a temporary crown on it, or a permanent crown, the final gingival/gum margin of the implant tooth will be known. At this point, the other teeth can be crown lengthened. All of the gingival margins and bone can be contoured so all the final crown margins match in the correct proportions. There is a lot of waiting time involved. But, this will be a process to get everything right.

Good luck.

At this point, what your are describing sounds normal. I have had crowns placed in which it took months before the sensitivity wasn't noticeable.

The sensitivity going away that fast, sounds like normal pulp (tooth nerve) response. Nobody can predict the future. But, here are some things to consider. If it gets better, that is a good sign. 

If you are sitting and reading, or watching TV or doing anything and NOT eating or drinking, and that tooth starts bothering you or throbbing, that could be signs of a problem. That spontaneous pain could be signs of the pulp being infected and dying. Then, a root canal might be needed and I would ask your dentist or an endodontist (root canal specialist) to evaluate. 

If you see a "pimple" form in the front area of the gum, high up, that is also a sign that pulp infection has set in. If this forms, then you may notice a small amount of pus draining. Get the tooth evaluated if this happens.

Also, the bite on these crowns should not be very noticeable and they should not hit heavier than your other teeth or feel like they are hitting hard. If this is the case, the bite needs to be adjusted. Good luck.

Age is not a limiting factor if you have enough bone, and you are healthy, as these others have mentioned. But, if you have loose teeth, then you most likely have periodontitis, which is causing the bone loss that leads to loose teeth. You should see a periodontist for a comprehensive periodontal exam, before doing anything else. The periodontist can address the cause of the bone loss and treat the causes. Just like a house, the foundation, which in the mouth is the bone support and gum support, needs to be stable. Your periodontist can also extract the loose teeth, if that is the decision that you both come to. He or she can graft bone and hopefully, preserve the area for future implants. Periodontists spend an extra 3 years in a residency to learn advanced surgical and implant placement techniques, as well as the science and literature behind why we choose the materials that we use in different situations. You may also have other issues and your periodontist can guide you to great dentists with which he or she works. 

As others have mentioned, you need to see a dentist as soon as possible. You may just need a new filling and perhaps a crown. Depending upon how far the broken edge of the tooth goes, you should also consider seeing a periodontist for a crown lengthening procedure. This will allow the dentist to have more visible tooth structure for a better crown and a better margin.