Your dentist has a good point. In most cases, a tooth with a root canal would not last more than a few decades. If you pull the 2nd molar and use braces to move the wisdom tooth, then you might have a healthy, living tooth for a lifetime. That being said, I always want to save teeth when possible. Before pulling it, you should talk to some orthodontists and make sure you can find someone that is confident about move the wisdom tooth into place. Moving molars laterally like that might take a few years.
Zygomatic implants are good options for patients that have a harder time growing bone, but are usually supporting a full denture, not just 1 or 2 teeth. Zygomatic implants transverse the sinus and are more invasive. In your case, I wonder if a bridge is an option. If not, you should find a dentist that can draw your blood and mix the blood healing factors with a graft. It may give you better results. This is called PRF or PRP grafting.
Yes, your teeth will naturally erupt in this case. You have a tremendous amount of nerves in your mouth and can feel the smallest difference, this is normal. If your chewing teeth start to hurt before the molars naturally erupt, then you should return to your dentist to have the filling adjusted.
Yes, you can get a new crown even though you recently got braces put on. The dentist will likely want to remove the wire when doing the crown. In my office, I would do a same day crown and make sure you have an appointment with the orthodontist either the same day or the next day to have the wires put back on correctly.
If at first you don't succeed, try and try again... does not apply to dentistry. Another apicoectomy would further shorten the roots and make the tooth more unstable. The first apicoectomy got you another 5/6 years out of the tooth. The second probably wouldn't get you that much time. An implant should last at least 15 years, so if you had gotten an implant instead of the first apicoectomy, you'd be doing just fine for another 10 years from now. Definitely go with the implant.
