My wife is a dentist, so I have a degree by marriage
and this advice doesn't come from her. We bring antibiotics for this type of emergency (and other "just in case" medications) when cruising.
Allan, your Crazy Glue idea would work (can also be used in place of sutures if you get a slice wound) but you're really better off with "Temp Bond" which is a two-part low-hardness adhesive
with gap-filling properties, used for temporary crowns. If a crown or bridge came off it's likely because there's decay underneath and the dentist needs to get back into at the earliest opportunity. Crazy glue is too tough to break the bond.
Your best bet is to discuss your situation with your dentist who knows your mouth, age and condition of fillings/crowns and other issues. Same with a medical
kit and your doctor, beside the standard general first-aid kit for trauma and contusions. In fact if you have any known conditions/risks and cruising out of the country it might be a good idea to get your copied medical
records to take in case you need them for reference. It's helpful for diagnosis when there is a baseline historical reference.
Also if you think you've been putting off dentistry -- the occasional sensitive tooth or bad taste or looseness, take care of it BEFORE you go so you don't have an emergency. If you haven't had recent exams and cleanings take care of that too before you go -- and not last-minute.... far enough in advance so you have time to take care of anything that might be discovered in the "survey".