Yes....it
could have fractured, but do have them take an x-ray (the crack may or may not show up) and do some better diagnostic testing. I know quite a few patients who had put off doing a crown, and then ended up losing the tooth altogether. It is a huge bummer.
I'm assuming this is an upper tooth, being you're talking about sinus problems too---that is pretty common. The upper molar roots are really close to the sinus floor--so alot of times those teeth/sinus problems go hand in hand! And, if you have an infection with the tooth/root due to a fracture, the bacteria is constantly 'wicking' itself down the crack & into the sinus--thus the sinus plugginess = (
I guess if I were you, I'd make an app't w/ a dentist---not the school---even though you do get a great deal on the work, but sometimes you just need an answer FAST! (and the schools have to have their docs check off on each & every step...makes for a long frustrating time, sometimes!)
Hang in there.....keep me posted, K???
If your gecko is broken, you have a reptile dysfunction.