About 2 months ago I had a crown put on over my upper back left molar. About a week later I had some sinus inflamation and my back upper molar felt a little high and my bite felt off. I have gone back twice and my dentist says my bite is fine. The new crown's center feels like it is lower than the center of my other back teeth. My dentist screwed the crown on and then covered it with a filling material. I wear a night guard but my bite is definitely not correct. Could the crown center be too low causing my back teeth to hit first and the bite to feel awkward? Any thoughts? Thank you.