Mucus in maxillary sinus - is this normal? (photos)

Good question. About 15-20% of patients with no history of sinus disease will have these type of changes on CT.  They are even more likely during or shortly after a viral upper respiratory illness.  The bone around the teeth looks good so it's highly unlikely to be related to the them.  Assuming you don't have a history of chronic or recurrent maxillary sinusitis I wouldn't be concerned. Hope that helps.