Hi woodfly,

Yes, UR means upper right. The infection in that posterior quadrant of jaw bone appears quite large and extensive. Given your description of your sinus and nasal symptoms in the UR are indicative that the bacteria has spread to the sinus. The only way to attempt the eradication of the infection is to remove the infected teeth. In that quadrant the premolar is root canaled and it is possible that the infection from that tooth spread to the adjacent teeth. So you would need vitality testing on those other teeth to determine the vitality and then proceed accordingly. An oral surgeon is the only type of dentist to see for this type of infection as a general dentist is not knowledgeable or experienced in dealing with it.