DWP.  17 y.o ASA 1 male presented with pain to percussion #15.  Tooth #15 was +++ percussion 14 13 ok.  Tooth #15 was +++ cold.  Relatively shallow occlusal restoration was completed 9 moths ago but given the young age of the pt the restoration was found to be proximal to the pulpal ceiling allowing for an avenue of bacterial infection. CBCT revealed occluded sinus and pt reported he was dealing with a “bad cold” recently.  Pt exhibited severe post nasal drip.  CBCT reveals root tips of #15 are proximal to the sinus floor.  DX irreversible pulpitis with symptomatic apical periodontitis.  Maxillary sinusitis is present but it is unclear if it is related to endodontic origin.  The question is can the inflammation from a vital symptomatic  pulp be capable of inducing a sinusitis?  I think the answer to this question may be “yes”  but this is a controversial topic.  PS Vital hyperemic pulp encountered during treatment.  Note:  No contralateral CBCT taken.