TY JOUR TI PERIAPICAL ABSCESS WITH FISTULA COMPLICATED BY MAXILLARY SINUSITIS (CLINICAL CASE) KW endodontics KW maxillary sinusitis KW periapical abscess KW apical dissection KW apical diameter JO Actual problems in dentistry AU Griroriev, S.S. AU Sorokoumova, D.V. AU Kudinov, P.N. PY 2022 IS 17 PB TIRAZH Publishing House