A 50-year-old patient comlains of difficult mastication, tooth mobility, halitosis, gingival hemorrhage. Objectively: gums are hyperemic, cyanotic, there is also dental scale. Parodontal pockets of upper molar teeth were 8 mm, of the rest teeth - 6 mm. X-ray picture showed resorption of bone tissue by 2/3-1/2 of root length. What is the most probable diagnosis?