A 29-year-old female patient complains of gingival hemorrhage and lower front teeth mobility she has been experiencing for the last 6 months. Objectively: the mucous membrane in the region of the front lower teeth is hyperemized, edematic, bleeds when touched. From under the gingival mucosa foul-smelling pus is discharged, tooth roots are exposed. The patient has been diagnosed with the III stage of parodonti-tis. What factor allowed to establish the stage of disease progress?