FIELD: medicine, oral surgery. SUBSTANCE: one should study mouth liquid due to atomic-absorption analysis, moreover, by signal of atomic absorption of phosphorus and calcium elements one should detect coefficient of phosphorus to calcium ratio (P/Ca) in mouth liquid corresponding to its information value before the moment of diagnostic threshold achievement being 3.4, that is at value being below 3.4 one should predict acute odontogenic phlegmon- complicated osteomyelitis, and at its value being above 3.4 - acute odontogenic abscess- complicated osteomyelitis. EFFECT: higher accuracy and efficiency of diagnostics. 4 tbl
