The efficiency of various protective treatments of teeth were studied in 50 patients divided into 4 groups: 1) (15 patients) 30 teeth with viable pulp were coated with fluorine varnish; 2) (15 patients) 30 teeth were examined after wearing temporary polypropylene crowns fixed on aqueous dentin; 3) (10 subjects) 30 teeth were examined after removal of permanent dentures and treatment of the enamel with fluorine-containing varnish; and 4) (10 subjects) after removal of permanent dentures the enamel was treated with calcium-containing gel using gingivodental kappa according to the proposed method. The status of dental hard tissues was evaluated using acid biopsy of the enamel (Leontyev and Distel's method in our modification) and analysis of the oral fluid. The efficiency of different methods of dental hard tissue protection from acid medium was evaluated. Positive results were obtained with pathogenetically justified new remineralizing procedure.