EFFECTS OF THE STATE OF THE ORAL CAVITY AND LIFESTYLE ON CHANGES IN THE PH OF THE MOUTH FLUID UNDER THE EFFECTS OF ACID IRRITANTS AND THE TIME OF SUBSEQUENT RESTORATION TO THE ORIGINAL VALUES OF ACIDITY Article Boykov D.V., Radzhepova K.B. Эколого-физиологические проблемы адаптации. Российский университет дружбы народов (РУДН). 2019. P. 46-49