 Sample collection Samples of buccal epithelial cells were collected from each participant using the swab technique immediately prior to the use of tested toothpaste and 30, 60, 90 and 120 days after the beginning of the research T0 - control prior to the use of tested toothpaste, T1- 30 days after the beginning of the use of non-fluoride toothpaste, T2 - 60 days after the beginning of the use of non-fluoride toothpaste, T3 - 90 days after the beginning of the study, using fluoride toothpaste for 30 days, T4 - 120 days after the beginning of the study, using fluoride toothpaste for 60 days. 