The purpose of this study is to determine if probiotic lozenges taken once a day before bedtime for twelve weeks can decrease the numbers of Streptococcus mutans

Streptococcus salivarius is one of the commensal bacteria of the mouth and the main component of biofilm. Research indicates that some microorganisms present in plaque, which until recently were considered not to cause caries, including Streptococcus salivarius, present in the supragingival microbiome, can also cause tooth decay.

Inclusion Criteria:

• generally healthy children aged 3-6;
• recognized caries of early childhood, dmf> 1,
• lack of active caries and inflammation of the mouth
• CFU> 105 / ml Streptococcus mutans
• a minimum of one-month period from: the last antibiotic therapy, probiotic use, professional fluoride prophylaxis or supervised tooth brushing with fluoride preparations, the use of fluoride toothpaste, not using xylitol, written consent of parents / legal guardians for participation in research.

Exclusion Criteria:

chronic diseases and chronically taken medicines in the past,

• planned change of residence during the year,
• age below 3 and above 6 years,
• healthy teeth, dmf = 0,
• CFU <105 / ml Streptococcus mutans
• Patient during antibiotic therapy, probiotic use, professional fluoride prophylaxis or supervised tooth brushing with fluoride preparations
• no toothpaste with fluoride
• using xylitol
• lack of written consent of parents / legal guardians for participation in research.