The aim of the randomized, double-blind clinical trial with placebo is to answer the clinical question , or in children with diagnosed childhood early caries the use of L.salivarius and cranberry contained in NutroPharma lozenges will reduce new carious lesions and reduce the titre of the carcinogenic bacteria Streptococcus mutans, compared to the control group in which the placebo will be administered? The main end point will be to reduce the titre of cariogenic bacteria.

Probiotic bacteria are used in the prevention and treatment of gastrointestinal diseases and infections, including the treatment of oral diseases. Probiotic bacteria can be found in saliva, plaque and adhering directly to the mucous membrane. They compete with cariogenic bacteria and pathogens of periodontal disease. Increased interest in probiotics means that attempts are being made to find new solutions regarding the methods of their administration. The use of probiotic bacteria brings beneficial health effects. Lactobacillus salivarius is a strain isolated from human milk. It is inactive (heat treatment) and therefore does not produce metabolites that can promote the formation of carious lesions in the mouth by lowering the mouth potential of hydrogen.

Inclusion Criteria:

• generally healthy children aged 3-6;
• recognized caries of early childhood, dmf> 1,
• lack of active caries and inflammation of the mouth
• colony forming unit 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,
• colony forming unit 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.