 Intervention and duration All families will receive comprehensive reinforcement of the oral health message by their dental hygienists prior to baseline. The focus will be on daily supervised brushing with fluoride toothpaste. At the baseline examination, plaque index, bleeding after brushing and caries are scored on special forms for optical reading. Data on ongoing medication etc will be extracted from the dental records. In addition, a caries risk assessment is carried out with the aid of a computerized program Cariogram according to Stecksén-Blicks et al. 2007 8. The parents of the children in the test-group group A will be instructed to give their children one EvoraKids tablet once daily, ideally after brushing, for a period of 12 months. The parents of the children in the control-group group B will receive the same instructions for the intake of tablets without live probiotic bacteria. The group assignment will be unknown both for the parents and the investigators and disclosed only after the statistical calculations. The allocation concealment is kept by the manufacturer. All parents are encouraged to maintain all their habitual oral hygiene routines and use fluoride toothpaste throughout the study period. 