The primary objective of this trial is to investigate the effect of a symbiotic lozenge on dental caries in young children.

The study is a multicentre, randomized, double-blind, placebo-controlled, parallel-group study in healthy children aged 5-8 years. The objective is to investigate the effect of a symbiotic lozenge on caries increment in primary molar teeth, primary canines and erupted occlusal surfaces at the first permanent molar teeth.The study will take place in Helsingør and Fredensborg municipality.

The study consists of a baseline visit prior to a 12 months intervention period, followed by a visit after completion. During the intervention period, two to four months after the baseline visit, a saliva sample will be collected.

All guardians to the subjects are encouraged to 1) brush their children's teeth twice daily with the fluoride toothpaste provided, 2) avoid the food provided in appendix D and 3) to continue the subject's dental appointments at local Public Dental Health Service (PDHS). No further specific oral hygiene or dietary instructions/restrictions are provided.

Assuming a dropout rate of 12.5%, 175 children will be included in each treatment group.

Inclusion Criteria:

1. Healthy children with absence of severe chronic disease
2. Age 5-8 years, both inclusive, at inclusion
3. Ability to cooperate at dental examination
4. Ability to cooperate to a daily intake of a lozenge
5. Parents/legal guarding provided voluntary written informed consent

Exclusion Criteria:

1. Children with severe medical conditions
2. Mentally or physically disabled children
3. Children of parents with language barriers and not able to give written informed consent