The study will identify children at high caries risk and then advise/instruct their parents/caregivers in practicing evidence-based risk-based at home preventive measures for their infants with daily use of xylitol or fluoride toothpaste. This study plan to invite the children aged 12-15 months old with high caries risk to do the clinical trial. Every infants will be randomly allocated into two groups. Participants in the test group will be asked to use xylitol (20%) toothpaste to brush their teeth twice every day with the help of caregivers. Participants in the test control group will be asked to use fluoride (1000ppm) toothpaste to brush their teeth twice every day with the help of caregivers. The same oral health instruction and children' diet instruction will be done for every participant's caregivers.

For every dental examination, clinical chatting form for the children will be collected after filling in by examiner. Questionnaire will be collected after filling in by the caregivers. And infants' plaque and saliva will be collected to detect the S. mutans level. We plan to do the dental examination three times for one infant including the first time recruiting, one year follow-up, and two year follow-up.

The establishments of the good oral health-related habits will safeguard and have sustained benefits for the children. The study can provide evidence on the effectiveness of xylitol toothpaste and risk of high fluoride toothpaste among young children. In the long term, the findings of the study might serve as a foundation for establishing an effective oral health care promotion programme throughout Hong Kong and beyond. The framework, if shown to be effective, could help development of the oral health policies and promotion programmes to achieve better oral health among young children eventually.

Inclusion Criteria:

Infants aged 12-15 months old with high caries risk

Exclusion Criteria:

Infants who has systematical disease