Aim of the study

1. Measuring the levels of salivary cystatin S protein and salivary buffering capacity to determine their relation to early childhood caries.
2. Predection of early childhood caries by using salivary cystatin S levels with demographic, clinical and nutrition habits characteristics of the participants.

Inclusion Criteria:

• Medically free children aged 36 to 71 months with one or more decayed (noncavitated or cavitated lesions), missing, or filled teeth due to caries in any primary tooth(cases).
• Medically free children aged 36 to 71 months with no decayed, missing, or filled teeth due to caries in any primary tooth(controls).

Exclusion Criteria:

• Children receiving antibiotic therapy within three month and fluoride prophylaxis within one year.
• Parents who will refuse to participate or refuse to sign the informed consent.
• Children who will not agree or cooperate with participation.

the patients going to diagnosis clinic of Pediatric dentistry and Dental Public Health Department, Cairo University