Black stains (BS) are type of extrinsic discoloration of the tooth. It's characterized as dark lines or an incomplete coalescence of dark dots found mostly on cervical third of the crown. Most studies worldwide found that children with the black stained teeth have low caries prevalence. A study on Brazilian population also suggested that black stains might be protective factor against development of dental caries. A study reported that chromogenic bacteria were proposed as etiological factor in production of black stains.The most common microbiological composition of BS was found to be Actinomycetes. Dental examination and saliva samples collection will be done for black stained teeth children of outpatient clinic of Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry, Cairo University. This research adopts null hypothesis; it assumes that there is no effect on dental caries experience in children with black stained teeth.

Inclusion Criteria:

• Patients with black stained teeth who were reported to outpatient clinic of Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry, Cairo University ranging in age between 4-6 years.
• With primary dentition.
• Both sexes will be included.
• Cooperative children.

Exclusion Criteria:

• Having oral disease (such as peridotites, salivary gland disorder, and oral mucosal disease).
• Having autoimmune disease.
• Receiving any antibiotic treatment in the past three months.
• Parents refuse to sign the consent

Egyptian children 4-6 years old with black stained teeth.