Early childhood caries (ECC) is the most common chronic non-communicable disease in preschool children, and is defined as the presence of one or more carious (uncavitated or cavited) lesions, the absence of one or more teeth (due to caries) or the presence of fillings. any deciduous tooth in a child 72 months of age or younger. Early childhood caries is a disease that is directly dependent on diet. Early childhood caries research is increasingly focused on establishing a link between general and oral health, as well as a local and systemic response to this disease. Antioxidants present in the human body include compounds that act to reduce oxidative stress and the action of free radicals on the human body. It is thought that saliva, through salivary antioxidants, may be the first line of defense against oxidative stress. Salivary antioxidants are a group of enzymes consisting of salivary peroxidase, salivary uric acid, and several smaller enzymes. The combined activity of these enzymes in reducing oxidative stress is often referred to in the literature as Total Antioxidant Capacity (TAC) of saliva. The connection between early childhood caries, rampant caries and increased total antioxidant capacity of saliva has already been described in the literature. Also, the total antioxidant capacity of saliva has been shown to have a linear relationship with age, while no significant dependence has been shown with sex. TAC and Feric Reduction Power (FRAP) have also been studied in patients with periodontitis. Lower TAC and FRAP values in unstimulated and stimulated saliva were confirmed, however, TAC and FRAP concentrations could not be related to the degree and stage of periodontal disease.

Leptin and adiponectin are considered key biomarkers of metabolic dysregulation and comorbidity in both children and adults. Leptin is a polypeptide hormone of 167 amino acids derived from adipocytes, which has been shown to reduce nutrient intake and increase energy expenditure. Its serum concentration is positively associated with total body fat in adults and children. Leptin is a hormone that regulates food intake and energy distribution. It is a protein secreted primarily by fat cells. The salivary glands produce, store and secrete leptin and its level increases with the flow of saliva. A link between leptin levels and tooth loosening during orthodontic treatment has also been found. On the other hand, patients with advanced periodontal disease had lower levels of this hormone. Its role in other diseases of the oral cavity has not been fully investigated. Adiponectin is an adipocyte-derived hormone that regulates glucose and lipid metabolism, improves fatty acid oxidation and insulin sensitivity, and inhibits glucose production in the liver. In addition, adiponectin has strong anti-inflammatory properties. In addition to its previously mentioned local effects, adiponectin in breast milk is involved in the regulation of energy balance regulation and may play a role in the regulation of growth and development in the neonatal period and childhood. Adiponectin is also locally produced in the oral cavity, salivary glands and its level is significantly correlated with plasma levels and as such salivary adiponectin has been used as an alternative to blood tests to measure adiponectin levels.