Early childhood caries (ECC) has been used to be defined as the presence of one or more decayed, missing, or filled primary teeth in children aged 71 months (5 years) or younger, but has recently been redefined at the 'Bangkok Declaration' by a group of international experts as the presence of a primary tooth with one or more carious (non-cavitated or cavitated lesions), missing (due to caries), or filled surfaces in a child under the age of six years.

The consequences of ECC include negative impacts on growth, development, nutritional problems, and oral health–related quality of life issues, from the child and his or her family.

Children with dental caries experience poor school performance and poor school attendance. Also, ECC poses significant social and economic consequences for the family.

Children who suffer from tooth decay at a very young age are at a higher risk of experiencing further decay in both their baby and adult teeth. The link between breastfeeding and early childhood caries (ECC) is complicated and influenced by various factors. These include biological elements like the presence of mutans streptococci bacteria, enamel weaknesses, and sugar consumption, as well as social factors like the parents' level of education and family's economic status, all of which can impact a child's dental health.

Unlike many infectious diseases, tooth decay doesn't heal on its own and always requires professional dental care to treat the infection and restore the tooth's functionality.

ECC typically starts as white-spot lesions near the gum line on upper primary incisors and can worsen, potentially destroying the entire crown. Key risk factors for ECC include microbial elements, dietary habits, and environmental conditions. Despite being largely preventable, ECC is still one of the most common diseases in children. Its prevalence is often linked to inappropriate feeding practices, socioeconomic factors, parental education levels, and limited access to dental care. Oral health is crucial for children, not only for eating and speech development but also for fostering positive self-esteem.