Baby teeth, more accurately called primary teeth or deciduous teeth, are a person’s first set of teeth. They begin to form during the first trimester of pregnancy (first 12 weeks) and begin to emerge (erupt) through an infant's gums around 6 months of age. All twenty primary teeth are typically fully erupted by the time a child is 3 years old and are later replaced by 32 permanent teeth.

Primary teeth have several functions. They help with biting and chewing, which contributes to good nutrition, and are crucial to a child’s ability to speak. They serve as a guide for permanent teeth to erupt and grow while maintaining the space. They also make a child look more attractive by supporting the shape of the face.

Proper dental hygiene is important for primary teeth, even though they eventually will be replaced by permanent teeth. Poor maintenance of baby teeth can cause them to fall out early, which in turn can cause permanent teeth to erupt prematurely and not in correct position.

If teeth are discolored when they erupt, it might indicate an underlying medical problem. Like permanent teeth, primary teeth are also vulnerable to plaque, a clear film that sticks to teeth and attracts bacteria and sugar. This can lead to cavities. Primary teeth are vulnerable to various injuries that can cause them to chip, fracture or completely come loose.