How Baby And Adult Teeth Develop

By April Toyer, DDS, FAAPD

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How Baby And Adult Teeth Develop

Watching your child’s teeth grow and change is an exciting part of development, but many parents wonder what to expect and when. Understanding how teeth develop from infancy through the teenage years can help you encourage healthy habits and recognize when a dental evaluation may be needed.

Understanding Tooth Development

Teeth begin developing before birth. The foundations of both primary and permanent teeth form beneath the gums during pregnancy. Baby teeth, also called primary or deciduous teeth, help children chew, develop speech, maintain space for permanent teeth, and support healthy jaw development.

Birth To Age 3: Baby Teeth Arrive

Most babies get their first tooth around six months, although timing varies. Lower central incisors typically appear around 6–10 months, followed by upper central incisors around 8–12 months. Lateral incisors usually emerge between 9–16 months, first molars around 13–19 months, canines around 16–23 months, and second molars around 23–33 months.

By age three, most children have all 20 primary teeth. Although these teeth eventually fall out, keeping them healthy is important for comfort, nutrition, and developing permanent teeth.

Ages 4 To 6: Building Healthy Habits

During the preschool years, parents should reinforce good oral hygiene. Children should brush twice daily with fluoride toothpaste, floss when teeth begin touching, limit sugary foods and drinks, visit the dentist regularly, and wear mouthguards during appropriate sports.

Ages 6 To 12: Permanent Teeth Emerge

Around age six, baby teeth begin falling out and permanent teeth start emerging. During this “mixed dentition” stage, children have both primary and permanent teeth.

First permanent molars and lower central incisors generally erupt around ages 6–7. Upper central incisors and lower lateral incisors follow around ages 7–8, with upper lateral incisors around ages 8–9. Canines and premolars typically appear between ages 9–12, with additional permanent teeth continuing to erupt through approximately age 13.

Loose teeth, temporary gaps, and changes in alignment are common during this transition. Regular dental visits help monitor development and identify potential concerns.

Ages 13 To 17: The Teenage Years

By the early teenage years, most adolescents have 28 permanent teeth. Consistent brushing, flossing, healthy food choices, and routine dental care remain essential because these teeth are intended to last a lifetime.

Wisdom teeth typically develop during the teenage years and may erupt during the late teens or early twenties. Dental examinations and X-rays can monitor their position and development.

Supporting Healthy Smiles

Every stage of tooth development matters. Understanding these milestones helps parents support good oral hygiene from the first baby tooth through the arrival of permanent teeth, laying the foundation for a lifetime of healthy, confident smiles.