Children have 20 primary teeth, sometimes called baby teeth or deciduous teeth. These 20 teeth are split evenly between the upper and lower jaws: 10 on top and 10 on the bottom. That’s 12 fewer than the 32 permanent teeth that eventually replace them, because primary teeth don’t include premolars or third molars (wisdom teeth).
Types of Primary Teeth
The 20 primary teeth break down into three types, each with a specific job:
- Incisors (8 total): Four upper and four lower front teeth used for biting. These include four central incisors and four lateral incisors.
- Canines (4 total): The pointed teeth flanking the incisors, two on top and two on the bottom, designed for tearing food.
- Molars (8 total): Four first molars and four second molars, positioned toward the back of the mouth for grinding and chewing.
Each jaw is divided into a right and left quadrant, and every quadrant holds exactly five teeth: two incisors, one canine, and two molars. Dentists label primary teeth with the letters A through T, starting from the upper right second molar and looping around to the lower right second molar.
When Primary Teeth Come In
Most babies get their first tooth around 6 months of age, though the timing varies widely. According to the American Academy of Pediatric Dentistry, the lower central incisors usually appear first, between 5 and 8 months. The upper central incisors follow at roughly 6 to 10 months.
From there, teeth generally arrive in this order:
- Lateral incisors: 7 to 12 months
- First molars: 11 to 18 months
- Canines: 16 to 20 months
- Second molars: 20 to 30 months
By about age 2½ to 3, most children have their full set of 20 primary teeth. That said, plenty of healthy infants don’t follow this schedule exactly. Some babies are born with a tooth already visible, while others don’t see their first one until closer to their first birthday.
Teething Symptoms to Expect
As each tooth pushes through the gum, the area often becomes red, swollen, and tender. Drooling picks up noticeably, and babies frequently want to bite or chew on anything they can reach. Fussiness, irritability, disrupted sleep, and a temporary dip in appetite are all common. These symptoms come and go with each new tooth and eventually pass on their own.
When Primary Teeth Fall Out
Primary teeth start shedding around age 6 or 7, typically in roughly the same order they arrived. The lower central incisors are usually the first to go. The process continues gradually until about age 12, when the last primary molars give way to their permanent replacements.
This long overlap period means children spend several years with a mix of baby and adult teeth. During that transition, the primary teeth play a critical role as placeholders, keeping the right amount of space open so permanent teeth can come in aligned.
Why Primary Teeth Matter
It’s easy to dismiss baby teeth as temporary, but they serve functions that affect a child’s health well beyond the toddler years. Beyond the obvious jobs of chewing food and supporting clear speech, primary teeth guide the positioning of the 32 permanent teeth developing beneath them.
When a primary tooth is lost too early from decay, injury, or extraction, the surrounding teeth can drift into the empty gap. That shifting narrows the space available for the incoming permanent tooth, which can lead to crowding or misalignment. In many cases, premature loss of a baby tooth results in a child eventually needing braces or other orthodontic work that might not have been necessary otherwise. Dentists sometimes place a device called a space maintainer to hold the gap open until the permanent tooth is ready to emerge.
The American Academy of Pediatric Dentistry, the American Dental Association, and the American Academy of Pediatrics all recommend scheduling a child’s first dental visit during the first year of life, ideally around the time that first tooth appears. Early visits help catch decay before it leads to premature tooth loss and give parents guidance on cleaning routines suited to each stage of development.
Primary vs. Permanent Teeth at a Glance
- Primary set: 20 teeth (8 incisors, 4 canines, 8 molars)
- Permanent set: 32 teeth (8 incisors, 4 canines, 8 premolars, 12 molars including wisdom teeth)
The permanent set adds premolars (which replace the primary molars) and third molars, accounting for the jump from 20 to 32. Not everyone develops all four wisdom teeth, so some adults end up with 28 permanent teeth instead.