Permanent teeth begin forming under the gums long before they appear, with the first ones breaking through around age 5 or 6 and the last (excluding wisdom teeth) arriving by age 12 or 13. The full process, from the earliest eruptions to the final root closure of wisdom teeth, can stretch into your mid-20s. Here’s a detailed look at when each tooth arrives and what influences the timeline.
The First Permanent Teeth: Ages 5 to 7
The lower central incisors and the first molars are typically the earliest permanent teeth to erupt. Lower central incisors come in around age 6, while the first permanent molars, often called “six-year molars,” appear behind the last baby teeth at roughly the same time. These molars don’t replace any baby tooth. They simply emerge at the back of the jaw, which is why parents sometimes miss them entirely.
The first permanent molars play an outsized role in shaping the dental arch. They act as anchors that help guide the rest of the permanent teeth into position. If a child loses a baby molar too early, the first permanent molar can drift forward, creating crowding, rotation, or impaction of later teeth. Dentists sometimes place space maintainers to prevent that shift.
The Full Eruption Timeline
After those first arrivals, permanent teeth follow a fairly predictable sequence over the next several years:
- Lower central incisors: 6 to 7 years
- First molars (upper and lower): 6 to 7 years
- Upper central incisors: 7 to 8 years
- Lower lateral incisors: 7 to 8 years
- Upper lateral incisors: 8 to 9 years
- Canines (upper and lower): 9 to 10 years
- Premolars (lower): 9 to 10 years
- Premolars (upper): 10 to 12 years
- Second molars (upper and lower): 11 to 13 years
- Third molars (wisdom teeth): 17 to 25 years
Lower teeth tend to erupt slightly before their upper counterparts. For example, the lower first molar comes in at a mean age of about 5.7 years, while the upper first molar follows around 6.2 to 6.3 years. The same pattern holds for incisors and canines.
Girls Typically Run Ahead of Boys
Girls tend to get their permanent teeth earlier than boys, a gap that shows up across populations worldwide. The difference varies by tooth but generally falls between 4 and 6 months. Researchers attribute this to the earlier physical maturation girls experience overall.
The gap is most noticeable during two windows. In the first phase of mixed dentition (roughly ages 6 to 8), girls are significantly ahead on lateral incisors. By the second phase (ages 9 to 11), the difference widens to include canines, premolars, and second molars, particularly in the lower jaw. There’s also a difference in sequence: in girls, upper canines typically erupt before upper premolars, whereas in boys the premolars tend to come first.
Wisdom Teeth: A Much Longer Process
Wisdom teeth follow a timeline all their own. The bony crypt where each tooth will form can appear on dental X-rays as early as age 6 or 7. Initial mineralization of the tooth itself begins around age 8 or 9 on average, though it starts a bit sooner in the upper jaw than the lower.
From there, development is slow. The crown finishes forming around age 14 to 15. Root growth continues through the late teens, and the roots don’t fully close at the tip until about age 22 on average. The youngest age at which fully complete roots have been observed is 17, and 75% of people with completed roots are younger than 23. Males tend to reach each developmental stage slightly earlier than females for wisdom teeth, which is the opposite of the pattern seen with the rest of the permanent teeth.
Of course, many people never see their wisdom teeth fully erupt. Impaction, lack of space, or unusual angulation can prevent them from coming in at all.
What Influences the Timing
Genetics is the single biggest factor in when permanent teeth show up. Research has identified at least four specific genetic regions associated with the timing of permanent tooth eruption. The interplay of regulatory genes triggers a cascade of signaling molecules that control how fast bone remodels and how quickly a tooth moves through it.
Beyond genetics, several other factors play a role:
- Nutrition: Chronic malnutrition extending past early childhood correlates with delayed eruption, typically by one to four months per tooth. Children from higher socioeconomic backgrounds, who generally have better nutrition and healthcare access, tend to develop teeth earlier.
- Hormones: Growth hormone influences the tissues surrounding the tooth root, and various signaling proteins in the body help regulate the pace of eruption.
- Ethnicity and geography: Populations differ in average eruption timing, likely reflecting a mix of genetic, hormonal, and nutritional differences.
There’s also evidence that children whose first baby tooth came in early tend to get their permanent teeth earlier as well, suggesting that a child’s overall “dental clock” is set from infancy.
When Eruption Is Considered Delayed
A permanent tooth arriving a few months late is normal. Dentists start paying closer attention when a tooth is more than a year behind its expected window. Delays are classified by severity: less than a year late is considered mild, one to two years is moderate, and more than two years (or complete failure to erupt) is severe.
Delayed eruption can happen for straightforward reasons, like a baby tooth that hasn’t fallen out yet or crowding that blocks the path. In rarer cases, it signals a condition called primary failure of eruption, where the tooth itself lacks the biological mechanism to move through bone properly. If your child’s teeth seem significantly behind the typical timeline, a dental X-ray can show whether the permanent teeth are present and developing normally beneath the surface, or whether something is preventing them from coming in.