When to Worry About Baby's Teeth Not Coming Through
You should be concerned if no teeth have erupted by 13 months of chronological age in full-term infants, or by 13 months corrected age in preterm infants, and arrange for dental evaluation.
Normal Tooth Eruption Timeline
The first primary tooth typically erupts around 6-8 months of chronological age in full-term infants. However, there is considerable normal variation, and eruption can occur anywhere from 4-12 months without being pathological. The key threshold for concern is when no teeth have appeared by approximately 13 months.
Special Considerations for Preterm Infants
Preterm infants require adjusted expectations:
- Use corrected age, not chronological age when assessing preterm infants 1, 2, 3, 4
- Preterm infants show a mean delay of approximately 2.7 months by chronological age, but only 1.4 months by corrected age 4
- When corrected for prematurity, the eruption timing largely normalizes 4
- More premature infants (lower gestational age, lower birth weight) may actually show earlier corrected-age eruption due to compensatory catch-up growth 1
Clinical Pearl: Always calculate corrected age for preterm infants (chronological age minus weeks born before 37 weeks gestation) when evaluating tooth eruption timing.
Risk Factors for Delayed Eruption
Be more vigilant about delayed eruption in infants with:
- Prematurity (especially <37 weeks gestational age) 1, 2, 3, 5
- Low birth weight 1, 5
- Intrauterine growth restriction (IUGR) 5
- Small head circumference at birth 1
- NICU admission history 2, 5
- Family history of tooth agenesis or ectodermal features 6
- Poor feeding/nutrition (formula-fed vs. breastfed infants may show differences) 1
When to Refer for Evaluation
Refer to pediatric dentistry if:
- No teeth by 13 months (chronological age for term infants, corrected age for preterm)
- Significant asymmetry in eruption pattern
- Family history of genetic tooth disorders
- Associated ectodermal abnormalities (hair, skin, nails)
The AAPD recommends the first dental visit occur within 6 months of the first tooth eruption but no later than 12 months of age 7. This timing allows for early identification of eruption abnormalities and other oral health issues.
Important Caveats
Delayed eruption prevalence is relatively low (approximately 9.1% in high-risk NICU graduates) 2, so most variation falls within normal limits. However, marked delay beyond 13 months warrants investigation as it may indicate:
- Genetic tooth agenesis (which may not be radiographically evident early) 6
- Systemic conditions affecting development
- Nutritional deficiencies
- Endocrine disorders
Avoid premature concern: Parents often become anxious about eruption timing, but variation of several months is completely normal. The critical distinction is between normal developmental variation (4-12 months) and true pathological delay (>13 months with no eruption).
Practical Assessment Approach
When evaluating a baby with delayed eruption:
- Calculate corrected age if preterm (subtract weeks premature from chronological age)
- Review perinatal history: gestational age, birth weight, NICU stay, maternal complications
- Assess current growth parameters: weight, height, head circumference trends
- Examine feeding history: breastfeeding vs. formula, nutritional adequacy
- Check family history: delayed eruption, tooth agenesis, ectodermal syndromes
- Palpate gums: feel for tooth buds beneath the surface
- Refer if no eruption by 13 months or if concerning features present
The evidence shows that while preterm birth and various perinatal factors influence eruption timing 1, 2, 3, 5, most infants will erupt teeth within an acceptable timeframe when corrected age is considered. Persistent delay beyond 13 months, however, requires professional dental evaluation to rule out underlying pathology 6.