Knowing what to expect – and when – helps parents understand whether their baby's teething is following a typical pattern. Tooth eruption timing and order follow a broadly consistent developmental sequence, though there is enough individual variation that early or late first teeth (within normal limits) are common.
Healthbooq covers infant health and oral development in the early years.
The Primary Dentition
Every child develops 20 primary teeth (also called milk teeth, baby teeth, or deciduous teeth). These are distributed as 10 upper and 10 lower, and they begin erupting from around 6 months. The full set is usually in place by the third birthday.
The research basis for eruption timing comes from several large studies. Philip Holman and colleagues at the University of Maryland have contributed to the understanding of normal eruption variation. The sequence described below represents the typical pattern but should be interpreted alongside the understanding that individual variation is wide and normal.
Typical Eruption Order
Lower central incisors (bottom front two teeth). These are usually the first to appear, typically between 6 and 10 months. Many parents notice gum swelling in this area before the teeth break through.
Upper central incisors (top front two teeth). These follow shortly after, usually erupting between 8 and 12 months. The characteristic gap-toothed smile of an infant with just two bottom and two top front teeth is familiar to most parents.
Upper lateral incisors (the teeth either side of the top front two). These usually appear between 9 and 13 months.
Lower lateral incisors (the teeth either side of the bottom front two). These typically emerge between 10 and 16 months.
First molars. The first molar eruption, between 13 and 19 months, is often commented on by parents because molars are larger and the eruption process may be more uncomfortable than the incisors. Upper and lower first molars erupt around the same time.
Canines (upper and lower). The canines erupt into the gap between the lateral incisors and first molars, usually between 16 and 22 months.
Second molars. The final teeth to arrive are the second molars, typically erupting between 23 and 33 months. Their arrival completes the primary dentition.
Normal Variation in Timing
First tooth timing ranges from 4 months at the early end to 12-13 months at the later end for healthy children. A baby with no teeth at 12 months is within the normal range and does not require investigation in the absence of other concerns. A baby with teeth at 3-4 months is also normal. NICE guidance suggests that a child with no teeth by 18 months should be assessed by a dentist.
Teeth in some families erupt later than average as a familial trait. Asking about parents' own teething timing is sometimes useful context.
Looking After Primary Teeth
Primary teeth matter. They hold space for the permanent teeth that will follow, they support speech development, and they are used for chewing for the best part of a decade. Early dental caries (tooth decay) in primary teeth is both common and preventable.
The NHS recommends starting tooth brushing as soon as the first tooth appears, using a small smear of fluoride toothpaste (at least 1000ppm fluoride). The temptation to delay tooth brushing "until there are more teeth" should be resisted – the habit of twice-daily brushing is most easily established from the beginning.
The first dental appointment should happen within 6 months of the first tooth appearing, or by the first birthday at the latest, according to NHS guidance.
Key Takeaways
The 20 primary (milk) teeth erupt in a broadly predictable order, beginning with the lower central incisors between 6-10 months and completing with the second molars by 2-3 years. There is significant individual variation in timing – some babies have their first tooth before 4 months, others not until 12 months – and any of these extremes within this range is normal. The order of eruption is more consistent than the timing. Teeth typically erupt in pairs, lower teeth usually before upper, and the sequence follows the pattern: central incisors, lateral incisors, first molars, canines, second molars.
