Milk teeth, also known as deciduous teeth, baby teeth, or primary teeth, are a set of temporary teeth that humans get during childhood before their permanent adult teeth grow in. Milk teeth start developing while babies are still in the womb, with the first ones usually erupting around 6 months of age. They help a child chew and speak while the jaw is still developing. Milk teeth also act as guides or placeholders for the permanent teeth growing under them.
When do milk teeth start coming in?
Milk teeth generally start erupting through the gums when a baby is between 6-12 months old. The first teeth to erupt are usually the two bottom front teeth (the lower central incisors), followed by the four upper front teeth (the upper central and lateral incisors). The first molars then come in between 12-16 months. Between 16-22 months, the canines (or fangs) erupt. Finally, between 22-33 months, the second molars emerge, completing the set of 20 milk teeth. While this is the typical eruption schedule, some babies may get teeth earlier or later.
Milk teeth eruption schedule
| Age | Teeth |
|---|---|
| 6-12 months | Lower central incisors |
| 8-12 months | Upper central incisors |
| 9-13 months | Upper lateral incisors |
| 16-22 months | Lower and upper first molars |
| 17-23 months | Lower and upper canines |
| 23-31 months | Lower and upper second molars |
Some variation is normal, but if no teeth have emerged by 18 months or so, parents should consult a pediatric dentist.
What are the names of milk teeth?
Like permanent adult teeth, milk teeth are categorized into different types based on their shape and function:
Incisors
The incisors are the eight front teeth (four on top and four on bottom) that have a flat edge for biting into food. The two middle incisors on each jaw are called central incisors. The incisors flanking them are called lateral incisors.
Canines
The four canine teeth have a pointed shape for tearing food and are sometimes called fangs or eye teeth. They are located lateral to the incisors.
Molars
The molars are the wider, flatter back teeth used for grinding food. There are a total of eight molars, with two sets on each side of the mouth in both jaws. The molars that emerge first are called first molars, while the molars that replace them are called second molars.
How many milk teeth do kids get?
Humans have two successive sets of teeth during their lifetime. The first set of 20 milk or primary teeth includes:
- 8 incisors (4 upper, 4 lower)
- 4 canines (2 upper, 2 lower)
- 8 molars (4 upper, 4 lower)
The primary teeth are smaller and whiter than the permanent set that replaces them. Each tooth has a similar function as the corresponding adult tooth that grows in after the milk tooth falls out.
Why are they called milk teeth?
Milk teeth get their nickname from the fact that they develop during the age when babies subsist primarily on breast milk or formula. However, the technical term deciduous is more descriptive of milk teeth. It means “temporary” or “destined to fall out and be replaced.”
Other theories suggest milk teeth are so called because:
- Calcium and nutrients from milk helps build the teeth
- Their white color resembles that of milk
- Nursing children bite down on the breast with their new teeth
Why do we have milk teeth?
Milk teeth serve several important functions for babies and young kids:
Allow chewing and biting
Milk teeth enable proper chewing, biting, and passing food from the front of the mouth to the back molars for grinding. Without milk teeth, infants would have to subsist only on liquids and soft foods.
Promote speech development
Teeth allow children to make certain sounds and form words as they learn to speak.
Guide permanent teeth
Milk teeth maintain the spacing and position for permanent teeth growing beneath the gums. If a milk tooth is lost too early, the teeth may shift position and make it harder for the adult tooth to erupt properly.
Facilitate facial growth
Chewing with milk teeth promotes normal development of the bones and muscles of the jaw.
Allow practice for kids
Milk teeth give children a chance to learn proper dental hygiene and get accustomed to teeth brushing before the higher-stakes permanent teeth come in.
Do milk teeth have roots?
Yes, milk teeth have roots that anchor them into the jaw bone, but they are much smaller and thinner than the roots of permanent teeth. The roots of milk teeth are fully developed at first but start resorbing (dissolving) once the permanent successors underneath begin forming. This weakens the milk tooth and causes it to loosen and fall out on its own as the permanent tooth pushes through.
Milk tooth structure
Like permanent teeth, milk teeth have a hard outer enamel layer over a thicker dentin layer. But the enamel coating is thinner, making milk teeth more prone to cavities and wear and tear. They also contain a hollow inner pulp chamber with nerves and blood vessels.
How do milk teeth fall out?
Milk teeth are naturally shed as the permanent teeth beneath them push upward into the mouth. As the permanent tooth develops, it puts pressure on the root of the milk tooth, causing its root to begin resorbing or dissolving. This weakens the milk tooth’s anchorage in the bone until it becomes loose and falls out on its own or with only the slightest nudge or wiggle.
Milk tooth shedding age
Shedding typically occurs in the same order that the teeth erupted:
- Front bottom incisors (6-7 years)
- Front top incisors (7-8 years)
- Front canines (9-12 years)
- Back molars (9-12 years)
Shedding age can vary by a few months depending on the child. Premature loss of milk teeth due to injury should also prompt eruption of permanent teeth a little earlier.
Do milk teeth need to be pulled?
Milk teeth should come out naturally on their own as the permanent teeth push through. However, there are some cases where a stubborn milk tooth needs to be extracted:
- The tooth is loose but won’t come out on its own
- A permanent tooth is impacted or delayed erupting because the milk tooth is refusing to loosen
- The tooth is damaged or decayed
- Orthodontic treatment requires creating space
Extractions are done as gently as possible, usually just numbing the area before wiggling out the tooth. Milk tooth extractions are generally easier than permanent teeth since the roots are smaller and less firmly anchored.
What happens if a milk tooth is knocked out?
Milk teeth sometimes come out prematurely due to injury or accident before the permanent successor is ready to erupt. If this occurs, the permanent tooth may start growing into the empty space at an abnormal angle or get impacted. For this reason, dentists often recommend placing a space maintainer appliance after a premature milk tooth loss. This holds open the gap until the permanent tooth is ready to erupt.
Types of space maintainers
- Band and loop – stainless steel band with wire loop to hold space
- Crown and loop – attachment to adjacent teeth
- Distal shoe appliance – keeps back molar space
- Lower lingual holding arch – bar attached behind lower teeth
Leaving the gap unattended could cause tooth misalignment later on. So it’s best to see a pediatric dentist promptly if a milk tooth is knocked out early.
Can you save a knocked out milk tooth?
There is no need to try preserving or reimplanting a prematurely lost milk tooth since a permanent replacement is on the way. Reimplantation and restoration may damage developing permanent tooth buds or fracture the delicate milk tooth roots. The best course of action is placing a space maintainer so permanent teeth come in properly positioned.
Conclusion
Milk teeth or primary teeth develop during early childhood before permanent teeth replace them. These temporary teeth help babies and kids chew food, speak properly, hold space for permanent teeth, and develop good oral habits. Milk teeth consist of incisors to bite, canines to tear, and molars to grind. Although called “milk teeth”, they get their nickname from their temporary nature, not their color. Milk teeth eventually fall out on their own as permanent teeth push through the gums. Parents should bring kids to the pediatric dentist regularly to monitor milk tooth shedding and catch any potential problems early.