Milk teeth, also known as baby teeth or primary teeth, are the first set of teeth that babies and young children get. They are eventually replaced by permanent adult teeth as a child grows older. Milk teeth play an important role in helping a child chew food, speak properly, and hold space for permanent teeth. Knowing how many milk teeth a child has and when they erupt can help parents monitor their child’s dental development.
How Many Milk Teeth are There?
Most babies have a total of 20 milk teeth, 10 on the top and 10 on the bottom. Here is a breakdown of how many teeth there are per section:
Central Incisors
There are 4 central incisors – 2 on the top, 2 on the bottom. These are the two middle front teeth on both the upper and lower jaws. They have a flat edge and are used for biting off food.
Lateral Incisors
There are 4 lateral incisors – 2 on the top, 2 on the bottom. These teeth flank the central incisors on both jaws. They have pointed edges and assist in biting and tearing food.
Canines
There are 4 canines – 2 on the top, 2 on the bottom. Canines are the pointed teeth located on either side of the lateral incisors. They help tear and shred food.
First Molars
There are 4 first molars – 2 on the top, 2 on the bottom. First molars are located next to the canines and have a wide surface area for grinding food.
Second Molars
There are 4 second molars – 2 on the top, 2 on the bottom. Second molars are the last milk teeth to erupt in the very back of the mouth behind the first molars. They assist in chewing and grinding food.
So in total, children have 10 milk teeth on the top jaw and 10 milk teeth on the bottom jaw, making 20 milk teeth.
When Do Milk Teeth Erupt?
Milk teeth generally begin erupting around 6 months of age. The eruption schedule is as follows:
6-12 months
– The central incisors on the bottom jaw erupt first between 6-12 months followed by the central incisors on the top jaw. So the 4 central incisors are usually the first milk teeth.
8-16 months
– Next the 4 lateral incisors erupt between 8-16 months. The lateral incisors on the bottom jaw come in just before the top.
16-22 months
– The first molars come in between 16-22 months. The bottom first molars erupt prior to the top first molars.
13-19 months
– The 4 canines come in between 13-19 months. Once again the lower canines tend to come in slightly ahead of the upper canines.
23-31 months
– Finally, the last milk teeth to erupt are the second molars which come in between 23-31 months. The lower second molars tend to erupt first.
So by the age of 3, a child usually has a full set of 20 primary teeth. While this is the typical eruption timeline, some children may get teeth earlier or later than these ranges. Premature babies may hit dental milestones later while some babies are born with neonatal teeth already erupted. Nevertheless, most babies have all their milk teeth between 2-3 years of age.
Do Milk Teeth Grow in Pairs?
Yes, milk teeth generally erupt in pairs – one tooth on the left and one tooth on the right side of the same jaw. The first teeth to erupt are usually the central bottom incisors around 6-12 months. A few months later, the top central incisors will emerge. This pattern continues with the lateral incisors, canines, and molars. With each new set of teeth, a matching pair will grow in on both sides of the mouth. Getting teeth symmetrically demonstrates healthy dental development. If a child erupts several teeth on just one side, it could indicate a problem that should be evaluated by a dentist. But in most cases, milk teeth do come in pairs.
Why Do We Have Milk Teeth?
Milk teeth serve several important functions for babies and young children:
Allow chewing of food
Milk teeth help babies transition from soft foods to solid foods that require biting, chewing, and grinding. The different tooth types – incisors, canines, molars – all play a role in processing foods of various textures.
Enable speech development
Teeth allow children to properly form certain words and sounds. Missing or malformed teeth can impair speech development.
Aid facial growth
Milk teeth maintain the proper spacing and alignment of a growing child’s jaw. This ensures their permanent teeth can grow in straight.
Save space for permanent teeth
Milk teeth hold open the gap until a child’s larger permanent teeth are ready to erupt. If milk teeth are lost prematurely, surrounding teeth may shift into the empty space making it harder for permanent teeth to come in.
So in summary, milk teeth allow essential functions like eating, speaking, and facial growth all while preserving space for the future permanent dentition.
Why are They Called Milk Teeth?
Milk teeth get their nickname from their white color resembling that of milk. Just like milk, the teeth are white due to the enamel covering the crown portion. The milk moniker may also refer to these being a baby’s first set of teeth that develop while they are still nursing and consuming milk. The terms “milk teeth”, “baby teeth”, and “primary teeth” all refer to the first set of 20 deciduous teeth.
Why Do We Lose Milk Teeth?
Milk teeth are intended to be a temporary set of teeth. Humans develop two dentitions over a lifetime:
1. A primary dentition consisting of milk teeth
2. A permanent dentition consisting of adult teeth
Milk teeth start forming in utero before birth but only remain for about 6-8 years after erupting. Around age 6-7, they begin shedding to make room for permanent teeth. This is a natural process as the jaws grow larger and adult teeth develop under the gums. The roots of milk teeth start dissolving until the teeth become loose and fall out. The entire milk set is usually gone by age 12-13.
The key reasons milk teeth give way to permanent teeth include:
– Milk teeth are smaller with shorter roots more prone to falling out as adult teeth push through.
– Primary teeth consist of enamel and dentin but lack the thicker protective layer of cementum covering permanent teeth roots.
– Milk teeth roots begin reabsorbing around age 4 as permanent teeth grow under them. The roots break down until the teeth become loose.
– Permanent teeth are larger than milk teeth and must take their place in order to function properly.
Losing milk teeth for permanent teeth allows children to maintain properly sized teeth and strong jaws throughout their growth and development.
Do Other Animals Have Milk Teeth?
Many animal species develop milk teeth that are later replaced by permanent adult dentition including:
– Primates – Humans, chimpanzees, and monkeys all get two sets of teeth.
– Rodents – Rats, mice, and beavers have baby teeth they shed.
– Cats – Kittens develop 26 baby teeth that fall out.
– Dogs – Puppies lose their 28 milk teeth at around 4-6 months old.
– Dolphins – Young dolphins have between 19-26 temporary teeth.
– Elephants – Calves begin tusk eruptions around 6-12 months.
– Horses – Foals are usually born with no teeth but grow 24 milk teeth.
So milk teeth definitely aren’t unique to just humans. Many fellow mammals develop deciduous baby teeth as juveniles. However, other species like turtles, sharks, and crocodiles only get one set of teeth their whole lives. But for mammals, replacing milk teeth enables juvenile eating and growth until the adult dentition finishes developing.
Interesting Facts About Milk Teeth
Here are some fascinating facts about milk teeth:
– Eruption can start before birth – Some babies are born with teeth partially erupted known as “natal teeth”.
– Milk teeth have thin enamel – The enamel coating milk teeth is only half as thick as on permanent teeth.
– Adult teeth form early – Permanent teeth begin developing in the jaw by age 6 months.
– Pairs may vary in timing – One side’s teeth may erupt before the opposite side.
– Grinding shows maturity – Molars coming in allows progression to chunky foods.
– Number of teeth varies – Some children are born missing certain milk teeth.
– Root resorptionloosens teeth – Cells basically “eat away” at the root making teeth loose.
– Lost teeth can’t reattach – Once removed, milk teeth won’t re-adhere to the gum.
– Permanent premolars replace first molars – Other milk teeth are replaced by like-named permanent teeth.
– Milk molars can last until ages 9-12 – Molars often hang on the longest before permanent teeth push them out.
– Adult teeth shift with loss of space – Premature loss of milk teeth causes crowding of incoming teeth.
– Brief toothless stage is normal – Children usually have a gap around ages 6-7 when teeth are switching.
– Decay is rapidly destructive – Cavities spread quickly in milk teeth due to thinner enamel.
– Discoloration can indicate death – Grey, brown, or black milk teeth are severely decayed.
– Cradle cap correlates with early eruption – Excessive infant scalp skin predicts precocious teething.
So milk teeth go through a very interesting developmental process before giving way to permanent teeth. Their unique features and nuances allow children to smile, eat properly and speak clearly.
Conclusion
In summary, milk teeth consist of 20 teeth – 10 on top and 10 on the bottom. The types of teeth are incisors, canines, and molars. Milk teeth generally erupt in pairs starting around 6 months through age 3. Their main role is helping children chew and speak properly while holding space for permanent teeth developing under the gums. Around ages 6-7, milk teeth roots start dissolving until the teeth fall out naturally. Adult teeth then take their place. Milk teeth go through an intriguing process that is critical for young children. While baby teeth are only meant to last several years, they pave the way for a healthy permanent smile.