How your teeth develop in your lifetime

As is the case with most mammals, we go through two sets of teeth in our lifetimes. The first set are temporary, known as milk teeth, which are followed by the second set of permanent adult teeth. Our teeth go through several significant changes throughout our lives, but how do they start and what happens after that?

5–8 months

When we’re born all we have are our gums, and it usually isn’t until five to eight months of age that the first milk teeth begin to push through. These are smaller than adult teeth due to the size of a baby’s jaw. The first to emerge are generally the incisors – these are the front, flat edged teeth used for biting and there are eight in all: four on the top and four on the bottom.

16–23 months

Next come the canines, which are your more pointed teeth. There are four in total and they bookend the incisors. The final eight teeth follow and should all be developed by the age of two years old, give or take a few months. These teeth are premolars with larger uneven surfaces, which we need for chewing, and complete our first set of 20 teeth, ten on top and ten on bottom.

6–13 years

Milk teeth are only temporary and will be replaced by a new set of adult teeth, which begin to emerge around the age of six. During this time, the milk teeth will begin to loosen and fall out, although you will rarely lose more than one or two at a time. It takes a few years for all of the old teeth to finally come out.

This is generally painless, but children can occasionally twist the loose teeth, getting them stuck the wrong way round, or pull them out slightly too early.

Adult teeth, or permanent teeth, are larger than milk teeth but by this time the jaw bone is developed enough to accommodate them. Again the first of these teeth to come through are the eight incisors, followed by four permanent canines, and then the four premolars. At the same time as replacing our milk teeth with larger adult teeth, we also develop additional teeth as our jaw grows. This begins around the ages of six to eight, when we cut our first set of four molars, followed by a second set of molars which come through at roughly 12 to 13. So, ideally, just before we head into our teens, we have a set of 28 permanent teeth.

Teens and Young Adults

During our teenage years it’s common for teeth to grow awkwardly and at angles, and so they may need straightening. Your Portman orthodontist will be able to advise on the most suitable treatments for teeth alignment. 

There are four final teeth yet to emerge at this point – your wisdom teeth. It is usually late-teens to early 20s when these teeth come through, however the timing is different for everyone: for some their wisdom teeth don’t appear until late 20s, while others don’t get them at all. Many experience difficulties with this last set of adult teeth, and the main problem with wisdom teeth is that there is not enough space to accommodate them. They can cause problems such as overcrowding your existing teeth and growing through at difficult angles. Wisdom teeth can become impacted and cause discomfort, at which point it is best to remove them. 


Your 32 permanent teeth are the ones you have for life, but that doesn’t mean they last forever. A daily routine of oral hygiene must be maintained or we may suffer irreversible damage. If we lose these teeth then the only other option is an artificial replacement. 

You will get a lot more out of your natural teeth if you look after them well – those with healthy diets and oral hygiene routines have held onto their original adult teeth for their whole lives.


Even a healthy mouth is more vulnerable when you are older. Gums are more likely to recede as you age and you’re more at risk of gum disease, especially if you drink or smoke. But all this means is that you need to stay vigilant and make sure you brush and floss carefully, twice every day.

If you do lose any teeth along the way, there are plenty of natural-looking alternatives such as crowns, dentures or dental implants. Speak to your Portman dentist to find out more.

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