Tooth Calendar Blog
Age 12 and All 28 Permanent Teeth: Helping Your Child Take Over Brushing
Usually by around 12 to 13, all 20 baby teeth are gone and 28 permanent teeth are in. Why cavities can creep back, how to hand over brushing, and what parents should check.
At a glance
- Usually all 20 baby teeth are gone and 28 permanent teeth are in
- Brushing is your child's job. You check once a week
- Keep up checkups every six months
The tooth changes that began around age six are nearly done by about 12 to 13. Now your child's mouth holds all the teeth they'll use for life. At this stage, the job of protecting those teeth starts moving, little by little, from you to your child. Here's what changes, and how much parents should still keep an eye on.
The forever teeth are all here
Usually around ages 12 to 13, all 20 baby teeth have fallen out, and the 28 permanent teeth (not counting wisdom teeth) are in place (it varies from child to child). That's eight front teeth, four canines, eight premolars, and eight large molars. Of the big molars at the back, the front four came in around age 6, and the back four come in around now.
With baby teeth, a cavity was on a tooth that "would be replaced anyway." Not anymore. Any damage from here on is for life. Once a permanent tooth wears away or decays, it doesn't grow back.
And this happens to be a time when cavities can creep back:
- Kids buy and choose more of their own snacks and drinks.
- Busy with after-school classes and homework, they skip brushing or rush through it.
- Parents get fewer chances to look inside their mouths.
Newly erupted permanent teeth haven't fully hardened on the surface yet, so they're more prone to cavities. That's why the habits your child builds now will shape their tooth health for a long time.
Wisdom teeth usually come in between 17 and 21, and some stay buried or never form at all. At checkups in the mid-to-late teens, if the dentist decides it's needed after an exam and a look at your child's growth, a panoramic X-ray or similar image is used to check them. X-rays aren't taken based on age alone, so there's nothing to worry about now.
Your child brushes, you spot-check
Brushing is now your child's job. Still, a parent's check helps. Try splitting it up like this.
What your child does on their own:
- Brush twice a day with fluoride toothpaste. Never skip the bedtime brushing.
- Floss once a day. A toothbrush can't reach between the teeth, so floss is needed.
- If any baby tooth is still there after age 13, tell you about it.
What you keep an eye on:
- Once a week, check the inside of the molars and along the gumline. Do it together in good light with a mirror.
- Keep up checkups every 6 months. At each one, check that the sealants are holding and whether fluoride treatment is needed.
- Choosing which snacks and drinks to keep at home is still your job. Make water and milk the defaults.
With snacks, how often matters. Even with the same amount, nibbling all day or slowly sipping a sweet drink gives the teeth no break. Help your child build the habit of snacking at set times and rinsing with water afterward. Tucking a small toothbrush and a water bottle into their after-school bag also works well.
Once puberty starts, kids may not like it when a parent asks to look in their mouth. Instead of making it feel like an inspection, keep it short, like "Let's just check the inside of your back teeth," and add some praise. That makes it less awkward. At this age, explaining why works better than nagging. A line like "A cavity you get now stays for life" tends to stick.
A common mistake is thinking regular checkups can take a break now that all the permanent teeth are in. In fact, this is a time when cavities creep back easily, so keep up checkups every 6 months.
United States guidance
US: School-entry dental exams
There is no national school dental screening program in the US, but some states and districts require a dental exam certificate for school entry or certain grades. Check with your school, and keep 6-month recall visits regardless.
Frequently asked questions
My child is 13 and still has one baby tooth.
If a baby tooth is still there after age 13, let the dentist know. For a baby tooth that isn't loose, an X-ray can check whether there's a permanent tooth underneath.
My child brushes well alone now. Do I still need to check?
You don't need to check every day, but looking at the inside of the molars and along the gumline once a week helps. Those are the spots kids miss most when brushing alone.
Should the wisdom teeth come out now too?
Wisdom teeth usually come in between 17 and 21. If the dentist decides it's needed at a checkup in the mid-to-late teens, an X-ray will be used to check them, so there's no need to worry now.
Is flossing really necessary?
Yes, flossing once a day is recommended. A toothbrush can't reach between the teeth, and that's where cavities and gum inflammation start easily.
Have the dentist take a look when
- A baby tooth is still there and isn't loose
- Nothing is showing where a permanent tooth should be
- The teeth overlap so much that they're hard to clean
- You see brown or black spots on the molars, or cold foods cause pain
- You've missed the 6-month checkup
English ebook · Dentist Ingyoon An
A guide to the decisions behind dental care
Tooth Calendar follows dental care from pregnancy to eighteen in 78 chapters. Explore the reasons behind feeding, brushing, baby-tooth decay, sedation, and injury decisions—including what can be watched and when to seek help. Age-based contents and a topic index help you find the concern you have today.
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Sources
- ADA · Eruption Charts (2024)
- MOE_KR · 학교건강검사규칙(학생 건강검사·구강검진) (2024)
The information in this article is for general educational purposes and does not replace professional dental care. Talk to a dentist about your child's condition.