First Molars Coming In: Timing, Brushing the Grooves, and Starting Floss

First molars usually come in at 13 to 19 months. Why molars get cavities easily, how to brush the grooves, when to start flossing, and signs to see a dentist.

Your child has been munching away with a few front teeth, and now broad molars are starting to come up deep in the mouth. Molars make chewing much stronger, but they're a lot trickier to brush than front teeth. Here's what to know about timing and care when the first molars come in.

After the front teeth come the molars

After the front teeth, the first molars arrive. There's one on each side, top and bottom, so four in all, and they usually come in between 13 and 19 months. A few months either way is normal. The first molars often come in before the canines, so for a while there may be a gap between the front teeth and the molars.

Molars are wider and thicker than front teeth, so it takes longer for them to push through the gum. While they're coming in, the gums may swell over a wide area, and it's common for kids to be fussy or put their hands deep into their mouths to chew. Slightly swollen gums and some fussiness are a natural part of it.

Molars are more prone to cavities than front teeth because of their shape.

• The chewing surface has deep grooves where food gets stuck, and the bristles don't reach well into them.
• They sit far back in the mouth, so they're hard for parents to see, and it's hard for kids to keep their mouths open for long.
• The sides where they touch the neighboring teeth can't be reached by a toothbrush at all.

It's easy to think of baby molars as "going to fall out anyway," but they stay in the mouth much longer than the front teeth and do the chewing. They also hold space for the permanent teeth that come later. That's why it's important to keep them cavity-free from the day they come in.

Get right into the grooves

1. Lay your child in your lap with the head toward your tummy. Looking down from above lets you see all the way to the back.
2. Use a rice-grain smear of fluoride toothpaste. Brush twice a day, and never skip bedtime.
3. Gently pull back the cheek with one finger so you can see the molars.
4. Place the brush on the chewing surface and use short back-and-forth strokes to get into the grooves. Many short strokes reach into the grooves better than big scrubbing motions.
5. Brush the outer and tongue-side surfaces too, following the line where the teeth meet the gums.

Once the sides of two teeth touch, clean between them with floss once a day. At first, floss with a handle (a floss pick) is easier to use. Gently slide the floss between the teeth, then softly sweep it up and down along the side of each tooth. Snapping it hard toward the gum hurts, so go slowly. It will be a long time before your child can floss on their own, so do it for them until then.

If your child clamps their mouth shut, rather than forcing it open, try brushing in short chunks, like one line of a song or a quick count. Brushing the molars first instead of saving them for last lets you do a thorough job while your child is less tired.

If the gums look uncomfortable where a molar is coming in, a chilled teething ring or gentle pressure from a clean finger can bring relief.

Frequently asked questions

Show the dentist a molar like this

• A new molar has white spots or brown stains
• The chewing surface looks rough and seems to chip easily
• The molar grooves have turned dark
• Swollen gums last a long time, or your child chews only on one side
• Regular checkups haven't started yet

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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.

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