If food keeps getting wedged between your toddler's back teeth, those teeth are probably touching, and that is the signal to start flossing. For many children the baby molars meet somewhere between two and three, though some children have natural spaces that stay open for years. The age matters less than the contact: once a brush can no longer reach the side of a tooth, something else has to.
Why touching teeth change the routine
Toothbrush bristles clean the front, back and chewing surfaces well, but they cannot squeeze into the point where two teeth press together. Plaque sitting just below that contact is undisturbed by brushing, and decay between baby molars often goes unseen until it is quite large, because it starts on a surface you cannot look at directly. Dentists frequently find it on X-rays rather than by eye.
While a child's teeth still have gaps, a good brush with fluoride toothpaste reaches every side and flossing adds little. A quick way to check is to slide a piece of floss between two back teeth. If it passes through with no resistance, there is no contact yet; if it snaps through a tight spot, cleaning between those teeth is now part of the job.
Research on flossing as a stand-alone measure is mixed, partly because it is hard to study well. The consistent advice from dental bodies is still to clean between teeth that touch, alongside fluoride toothpaste and regular checks.
Parents do it first
Flossing needs more hand control than brushing, so for preschoolers it is entirely a parent's task. Sitting on the floor with your child's head resting back in your lap gives a clear view of the back teeth and a steady angle. Ease the floss through the contact with a gentle sawing motion, curve it against the side of each tooth, and slide it up and down rather than snapping it into the gum.
Floss picks with a small handle are usually easier than wrapping floss around your fingers inside a small mouth. The best tool is the one you will actually use every evening, so try a couple and keep whichever feels least fiddly.
Handing over gradually
Somewhere in the early primary school years, most children want to have a go themselves. Let them start, then finish off the back teeth yourself. The Australian Dental Association suggests parents keep helping with brushing and flossing until about eight or nine. Even after that, an occasional check helps, because the molars at the back are where children miss most.
Keeping it from becoming a fight
Attach flossing to something that already happens every night, such as straight after brushing before a story. Keep it short; for a young child, the few contacts between the back baby molars are the ones that matter most. Some children enjoy taking a turn flossing a parent's teeth, and a sticker chart works for others. A calm routine at home also tends to make dental visits easier, which our article on a child's first filling touches on.
A little bleeding in the first week is common, because gums that have not been cleaned between are often mildly inflamed. It usually settles with gentle daily flossing. If it continues beyond a couple of weeks, our guide to bleeding gums explains when to have it checked.
Part of a wider plan
Flossing covers the contacts, fluoride toothpaste protects the open surfaces, and fissure sealants can shield the deep grooves of new adult molars. Our article on how long sealants last explains that last layer, and our guide to when adult teeth come in shows which new teeth will need flossing as they arrive.
Questions we are often asked
My child is four and has gaps everywhere. Do I still need to floss?
Not between teeth that have clear spaces. Check the back molars every few months, since they are usually the first to close up.
Are water flossers suitable for children?
Some older children like them, but reviews have not shown that they add much to brushing, including for children with braces, and they are messy for toddlers. Floss or floss picks are simpler for young children.
Can the dentist or OHT show me how?
Yes. A demonstration in the chair, on your child's own teeth, is often the quickest way to find a position and tool that work.
A hands-on demonstration
Our dentists and OHTs see children and families and are happy to show you a flossing technique that suits your child's mouth at their next check-up. Read about family dental care at our Melrose Park practice or see our current deals.
This article is general information and not a substitute for personal dental advice.
