“Shark Teeth”: What to Do When a Permanent Tooth Comes In Behind a Baby Tooth

Two rows of teeth — and one worried parent

You're brushing your child's teeth and there it is: a brand-new adult tooth poking up behind a baby tooth that hasn't gone anywhere. Two rows of teeth, like a little shark. It looks alarming — and it's one of the most common reasons parents call a pediatric dentist in a mild panic.

Here's the short answer up front: shark teeth are common, they're almost never an emergency, and in many children the situation resolves on its own once the baby tooth falls out. The main question is whether that baby tooth is loosening. If it is, patience and wiggling usually finish the job. If it isn't, a quick dental visit sorts it out.

What exactly are “shark teeth”?

“Shark teeth” is the parent-friendly nickname for a permanent tooth that erupts before the baby tooth above it has fallen out, so both are visible at once. (Real sharks grow rows of replacement teeth behind the active row — hence the name.) Dentists sometimes call it ectopic eruption, which simply means the new tooth is coming in away from its expected path.

It most often shows up in two windows: around ages 5 to 7, when the lower front teeth are being replaced, and again around ages 10 to 12, when the back baby molars are on their way out. The lower front teeth are the classic spot — that's where most parents first see the double row.

Why it happens

Normally, a permanent tooth pushes up directly beneath its baby tooth, dissolving the baby tooth's root as it comes. With the root gone, the baby tooth loosens and falls out, and the adult tooth slides into the empty spot.

With shark teeth, the permanent tooth takes a path slightly behind the baby tooth instead. Because it isn't pressing on the root, the root doesn't dissolve on schedule — so the baby tooth sits tight while its replacement comes up behind it. Nothing about this means your child's teeth are “bad”; it's a variation in timing and position that pediatric dentists see all the time.

What to do at home

• Check whether the baby tooth is loose — if it wiggles, that's the best sign: the root is dissolving and the tooth is on its way out
• Encourage gentle wiggling with a clean finger or the tongue throughout the day; there's no need to force it
• Keep brushing the area — a double row traps food more easily, so brush both rows gently
• Don't panic about position: once the baby tooth is out, the tongue presses against the new tooth many times a day, and in many children that steady pressure guides it forward over the following weeks and months

When to call a pediatric dentist

Make an appointment if any of these apply:

• The baby tooth isn't loose at all and the permanent tooth behind it is clearly coming in — especially if a month or two passes with no change
• Your child has pain, swelling, or trouble eating
• The double row involves back teeth (molars), which are less likely to sort themselves out than front teeth
• You're simply not sure — a quick look settles it, and it's a far easier visit than waiting and wondering

What happens at the visit

The dentist will look at how loose the baby tooth is and how the permanent tooth is positioned, sometimes with a quick digital X-ray to see the root. If the baby tooth is on its way out, the plan may simply be to keep wiggling and watch. If the root isn't dissolving, removing the stubborn baby tooth is typically a quick, simple procedure — done gently, with numbing, and usually much less dramatic than parents expect. Clearing the spot gives the permanent tooth room to drift into place.

Seeing two rows and not sure what to do? Families in Sarasota and Lakewood Ranch ask us about this every week — call (941) 529-0331 or request an appointment online, and we'll help you figure out whether to wiggle, wait, or come in.

Quick answers for parents