What are "shark teeth" (an adult tooth behind the baby tooth)?

It can be genuinely startling to look in your child's mouth and spot a second row of teeth coming in behind the baby teeth — but "shark teeth," as parents often call them, are common, usually harmless, and most often sort themselves out on their own. They happen when a permanent tooth erupts behind a baby tooth that's still firmly in place, creating a temporary double row. It occurs most often with the lower front teeth, typically around ages five to seven when those first adult teeth are coming in, and it can happen with the upper front teeth as well.

Here's why it usually isn't a problem. In the normal sequence, an erupting adult tooth dissolves the root of the baby tooth above it, which is what makes the baby tooth loosen and eventually fall out. With shark teeth, the adult tooth has simply come in slightly behind schedule relative to the baby tooth's loosening — the baby tooth is a bit slow to let go. In most cases, as the adult tooth continues to come in and the baby tooth's root continues to dissolve, the baby tooth loosens and falls out on its own, and the adult tooth then gradually drifts forward into its proper position over a few weeks to a few months. The tongue naturally helps nudge it into place.

So in many cases, the best thing to do is simply encourage your child to wiggle the loose baby tooth (clean hands!) and give it a little time. Wiggling can help the baby tooth work its way out and make room. Patience is often all that's needed.

When should you call us? Reach out if the baby tooth isn't loosening at all after a few weeks, if the baby tooth seems solidly stuck with no signs of coming out, if the double row is causing crowding, discomfort, or difficulty keeping the area clean, or if you're simply unsure and would feel better having it checked. Sometimes a stubborn baby tooth that won't loosen benefits from a simple, gentle removal so the adult tooth can move into its correct spot — this is a quick, routine visit, and it prevents the adult tooth from settling into a crooked position.

So the bottom line is reassuring: shark teeth are usually nothing to worry about and frequently self-correct with a little time and wiggling. But it's an easy thing to have us check if that baby tooth is holding on stubbornly, and we're always glad to take a look and set your mind at ease.