Baby teeth fall out because the permanent teeth growing beneath them slowly dissolve their roots, loosening them until they detach. This process typically starts around age 6 and continues until about age 12, when the last baby tooth gives way. It’s one of the most precisely orchestrated events in childhood development, driven by specialized cells and chemical signals that essentially dismantle each baby tooth from the inside out.
What Happens Inside the Gum
Each baby tooth has roots anchoring it into the jawbone, just like an adult tooth. When the permanent replacement underneath begins to develop, a sac of tissue called the dental follicle surrounding that developing tooth starts releasing chemical signals. These signals recruit specialized cells called odontoclasts, which attach to the baby tooth’s root and break it down bit by bit. The process works almost identically to the way bone is constantly being broken down and rebuilt throughout your body, using the same molecular signaling system.
The resorption doesn’t happen all at once. It can take weeks or months as the odontoclasts chip away at the root material. Eventually, so little root remains that only the gum tissue holds the tooth in place. That’s the wobbly stage kids know well. A little pressure from the tongue, a bite into an apple, or some wiggling with a finger is usually enough to pop it free. By the time a baby tooth actually falls out, there’s almost no root left at all.
Why the Body Needs to Replace Them
Baby teeth are sized for a small child’s jaw. A toddler’s mouth simply doesn’t have room for the 32 full-sized teeth an adult needs, so the body starts with a set of 20 smaller ones that serve as functional placeholders. They allow children to chew, speak, and develop normal facial structure during the years when the jaw is still growing.
Critically, baby teeth also act as guides. Each one holds a specific spot in the jaw, reserving space for the permanent tooth forming below it. Natural gaps between baby teeth leave additional room for the larger adult teeth to fit. When a baby tooth is lost too early, from decay or injury, the surrounding teeth can drift into the gap, potentially crowding out the permanent tooth trying to come in.
The Usual Order and Timeline
Baby teeth generally fall out in the same order they arrived. The two bottom front teeth (lower central incisors) come out first, usually around age 6 or 7, followed closely by the two upper front teeth. After that, the sequence moves outward: the lateral incisors on either side of the front teeth, then the first molars, the canines, and finally the second molars, which are typically the last to go around age 11 or 12.
There’s a wide range of normal here. Some children lose their first tooth at 5, others not until 7. Girls tend to lose teeth slightly earlier than boys. What matters more than exact timing is the pattern. If your child loses teeth roughly in the expected sequence and the permanent teeth follow within a few months, everything is likely on track.
What Triggers the Process to Start
The timing isn’t random. Root resorption begins once the crown of the permanent tooth underneath has fully formed and its root starts developing. At that point, the tissue surrounding the developing tooth sends out signaling molecules, including certain proteins and growth factors, that essentially tell the body to start clearing a path. This signaling activates the resorption cells and directs them toward the baby tooth’s root.
Interestingly, the permanent tooth’s dental follicle appears to drive the process independently of the tooth crown itself. Research on animal models has shown that even without the crown’s direct influence, the follicle ensures the baby tooth is broken down on schedule. This is why, in rare cases where a permanent tooth is congenitally missing, the baby tooth above it may never loosen at all and can remain functional well into adulthood.
When Two Teeth Show Up at Once
Sometimes a permanent tooth erupts before the baby tooth has fallen out, creating a double row that parents often call “shark teeth.” This is most common with the lower front teeth and looks more alarming than it is. In most cases, the tongue’s natural pressure against the baby tooth will push it out within a few weeks, and the permanent tooth will drift forward into the correct position on its own.
There are a few situations where it’s worth checking in with a dentist: if your child has pain or swelling around the area, if a top front permanent tooth is coming in behind the baby tooth (upper teeth are less likely to self-correct), or if the baby tooth hasn’t loosened within about a month of the new tooth appearing. In those cases, a simple extraction of the baby tooth can resolve the crowding quickly.
Early or Late Tooth Loss
Losing a baby tooth before age 4 is uncommon enough to warrant a dental visit. Early loss is usually caused by decay or trauma rather than normal resorption, and a dentist may recommend a space maintainer, a small device that keeps neighboring teeth from shifting into the gap before the permanent tooth is ready.
On the other end, some children still have baby teeth at 13 or 14. Delayed loss can happen when permanent teeth are slow to develop, when they’re growing in at an unusual angle, or when a permanent tooth is missing entirely. An X-ray can show what’s happening below the gumline and whether any intervention is needed. In many cases, a retained baby tooth that stays healthy can function perfectly well for years, though it may eventually need monitoring as the jawbone continues to change in adulthood.