Infected Baby Tooth: Thirteen Months On, His Adult Front Tooth Was Still Lying Sideways
An infected baby tooth can reach the adult tooth waiting above it, our Brisbane Paediatric Dentist explains. One of our little patients was four when it happened. Two of his top front baby teeth were badly decayed, and the infection had been working quietly for long enough to do something most parents never hear about; it had grown a cyst in the bone. Not on the baby tooth. Higher up, right where the adult front tooth was still forming. That cyst shoved the adult tooth over onto its side and pushed it up high. Our dentist took the two rotten front teeth out. Thirteen months on, a 3D scan of his jaw, called a CBCT, showed the adult tooth had barely shifted. Still lying flat. We don’t see this often. It’s also why we don’t leave a badly decayed front baby tooth in place and hope it falls out on its own. There was more on that scan than the cyst.
What An Infected Baby Tooth Can Do To The Adult Tooth Above It
An infected baby tooth can damage the adult tooth being built above it. Four ways, mainly. Dr Ellie Nadian explains that it can mark the enamel, alter the tooth’s shape, change when the tooth arrives, and push it off the line it was meant to travel. The reason is that infection around a baby tooth root does not wall itself off the way it often does in a grown jaw. It spreads through the bone instead, and the adult tooth is sitting right in its path.
- Marks on the enamel: An infected baby tooth may leave a permanent mark on the enamel of the adult tooth underneath. Infection reaches that tooth while its enamel is still being laid down. Some of the cells doing that work stop while others carry on, which is why the mark sits in one patch instead of across the whole tooth. The adult tooth arrives years later with a white, cream or yellowish brown patch, often with a clear edge to it, and sometimes with enamel that is thin or pitted. Dentists call this a Turner tooth. It usually shows on one tooth alone, unlike the enamel problems that turn up on several teeth at once.
- How likely it is: Decay in a baby front tooth can roughly double the odds that the adult tooth behind it comes through with a marked patch of enamel. Researchers in Dunedin followed 663 children, checked their baby front teeth at age five and their adult front teeth at age nine, and found that the link held even after they accounted for knocks to the mouth, fluoride in the water and family income. Doubling the odds is a shift in risk, not a sentence. And note what that study measured. Decay, not infection. The infection part is what the rest of this list is about.
- A different shape: According to our Brisbane dentists, infection around a baby tooth can change the shape of the adult tooth forming underneath. A study of children with lasting infection around their baby molars found that the adult teeth beneath them came through with their shape altered and their development held back. At the far end of it, infection from a dead baby tooth travels through the sac around the adult tooth and can stop that tooth forming at all.
- A change in timing: An infected baby tooth can change when the adult tooth arrives, and it works in both directions. Infection in a baby tooth is a documented cause of delayed eruption of the tooth underneath. Ongoing infection around baby molars also holds back how fast that adult tooth develops. It can go the other way, too. A severe infection can eat away the bone between a baby tooth’s roots, uncovering the adult tooth and allowing it to erupt before its root has fully formed.
- A change in direction: Infection around a baby tooth can alter the path the adult tooth takes as it comes through. The same study of children with infected baby molars found exactly that in the adult teeth beneath them. Not just late. Off course.
- How far it got is the part that matters: Damage to the adult tooth is not all or nothing. In that study, researchers compared each child’s infected side against that same child’s healthy side. Same genes, same diet, same water, same house. The further the infection around the baby molar had progressed, the more damage showed up in the adult tooth underneath. Older work on Turner tooth says the same thing in a different way. How the damage looks depends on how bad the infection got and how long it ran. So this is a risk that builds, and the building is the part that a parent can still interrupt.
His Scan At Four: A Cyst Sitting Where The Adult Tooth Should Have Been
He was four, and not far off five, the first time we saw him. He had decay in a lot of places. Two of them were his top right baby front teeth, and the scan is where the real trouble turned up. Sitting at the root of those two rotten teeth was a radicular cyst, which is a fluid filled sac that grows in the bone once the nerve inside a tooth has died. It hadn’t stayed put. It had shoved his adult front tooth, the one that should have been sitting upright and waiting its turn, over onto its side and up high into the bone. He was four. The tooth he wouldn’t need for another two years was already lying flat.
How A Rotten Baby Tooth Grows A Cyst In The Bone
A rotten baby tooth doesn’t grow a cyst on its own. The decay has to get deep enough to kill the nerve first, and then the infection has to escape out through the tip of the root into the bone. What happens next is the strange part. There are leftover cells sitting in the thin ligament that holds the root in place, doing nothing at all, and infection is what wakes them up. Here’s the chain, in order:
- The nerve dies first: A cyst can’t start while the tooth is still alive. Decay has to reach the pulp, which is the soft bundle of nerves and blood supply in the middle of the tooth, and kill it. In baby teeth, decay is the most common reason that happens.
- The infection escapes into the bone: Once the pulp is dead, the bacteria don’t stay put. They pass out through the tip of the root, and the bone around that tip becomes inflamed and stays that way. Dentists call it apical periodontitis.
- Sleeping cells wake up: This is the part almost nobody explains. A tooth sits in its socket, held by a thin ligament, and scattered through that ligament are cells left over from when the root was built. They’re called the rests of Malassez. Normally, they just sit there. Inflammation is what wakes them, and they start dividing.
- The dividing cells hollow out: They multiply until the middle of the mass dies off, and that leaves a space. The space fills with fluid and takes on a lining of its own. That’s the cyst. It isn’t a lump of infection. It’s a bag of fluid in the bone, with a wall.
- It grows without hurting: This is what makes it worth knowing about. These cysts usually cause no symptoms at all, and most are found only when someone takes an X-ray for a different reason. No ache. No swelling. Nothing, until it’s big enough to shift something out of its way.
- It’s rare, and the rarity might be a counting problem: Cysts like this make up somewhere between 0.5 and 3.3 per cent of all the ones dentists see. Most of the reported ones sit under baby molars, and under baby front teeth, the papers use the word rare. But researchers who study this think the published number is too low, because when a baby tooth with a cyst comes out, the tissue usually never goes to a lab, so the cyst never gets counted.
Why The Top Front Baby Teeth Are The Ones That Rot First
The top front baby teeth come through long before the molars do, so they get the longest run at the sugar. They’re also the least protected. The tongue lies over the bottom front teeth, and the salivary glands sit right there washing them, which is why the bottom ones usually stay sound while the top four rot. That’s the pattern in toddlers. The top front teeth are the worst, and the bottom front teeth are fine. And when the top front ones go, they usually go deep enough to reach the nerve, which is the starting gun for everything above them. The first sign is a chalky white band along the gumline. It’s the one parents usually miss.
The Extra Tooth We Found On The Same Scan
There’s a part of this we could have left out. He had an extra tooth. A spare one, what dentists call a supernumerary. When his dad came in for the chat about the scan, taking that spare out was one of the two things on the table, and it did come out, under the same anaesthetic as the two rotten front ones. Extra teeth are a known reason adult front teeth don’t come through, so we won’t pretend this one wasn’t there. But the notes never say it was blocking anything. By the time we first looked, the cyst had already shoved his front tooth sideways, and the cyst is what the notes name. Not the spare. Leaving it out would have made this a cleaner story than it was.
What We Recommended, And What Went Ahead
We put two things on the table. Take out the spare tooth, and deal with every decayed tooth in his mouth. His dad said yes to the first one. The operation went ahead at Brisbane South Private Hospital under Sleep Dentistry in Brisbane through general anaesthesia, and in the end, the two rotten front teeth came out alongside the spare. The rest of the decay stayed where it was. Thirteen months later, he was back in our chair in pain, and two of his back teeth came out under local anaesthetic.
Thirteen Months On, The Scan Showed Barely Any Change
He came back for something else entirely. His back teeth were hurting. While he was in the chair,, we took a second CBCT to compare with the one from a year before and see whether the front tooth had returned. It hadn’t. Not enough to matter. The rotten teeth were gone, the spare was gone, and the adult front tooth was still lying flat on its side, in the same place the cyst had put it. In the mouth and on the scan, both said the same thing.
Will The Adult Tooth Still Come Down?
Two roads sit in front of him. Wait, and hope the tooth rights itself now that the cyst that pushed it is out of the way. Or it may be guided into place with orthodontic treatment over time, which an orthodontist would plan and oversee. We sent his scans across and asked exactly that, and whether anything needed doing urgently. Here’s the honest part. Thirteen months of no movement isn’t proof of anything. It isn’t encouraging either. A tooth that hasn’t budged in a year has told you something, even if it hasn’t told you everything.
Some Damage Only Our Scan Will Show
If you’ve spotted something on your child’s teeth and you’re not sure whether it needs attention, that uncertainty is reason enough to come in. Bring them along, and we’ll take a proper look, explain what we’re seeing, and tell you honestly whether it needs doing about: 07 3343 4869
For families who need it, eligible patients can spread the cost through Humm or use early-release superannuation for treatment through SuperCare.
Sources:
- ten Cate AR. The epithelial cell rests of Malassez and the genesis of the dental cyst. Oral Surg Oral Med Oral Pathol. 1972;34(6):956-964.
- Lustmann J, Shear M. Radicular cysts arising from deciduous teeth. Review of the literature and report of 23 cases. Int J Oral Surg. 1985;14(2):153-161.
- Savage NW, Adkins KF, Weir AV, Grundy GE. An histological study of cystic lesions following pulp therapy in deciduous molars. J Oral Pathol. 1986;15(4):209-212.
- Mass E, Kaplan I, Hirshberg A. A clinical and histopathological study of radicular cysts associated with primary molars. J Oral Pathol Med. 1995;24(10):458-461.
- Nair PNR. New perspectives on radicular cysts: do they heal? Int Endod J. 1998;31(3):155-160.
- Shear M. Cysts of the Oral Regions. 3rd ed. Bristol: Wright; 1992.
