What Is Abnormal Tooth Eruption?
Abnormal eruption of teeth is when a tooth grows through the gum in the wrong position, wrong direction, or fails to fully emerge at the expected time. The tooth may tilt toward an adjacent tooth, erupt on the wrong side of the arch, sit partially buried in bone, or never surface at all. Dentists use terms like ectopic tooth eruption, ectopia, or impaction depending on how severely the tooth has deviated from its expected path.
It is more common than many parents realise. At Conder Dental Centre, we identify cases of abnormal tooth eruption in children almost every week during routine check-ups in our Canberra families — most often in the 6–12 age group, when the transition from baby teeth to permanent teeth is at its busiest.
Why Does It Happen? The Causes Behind Ectopic Eruption
No single cause explains every case. What we typically see is a combination of factors:
Jaw-tooth size discrepancy is the most common driver. Modern humans have smaller jaws than our ancestors, yet we still grow the same number of teeth. When there is not enough arch space, the tooth takes a detour.
Retained baby teeth that fail to fall out on schedule block the path of the incoming permanent tooth, pushing it sideways or backward. This is the mechanism behind the “shark teeth” presentation lower permanent incisors erupting behind the baby teeth rather than pushing them out.
Supernumerary (extra) teeth physically obstruct normal eruption. We see this occasionally in children, particularly mesiodens a small extra tooth sitting between the two upper front incisors that can push them apart or block one entirely.
Genetics and systemic conditions play a role. Cleidocranial dysplasia, hypothyroidism, and certain medications that affect bone turnover can all delay or redirect tooth eruption. If multiple teeth are affected simultaneously, a systemic cause is worth investigating.
Trauma to baby teeth can damage the developing permanent tooth bud beneath, causing it to erupt in an altered position years later. This is a reason we take even minor falls onto children’s front teeth seriously at our practice.
Impacted Teeth Symptoms: How to Recognise the Warning Signs
A self-contained, extractable answer for quick reference: Impacted teeth symptoms include swelling or tenderness in the gum above a tooth that hasn’t emerged, a gap in the arch where a tooth should be, neighbouring teeth shifting or tilting, pain when chewing, or a visible tooth erupting in the wrong location. In children, the most visible sign is often a double row of teeth.
Here is what to watch for at different ages:
Ages 5–8 (early mixed dentition): Lower front baby teeth that haven’t loosened by the time the permanent teeth are already visibly erupting behind them; upper first molars that seem to be “stuck” and haven’t fully come through by age 7; any gum swelling in the upper canine region.
Ages 9–13 (late mixed dentition): Upper canines are the teeth most commonly impacted after wisdom teeth. A canine that hasn’t emerged by age 13, or one that you can feel as a hard lump high up under the gum in front of the cheekbone, needs an X-ray promptly. Canine impaction affects roughly 2% of the population and is far easier to treat when caught at 10–11 than at 16.
Adults: Wisdom teeth (third molars) are the classic adult presentation. Symptoms include pain at the back of the jaw, swelling, difficulty opening the mouth fully, and repeated infections in the gum flap (pericoronitis) overlying a partially erupted wisdom tooth.
The sign that parents most frequently miss is the absence of a tooth a gap that persists past the expected eruption window. A tooth that is simply not there is just as significant as one that appeared in the wrong place.
How We Diagnose Abnormal Eruption at Conder Dental Centre
Clinical examination tells us a lot — we can feel for unerupted canines by pressing gently along the gum, assess the timing and sequence of eruption against development charts, and identify visible ectopic teeth. But you cannot manage what you cannot see in full. An OPG (Orthopantomogram) X-ray is the foundation of any eruption assessment. A single low-dose panoramic image shows all developing teeth, their positions, angles, and any resorption they may be causing to adjacent roots.
For upper canines specifically, we may take additional periapical X-rays or request a CBCT scan when surgical planning is needed this gives us a three-dimensional map of exactly where the tooth sits relative to the roots beside it.
We recommend a baseline OPG at around age 8–9 for most children at our practice, not as routine radiation exposure, but as a targeted diagnostic tool when we have clinical reason to suspect an eruption problem. If your child has already been identified as having crowding, a retained baby tooth, or a missing permanent tooth, that is the time to look.
Abnormal Tooth Eruption in Children: The “Watch, Guide, or Act” Decision
This is the question we spend the most time discussing with Canberra parents, and the answer is genuinely case-by-case. Here is how we think about it:
Watch: Ectopic first permanent molars that are only mildly off-angle resolve on their own approximately 70% of the time, according to research published in the Australian Dental Association’s News Bulletin. Lingually erupting lower incisors (“shark teeth”) correct without intervention in more than 90% of cases once the baby tooth naturally exfoliates. For these presentations, we schedule a review in 3–6 months rather than intervening immediately because unnecessary early extraction of a baby tooth can be a child’s first frightening dental experience, and that matters.
Guide: When there is enough time and space, orthodontic treatment can literally redirect a tooth. Myobrace, expansion plates, and Fastbraces are tools we use at Conder Dental Centre to create the arch space that allows a displaced tooth to find its way. For impacted upper canines, a bracket is bonded to the exposed tooth during a minor surgical procedure and a chain attached to the orthodontic wire gently guides the canine into position over 12–18 months. The results, when started early, are excellent.
Act: Surgical extraction becomes necessary when a tooth is actively resorbing the root of an adjacent tooth, when it is infected, when it is supernumerary and blocking everything around it, or when orthodontic guidance is simply not viable. We discuss all of this — including referral to an oral surgeon if needed — clearly and without pressure, so you can make an informed decision for your child or yourself. You can read more about what that process involves on our oral surgery page.
What About Abnormal Eruption in Adults?
Adult cases most often involve wisdom teeth, but we also see adults who discover sometimes through an incidental X-ray that they have a canine or premolar that never erupted and has been sitting dormant in the bone for decades. In these cases the approach depends on whether the unerupted tooth is causing harm (resorbing roots, forming a cyst, contributing to crowding), its position, and the patient’s overall treatment goals.
For wisdom teeth causing recurrent pericoronitis or crowding pressure on the second molar, extraction at our Canberra practice is the most straightforward resolution. We discuss sedation options with any patient who is anxious about the procedure — we have specific support pathways for nervous patients, including happy gas and oral sedation.
Frequently Asked Questions
Does abnormal eruption always need braces?
No. Many mild cases of ectopic tooth eruption resolve without any orthodontic treatment, particularly in younger children whose jaws are still growing. Whether braces or aligners are needed depends on the severity of the displacement, available arch space, and the patient’s age. An early orthodontic check at around 8–9 years gives us the information to plan ahead even if treatment doesn’t start for another two or three years.
My child has a double row of teeth at the bottom is this an emergency?
In most cases, no. Lingually erupting lower incisors (the “shark teeth” pattern) are very common and typically self-correct once the baby tooth naturally loosens and falls out. We ask parents to encourage wiggling of the baby tooth. If the baby tooth shows no mobility after 2–3 months and the permanent tooth is fully erupted, a straightforward extraction is usually all that’s needed. Call us, but don’t panic.
Can adults have ectopic tooth eruption treated?
Yes, though the timeline is longer than in children because adult bone is denser. Surgical exposure of an impacted canine followed by orthodontic traction is effective into the mid-30s in motivated patients. Beyond that, individual case assessment matters more than age alone a CBCT scan gives us the full picture before recommending any path.
