Shark Teeth in Children: What They Are and What to Do
The Name That Perfectly Describes the Problem
When parents first see a second row of teeth appearing behind their child's baby teeth, the term that gets searched most often is exactly the one that captures what it looks like: shark teeth. Like a shark, which famously grows multiple rows of teeth, the child appears to have two rows — the original baby teeth in front and a new row of permanent teeth emerging behind them.
It is one of the most visually striking things that happens during the mixed dentition years, and one of the most reliable causes of an urgent parental call to Dr Gray Dentistry in Durban. The reassuring news, which Dr Gray delivers regularly to concerned parents, is that shark teeth are extremely common, well understood, and in the majority of cases resolve without any significant intervention.
But not always — and knowing when shark teeth need attention versus when they can be safely monitored is exactly what this post is here to explain.
What Exactly Are Shark Teeth?
Shark teeth is the colloquial term for a condition called ectopic eruption — where a permanent tooth erupts in an abnormal position, specifically behind the baby tooth it is supposed to replace rather than directly beneath it.
Normally, the permanent tooth develops directly below the baby tooth it will eventually replace. As the permanent tooth grows and rises toward the surface, it applies pressure to the roots of the baby tooth above it. This pressure triggers a process called root resorption — the gradual dissolving of the baby tooth roots — which causes the baby tooth to loosen and eventually fall out, making way for the permanent tooth to erupt neatly into the vacated space.
When shark teeth occur, the permanent tooth is not positioned directly below the baby tooth. It sits slightly behind it, meaning the resorption pressure is not applied to the baby tooth roots in the normal way. The baby tooth roots do not dissolve, the baby tooth stays firmly in place, and the permanent tooth — continuing its eruption regardless — emerges behind the row of baby teeth rather than replacing one of them.
Where Do Shark Teeth Most Commonly Occur?
Lower front teeth
By far the most common location for shark teeth is the lower front teeth — the lower incisors. The lower permanent incisors are among the first permanent teeth to erupt, typically between ages five and seven, and their natural eruption path sits slightly behind and below the baby incisors. This positioning makes them particularly prone to erupting behind rather than beneath the baby teeth, and the dual-row appearance in the lower front of the mouth is what most parents encounter when they first discover shark teeth in their child.
Upper front teeth
Shark teeth in the upper front teeth are less common but do occur. They tend to attract more parental concern because they are more visible when the child smiles or speaks, and because the natural forward migration that often corrects lower shark teeth is somewhat less reliable in the upper arch.
Back teeth
Shark teeth involving the premolars erupting behind retained baby molars are less common than the front tooth presentation but do occur, particularly in children with significant crowding where the arch is simply too narrow to accommodate the erupting permanent teeth in their correct positions. This posterior shark teeth pattern is more likely to require intervention than the typical lower front tooth presentation.
Why Do Some Children Get Shark Teeth and Others Don't?
Several factors influence whether a child develops shark teeth:
Insufficient arch length
The most significant contributing factor is a jaw that does not have sufficient length or width to accommodate the permanent teeth in their correct positions. When the arch is too narrow or too short, the permanent teeth may not be able to erupt directly beneath the baby teeth and instead find alternative paths — behind the baby teeth being the most common.
This is directly relevant to the content earlier in this child development series on mouth breathing, tongue tie, and palatal expanders. Children who have developed narrow upper arches as a result of mouth breathing, low tongue posture, or tongue tie are at higher risk of developing shark teeth because the arch narrowing creates precisely the space deficit that forces permanent teeth off their intended eruption path.
Genetics
Jaw size and tooth size are both significantly influenced by genetics. Children from families where crowding and dental arch narrowing are common are at higher risk of shark teeth than those with a family history of well-spaced, roomy dental arches.
Early or delayed loss of baby teeth
Abnormal timing of baby tooth loss — whether earlier or later than expected — can disrupt the normal eruption sequence of permanent teeth and contribute to ectopic eruption patterns.
The size of the permanent teeth
Some children simply have permanent teeth that are larger than average relative to their jaw size. When the permanent teeth are large and the jaw is not, there is insufficient room for the permanent teeth to erupt in their planned positions, and displacement — including behind the baby teeth — becomes more likely.
When Do Shark Teeth Resolve on Their Own?
In the typical lower front tooth presentation, shark teeth frequently resolve naturally without any intervention. Here is why:
Once the permanent tooth has erupted behind the baby tooth, its presence often stimulates the belated loosening of the baby tooth. The tongue, sitting immediately behind the lower front teeth, applies forward pressure with every swallow — thousands of times per day — which gradually guides the permanent tooth forward toward its correct position. As the baby tooth loosens and falls out, the permanent tooth continues its forward migration and typically settles into a reasonable position within a few weeks to months.
The natural resolution of lower shark teeth is reliable enough that Dr Gray at Dr Gray Dentistry frequently advises a period of watchful waiting before recommending any intervention. The natural loosening stimulated by the erupting permanent tooth, and the forward tongue pressure often resolves the situation without any need for professional intervention beyond monitoring.
When Do Shark Teeth Need Treatment?
While natural resolution is common, several specific circumstances warrant professional assessment and likely intervention:
The baby tooth is not loosening
If the permanent tooth has been visible behind the baby tooth for three to four weeks and the baby tooth remains completely firm with no wobble developing, the roots are likely not resorbing as they should. In this situation, Dr Gray will typically recommend extracting the baby tooth to remove the obstacle. This is a simple, quick procedure that allows the permanent tooth to move forward into the correct position.
The permanent tooth is erupting very far out of position
If the permanent tooth is not just slightly behind the baby tooth but is significantly displaced — erupting well behind the line of the other teeth or at a noticeable angle — this degree of displacement warrants assessment rather than simple monitoring. The further out of position the permanent tooth erupts, the less likely it is to self-correct with tongue pressure alone.
Upper shark teeth
Upper permanent incisors erupting behind baby teeth warrant earlier assessment than lower ones. The forward migration that reliably corrects lower shark teeth is less predictable in the upper arch, and the cosmetic and functional implications of displaced upper front teeth make earlier intervention more appropriate.
Shark teeth in the back of the mouth
When premolars are erupting behind retained baby molars, this pattern is less likely to self-correct than the lower front tooth presentation and warrants prompt assessment. Retained baby molars with permanent teeth erupting behind them may need to be extracted to allow the premolars to find their correct positions.
The child is significantly older than the typical age range
Shark teeth occurring in a child who is already nine or ten rather than the typical five to seven age range may reflect a more significant eruption issue worth investigating beyond simple monitoring.
Multiple teeth are affected
If shark teeth are visible in multiple locations simultaneously, this pattern suggests a systemic arch length deficit that warrants a comprehensive orthodontic assessment rather than piecemeal management of individual teeth.
Will the Permanent Tooth End Up in the Right Place?
This is the question parents ask most often after the baby tooth has come out and the permanent tooth is sitting behind where it should be. The answer, for lower front teeth in particular, is almost always yes — provided the baby tooth has been lost and the permanent tooth has freedom to move forward.
The tongue pressure acting on the lower front teeth from behind is a remarkably effective repositioning force. Combined with the continuing growth of the jaw, which creates additional arch length into which the permanent teeth can migrate, most lower permanent incisors that erupted as shark teeth are in reasonable positions within a few months of the baby tooth being lost.
Perfect alignment at this stage is not expected and should not be judged too early. The canines and premolars that erupt later contribute significantly to the final spacing and alignment of the front teeth, and mild irregularities visible at age six or seven frequently improve substantially by age ten or eleven without any active orthodontic treatment.
Book Your Child's Assessment at Dr Gray Dentistry, Durban
Shark teeth are alarming to discover but rarely as serious as they look. With the right assessment and timely intervention where needed, the vast majority of children with shark teeth go on to develop well-aligned permanent teeth without any lasting consequence.
Dr Gray at Dr Gray Dentistry in Durban, South Africa assesses shark teeth as part of a comprehensive approach to children's dental development — giving parents clear, honest guidance on whether to monitor, intervene, or simply encourage more wiggling.
Book your child's dental assessment at Dr Gray Dentistry in Durban today.