Permanent tooth growing behind baby tooth? The double row can look alarming. Parents often call this appearance “shark teeth.” It is most often seen around the lower front teeth when a child is about six or seven, although the timing varies. In many children, the baby tooth becomes loose and falls out while the tongue and normal jaw growth help the new tooth move forward. A dentist should still assess a baby tooth that remains firm, an eruption that looks crowded, or any pain, swelling or trauma.
Written and dentally reviewed by Dr. Manish Pandey, BDS, Dental Surgeon
Last reviewed: 2 September 2026
Quick answer: is a permanent tooth behind a baby tooth normal?
It is a fairly common eruption pattern during mixed dentition, when baby and permanent teeth are present together. It is not automatically an emergency. Ask your child to wiggle the baby tooth gently with a clean tongue or finger, keep the area well brushed, and arrange a dental check if the baby tooth is not becoming looser, the adult tooth is continuing to erupt out of line, or there is not enough visible space.
Why do “shark teeth” happen?
Normally, a developing permanent tooth helps dissolve, or resorb, the root of the baby tooth above it. The shortened root allows the baby tooth to loosen and shed. Sometimes the permanent incisor follows a slightly tongue-side path instead. Its pressure may not remove the baby-tooth root as quickly, so the new tooth appears before the old one has fallen out.
Other factors can influence the pattern:
- the baby tooth is slow to loosen or has an unusually persistent root;
- there is limited room in the dental arch;
- the permanent tooth is angled away from its usual eruption path;
- a previous injury or infection affected the baby tooth;
- less commonly, an extra tooth or another local obstruction alters eruption.
The lower central incisors are often the first baby teeth to be replaced. For a clear overview of primary and adult dentition, see our guide to teeth names, functions and eruption patterns.
Will the baby tooth fall out on its own?
Often it does—especially when the baby tooth is already mobile. As it loosens, it may shed naturally over days or weeks. Once the obstruction is gone, tongue pressure and normal growth may guide a mildly displaced lower incisor toward the arch. However, every child has a different amount of space and a different eruption path. A photograph cannot show root shape or the position of teeth beneath the gum, so avoid relying on online comparisons alone.
What should parents do at home?
- Check mobility gently. Let your child move a loose baby tooth with the tongue or a clean finger. Do not force it.
- Brush both rows carefully. Plaque and food can collect between the retained tooth and the new tooth. Use a small, soft brush twice daily.
- Use age-appropriate fluoride toothpaste. Supervise brushing and encourage spitting rather than swallowing. Our children’s toothpaste guide explains practical choices.
- Choose comfortable foods if tender. Temporary sensitivity while a tooth loosens can make very hard foods uncomfortable.
- Take a clear dated photo. A weekly photo can help you notice whether the baby tooth is loosening and whether the permanent tooth is moving.
- Keep routine dental visits. The dentist can assess space, the bite, decay, mobility and eruption symmetry.
Should you pull the baby tooth at home?
Do not pull a firm tooth or use string, tools or repeated force. This can cause pain, bleeding, a broken root or fear of dental care. If a tooth is extremely loose and comes away with gentle movement, that is different from forcing a retained tooth. When there is doubt, let a dentist determine whether observation or removal is safer.
When should a dentist see the child?
Book a dental visit if the permanent tooth is visible but the baby tooth remains firm, if the double row is not changing, or if you are unsure whether enough space exists. An examination is also important when the matching tooth on the other side erupted months earlier, the child had previous dental trauma, or the eruption seems markedly displaced.
Seek prompt care for facial or gum swelling, pus, fever, worsening pain, uncontrolled bleeding, a recent injury, difficulty eating, or a tooth that looks badly displaced. These findings are not explained by uncomplicated “shark teeth” and may indicate infection or trauma.
Will the dentist remove the retained baby tooth?
Not always. If the baby tooth is loose, the child is comfortable and there appears to be adequate space, monitoring may be reasonable. A dentist may consider removal when the tooth stays firm, blocks cleaning, causes discomfort, contributes to crowding, or interferes with the eruption path. The decision depends on clinical findings and, when necessary, a carefully selected dental X-ray—not on the appearance alone.
Will the permanent tooth move into place?
A mildly tongue-side lower incisor often improves after the baby tooth is lost, particularly when there is adequate space. Improvement is not guaranteed. Significant crowding, a crossbite, an unusual eruption angle or a tooth that remains far outside the arch may need further assessment. The American Association of Orthodontists recommends an orthodontic check when a problem is first recognized and no later than age seven; this does not mean every child needs braces at seven.
How does a dentist evaluate a double row of teeth?
The dentist looks at which tooth is erupting, how loose the baby tooth is, the amount of available space, the child’s bite and whether the same tooth on the opposite side has erupted. They also check for decay, gum inflammation and a history of injury. An X-ray may be advised when it could change management—for example, if the eruption path, root, extra teeth or a possible obstruction cannot be assessed clinically.
Frequently asked questions
How long can shark teeth be watched?
There is no single safe waiting period for every child. A loose, painless baby tooth that is clearly progressing is different from a firm tooth with crowding or pain. Arrange a dental review if progress is uncertain rather than waiting for a fixed number of weeks.
Are shark teeth more common on the bottom?
The pattern is often noticed behind the lower front baby teeth during the early mixed-dentition years. It can occur elsewhere, so an upper or side tooth erupting out of position still deserves individual assessment.
Can shark teeth cause crooked teeth?
The double row can be associated with temporary displacement, but it does not by itself determine the final alignment. Available jaw space, tooth size, eruption direction and bite development all matter.
Does every retained baby tooth need extraction?
No. Some loose baby teeth shed without treatment. Extraction is considered when the clinical benefits outweigh observation, such as persistent firmness, blocked eruption, hygiene problems, pain or an unfavorable bite.
Key takeaway
A permanent tooth growing behind a baby tooth is commonly seen during the transition to adult teeth. Keep the area clean, allow only gentle wiggling of a loose tooth, and avoid forceful home removal. A dental examination is the safest way to decide whether the child needs monitoring, removal of a retained tooth, or an orthodontic opinion.
Dental disclaimer: This article provides general education and cannot diagnose your child’s eruption pattern. Advice must be individualized after an examination. Seek prompt professional care for swelling, fever, trauma, significant pain or difficulty eating.
Authoritative references
- American Dental Association: Primary and permanent tooth eruption charts
- American Dental Association: Removing a loose tooth
- American Academy of Pediatric Dentistry archive: Local factors affecting permanent tooth eruption
- American Association of Orthodontists: Benefits of early orthodontic evaluation
- NHS: Taking care of children’s teeth