Over-retained primary teeth (baby teeth) is a dental condition in which one or more of a child’s primary teeth do not come out at the expected time to allow permanent tooth eruption. Normally, the primary teeth exfoliate naturally on a fairly predictable timeline (beginning around age 6 on average), and the permanent teeth erupt within a few months, subsequent to each primary tooth loss. When this process does not occur within a year of expectation, a comprehensive dental exam, along with dental x-rays, is needed to evaluate the tooth or teeth to determine the cause of over-retention.
Your pediatric dentist will assess the tooth’s:
This assessment will help determine the cause of the primary tooth being retained and if it has become fused to the jawbone (ankylosis).
The most common primary teeth that become over-retained are the maxillary (upper) second molars and the maxillary canines.
Causes of Over-Retained Primary Teeth
The most common reason that a primary tooth becomes over-retained is the absence of an underlying permanent tooth. The permanent tooth usually breaks down the root of the primary tooth and pushes it until the baby tooth falls out, therefore, without that pressure, the primary tooth often remains in place.
Missing permanent teeth are a common occurrence, presenting in 2-7% of all patients and more often in girls than boys. Permanent teeth that are most commonly missing are the upper and lower second pre-molars and the upper and lower lateral incisors. If a patient is missing 1-5 permanent teeth, it is called hypodontia. Six or more missing permanent teeth is known as oligodontia. There is not an exact reason to explain missing teeth, although genetics is believed to play a role in it.
Other possible contributors to missing permanent teeth may be:
- Certain syndromes
- Endocrine disorders
In some cases of over-retained primary teeth, the baby tooth has loosened, but then tightens back into the gum, keeping the permanent tooth from erupting.
Other common causes of over-retained primary teeth include:
- Ankylosis (bone fusion): A primary tooth may become fused to the bone, keeping it from falling out.
- Incomplete resorption of the root: The primary tooth root may not completely resorb, therefore obstructing the permanent tooth’s eruption.
- Misalignment of the permanent tooth: When the incoming permanent tooth is erupting at an improper angle or becomes stuck under the jawbone, there may not be enough pressure to push the primary tooth out.
- Trauma: Injury to the tooth roots or nerves may delay the formation of the permanent tooth and retain the primary tooth.
- Infection: Poor oral hygiene can result in damage to permanent teeth before they erupt, causing them to resorb into the jaw and the baby teeth to remain.
- Pathology: Some diseases or medical conditions can hinder permanent tooth formation and eruption.
- Genetics: Children whose parents retained primary teeth are more likely to also have over-retained baby teeth.
If you are concerned that one or more of your child’s primary teeth may be over-retained, contact the pediatric dental and orthodontic specialists at Kids Dental for an evaluation.
At Kids Dental, we offer comprehensive, family-centered pediatric dental care in a child-friendly nurturing environment. If you are looking for a place to call your dental home, please schedule a consultation with one of our pediatric dentists by completing an Online Appointment Request or calling either office.