Primary (baby) teeth are the first set of teeth, emerging around six months of age. Most children develop a full set of 20 by age three. These teeth shed between ages six and twelve, making way for permanent adult teeth. While most lose all primary teeth by adolescence, some adults retain one or more into adulthood.
Common Reasons for Retained Baby Teeth
A frequent reason for a retained baby tooth is the congenital absence of its permanent successor, known as agenesis or hypodontia. The adult tooth simply never forms, so there’s no natural force to push out the primary tooth. Hypodontia, affecting 2% to 8% of the population and often inherited, means one to five permanent teeth are missing.
Ankylosis is another cause where a baby tooth’s root fuses directly to the jawbone, preventing natural shedding. This fusion eliminates the periodontal ligament, which normally holds the tooth and allows movement. Ankylosed teeth become immobile and appear sunken or submerged compared to adjacent teeth as the jaw grows. Trauma, genetics, and local infections are considered contributing factors, though the exact cause is not fully understood.
Sometimes, a permanent tooth may be present but becomes impacted, blocked from erupting correctly. This impaction can be caused by overcrowding, lack of jaw space, or the permanent tooth growing at an improper angle. If the permanent tooth cannot exert enough pressure on the primary tooth’s root, the baby tooth will not loosen.
Genetic factors often contribute to retained primary teeth or missing permanent teeth. A family history of retained baby teeth increases the likelihood of this trait being passed down. Certain genetic conditions can also affect tooth development, leading to non-eruption of permanent teeth and primary tooth persistence.
Early trauma or infection to a primary tooth can damage the developing permanent tooth bud underneath. A severe injury, especially early on, can disrupt permanent tooth formation, potentially slowing or stopping its development. Similarly, severe tooth decay in a primary tooth can affect the underlying permanent tooth, preventing its eruption.
Potential Implications of Keeping a Baby Tooth
Retaining a baby tooth into adulthood can lead to various dental issues, even if the tooth appears healthy. A smaller baby tooth among larger adult teeth can disrupt dental arch alignment. This can cause surrounding permanent teeth to shift, leading to misalignment, crowding, or bite problems (malocclusion).
Misaligned teeth from a retained baby tooth can impact chewing efficiency, making chewing difficult. An uneven bite can also place undue stress on certain teeth and jaw joints, leading to discomfort or pain.
Retained primary teeth, particularly if misaligned or submerged, can be more challenging to clean effectively. This difficulty increases plaque accumulation, raising the risk of tooth decay and gum disease around the retained tooth and its neighbors.
Aesthetic concerns are common, as baby teeth are smaller and may have a different shade or shape than permanent teeth. This discrepancy can be noticeable, especially if the tooth is prominent, affecting a person’s smile and confidence.
Long-term retention of a baby tooth can sometimes result in root resorption or bone loss in the jaw. If the retained primary tooth does not receive the normal stimulation a permanent tooth provides, the jawbone in that area may gradually diminish. This can complicate future treatment if the tooth needs removal.
Management and Treatment Options
Dental professionals assess a retained baby tooth’s health, position, and presence of a permanent successor. If the tooth is healthy, stable, and causes no functional or aesthetic problems, a “wait and see” approach may be recommended. This involves regular monitoring to ensure it remains intact, free of decay, and does not negatively affect adjacent teeth or bone.
Extraction is often necessary if the retained baby tooth is compromised by decay, gum disease, severe root resorption, or alignment issues. If the baby tooth is ankylosed (fused to the bone) or blocking a permanent tooth’s eruption, extraction is typically chosen. After extraction, a space maintainer might be used to preserve the gap.
Orthodontic treatment (braces or clear aligners) can create space for an impacted permanent tooth to erupt, or close gaps if the baby tooth is extracted and no replacement is planned. Orthodontics can also correct misalignment or bite problems from the retained tooth. This may involve moving existing teeth to fill space or properly position adult teeth.
Restorative options are available to improve the appearance or function of an otherwise healthy retained baby tooth. These include dental bonding, where tooth-colored resin reshapes and enlarges the tooth, or crowns and veneers for a more uniform look with surrounding adult teeth.
If a retained baby tooth is extracted, especially due to a missing permanent tooth, various replacement options exist. Dental implants offer a durable solution: a prosthetic tooth with a metal root that integrates with the jawbone, stimulating it and preventing bone loss. Other options include dental bridges, using adjacent teeth as anchors, or removable partial dentures.