Milk teeth, or baby teeth, don't fall out when the permanent tooth underneath fails to dissolve the roots of the milk tooth. This process, called resorption, is crucial for the natural shedding of baby teeth.
Here's a more detailed explanation:
The Normal Process of Tooth Shedding
Normally, when a permanent tooth develops, it begins to exert pressure on the roots of the milk tooth above it. This pressure triggers specialized cells called odontoclasts to break down the root structure of the milk tooth. As the root dissolves, the milk tooth loosens and eventually falls out, making way for the permanent tooth to erupt.
When Things Go Wrong: Impaction and Misalignment
Sometimes, this process is disrupted, leading to a retained milk tooth:
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Lack of Space: If there isn't enough space in the jaw, the permanent tooth might become impacted, meaning it gets stuck and cannot properly align to push on and resorb the milk tooth's root.
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Misalignment: The permanent tooth might be misaligned and positioned away from the milk tooth root. In this scenario, it cannot effectively trigger the resorption process.
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Root Fusion: Rarely, the root of the primary tooth can fuse with the jaw bone, preventing the permanent tooth from applying the necessary pressure for resorption.
The Result: Retained Milk Teeth
When resorption doesn't happen as it should, the milk tooth remains firmly in place, even beyond the age when it's expected to fall out. This can cause several problems:
- Crowding: The permanent tooth might erupt in an abnormal position, leading to crowding and misalignment of other teeth.
- Delayed Eruption: The retained milk tooth can block the permanent tooth from erupting altogether.
- Damage to Permanent Tooth: In some cases, the impacted permanent tooth can damage the roots of adjacent teeth.
What Can Be Done?
If a milk tooth is retained longer than expected, it's important to consult a dentist. The dentist will assess the situation, take X-rays to determine the position of the permanent tooth, and may recommend extraction of the milk tooth to allow the permanent tooth to erupt properly. In some instances, orthodontic treatment might be needed to guide the permanent tooth into its correct position.
