Sometimes the permanent teeth erupt behind the primary teeth in children, before they are lost. Many parents become concerned if they see the permanent teeth coming behind the primary teeth in their child's mouth. With this child develops double rows of teeth. This condition is sometimes referred to as “Shark teeth”. The name comes from the fact that sharks also have a double row of teeth.
It is a common condition and occurs in about 10 percent of all children. These are most commonly seen in the lower incisors region, but they can also occur at the upper incisors or primary molars region.
It can occur at any time, but are most common during two periods in a child's development. The first time is around age of 6 yrs, when the lower incisors erupt. The second is around age of 10 to11 yrs, when the upper premolars erupt.
During the normal development, the permanent tooth slowly resorbs the primary tooth root when it erupts under it. When the root is almost completely lost, the primary tooth loses its attachment and falls out of the tooth socket. The permanent tooth then moves and erupts into the empty space.
Normally the permanent teeth develop lingual to the primary teeth, so any kind of deviation of permanent tooth from normal position can lead to retained primary tooth. Another condition causing retention of primary teeth is crowding of the dentition. The new tooth then erupts behind the primary tooth by taking the path of least resistance. This ultimately ends up with two rows of teething in child’s mouth.
If you find that both permanent and temporary teeth are there in your child’s mouth for more than three weeks then it is advised to take him/her to pedodontist. It is important to monitor permanent tooth eruption. No two teeth should occupy the same space at the same time period. The dentist will evaluate the condition and decide according to the situation.
Though it is not an emergency situation, but it should be treated. If the retained primary teeth are not removed, it may lead to the development of various malocclusions such as crowding, narrow dental arch, cross bite in the resulting permanent dentition.
If the primary tooth is getting mobile and the permanent tooth continues to erupt, the primary tooth will fall out and the situation corrects itself.
Once the permanent tooth erupts completely behind the primary tooth, there is nothing to push or resorb the root. This allows the primary tooth to stay in place. A dentist will usually extract the primary tooth and create space for the permanent tooth to erupt.
In most of the cases, the permanent tooth will come into position in a few weeks or months time. The normal tongue movements will push the malaligned permanent teeth into line.
In some cases still there is not enough space for the permanent tooth to move into the position even after the primary tooth is removed. In these cases, proximal slicing or disking of adjacent teeth may be performed. However, orthodontic treatment may be required in some severe cases.
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