With some frequency parents come to the consultation to resolve the situation of their child: he has double row teeth. The permanent lower incisors are erupting without the milk ones yet having fallen out. Or they are just coming 'from behind'.
The final ones coming out from behind, in fact, is normal. But it is also normal for the milk to begin to move first, to fall, and the others to come out. However, sometimes it happens that those behind are already emerging and those in front do not move at all. Is this cause for concern? Well, not in principle.
The normal thing is that with the push of the tongue the definitive incisors go to the place that corresponds to them and little by little they reabsorb the roots of the milk ones, which will move more and more and end up falling off. That can happen over the course of several weeks and seem like a slow process. But whenever the mobility of those with milk increases, it means that the path is being traveled in an adequate way.
Sometimes the final teeth erupt completely parallel to the milk teeth, a little behind. If they are parallel, one behind the other, it means that the roots of the milk are not being reabsorbed, as would be normal, and therefore they will not move at all. In these cases, and if this remains so for a while, you will have to consult with the dentist, who will do an X-ray to confirm the situation. In such cases it is possible that the milk ones have to be extracted, which will have their roots practically intact.
There are cases in which the permanent teeth have little room to come out. The milk teeth are seen very close together, without the typical spaces between tooth and tooth (diastemas) and with a very narrow dental arch. This is typical in children who suck their fingers or breathe through their mouths (or both at the same time). In these cases, it is already appreciated that there is a lack of space, that the definitive teeth, starting with the incisors, have nowhere to erupt. It is the beginning of dental crowding. The permanent teeth will be placed on their side because they take up less space. This makes them more prone to cavities and gingivitis because it is very difficult to clean the teeth properly, especially on the interdental surfaces. In these cases we are already having early signs that something is happening in that mouth and it will be necessary to act as soon as possible to promote the correct growth of the bone and that the teeth are placed in their correct place.
All these things are very easily controllable in the routine check-ups that have to be done to children every 6 months. It is a more than reasonable time to check for alterations, if it is necessary to act or review more frequently.
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