The teeth begin to emerge through the gums (emerge) in infancy.

The teeth begin to emerge through the gums (emerge) in infancy, and again when the permanent teeth to replace the first tooth (teeth). If a tooth does not achieve what you leave or in part, is considered to be impacted. The third set of molars and molars, which are the last teeth to emerge, usually between 17 and 21 years, are the teeth that are impacted more frequently. An impacted tooth remains stuck in the soft tissue of the gums or the bone for several reasons. It may be that the area is simply not crowded and there is space for the teeth out. For example, the jaw may be too small to accommodate the molars. The teeth also can tilt, twist or move around while trying to escape, causing the impacted teeth.
The wheels impacted molars are very common and often do not cause any pain or problem clearly. However, some professionals believe that an impacted tooth pushes closer to the tooth, which in turn pushes to the next, finally producing a misalignment in the bite. A tooth that may emerge in part to trap food, plaque and other debris in the soft tissue around them, leading to inflammation and this sensitivity of the gums, like unpleasant odor in the mouth. This is called pericoronitis.