An exciting event in the life of most parents is the eruption of their child’s first baby tooth. This normally occurs between 6 and 12 months of age. In contrast, children look forward to loss of their first baby tooth and welcoming a visit from the tooth fairy, usually between the ages of 5-7 years of age.

Eruption of the new permanent tooth typically follows within a few months after exfoliation (loss) of the deciduous (baby) tooth. In general, while overall timing of the tooth eruption varies by individual person, similar types of teeth (both right to left, and top to bottom) usually grow into the mouth at comparable times. However, sometimes the permanent tooth does not erupt when expected.

What causes delay or failure of permanent tooth eruption?
At times, the permanent tooth simply is not there. Congenitally missing teeth are fairly common, and often in this case the deciduous tooth in that position will not exfoliate. There are situations where the permanent tooth is mechanically blocked from eruption due to its proximity to an adjacent tooth, because the overlying gum tissue (gingiva) is too dense or fibrous to permit eruption, because the permanent tooth is tipped within the jaw bone, or even due to the presence of an extra tooth. Benign or malignant growths can also block eruption. A tooth bud could form far from the arch, for example, on the palate. Typically, these teeth will not erupt without assistance from orthodontic appliances.

There could be a problem with the formation of the tooth itself or its root, which could grow slowly or cease to grow completely, preventing its movement. Sometimes these abnormalities in formation occur when there has been trauma to the overlying deciduous tooth that damages the developing permanent tooth.

Whatever the reason, it is essential that most cases of unerupted teeth be identified to prevent other dental issues from developing. If you notice that your child or grandchild’s tooth is not growing in when the same tooth on the other side of the mouth is doing so, or if their smile is becoming asymmetric, it would be wise to visit an orthodontist, who receives special training to identify abnormalities in eruption that can affect the overall dentition and bite, and who will determine the cause and establish a plan for its correction.