Teeth are described as impacted when they have not fully erupted, that is they have not fully emerged from the gums. Where a tooth is fully impacted it has not broken through the gum at all, although a tooth can also be partially impacted, where it has appeared, but not fully.
Baby teeth are normally fully replaced between 10-14 years of age. The wisdom teeth, appear later generally between the ages of 17-25.
Some teeth are more prone to impaction than others – the most commonly teeth to be affected are wisdom teeth (also referred to as third molars), followed by upper eye teeth (also referred to as maxillary canines or cuspids).
In many cases impacted teeth have no symptoms and are often discovered during a routine x-ray. In children, a baby tooth remaining in place and /or the lack of emergence of the replacement adult tooth can be a sign of an impaction. Be especially suspicious if the baby tooth on one side has fallen out and the same tooth on the other side is still solid some months later. A firm, tooth sized bulge on the gum next to an over-retained baby tooth may also indicate an impacted permanent tooth. If you are concerned please seek advice.
For wisdom teeth in particular, development of the jaws has generally stopped by the time they are due to appear, and so the jaws may not have enough room on them to accommodate the new teeth. Both with wisdom teeth and other impacted teeth, genetics may also play a role.
A decision as to whether or not to have impacted teeth removed will depend on each individual case. Where the impaction is not causing any symptoms, an option is to monitor the tooth and treat if necessary. Impacted teeth may need to be removed for a number of reasons related to a higher risk of developing dental problems, such as…
- Dental cavities.
- Tooth decay.
- Gum disease.
- Bone / tooth absorption.
- Damage to roots of adjacent teeth or to jawbone (caused by the development of cysts).
Partially impacted teeth are especially prone to problems due to the difficulty of cleaning. Impacted teeth may grow into an adjacent tooth damaging the root and causing that tooth to be lost.
An impacted tooth may need to be extracted. In some cases – particularly where the impacted tooth is a maxillary canine – it may be preferable to encourage the tooth to erupt. This can be done using a variety of approaches, from extracting any remaining baby tooth, to using brackets, braces or expanders.
See also Ectopic Teeth.