Ectopic teeth are similar to impacted teeth. The difference is that ectopic teeth erupt somewhere they shouldn't (referred to as an 'abnormal eruption path'), whereas impacted teeth may be on course to erupt in the right spot, but are simply not able to. A tooth can be both ectopic and impacted.
As with impacted teeth, it is relatively common for maxillary canine teeth to develop ectopically, in which case they often erupt in the upper palate (the roof of the mouth), instead of on the gumline. Maxillary first molar teeth are also prone to ectopic development.
As with many other orthodontic issues, ectopic teeth are caused by genetic factors, often linked to a lack of space on the jawbone for the ectopic tooth.
Most ectopic teeth can be repositioned using braces, and in some cases the tooth may need to be surgically exposed before braces are fitted. Occasionally, extraction of the ectopic tooth may be recommended, however this may impact the aesthetics of the remaining teeth and may only be suitable if there is already significant crowding.