Impacted / unerupted premolars & canines

A dental radiograph (xray), which shows an unerupted and impacted upper left and right permanent canine tooth. This occurs in less than 0.1% of the population. This is often seen in cases in which the permanent lateral incisor is missing, small in shape and in certain malocclusion types (Class II division II). In the radiograph shown the patient has ‘peg shaped’ or diminutive laterals (small in shape). In 85% of cases, the canine tooth drifts towards the palate (roof of mouth), with only 15% ending up bucally (towards the cheek/lip). When teeth drift away from their correct position, adjacent teeth are at risk from damage by resorption or cystic enlargement. The position of the tooth is located using a radiographic (xray) technique called ‘parallax’. The higher the crown of the canine tooth and the closer to the mid-line, the poorer the prognosis for orthodontic alignment. An orthodontist may advise the removal of this unerupted tooth or attempt to align it with fixed braces as part of the overall orthodontics treatment plan. Dentists should palpate for the upper canines around 9-10 years of age in the buccal sulcus.