2.1
Permanent molar teeth normally erupt from the age of 6 onwards, with the third molars (wisdom teeth) being the last to erupt, usually between the ages of 18 and 24 years. Wisdom teeth may erupt normally into correct dental alignment and function or conversely develop in non- or minimally functional positions. Impaction occurs when there is prevention of complete eruption due to lack of space, obstruction or development in an abnormal position. This may result in a tooth erupting partially or not at all. Wisdom teeth can also be impacted, either erupting partially or not at all. Impaction may be associated with pathological changes including pericoronitis, an increased risk of caries and periodontal disease in adjacent teeth, and orthodontic problems in later life.