2 Clinical Need and Practice
2.1 Permanent molar teeth normally erupt from the age of six onwards, with the third molars (wisdom teeth) being the last to erupt, usually between the ages of eighteen and twenty four 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.
2.2 Removal of wisdom teeth is one of the most common surgical procedures performed in the UK. Current practice includes both the removal of impacted third molars causing pathological changes as well as the early prophylactic removal of pathology-free impacted third molars. Wide variations in the rates of this latter procedure across the country, which suggest that in the past, up to 44% of wisdom teeth removals and prophylactic surgery may have been inappropriate, have been reported. However, in recent years, changes in the practice of removal of wisdom teeth may have taken place in response to Faculty of Dental Surgery, Royal College of Surgeon's guidelines. Even so, some 22% of procedures may still be inappropriate. In 1994/95 there were approximately 36,000 inpatient and 60,000 day case admissions in England. More recent figures (1998/99) for Wales indicate that there were up to 3000 procedures. It is estimated that the total cost to the NHS in England and Wales of wisdom teeth extractions is up to £12 million per year.
 Current clinical practice and parameters of care: The management of patients with third molar teeth. Faculty of Dental Surgery of the Royal College of Surgeons September 1997.