[Preventive extraction of the lower wisdom teeth: radiological criteria].

Many lower wisdom teeth are impacted. Various authors advocate systematic and prophylactic removal of all third molars. The reasons for such procedure are not always clear, and often, radiological evaluation is missing. A study of over 200 patients was carried out to determine whether systematic extraction of wisdom teeth is justified. Another study was undertaken, to observe the development of 42 lower impacted third molars. It was tried to find conclusions which might justify the radiological criteria for such an extraction. The factors, leading to diagnosis and radiographic analysis were discussed and four radiological criteria were finally established. In conclusion, it seems that early radiological evidence (age 16--17) is very important.