How often do asymptomatic, disease-free third molars need to be removed?

The preventive removal of third molars (M3s) should be based on evidence. To optimize the timing of removal of M3s, it is essential to predict the eruption of the tooth and, even more importantly, to recognize beforehand which teeth will become involved in pathologic conditions later in life. The first aim of this review was to determine how well physicians currently can predict the eruption of an M3. The second aim was to review how frequently impacted M3s are removed. The third aim was to summarize the indications for preventive removals as presented in the evidence-based Current Care Guideline for the management of M3s in Finland. The prediction of eruption can be made at accuracies from 80% to 97%. In addition, the decrease in the number of M3s is very rapid, with only 31% remaining at 38 years of age. According to the Current Care Guideline, preventive removals at a young age are justified for 3 groups of teeth in the mandible: partially impacted teeth in the horizontal position, partially erupted teeth in the vertical position, and incomplete roots growing close to the mandibular canal. In conclusion, one fourth of retained and disease-free M3s need to be removed preventively at a young age, whereas the rest should be treated according to signs and symptoms.