Root resorption of mandibular second molar teeth associated with the presence of the third molars.

Although pressure resorption of second molars is associated with impacted and/or erupting third molars, the relationship between pressure resorption and age is unclear. In order to investigate this relationship, 3883 dental radiographs were studied in 3174 individuals of various ages. The incidence of superimposition of the second molar on the third molar was not elevated in any subgroup except that of women of 16-40 years of age. There were no age or sex differences for the incidence of second molar root resorption. In older individuals, root resorption associated with a completely impacted third molar was more frequent than with a partially impacted third molar, and root resorption at the apex was mainly seen in individuals over 50 years of age. There was a higher incidence of superimposition and root resorption in men than women. Apical root resorption may be seen long after the formation of completely impacted third molars in both genders.