[Distal surface caries in the mandibular second molar in the presence of a partially erupted/impacted third molar]

Distal surface caries in the mandibular second molar is a common outcome of impaction of the adjacent third molar. To determine the prevalence of this type of caries in the Netherlands, 250 radiographs were evaluated. The prevalence among the research population was 26%. Risk factors for developing distal surface caries in the mandibular second molar were partially erupted/impacted third molars with a mesioangular or horizontal angulation, an LD loss of ≥ 2mm and an increased modified DMFT score. The relation between the point of contact of the third molar and the adjacent mandibular second molar, on the one hand, and, on the other, the cemento-enamel junction of the mandibular second molar and the prevalence of distal surface caries almost reached statistical significance (p = 0.052). The relatively low prevalence of distal surface caries in the Netherlands is probably related to the current clinical guidelines recommending early extraction of partially erupted/impacted third molars, particularly in cases of third molars with a mesioangular or horizontal angulation.