Fig. 47.2 Radiograph showing a full set of 32 permanent teeth. In three quadrants, the third permanent molars (M3s) have erupted into a normal position. The lower right M3 (circled) became impacted into the adjacent second permanent molar, which as a consequence has suffered extensive dental caries (the radiolucent area in the crown of the tooth) resulting in a dental abscess (the radiolucent area around the apices of the roots of the tooth).