Long-term follow-up of orthopantomographs of 251 adults orthodontically treated former patients showed 113 clinically asymptomatic impacted 3rd molars in 58 patients. Radiographic assessment revealed contact of impacted 3rd molars with the 2nd molars, resorption of upper and lower 2nd molars, reduced bone height on the distal side of the maxillary and mandibular 2nd molars, as well as pathologically widened pericoronal spaces of the upper and lower 3rd molars. The comparison of the sagittal 3rd molar position in 52 impacted teeth revealed a sagittal change in all 3rd molars from post-treatment to follow-up: maxillary and mandibular 3rd molars had rotated to a more upright position and showed an increase in mesio- or distoangulation or a change of axial inclination. The lack of predicting factors such as age, period of impaction, extent of space deficiency, developmental stage, level of eruption, and bone conditions leads the authors to recommend that former orthodontic patients be recalled at regular intervals for assessment of changes in the condition and position of erupting or impacted 3rd molars.