This report describes a rare situation in which external cervical resorption was associated with gingival enlargement (pyogenic granuloma) in the upper left central incisor (tooth 21) in a 28-year-old man. Tissue from the lesion was examined histopathologically; periodontal, endodontic and restorative treatments were performed; and the occlusal disharmony, which had resulted in traumatic occlusion, was corrected. Three years after these treatments, the gingiva is normal and healthy and there is no sign of recurrence of the pathologic enlargement. The patient's periodontal condition is now routinely evaluated. In the presence of gingival enlargement resulting from inflammation, traumatic occlusion can cause progressive external root resorption.