Case referred to the clinic by a colleague for possible surgical treatment of a periapical lesion initially related to tooth 12, observed on periapical radiograph. Patient reported pain when pressing the vestibular gingival region. On clinical examination, there was pain on palpation of teeth 11 and 12, mainly on the palate, and no response to thermal testing on teeth 11 and 12. Radiographic examination using Clark's technique showed that the image was displaced in relation to the apex of tooth 12, suggesting that the lesion was not related to this tooth. It was decided that tooth 11 should be treated endodontically and then preserved. Tooth 12 was accessed by another professional for internal whitening. After 2 years we observed ongoing tissue repair and remission of signs and symptoms. The case is interesting because it showed that a careful diagnosis avoided an invasive intervention on tooth 12, which was not the origin of the inflammatory process. Simple radiographic resources can be very useful in cases where a tomography is not possible, as was the case, since the patient was unable to afford one.