Abstract: Objective:To explore the process of diagnosis and treatment of the patients with dens invaginatus of right maxillary second molar, to analyze the clinical features, the radiographic features and the pathological features of the dens invaginatus, and to make a reasonable treatment plan. Methods:The clinical data, imaging findings and pathological data of a patient with dens invagination were collected. The clinical diagnostic criteria and treatment methods of these cases were summarized with relevant literature review. Results:The patient, female, 28 years old, was diagnosed with a hole in the upper right posterior teeth for 6 months. The special examination results showed that the 17-toothed face was flat, the crown was huge, and the occlusal surface was seen in the sag and sputum; the medullary cavity was not reached. The radiograghic examination results showed that the enamel density image of the 17-toothed surface was sunken to the root, with a depth of about 7.7 mm, diagnosed as dens invaginatus. At the time of initial treatment, the humus was removed and the sag received sedative treatment. The spontaneous pain still existed during the follow-up examination, and the problem of food embolism was not solved. Considering the poor recovery after treatment, the patient agreed to remove the tooth. The isolated tooth was observed by pathological grinding, and the enamel and dentin structures of the invaginatus were abnormal observed under microscope. Conclusion:The patients with dens invagination occurs in the molar area are rare;the type of disease and treatment plan should be determined by imaging examination during the process of diagnosis and treatment; it suggests that the patients with poor recovery after treatment should remove the teeth.

Key words: dens invaginatus, teeth dysplasia, right maxillary, second molar