CBCTを用いた陥入歯に対する考察

抄録

Abstract : Purpose : Dens invaginatus is a morphologically abnormal tooth in which enamel and dentin are deeply invaginated into the pulp cavity due to developmental abnormalities during tooth formation. Difficulties may arise if we encounter dens invaginatus clinically and root canal treatment is required. We report a case in which the condition of dens invaginatus was accurately grasped by using cone beam computed tomography (CBCT) and root canal treatment was performed.

 Case : The maxillary left lateral incisor had undergone restoration treatment about 10 years ago, but recently the symptoms had gradually become stronger, so the patient visited our clinic. The maxillary left lateral incisor had a negative reaction in the electrical pulp test and thermal test, and severe percussion pain was observed. Upon X-ray examination, an X-ray transmission image was found at the apex of the maxillary left lateral incisor. In addition, an unusual pulp cavity structure was observed. The pulp cavity branched from near the center of the root to the crown side. A structure suspected of invagination was confirmed in the center. The findings of CBCT showed that the dental pulp cavity expanded in a dome shape from the center of the root to the crown side, and lesion-like transmission images were confirmed on the apical and palatal sides. The affected tooth was the left maxillary incisor, the pulp was diagnosed as necrotic, and the apical periodontal tissue was diagnosed as acute apical periodontitis. It was decided to perform root canal treatment first, and if there was no healing tendency, to consider surgical endodontic treatment. The symptoms disappeared after root canal treatment, and a postoperative evaluation was performed by CBCT imaging at follow-up 12 months after treatment, which confirmed that the lesion-like X-ray transmission images on the apical and palatal sides had disappeared.

 Discussion : AAE and AAOMR have expressed the view that CBCT imaging to clarify the anatomical morphology is the optimal diagnostic imaging method before operating on teeth with suspected complex morphology. It was confirmed by CBCT images that this case was classified as Oehlers type 2. In addition, by sufficiently grasping the morphology by CBCT imaging, it was relatively easy to remove the invaginated part by file attached to the ultrasonic transmitter.

 Conclusion : By accurately grasping the pathophysiology of dens invaginatus using CBCT, root canal treatment could be performed safely. CBCT imaging is considered to be useful for dens invaginatus.