ENDODONTIC TREATMENT FOR A MANDIBULAR SECOND MOLAR FUSED WITH A PARAMOLAR BY THE SKILLFUL USE OF CONE-BEAM COMPUTED TOMOGRAPHY AND A DENTAL OPERATIVE MICROSCOPE

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Fused teeth have complex root canal morphologies and are difficult to treat, because the tooth embryos combine to form composite teeth and share their pulp cavity. In this case, the mandibular second molar and the paramolar had fused, and the pulp cavity showed a complex configuration. Even on dental X-ray examination, it was still difficult to confirm the morphology of the root and root canal. Therefore, cone-beam computed tomography (CBCT), which supports clinicians treating complex unusual cases to enable them to accurately confirm the pulp cavity morphology in three dimensions, was performed. The outline of the access cavity should be designed in a similar form to the cross-sectional transverse images at the level of the cement enamel junction (CEJ) rather than the contour of their occlusal surface, since fused teeth share their pulpal floor intricately. In the case of fused teeth, micro-endodontic treatments including proper access opening designs, adequate cleaning, and a shaping protocol are crucial points to ensure success, and they are accomplished by suitable pre-treatment planning and precise procedures.