PMC9868999_01
Periapical radiographs (PR), clinical photographs, and micro-CT images of the case. A) Immediate post-treatment PR shows a mandibular right first molar treated with a CEM pulpotomy; B) PR at 5-year recall shows dentinal bridge formation at canal orifices and normal PDL, indicating successful results; C) Clinical photograph shows a vertical fracture which made the tooth unrestorable; D) Separation of the mesial and distal roots during surgical tooth extraction; E) MCT image from the apical aspect of the root specimen, showing two open root canals connected with an isthmus; F-G) MCT images from the coronal plan, illustrating dentinal bridge formation at buccal and lingual canal orifices
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Tehran, Iran) and permanent restoration using resin-based dental composite restorative materials (Z250/Z350, 3M, ESPE, USA) (Figure 1A). The treated tooth was asymptomatic and fully functional in routine follow-ups, with radiographic evaluations clearly showing hard tissue formation at root canal orifices at 5-year recall (Figure 1B). Clinical examination revealed a vertical coronal fracture that separated the buccal cusps from the main structure of the tooth, making it unrestorable (Figure 1C). After obtaining informed consent and during the tooth extraction, the remaining crown broke, and to protect the alveolar bone from further traumatic damage, the roots were carefully separated and then, cautiously extracted (Figure 1D).  The micro-CT images proved the unblocking of root canals at the apical end of the mesial root and displayed the deposition of formed hard tissue over the two canal orifices capped with CEM cement (Figures 1E and 1F). Moreover, the mineralized bridge showed identical density with its surrounding normal dentin without any tunnel defects, and entirely re-closed the remaining radicular pulp similar to normal conditions (Figure 1G).