PMC9217544_01
Mandibular left second molar with large periapical radiolucency: (a) mandibular left second molar with inappropriate previous root canal therapy, intracanal broken instruments, large periapical radiolucency, and furcation involvement; (b) former mandibular second molar was diagnosed hopeless and thus was removed whereas the mandibular left third molar was soundly extracted, and root-end cavities were cautiously prepared, carefully sealed using calcium enriched mixture (CEM) cement, and transplanted as a replacement for the mandibular left second molar; (c) in the 3-month follow-up, relative healing of periradicular bone was evident; however, radiolucencies in the mesial periapical region and furcation persisted, and signs of external inflammatory root resorption (EIRR) appeared on the distal root; (d) after the 6-month follow-up from the first treatment session and persistence of EIRR signs, the coronal restoration was removed, root canals were prepared, canals were medicated with a new combination of triple antibiotics (PMC), and the coronal cavity was sealed with Zonalin ; (e) after 3 weeks from the previous appointment, relative bone healing and complete arrest in EIRR progression were seen. Root canals were then filled with CEM cement, and the coronal cavity was restored using amalgam; (f) in the 2-year follow-up, thorough bone healing, disappearance of periapical and furcation radiolucency, and arrest/treatment of IERR were observed.
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Diagnostic radiographic evaluation of tooth #18 primarily showed broken instruments and large periapical radiolucency around the mesial root, involving the bifurcation area attributed to previous poor endodontic therapy (Figure 1(a)). After the radiographic confirmation of the procedure and the proper placement of the transplanted tooth, the patient was given verbal and written postsurgical instructions and dismissed for future follow-ups (Figure 1(b)). Additionally, the closer radiographic evaluation showed signs of possible EIRR on the distal root (Figure 1(c)). After 6-month recall from the 1st treatment session, despite the healing of bone around the mesial root, the furcation and distal root seemed involved, and signs of EIRR appeared to progress; consequently, the coronal restoration was removed, proper access cavity was created, canal preparation (thorough cleaning and shaping) was performed, and the mesial as well as distal canals were medicated using PMC as the intracanal medicament to remove possible causative microbiota (Figure 1(d)). Iran), and the patient was dismissed (Figure 1(e)). The arrest of EIRR was seemingly due to the proper preparation of root canals (cleaning and shaping of the root canal system), application of intracanal medication (PMC), and eventual filling of canals with the selected biomaterial (CEM cement). In a 2-year follow-up, the healing of bone surrounding the roots, arrest of EIRR, and normal PDL were observed (Figure 1(f)).
Cone-beam computed tomography (CBCT) showed large periradicular radiolucency around the mesial root in tooth #18, with sizable bone loss/resorption and the furcation involvement.
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In the same session, cone-beam computed tomography (CBCT) was obtained and confirmed large periapical radiolucency around the mesial root in tooth #18, severe bone loss, and rigorous furcation involvement of the tooth (Figure 2).