Successful Intentional Replantation for Apical Abscess due to Root Resorption and Abnormal Root Morphology: A Case Report

<p> Purpose: Root resorption and abnormalities of root morphology affect the success or failure of root canal and periodontal disease treatment. Even though cone-beam computed tomography (CBCT) images have made it possible to understand the three-dimensional morphology of teeth preoperatively, there are still cases in which non-surgical endodontic treatment is not successful due to these factors. In this case report, intentional replantation was performed for a two-rooted maxillary right second premolar with root resorption and a root groove continuous with the fracture line to remove the infected part, and favorable healing progress was achieved.</p><p> Case: The case was a 19-year-old female who had received dental caries treatment for the maxillary right second premolar three years earlier. The following year, she experienced spontaneous pain in the same tooth. The tooth showed a pulpal reaction to cold stimulation, and the bite pain subsided with occlusal adjustment. Eight months later, she noticed spontaneous pain again; a dental X-ray image revealed an abnormality in the morphology of the pulp, and she was referred to our dental hospital.</p><p> Clinical examination: spontaneous pain (－), percussion pain (＋/－, discomfort), gingival swelling (＋), mobility (degree 0), root apical palpation pain (＋/－, discomfort), sinus tract (＋) and probing depth (6 mm, mesial). The pulp sensitivity test was positive. Dental radiography showed the presence of internal root resorption and apical periodontitis.</p><p> Diagnosis: Maxillary right second premolar, chronic apical abscess, partial pulp necrosis, internal resorption.</p><p> Treatment process: CBCT images revealed that the root canal morphology was complicated by both internal and external resorption. Non-surgical root canal treatment could not improve the clinical symptoms, because the continuous supply of infection could not be cut off due to the communication between the fracture line and the root groove from the mesial region to the floor of pulp chamber. Therefore, intentional replantation was performed. As surgical endodontic treatment, the infected part was selectively removed by root excision and retro cavity preparation extra-orally using a diamond point under a magnified view. Retro root canal obturation was used with resin modified MTA cement, and the root groove and fracture line were filled with 4META/MMA-TBB resin. All clinical symptoms disappeared after the surgery, and CBCT images taken at 17 months follow-up confirmed that the periradicular and periodontal lesions were intact.</p><p> Conclusion: Non-surgical root canal treatment could not achieve a sterile condition due to root resorption and a root groove continuous to the fracture line on the maxillary right second molar. Intentional replantation resolved these clinical problems and led to a good clinical outcome.</p>