Saving A Mandibular Molar With Furcation Involvement And Root Resorption

External root resorption (ERR) and class III furcation defect are both factors that can lead to tooth extraction. In this case study, the affected tooth with external root resorption and furcation involvement (FI) class III was successfully preserved by combined endodontic and periodontal treatment. A 28-year-old male patient presented with a lower right first molar periodontal abscess. Radiographic examination revealed a large area of radiolucent lesion under the root furcation, ERR of root and the class III furcation defect. The affected tooth was treated by root canal treatment + MTA repair external root resorption + periodontal bone grafting + all-ceramic crown. After 18 months of follow-up, the FI disappeared, the gingiva was healthy, the tooth structure was intact, and the chewing function could be well exercised. In this case, although the part of ERR had touched the pulp of the tooth, the shape of ERR was shallow dish, and no stress concentration point was found in the rest of the tooth. The root FI angle is large, surgical instruments can enter and repair the part of ERR. Despite it was class III furcation defect, two-thirds of the bony defect at the FI was infra-bony pocket, and the buccal and lingual gingiva were thick-gingival biological type. Therefore, the affected tooth has the possibility of obtaining a good prognosis. For such teeth with multiple adverse factors, we should be brave to try and explore under the premise of fully evaluated dental conditions.