Implant rehabilitation adjacent to a periodontally compromised molar managed by tooth hemisection: a case report

Severe localized alveolar bone loss associated with adjacent periodontal destruction can result in complex mesiodistal discrepancies, posing challenges to implant rehabilitation. Although conventional bone augmentation may achieve favorable clinical and radiographic outcomes, the biological predictability of regeneration, particularly adjacent to diseased root surfaces, remains uncertain. Clear clinical guidance for managing these combined osseous and radicular challenges remains limited. A 30-year-old Chinese female presented for rehabilitation of a missing mandibular right second premolar (#45). Clinical examination and radiographic assessment identified severe periodontitis affecting the mesial root of the adjacent first molar (#46), characterized by deep periodontal pockets and a vertical osseous defect. A staged treatment protocol was implemented. Following initial periodontal therapy and root canal treatment (RCT) for #46, the compromised mesial root was hemisected, and guided bone regeneration (GBR) was simultaneously performed at site #45. After 6 months of healing, an implant was placed. Definitive restorations, comprising a screw-retained crown on the implant at site #45 and a full zirconia crown on the distal root of tooth #46, were placed 3 months later. At 36 months after initial presentation (corresponding to 21 months after definitive crown delivery) the implant demonstrated stable marginal bone levels (MBL), and the retained distal root remained functional and periodontally healthy. At 36 months after initial presentation (21 months after definitive crown delivery), the patient demonstrated stable clinical and radiographic findings. Patient-reported outcomes, assessed using the Oral Health Impact Profile-14 (OHIP-14) showed improvement from baseline to T6; however, these assessments were not repeated at the final follow-up. This case illustrates the clinical feasibility of combining hemisection and GBR for managing localized periodontal–implant challenges. However, these findings represent a single-case experience and should not be generalized. Longer follow-up and larger cohort studies are required to further assess the long-term periodontal and peri-implant stability associated with this treatment strategy.