Introduction
Exodontia is associated with complications such as postoperative infection, accounting for 1.4% of treated cases.1 A large-scale prospective study reported very low incidence of postoperative infection in teeth with preoperative history of infection.2 As an alternative to tooth replacement, implant-supported restorations may comprise a viable treatment modality for rehabilitation of partially edentulous patients and have shown higher success rates for single-tooth replacement.3Chen and Buser4 published a classification system for the implant-placement timing following tooth extraction and categorized the placement as immediate, early with soft-tissue healing, early with partial bone healing, or delayed. Although immediate dental-implant placement in fresh extraction sockets is an established treatment modality,5-7 a recent meta-analysis8reported that immediate implant placement is associated with a higher risk of early implant loss. The success rate could significantly decrease by the presence of risk factors leading to early implant failure at second-stage surgery, and infection was the most significant risk factor with the highest odds ratio compared to other factors.9 Immediate implants can offer predictable results in sites with history of periapical and periodontal infections, as careful debridement is performed before implant insertion.10 Moreover, infection of the adjacent teeth may complicate the success of immediate implants in short- and long-term follow-up assessments.11 Thus, socket infection may compromise the anatomical structures necessary for primary implant stability and the success of immediate implants. The inter-radicular bone in molar sites, for instance, is a crucial parameter playing a role in dental implant stability and success.12 Therefore, in such cases, guided bone regeneration may be the first step to prepare the implant bed for later surgical placement.13
In addition to mechanical debridement of the infected socket, pharmacological interventions may be helpful for management of local aseptic conditions. The potential benefits of systemic antibiotic treatment following guided tissue and bone regeneration have been questioned.14-17 The application of postoperative systemic antibiotics may be helpful in reducing discomfort following the guided tissue-regeneration procedure.18 Local application of chlorhexidine chips19 and metronidazole gel20 showed promising results in guided tissue regeneration of periodontal defects. Nonetheless, applying these agents for guided bone regeneration of compromised extraction sockets as a preparatory step for future implant therapy requires evaluation. This report aims to introduce the strategic application of pre-medicated collagen sponges containing both chlorhexidine and metronidazole together with a particulate bone graft and collagen membrane for guided tissue and bone regeneration following extraction of a split mandibular first molar with purulent infection, fistula opening, and severe vertical bony defect of the adjacent second premolar.