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.