Discussion
This report presented a clinical approach for application of local pharmaceutical agents together with standard biomaterials for guided tissue and bone regeneration. Although natural teeth may be extracted for many reasons, Osaghae and Azodo21 reported that tooth splitting was the etiological factor for 5% of the extracted posterior teeth, of which 10% were mandibular first molars. The prognosis of split teeth with a fracture line extending deep in the sub-gingival area is usually poor22; therefore, the teeth in question require replacement with implant or tooth-supported prosthesis.
A meta-analysis23 reported no difference in success rates between immediate implant placement in infected and non-infected extraction sockets. However, such treatment options are contraindicated in cases with purulent socket infection and poor bone configuration following extraction.24 Accordingly, a more careful approach involving proper implant site preparation prior to placement is feasible to render favorable implant positioning and angulation as described here.
Management of post-extraction sockets is variable. Introduction of hemostatic collagen sponges caused delays in the healing process of the extraction sockets and suppressed differentiation of bone-forming cells.25 As a variant of the bone graft form used here, sticky bone resulted in better soft- and hard-tissue healing and regeneration when used for socket grafting following third-molar extraction in a split-mouth clinical study.26 Several biological agents have been reported to supplement the standard biomaterials in expediting healing and improving postoperative results following guided tissue and bone-regeneration procedures.27 Compared with a collagen-sponge group, supplemental use of recombinant human bone morphogenetic protein 2 with bone graft material resulted in superior bone gain on the distal surfaces of second mandibular molars following third molar extraction.28 A recently published systematic review and meta-analysis supported the use of platelet-rich fibrin following extraction and reported a faster wound-healing rate and lesser postoperative complications.29 The application of readily available agents such as pre-medicated collagen sponges may present a convenient strategic option to supplement readily successful biomaterials for regenerative therapies.
A randomized double-blinded clinical trial30 found that repeated application of chlorhexidine-containing chips is beneficial to control sites with active periodontal disease. Local application of controlled-release chlorhexidine chips improved the quantity of bone gain upon tissue-regenerative procedures, and infection control may be crucial for the success of such treatment interventions.19 Additionally, evaluation of metronidazole-gel application for tissue regeneration showed that local application of metronidazole gel yielded successful clinical outcomes in treating vertical bony-defect cases along with other biomaterials used for guided tissue regeneration.20 However, no study has outlined the effects of combined application of these agents in tissue and bone-regeneration procedures. This report utilized a pre-medicated collagen sponge containing both active agents in a scaffold form, facilitating convenient manipulation and adaptation during the surgical procedure and ensuring local release of these agents during the healing process of tissue and bone regeneration.