Dentin as a suitable bone substitute comparable to ß-TCP--an experimental study in mice.

Microvascular supply is of fundamental importance to the survival and integration of grafting. Since the autogenous bone is still the gold standard for osseous augmentation, the aim of this study was to analyze the initial osseous, angiogenic and inflammatory response and subsequent osseointegration after implantation of dentin and beta-tricalcium phosphate (ß-TCP) scaffolds into the calvaria chamber of balb/c mice comparing with bone. The vascularisation of perforated implants of dentin (n=8), ß-TCP (n=8) and isogenic calvarial bone (n=8) displaying pores similar in size and structure was analyzed in vivo using intravital fluorescence microscopy. In additional animals (n=24) the osseointegration of dentin, ß-TCP and bone implants was assessed by fluorochrome sequential labelling of growing bone for up to 12 weeks. Animals without implants served as controls. Intravital fluorescence microscopy revealed that implantation of bone substitutes caused an only mild inflammatory response. Comparable to isogenic bone both dentin and ß-TCP scaffolds were found nearly completely vascularized by day 22 and osseointegrated within 12 weeks. In conclusion, dentin and ß-TCP scaffolds are similar to isogenic bone in terms of inflammatory and neovascularization response, highlighting their potential utility in regeneration of bone defects.

Reduction of midfacial periosteal perfusion failure by subperiosteal versus supraperiosteal dissection.

PURPOSE: Detachment of soft tissue is a prerequisite for cleft repair. Recent experimental studies have indicated that supraperiosteal rather than subperiosteal soft tissue detachment causes midfacial hypoplasia, although, the cause has not been clarified yet. We hypothesized that microcirculatory dysfunction may be responsible for hypoplasia development, and established in rabbits an experimental model to study the differences in nutritive perfusion of midfacial periosteum in dependency on the applied technique of soft tissue detachment. MATERIALS AND METHODS: In anesthetized New Zealand White rabbits a cranially broadly based rectangular soft tissue flap was intraorally circumcised on the anteromedial aspect of the maxilla. After either supraperiosteal or subperiosteal soft tissue detachment fluorescence microscopy allowed quantitative in vivo analysis of the nutritive perfusion of midfacial periosteum. RESULTS: Microscopic analysis of individually perfused capillaries showed that blood flow was comparable in supraperiosteally and subperiosteally dissected maxillary periosteum. Nonetheless, both dissection techniques were associated with a remarkable capillary perfusion failure. However, the functional capillary density, which indicates the number of perfused capillaries per tissue area and thus the overall quality of capillary perfusion, was found significantly ( P < .05) lower in supraperiosteally than in subperiosteally dissected periosteum. CONCLUSION: Using a new model for in vivo quantification of periosteal perfusion in the maxilla of rabbits, periosteal perfusion was found significantly more deteriorated after supraperiosteal compared with subperiosteal soft tissue detachment. The marked reduction of periosteal microcirculatory perfusion failure after subperiosteal soft tissue detachment may contribute to the clinically observed protection from manifestation of midfacial hypoplasia after cleft repair.

Segment distraction to reduce a wide alveolar cleft before alveolar bone grafting.

OBJECTIVE: To demonstrate a method for reduction of wide alveolar clefts prior to bone grafting. This method aims to facilitate bone grafting and achieve adequate soft tissue coverage of the graft with attached gingiva. CASE REPORT: Treatment of a patient with bilateral cleft lip and palate with a severe alveolar defect on the left side is illustrated. Distraction osteogenesis was used to mesialize the left segment so that the alveolar cleft was reduced to a minimum. After a 10-week retention period, bone grafting of the reduced alveolar defect was successfully performed. After consolidation of the bone graft, the alveolar cleft was found to have an osseous closure with adequate soft tissue coverage. CONCLUSION: In patients with a wide alveolar cleft, soft tissue coverage with keratinized mucosa can be more readily assured by reducing the alveolar cleft by callus distraction to mesialize the lateral segment prior to bone grafting.