ABSTRACT
BACKGROUND: Insufficient development of craniofacial bone and jaw defects are common problems in clinical practice of maxillofacial surgery. How to repair is always a problem. Because distraction osteogenesis has the advantages of small trauma, avoiding bone grafting, and prolonging the synchronization of surrounding soft tissue, it holds critical role in increasing alveolar bone mass, prolonging jaw bone, repairing bone defect, and closing bone gap. OBJECTIVE: To summarize and discuss the technical methods, application, limitations and development trends of various curved distractors. METHODS: Relevant articles published from January 2000 to October 2018 were retrieved from CNKI, WanFang, PubMed and Embase databases and National Intellectual Property Office Patent Search and Analysis Platform. The key words were "distraction osteogenesis, curvilinear distraction, curved distractor, reconstruction, research progress, mandibular, maxilla, defect, customized distractor, finite element method" in Chinese and English, respectively. Fifty-eight eligible articles were included for review. RESULTS AND CONCLUSION: (1) The early distraction osteogenesis devices are mostly external unidirectional distractors. With the development of various technologies, various intra-oral distractors, such as spiral distractor, curve distractor, bidirectional distractor, three-focus distractor and automatic distractor. (2) In view of the special anatomical shape of the jaw, there are many arc-faced structures. In order to make the new bone closer to the contour shape of the jaw, curved distraction osteogenesis has gradually become a research hotspot. (3) Although the existing curved distractors provide a reliable technical means for jaw defects, they still have a certain degree of limitation. Due to the existence of problems such as traction and force, the true meaning curve and even the three-dimensional distraction are not completed. The development of individualized stretchers combined with relevant innovations, and towards miniaturization and stabilization development is still the mainstream trend of future research on curvilinear distraction.
ABSTRACT
Objective To demonstrate the histology in acellular dermal matrix(ADM)after being transplanted in vivo over time. Methods Forty male SD rats were recruited for the experiment. Subcutaneous implantation of an 1 cm × 1 cm ADM was given in the left sides on the back of the rat for the experimental group, while only dissection and suturing were performed in right side of the back for the control group. All the animals will be sacrificed at appointed time after operation, Five ADM samples were harvested in each time point. The content and proportion of collagen type were examined with HE staining, Picrosirius staining, Masson′s trichrome staining, and Immunohistochemical staining (targets: pan macrophage, M1 macrophage and M2 macrophage). Results All rats survived after operative without any complications. Significant differences of thickness were not observed at the end of 5 months; HE scores suggested that ADM increased in cell infiltration scores in 2 weeks before the plateau , vascularity also showed a similar trend; Collagen trichrome staining showed a substantial increase in density of collagen bundles with time. The comparison of the proportion of collagen among days showed significant differences (P < 0.05). Immunohistochemical staining of M1 and M2 showed that macrophages had distinct polarization profiles in materials. Furthermore, the comparison of M1 vs M2 response associated with different materials showed significant differences in all time points (P < 0.05). Conclusions The chemically cross-linked ADM could keep long time in the body; ADM significantly stimulated proinflammatory of M2 differentiation from M1 in constructive remodeling.
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Objective:To explore the function of the bridging epithelium between maxillary process and nasal process in the devel-opment of lip and palate.Methods:The fertilized white leghorn chick eggs incubated to the appropriate Hamburger and Hamilton(H-H)stages were examined by tissue histologic studies,scanning electron microscopy observation,BrdU assay and TUNEL assay re-spectively.Results:At H-H stage 24,the epithelia between maxillary,lateral nasal and globular process were juxtaposed.At H-H stage 26-27,string-like filopodia appeared and the bridging epithelium formed,then in the bridging epithelium cell proliferation was decreased and the apoptotic cells appeared.At H-H stage 28,the apoptosis of the bridging epithelium cells increased,the full fusion of the processes was completed.Conclusion:The occurrence of bridging epithelium between maxillary process and nasal process plays an important role in the development of lip and palate.
ABSTRACT
BACKGROUND:Alveolar distraction osteogenesis is an important method for treating alveolar bone atrophy, the osteogenesis process and biomechanics play a crucial role in the fol owing implantation and repair. At present, no related experimental studies are found. OBJECTIVE:To analyze the biomechanical and histological characteristics of alveolar distraction osteogenesis in a canine model. METHODS:Twelve adult mongrel canines received premolars extraction and alveoloplasty in mandible to establish an atrophy alveolar model. After 3 months, a segmental alveolar osteotomy was performed in the randomly selected unilateral atrophy alveolar and two intra-osseous distractors were placed. After a 7-days latency period, the alveolar ridge was augmented at a rate of 1.0 mm/d for 5 days. After a consolidation of 1, 2, and 3 months, the canines were sacrificed and the specimens of the distracted alveolar bone were harvested for clinical, radiographic, histological and biomechanical analysis. RESULTS AND CONCLUSION:The alveolar distractors obtained good healing with surrounding tissue. The atrophy alveolar bones were augmented for (4.80±0.50) mm and (5.12±0.47) mm by clinical and radiographic findings immediately after distraction, respectively. The bone trabeculae in the distracted chamber matured from 1 to 3 months of consolidation by histological analysis. The shearing force of alveolar distraction chamber increased from 1 to 3 months. After 3 months’ consolidation, the shearing force of distracted chamber was comparable to host bone. The histological and biomechanical property of distracted alveolar chamber is comparable to host bone after 3 months’ consolidation.