Objective To explore a novel nanometer biomaterial which could induce the regeneration of tooth tissues intell igently, and to evaluate the feasibil ity of using this kind of biomaterial as the scaffold for tooth tissue engineering by investigating the role it plays in tooth tissue engineering. Methods The scaffold for tooth tissue engineering containing recombinant human bone morphogenetic protein 2 (rhBMP-2) was prepared by mixing nanoscale β tricalcium phosphate (β-TCP)/collagen particles. Forty-six 8-10 weeks old specific pathogen free Sprague Dawley (SD)rats, including 34 females and 12 males, weighing 250-300 g, were involved in this study. Tooth germs were removed under a stereomicroscope from the mandible of newborn SD rat, then digested and suspended. Scanning electronic microscope (SEM), adhesion rate of cells, and MTT assay were used to evaluate the effects of the scaffold on the tooth germ cells cultured in vitro. The tissue engineered tooth germ which was constructed by tooth germ cells and scaffold was transplanted under SD rat’s kidney capsule as the experimental group (n=12); the tooth germ cells (cell-control group, n=12) or scaffold without cells (material-control group, n=4) were transplanted separately as control groups Specimens were harvested to perform general and histological observations at 4 and 8 weeks after transplantation. Results β-TCP/collagen showed a loose and porous appearance with soft texture and excellent hydrophil icity. Tooth germ cells grew well and could attach to the scaffold tightly 3 days after coculture. The adhesion rates of tooth germ cells were 27.20% ± 2.37%, 44.52% ± 1.87%, and 73.81% ± 4.15% when cocultured with scaffold for 4, 8, and 12 hours, respectively. MTT assay showed that the cell prol iferation status of experimental group was similar to that of the control group, showing no significant difference (P gt; 0.05). Some white calcified specimens could be harvested at 4-8 weeks after transplantation. At 4 weeks after transplantation some typical structures of dental cusp and enamel-dentin l ike tissues could be seen in the experimental group. Enamel-dentin l ike tissues also formed in some specimens of cell-control group, but they arranged irregularly. At 8 weeks after transplantation the enamel-dentin l ike tissue of experimental group exhibited a mature appearance and organized structure in comparison with that at 4 weeks. And mature enamel or dentin l ike tissue also could be seen in cell-control group. In contrast, there was no enamel or dentin l ike tissue in material-control group at 4 or 8 weeks after transplantation. Conclusion rhBMP-2 decorated β-TCP/collagen scaffold has good biocompatibil ity and can be used as a novel nanometer biomaterial, so it is a good choice in scaffolds for tooth tissue engineering.
ObjectiveTo investigate the effectiveness of medial sural artery perforator free flap (MSAP) for repairing defect after tongue cancer ablation. MethodsBetween March 2013 and April 2014, the defects after tongue carcinoma resection were repaired with MSAP in 12 patients, including 8 cases of high or medium differentiated squamous cell carcinoma (SCC) and 4 cases of moderately-poor differentiated SCC. There were 7 males and 5 females with a median age of 55 years (range, 45-68 years). The disease duration ranged from 2.0 to 8.5 months (mean, 4.3 months). The tumor located at the tongue edge in 8 cases and at the tongue abdomen in 4 cases (mouth floor infiltration in 1 case). According to TNM stage, 7 cases were rated as T2N0M0, 2 cases as T2N1M0, 2 cases as T3N1M0, and 1 case as T4N1M0. The size of tumor ranged from 3.0 cm×2.0 cm to 4.5 cm×3.0 cm. The size of MSAP varied from 4.0 cm×3.5 cm to 6.5 cm×6.0 cm. ResultsThe time of total operation ranged from 5.5 to 8.3 hours (mean, 6.8 hours), and flap harvesting time ranged from 54 to 85 minutes (mean, 65.6 minutes). The other flaps survived except 1 case of vein crisis. All the patients were followed up 6-18 months (mean, 13.7 months). With time passing, the pronunciation got better, and the skin showed mucosa-like change; the patients were capable of normal language exchange at 6 months after operation. No obvious scar on the leg or limitation of limb motion was observed. ConclusionThe MSAP is reliable for repair of defect after tongue cancer ablation, with the advantages of satisfactory recovery of tongue appearance, language function, and less donor site morbidity.
Atherosclerosis is a complex and multi-factorial pathophysiological process. Researches over the past decades have shown that the development of atherosclerotic vulnerable plaque is closely related to its components, morphology, and stress status. Biomechanical models have been developed by combining with medical imaging, biological experiments, and mechanical analysis, to study and analyze the biomechanical factors related to plaque vulnerability. Numerical simulation could quantify the dynamic changes of the microenvironment within the plaque, providing a method to represent the distribution of cellular and acellular components within the plaque microenvironment and to explore the interaction of lipid deposition, inflammation, angiogenesis, and other processes. Studying the pathological mechanism of plaque development would improve our understanding of cardiovascular disease and assist non-invasive inspection and early diagnosis of vulnerable plaques. The biomechanical models and numerical methods may serve as a theoretical support for designing and optimizing treatment strategies for vulnerable atherosclerosis.
ObjectiveTo investigate the clinical outcomes of resection of mandibular benign tumors and primary reconstruction with autogenous bone graft via an intraoral approach. MethodsFifteen patients with mandibular benign tumors were treated between January 2009 and September 2012. There were 7 males and 8 females, aged from 18 to 45 years (mean, 30 years). The pathological diagnosis identified 11 cases of ameloblastoma, 3 cases of odontogenic keratocyst, and 1 case of odontogenic myxoma. According to the Urken's CRBS (Condyle, Ramus, Body, Symphysis) classification criteria based on the location of the mandibular defect, there were 3 cases of body type (B type), 3 cases of ramus type (R type), and 9 cases of body and ramus type (BR type). The surgeries were performed via an intraoral approach, except 1 patient with the lesion at the level of sigmoid notch via an auxiliary preauricular incision. To fix the bone grafts to the dissected mandibular defects, reconstructive titanium plates were used, either indirectly according to the computer aided design/computer aided manufacturing mandibular models before surgery (9 patients) or directly according to the exposed mandibles during surgery (6 patients). The patients received benign mandibular tumor resection and primary autogenous bone graft reconstruction with free iliac bones (11 cases) or vascularized fibular flaps (4 cases). The mandibular inferior alveolar nerves were preserved in 6 cases. ResultsPrimary healing of incision was obtained in 14 patients, while secondary healing in 1 patient suffering from bone graft infection. All the patients were followed up 1-4 years (mean, 2.5 years). At last follow-up, no patients showed facial nerve damage; occlusion of remaining teeth was similar to preoperative conditions; the chewing function was satisfactory; mouth opening was 30-35 mm (mean, 33 mm); and swallowing and speaking functions were normal. Only slight extraoral scars caused by the auxiliary incision and the transbuccal appliances were observed, and all the patients were satisfied with the facial appearance. Lower lip numbness was relived in patients with preserved inferior alveolar nerves. There was no tumor recurrence during follow-up period. ConclusionThe intraoral approach is a feasible and proper approach for resection of benign mandibular tumors and primary reconstruction with autogenous bone grafts, with the advantages of inconspicuous facial scars, minimum damage to the facial nerve, and expectable aesthetic appearance.
ObjectiveTo explore the application of three-dimensional (3-D) printing technique in repair and reconstruction of maxillofacial bone defect. MethodsThe related literature on the recent advance in the application of 3-D printing technique for repair and reconstructing maxillofacial bone defect was reviewed and summarized in the following aspects:3-D models for teaching, preoperative planning, and practicing; surgical templates for accurate positioning during operation; individual implantable prosthetics for repair and reconstructing the maxillofacial bone defect. Results3-D printing technique is profoundly affecting the treatment level in repair and reconstruction of maxillofacial bone defect. Conclusion3-D printing technique will promote the development of the repair and reconstructing maxillofacial bone defect toward more accurate, personalized, and safer surgery.
ObjectiveTo evaluate the value of computer assisted navigation system (CANS) in the reconstruction of mandibular defects. MethodsBetween April 2012 and September 2014, 8 patients with mandibular defects were included in this study. There were 5 males and 3 females with an age range of 22-50 years (mean, 34.5 years), including 4 cases of ameloblastoma, 3 cases of odontogenic keratocyst, and 1 case of condylar osteoma. According to the CRABS (condyle, ramus, angle, body, symphysis) classification criteria based on the location of mandibular defect, there were 1 case of right CRAB type, 1 case of left RABS type, 1 case of left CR type, 1 case of right RAB type, 1 case of left C type, 1 case of right RABS+left S type, and 2 cases of right AB type. With the biteplate fixing mandible, maxillofacial CT and the donor site CT scan were done. Computer assisted design was made by using Surgicase CMF5.0 software and BrainLab Iplan software, included delineating the osteotomy lines for resection, ascertaining the normal anatomic structures for defect reconstruction, and determining the reconstructive morphology. With guide plates and the guidance of BrainLab navigation system, an en bloc tumor resection and simultaneous defect reconstruction were performed under the precise localization of mandibular angle and condyle. Preoperative and postoperative CT images were superimposed in Geomagic studio12.0 software system, and both were compared by three-dimensional (3D) objects and 2D slices. The complications and signs of recurrence were observed. ResultsUnder the guidance of navigation, preoperative facial symmetry design, surgery simulation, and simultaneous navigation operation were performed successfully. The postoperative CT and postoperative 3D error analysis showed osteotomy lines and reconstruction contour had good matching with the preoperative planning. The error of important corresponding points (mandibular angle and external pole of condyle) in the reconstruction of mandibular defects were (1.83±0.19) mm and (1.61±0.24) mm. The patients were followed up 2-6 months (mean, 3.5 months). No complication was observed in the other patients except the patients undergoing rib transplantation who had mild limitation of mouth opening. Good facial symmetry was obtained, and no tumor recurrence was found. ConclusionCANS can effectively increase the surgical precision in the reconstruction of mandibular defects and reduce complications, and recover facial symmetry. It is regarded as a valuable technique in this potentially complicated procedure.