Multichannel polymer scaffold seeded with activated Schwann cells and bone mesenchymal stem cells improves axonal regeneration and functional recovery after rat spinal cord injury.

The adult mammalian CNS has a limited capacity to regenerate after traumatic injury. In this study, a combinatorial strategy to promote axonal regeneration and functional recovery after spinal cord injury (SCI) was evaluated in adult rats. The rats were subjected to a complete transection in the thoracic spinal cord, and multichannel scaffolds seeded with activated Schwann cells (ASCs) and/or rat bone marrow-derived mesenchymal stem cells (MSCs) were acutely grafted into the 3-mm-wide transection gap. At 4 weeks post-transplantation and thereafter, the rats receiving scaffolds seeded with ASCs and MSCs exhibited significant recovery of nerve function as shown by the Basso, Beattie and Bresnahan (BBB) score and electrophysiological test results. Immunohistochemical analyses at 4 and 8 weeks after transplantation revealed that the implanted MSCs at the lesion/graft site survived and differentiated into neuron-like cells and co-localized with host neurons. Robust bundles of regenerated fibers were identified in the lesion/graft site in the ASC and MSC co-transplantation rats, and neurofilament 200 (NF) staining confirmed that these fibers were axons. Furthermore, myelin basic protein (MBP)-positive myelin sheaths were also identified at the lesion/graft site and confirmed via electron microscopy. In addition to expressing mature neuronal markers, sparse MSC-derived neuron-like cells expressed choline acetyltransferase (ChAT) at the injury site of the ASC and MSC co-transplantation rats. These findings suggest that co-transplantation of ASCs and MSCs in a multichannel polymer scaffold may represent a novel combinatorial strategy for the treatment of spinal cord injury.

Periodontally accelerated osteogenic orthodontics with platelet-rich fibrin in an adult patient with periodontal disease: A case report and review of literature.

BACKGROUND: In the clinical scenario, adult patients with periodontal diseases and dental malformation, characterized by dental crowding in lower anterior teeth with the thin biotype, often require orthodontic treatment. This case report aimed to evaluate the clinical and radiographic outcomes of periodontally accelerated osteogenic orthodontics (PAOO) combined with autologous platelet-rich fibrin (PRF) in an adult patient with class I malocclusion along with dental crowding, a thin periodontal biotype, and buccal plate deficiency. CASE SUMMARY: A 32-year-old female complaining of dental crowding and gingival bleeding was referred to the orthodontic clinic. The patient underwent periodontal risk assessment prior to orthodontic treatment. She was diagnosed with a high risk of gingival recession due to dental crowding, root prominence, loss of buccal plates, and a thin gingival tissue biotype. The treatment regimen included PAOO combined with autologous PRF for alveolar augmentation and interproximal enamel reduction for moderate dental crowding. Clinically, PAOO-assisted orthodontic tooth movement in this case showed enhanced periodontium remodeling. Radiographic outcomes also showed statistically significant improvements (P < 0.01) in the mandibular buccal alveolar bone. CONCLUSION: This case report suggests the combination of autologous PRF with PAOO to enhance bone augmentation and long-term tissue support in adult orthodontic patients with periodontal disease.

TGF-ß1-induced differentiation of SHED into functional smooth muscle cells.

BACKGROUND: Adequate vascularization is crucial for supplying nutrition and discharging metabolic waste in freshly transplanted tissue-engineered constructs. Obtaining the appropriate building blocks for vascular tissue engineering (i.e. endothelial and mural cells) is a challenging task for tissue neovascularization. Hence, we investigated whether stem cells from human exfoliated deciduous teeth (SHED) could be induced to differentiate into functional vascular smooth muscle cells (vSMCs). METHODS: We utilized two cytokines of the TGF-ß family, transforming growth factor beta 1 (TGF-ß1) and bone morphogenetic protein 4 (BMP4), to induce SHED differentiation into SMCs. Quantitative real-time polymerase chain reaction (RT-qPCR) was used to assess mRNA expression, and protein expression was analyzed using flow cytometry, western blot and immunostaining. Additionally, to examine whether these SHED-derived SMCs possess the same function as primary SMCs, in vitro Matrigel angiogenesis assay, fibrin gel bead assay, and functional contraction study were used here. RESULTS: By analyzing the expression of specific markers of SMCs (α-SMA, SM22α, Calponin, and SM-MHC), we confirmed that TGF-ß1, and not BMP4, could induce SHED differentiation into SMCs. The differentiation efficiency was relatively high (α-SMA+ 86.1%, SM22α+ 93.9%, Calponin+ 56.8%, and SM-MHC+ 88.2%) as assessed by flow cytometry. In vitro Matrigel angiogenesis assay showed that the vascular structures generated by SHED-derived SMCs and human umbilical vein endothelial cells (HUVECs) were comparable to primary SMCs and HUVECs in terms of vessel stability. Fibrin gel bead assay showed that SHED-derived SMCs had a stronger capacity for promoting vessel formation compared with primary SMCs. Further analyses of protein expression in fibrin gel showed that cultures containing SHED-derived SMCs exhibited higher expression levels of Fibronectin than the primary SMCs group. Additionally, it was also confirmed that SHED-derived SMCs exhibited functional contractility. When SB-431542, a specific inhibitor of ALK5 was administered, TGF-ß1 stimulation could not induce SHED into SMCs, indicating that the differentiation of SHED into SMCs is somehow related to the TGF-ß1-ALK5 signaling pathway. CONCLUSIONS: SHED could be successfully induced into functional SMCs for vascular tissue engineering, and this course could be regulated through the ALK5 signaling pathway. Hence, SHED appear to be a promising candidate cell type for vascular tissue engineering.

[Establishment of animal model for research of first molar mesial movement in rat].

PURPOSE: To establish an animal model for research of first molar mesial movement in rat. METHODS: Forty 7-weeks-old SPF female Wistar rats were chosen in this experiment, which were divided into two groups. In each group, the two central incisors were used as anchorage to move the maxillary first molars mesially. In one group, traditional orthodontic appliances was used to move the first molars, while in another group modified device was used for moving the first molars. The distance of first molar mesial movement, the drop-off rate of orthodontic appliances and the periodontal status of first molars were evaluated. The data were analyzed with SPSS 11.0 software package. RESULTS: The drop-off rate in the group of individual orthodontic appliances was 5%. The drop-off rate in the group of traditional orthodontic appliance was 35%. There was significant difference in drop-off rate of orthodontic appliances and periodontal status of first molars between the two groups. But there was no significant difference on the molar moving distance. CONCLUSIONS: Individual orthodontic appliances are more suitable for tooth movement research than traditional ones. This animal model using individual orthodontic appliances can be used in future tooth movement research.

[A study of three dimensional changes in superior teeth with rocking chair archwire].

PURPOSE: To observe the three dimensional changes of upper arch using laser scan. METHODS: 40 patients aged from 15 to 21 suffering from Angle's Class II subdivision I malocclusion combined with deep overbite were selected from the Department of Orthodontics, School of Stomatology, Shandong University. The patients were divided into two groups randomly, after the overbites of the two groups were opened using different methods, plaster models were made for each patient. Then, digital research models were available through laser san and three dimensional imaging technique. Finally, the changes in three dimensions of the maxillary teeth were measured. Student's t test was performed using SPSS 13.0 software package. RESULTS: In the sagittal dimension, the incisors had a tendency of labial inclination. Canines and the first permanent molars were likely to move distally. No distinct changes were found in the second premolars. According to whether or not there were tip back of the archwires and "8" shaped ligation there was significant difference in the change of both incisors and the first molars (P<0.05), while there was no significant difference in the change of canines and the second molars. In the vertical dimension, incisors and the distal-buccal cuspids of the first molars had a tendency of intrusion while the second premolars were likely to extrude; there was no significant change in canines and the mesio-buccal cuspids of the first molars and there was no significant difference between the two groups(P>0.05). In the transverse dimension, the widths of arches in the molar zone had a tendency to increase, while there was no significant change in canine and premolar zones between the two groups(P>0.05). CONCLUSION: Standard Ni-Ti rocking chair arch wire can bring about many changes to the teeth and dental arch in three dimensions and its effect on deep overbite is remarkable.

[Myoelectricity study on wearing flat bite plate under different raised distances in deep overbite therapy].

OBJECTIVE: To analyze changes of myoelectrical activity of anterior funicle of temporal muscle (TA) and masseter muscle (MM) after raising vertical distance of occlusion by flat bite plate during treatment of deep overbite in order to approach an optimal raised vertical distance. METHODS: A total of 70 persons were selected and divided into two groups: Experiment group (36 patients) with deep overbite and control group (34 persons) with individual normal occlusion. The experiment group was subdivided into three groups that were respectively raised D, D+2 mm and D+4 mm (D means free way space, mm). Electromyologram (EMG) was utilized to measure the average peak potential of TA and MM on quiescent condition before treatment and two weeks after wearing flat bite plate. RESULTS: 1) Before treatment, the average peak potential of experiment group was obviously higher than that of the control group (P<0.05). 2) After two weeks the potential of TA and MM of all persons in experiment group was obviously lower than before (P<0.05), the degree between the group D+2 mm and the group D+4 mm was not manifestly different, but both of the two groups were more obvious than the group D. CONCLUSION: The raised vertical distance of occlusion by flat bite plate, which exceeded free way space, was favourable to the functional recovery of masticatory muscles.

[Clinical application of spiral 3-D CT reconstruction for maxillary impacted teeth].

PURPOSE: To evaluate the clinical usefulness of spiral 3-D CT reconstruction for maxillary impacted teeth. METHODS: Spiral CT was performed in 47 patients whose maxillary impacted teeth couldn't be judged clearly through the panoramic radiograph and occlusal film. 3-D reconstruction, including MIP (maximum intensity projection) and MPR (multiplanar reconstructions) was made to display the impacted teeth's shape, location and its relationship with adjacent teeth. RESULTS: There were 67 maxillary impacted teeth in 47 patients. Spiral 3-D CT could clearly demonstrate the dental image including crown, root, neck and root bifurcation, and 3-D imaging could clearly display the maxilla anatomy and the dental structure. CONCLUSION: Spiral CT 3-D reconstruction is a useful technique to display three-dimensional configuration of teeth.Three dimensional reconstruction is an accurate and effective method to localize impacted teeth before orthodontic treatment.

[Orthodontic traction of impacted maxillary canine: a comparison of different ages].

PURPOSE: To evaluate the success rate and the length of orthodontic treatment of impacted maxillary canines in adult and adolescent patients. METHODS: 17 adults who had been treated for a total of 21 impacted maxillary canines, was compared with a younger control group. The control group were chosen for a similar degree of impaction by carefully matching the positions of the impacted canines in 3 dimension. SPSS11.0 software package was used for Chi-square and paired t test. RESULTS: The success rate among the adults was 85.71% compared with 100% among the control group. There was significant difference between the two groups (P<0.01). The adults showed significant increase in the duration of treating the impacted canines (P<0.001). CONCLUSION: The success rate for orthodontic resolution of an impacted canine in an adult is significantly lower than in a younger patient and the duration of treatment in adults is expected to take considerably longer.