ABSTRACT
Objective In order to meet the needs of maxillofacical bone defect repair, the aim of this study was to synthesize graphene oxide(GO) modified three-dimensional conneted nano- zirconia(ZrO2) bone tissue engineering scaffold and evaluate its surface morphology, compressive strength and cytocompatibility. Methods GO was synthesized by a modified Hummers method and then was testified by scanning electron microscope, transmission electron microscopy and fourier transform infrared spectroscopy. ZrO2 scaffold was modified by different concentrations(0.5,1.0,1.5mg/mL) of GO dispersion via a silane-mediated method. The composite scaffold with uniform GO coating was chosen for compressive strength test and co-cultured with human dental pulp stem cells(hDPSCs). Actin staining was used to observe the growth of the cells on the scaffold, and MTS was used to detect the cell activity. Results The characterization results showed that, under scanning electron microscope, the GO was flaky and the surface morphology of folds could be seen. Part of the GO layer folds up at the edge. Under transmission electron microscopy, the GO was clearly observed to have a gossylike, translucent and slightly wrinkled lamellar structure. The crystal structure in this area in the high-resolution filter image showed a six-member ring structure like graphite. Under high power electron microscope, the 1.0mg/ml GO-ZrO2 scaffold could be seen to deposit a thin layer of GO at the crack of the scaffold skeleton, connecting the two ends of the crack, and lamellar GO with folds could be observed on the surface of ceramic particles. The comparison of mechanical properties showed that the compression strength of GO-ZrO2 scaffold was sgnificantly increased compared with that of ZrO2 scaffold[（1.292±0.087）vs（1.031±0.076）, P<0.05]. Compared with the simple ZrO2 scaffold, the GO-ZrO2 scaffold showed more dense extension and adhesion to the surface of scaffolds, showing more active cell proliferation. The cell viability test showed that the viability of hDPSCs was significantly improved on GO-ZrO2 scaffold after 1, 3 and 5 days of proliferation compared with the simple ZrO2 scaffold(P<0.05). Conclusion The ZrO2 scaffold modified by GO improved compressive strength, promoted the early proliferation of hDPSCs with good cytocompatibility.
ABSTRACT
<p><b>BACKGROUND</b>Regenerative techniques help promote the formation of new attachment and bone filling in periodontal defects. However, the dimensions of intraosseous defects are a key determinant of periodontal regeneration outcomes. In this study, we evaluated the efficacy of use of anorganic bovine bone (ABB) graft in combination with collagen membrane (CM), to facilitate healing of noncontained (1-wall) and contained (3-wall) critical size periodontal defects.</p><p><b>METHODS</b>The study began on March 2013, and was completed on May 2014. One-wall (7 mm × 4 mm) and 3-wall (5 mm × 4 mm) intrabony periodontal defects were surgically created bilaterally in the mandibular third premolars and first molars in eight beagles. The defects were treated with ABB in combination with CM (ABB + CM group) or open flap debridement (OFD group). The animals were euthanized at 8-week postsurgery for histological analysis. Two independent Student's t-tests (1-wall [ABB + CM] vs. 1-wall [OFD] and 3-wall [ABB + CM] vs. 3-wall [OFD]) were used to assess between-group differences.</p><p><b>RESULTS</b>The mean new bone height in both 1- and 3-wall intrabony defects in the ABB + CM group was significantly greater than that in the OFD group (1-wall: 4.99 ± 0.70 mm vs. 3.01 ± 0.37 mm, P < 0.05; 3-wall: 3.11 ± 0.59 mm vs. 2.08 ± 0.24 mm, P < 0.05). The mean new cementum in 1-wall intrabony defects in the ABB + CM group was significantly greater than that in their counterparts in the OFD group (5.08 ± 0.68 mm vs. 1.16 ± 0.38 mm; P < 0.05). Likewise, only the 1-wall intrabony defect model showed a significant difference with respect to junctional epithelium between ABB + CM and OFD groups (0.67 ± 0.23 mm vs. 1.12 ± 0.28 mm, P < 0.05).</p><p><b>CONCLUSIONS</b>One-wall intrabony defects treated with ABB and CM did not show less periodontal regeneration than that in 3-wall intrabony defect. The noncontained 1-wall intrabony defect might be a more discriminative defect model for further research into periodontal regeneration.</p>