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Background. Implant insertion in regions with poor bone quantity, such as the posterior maxilla, is potentially associated with an increased rate of implant failure. Calcium sulfate can be used as the coating material for commercially pure titanium (CpTi) and as the bone graft material around implants when bound to eggshell powder to enhance the bone quality and quantity of bone defect regions. This study performed a torque removal test to evaluate the effectiveness of eggshell powder as a bone substitute for filling bone defects around CpTi-coated implants coated with nanocrystalline calcium sulfate. Materials and Methods. Eighty screw implant designs were used in the tibiae of 20 white New Zealand rabbits. A total of uncoated 20 screws constituted the control group, and the remaining 60 screws coated with nano calcium sulfate nanoparticles were used as the experimental groups as follows: 20 screws coated with nano calcium sulfate were used alone in the tibiae without gaps around them, 20 screws coated with nano calcium sulfate were used with the gaps made around them and filled with eggshell powder as the bone graft material, and 20 screws coated with nano calcium sulfate were used with the gaps made around them left unfilled. Results. After 2 to 6 weeks of healing, a significant improvement in bone regeneration and an increase in torque removal values were observed when the bone defect around the CpTi implant coated with nano calcium sulfate was filled with eggshell powder as the bone substitute. Conclusions. Nano calcium sulfate particles applied through the dip-coating method can successfully work as the coating material of CpTi implants. These particles work in synergy with eggshell powder to act as the bone graft around the implants. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine the effects of polymethylmetnacrylate (PMMA) spacer loaded with different concentrations of vancomycin on the proliferative, osteogenic, and angiogenic capacity of the induced membrane.Methods: Varying concentrations of vancomycin (0, 1, 2, 4, 6, 8, and 10 g) were fully mixed with bone cement powder (40 g), resulting in seven experimental groups. Hollow cylindrical PMMA spacers (10 mm height, 3 mm external diameter, and 0.8 mm internal diameter) were formed by a mold and submerged in phosphate-buffered saline for antibiotic release by spectrophotometry. Eighty-four New Zealand white rabbits were evenly randomized into seven groups, and segmental radius shaft defects (10 mm) were created. Defects were filled with cylindrical PMMA spacers containing different vancomycin concentrations, and subsequently underwent intramedullary fixation with a retrograde Kirschner's wire. Tissue toxicity was assessed and the proliferative, osteogenic, and angiogenic capacity of induced membranes were qualitatively analyzed by immunohistochemistry and real-time PCR.Results: No obvious toxicity was observed in the animal model. Alizarin red s staining and qualitative detection of type I collagen, CD31, Ki67, and STRO-1 by immunohistochemistry revealed an obvious decrease in the percentage of positively stained cells and in osteogenic capacity when the concentration of vancomycin was more than 6 g per cement dose. Quantitation of gene expression related to osteogenesis (Col1a, Alp, and Runx2), vascularization (Vegf, Tgfb1, and vWF), and proliferation (Oct4 and Stro-1) by real-time PCR revealed slight increases in the expression of selected genes at low vancomycin concentrations (1-4 g per cement dose), and relatively lower gene expression when the concentration of vancomycin was more than 6 g per cement dose.Conclusion: PMMA spacers loaded with relatively low concentrations of vancomycin (1-4 g per cement dose) did not interfere with the proliferative, osteogenic, and angiogenic capacity of induced membranes, and even promoted their capacity. In contrast, spacers loaded with relatively high concentrations of vancomycin (6-10 g per cement dose) had negative effects on osteoblast viability, angiogenesis, and proliferation. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effectiveness of different graft materials using induced membrane technique for reconstruction of mandibular segmental bone defects. New Zealand rabbits were used as the experimental animal. As first-stage surgical procedure, segmental bone defects were created at the lower border of the mandibula in all groups. Polymethylmethacrylate (PMMA) cement was inserted into the defects. After 6 weeks, PMMA cement was removed in all groups. In the Control group, defect areas were left empty. Defects were filled with autogenous graft in the Autograft group, xenograft in the Xenograft group, and a mixture of autogenous graft and xenograft in the Autograft + Xenograft group. Histopathological, stereological, and immunohistochemical analyses were performed. A total of 40 New Zealand rabbits were used. Rabbits were randomly divided into four subgroups as Control, Autograft, Xenograft and Autograft + Xenograft groups (n = 10). When the groups were compared in terms of newly formed bone tissue volumes, significant difference was found between the Control group and Autograft group, Xenograft group and Autograft + Xenograft group (p < 0.001, p < 0.001, p = 0.003). The results of immunohistochemical examination were consistent with this finding. Stereological and immunohistochemical results can be used as a justification to adopt the induced membrane technique on an experimental basis in humans when it comes to the reconstruction of small segmental mandibular defects. [ABSTRACT FROM AUTHOR]

BACKGROUND: Photodynamic antimicrobial chemotherapy holds broad-spectrum antibacterial ability, fast onset of action and non-resistance, which has been extensively applied in the treatment of superficial localized infection. OBJECTIVE: To explore the efficacy of photodynamic antimicrobial chemotherapy for treating osteomyelitis. METHODS: Thirty-six New Zealand white rabbits (provided by Laboratory Animal Center of Academy of Military Medical Sciences) were selected, and a left tibia osteomyelitis model was established. At 28 days after modeling, rabbit models were randomly divided into three groups: blank group (tibia debridement only), control group (vancomycinlpolymethylmethacrylate bone cement was filled into the intramedullary cavity of the infectious tibia after debridement), and experimental group (intramedullary treatment of photodynamic antimicrobial chemotherapy after debridement). The gross observation, imaging examination and bacterial culture were performed at 4, 8, and 12 weeks after surgery. The study was approved by the Ethical Committee of Affiliated Hospital of Logistics College of CAPF, with the approval No. (2015)-0002. RESULTS AND CONCLUSION: (1) Appearance of the skin: purulent secretion was observed in the blank group, but disappeared in the control and experimental groups where the skin healed well. (2) X-ray examination: with time going, the osteomyelitis aggravated in the blank group. The bone destruction was reduced gradually in the control and experimental groups, and the bone defects healed gradually. There was no significant difference between control and experimental groups at different time points after surgery. (3) Bacterial culture: with time increasing, the bacterial positive rate showed no significant change in the blank group. The bacterial positive rate in the control and experimental groups was on a decline, which showed no significant difference between control and experimental groups at different time points after surgery (P > 0.05). {4) These results indicate that photodynamic antimicrobial chemotherapy is a new treatment for osteomyelitis to effectively control infection, providing experimental basis in clinical practice. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the biological activity, safety, and effectiveness of poly(lactic acid)–poly(glycolic acid)–poly(ethylene glycol)–calcium phosphate cement (PLGA-PEG-PLGA/CPC). Methods: The PLGA-PEG-PLGA/CPC composite bone cement was used for interaction with MC3T3-E1 mouse osteoblasts in vitro and its compatibility was tested using Cell Counting Kit-8 (CCK-8). Alizarin Red staining and alkaline phosphatase activity were used to detect the osteogenic properties. Twenty healthy female New Zealand rabbits were selected to establish osteoporosis models, which were randomly divided into two groups. The experimental group was treated with 30 wt.% PLGA-PEG-PLGA/CPC, while the control group was treated with polymethyl methacrylate (PMMA) bone cement. Imaging and histomorphology of the vertebral body were analyzed after 12 weeks. The distribution and degradation of bone cement were assessed using micro-computed tomography examination and hematoxylin–eosin (HE) staining. Results: In vitro, CCK-8 revealed significant proliferation of osteoblasts in the PLGA-PEG-PLGA/CPC composite bone cement. Alizarin Red staining showed that the degree of staining increased with time. Quantitative results showed that absorbance was significantly higher in this group than in the CPC group on days 7 and 14. The alkaline phosphatase activity levels on days 7 and 14 were significantly higher in the 30 wt.% PLGA-PEG-PLGA/CPC group than in the CPC group. In vivo, postoperative micro-computed tomography and histomorphology showed that the material was evenly distributed in the vertebral body and a small amount penetrated into the trabecular bone. After 12 weeks, CPC degradation and absorption and the formation of new bone matrix were observed and the formation of a callus was obvious. Conclusion: PLGA-PEG-PLGA/CPC composite bone cement has a positive effect on the treatment of osteoporosis. [ABSTRACT FROM AUTHOR]