[Robot-assisted PVP for the treatment of osteoporotic fractures of the upper thoracic vertebra].

OBJECTIVE: To investigate the clinical effect of "Tianji" orthopedic robot-assisted percutaneous vertebro plasty(PVP) surgery in the treatment of upper thoracic osteoporotic fracture. METHODS: A retrospective analysis was performed on 32 patients with upper thoracic osteoporotic fracture who underwent PVP surgery in Shenzhen Hospital of Traditional Chinese Medicine from August 2016 to June 2022. There were 8 males and 24 females, ranging in age from 58 to 90 years old, with a mean of (67.75±12.27) years old. Fifteen patients were treated with robot-assisted PVP surgery (robot group), including 3 males and 12 females, with an average age of (68.5±10.3) years. Fracture location:1 case of T2 fracture, 1 case of T3 fracture, 3 cases of T4 fracture, 3 cases of T5 fracture, and 7 cases of T6 fracture. The follow-up period ranged from 1.0 to 3.0 months, with a mean of (1.6±0.7) months. Seventeen patients underwent routine PVP surgery (conventional group), including 5 males and 12 females, with an average age of (66.8±11.6) years old. Fracture location:1 case of T1 fracture, 5 cases of T4 fracture, 2 cases of T5 fracture and 9 cases of T6 fracture. The follow-up period ranged from 0.5 to 4.0 months, with a mean of (1.5±0.6) months. Preoperative and postoperative visual analogue scale(VAS) and Oswestry disability index(ODI) scores were compared between the two groups, and the number of punctures, perspective times, operation time, intraoperative blood loss, bone cement distribution, bone cement leakage, and intraoperative radiation dose were compared between the two groups. RESULTS: Number of punctures times, perspective times, operation time, intraoperative blood loss, bone cement distribution, bone cement leakage and intraoperative radiation dose in the robot group were all significantly better than those in the conventional group(P<0.05). VAS of 2.03±0.05 and ODI of (22.16±4.03) % in the robot group were significantly better than those of the robot group before surgery, which were (8.67±0.25) score and (79.40±7.72)%(t=100.869, P<0.001;t=25.456, P<0.001). VAS of 2.17±0.13 and ODI of (23.88±6.15)% in the conventional group were significantly better than those before surgery, which were (8.73±0.18) score and (80.01±7.59)%(t=121.816, P<0.001;t=23.691, P<0.001). There was no significant difference in VAS and ODI between the two groups after operation (t=-3.917, P=0.476;t=-0.922, P=0.364). CONCLUSION: Robot-assisted PVP in the treatment of upper thoracic osteoporotic fractures can further improve surgical safety, reduce bone cement leakage, and achieve satisfactory clinical efficacy.

[Characterization and osteogenic activity of FSP-modified TiNbTaZr/Zn].

PURPOSE: To investigate whether Ti-35Nb-2Ta-3Zr/Zn (TNTZ/Zn) composite material processed by friction stir processing has osteogenic activity. METHODS: Zn was added to the surface of TNTZ alloy by friction stir processing. The control group was TNTZ(TNTZ without FSP), the experimental groups was FSP(FSP without Zn), TNTZ/Zn-0.5 (0.5 mm pre-made holes) and TNTZ/Zn-1(1 mm pre-made holes). Surface characterization was performed by scanning electron microscope and X-ray diffraction. Alkaline phosphatase(ALP) activity of co-cultured rat bone marrow stromal stem cells (BMSCs) and COL-1α, OPN and OCN gene expression were detected by real-time quantitative PCR. SAS version 8.2 software was used for data analysis. RESULTS: Zn nanoparticles on the surface of the TNTZ/Zn-1 group were distributed homogeneously, with a diameter range of 70-80 nm. Compared with TNTZ group, the activity of ALP in TNTZ/Zn-0.5 and TNTZ/Zn-1 groups was up-regulated (P<0.05 and P<0.01). Compared with TNTZ group, ALP, COL-1α, OPN and OCN gene expression increased in TNTZ/Zn-0.5 and TNTZ/Zn-1 group, and the difference was statistically significant (P<0.05). CONCLUSIONS: Through FSP, Zn can be successfully integrated onto the surface of TNTZ alloy with nano-scale microstructures. TNTZ/Zn composite material can effectively induce bone formation and is a potential implant material.

[Experimental evaluation of the spraying disinfection efficiency on dental models].

PURPOSE: To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. METHODS: The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. RESULTS: All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. CONCLUSIONS: The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.

[The effect of different retention pin on the shear force of anterior base plate].

PURPOSE: The purpose of this study was to compare the effect of enhancement by different shape retention nails on the anterior region resin denture base through shear strength measurements. METHODS: 24 specimens with the same size and thickness were divided into 4 groups by the shape of retention nails. Three experimental groups of the resin denture base specimen were placed a retention nail with different shape, Δtype, V type and I type. Another group of 6 specimens without nail was used as control. All the samples' shear forces were tested by universal mechanical testing machine, and the data was statistically analyzed by SPSS 10.1 software package. RESULTS: The shear forces of Δtype group, V type group, the I type group and control group, were respectively (326.80±64.17) N, (225.07±31.76) N, (182.85±15.18) N, and (116.67soil 4.35) N. According to the statistical results, the difference of shear forces had no significant difference (P>0.05) between I type and V type, although the shear forces of these two groups were significantly greater than the control group (P<0.05). The shear forces of Δ type group were significantly greater than the other three groups (P<0.05). CONCLUSIONS: The retention nail of Δ shape can significantly enhance the anti-shear ability of resin denture base.

[Fabrication and physical properties of porous individual beta-TCP scaffold to reconstruct residual alveolar ridge in dog].

PURPOSE: To fabricate porous individual beta-tricalcium phosphate scaffold and test its properties in dog. METHODS: A model of residual alveolar ridge in mandible of a dog was made and CT scanned after 3 months.The data of CT was transformed to 3-D format by MIMICS 7.0 and was made to resin model by rapid prototype technique.The residual alveolar ridge was reconstructed using silicon rubber, and its impression was made.Porous individual beta-tricalcium phosphate scaffold and 5 samples were fabricated for precision and properties test.Porosity, water absorbing capacity and compressive strength of samples were tested with crystalling phase and pore structure were analysed by XRD and scanning electron microscope. RESULTS: We successfully fabricated a scaffold which fit the resin model well and consisted of beta-TCP. Its porosity was 74%,water absorbing capacity was 48%,compressive strength was 4 MPa,diameter of pore was 150 to 400 microm,connecting diameter was 40 microm. CONCLUSIONS: We can fabricate individual beta-TCP scaffold which fit the model well by combination of traditional method and rapid prototype technique.Supported by Shanghai Leading Academic Discipline Project(Grant No.T0202).

[Advances in research and application of beta-tricalcium phosphate, collagen and beta-tricalcium phosphate/collagen composite in bone tissue engineering].

Bone defects in oral and maxillofacial region was a common problem. To repair the defect, bone grafts including autograft, allograft and artificial bone graft were used in clinic despite of their disadvantages. Nowadays, bone tissue engineering has become a commonly used method to repair bone defect. This paper reviewed the application of beta-TCP, collagen and beta-TCP/collagen composite in bone tissue engineering. It was concluded that beta-TCP/collagen composite was a promising materials in bone tissue engineering.

[Culture and characteristics of porcine dental papilla cells (pDPCs) in vitro].

PURPOSE: To culture porcine dental papilla cells (pDPCs) and to study the cytobiological characteristics of the cells in vitro. METHODS: Dental papillae were collected from postnatal (1-3 days) pigs, then the pDPCs were isolated and cultured through the method of enzyme-digestion. Vimentin and cytokeratin (CK) were used to demonstrate the cells' mesenchymal derivation. Collagen I collagen III and dentin sialoprotein (DSP) were detected in pDPCs by immunohistochemistry. RESULTS: The pDPCs were well cultured in the medium of DMEM/F12 containing 10% FBS in vitro. Vimentin was positively expressed in pDPCs but CK was not. Collagen I, collagen III, and DSP were all positive in the plasma of the pDPCs. CONCLUSIONS: The pDPCs were successfully isolated and cultured in vitro. The pDPCs come from mesenchymal tissue and have the capability of synthesizing extracellular matrix (collagen I, collagen III, and DSP) of dentin-pulp complex. This study indicated that the pDPCs may have the potential to be used as seed cell in regeneration of dentin-pulp complex.

[Comparison of the cytotoxicity in vitro among six types of nano-silver base inorganic antibacterial agents].

OBJECTIVE: To evaluate the biocompatibility of nano-silver base inorganic antibacterial agents and compare the cytotoxicity in vitro among six types of nano-silver base inorganic antibacterial agents. METHODS: FUMAT T200-4, HN300, Novaron, Kangwang, MOD and SR1000 were diluted to different concentrations, such as 100 g/L, 50 g/L, 25 g/L and 12.5 g/L. The cytotoxicity in vitro of these agents on rat's fibroblast was assayed with MTT method. And the grades of cytotoxicity were compared. RESULTS: High concentrations of nano-silver base inorganic antibacterial agents had cytotoxic effects on rat's fibroblasts L-929. As the concentration decreased, the cytotoxicity decreased. No cytotoxic effects were observed at or below the concentration of 25 g/L. FUMAT T200-4, Kongwang and SR1000, with the carrier of phosphate zirconium, had less cytotoxity than the others. CONCLUSIONS: Nano-Silver base inorganic antibacterial agents, such as FUMAT T200-4, Kangwang, SR1000, have good biocompatibility. And they have the possibility of clinical application. The safe concentration of these agents is at or below 25 g/L.

[The use of computer-aided colorimeter in porcelain-fused-to-metal (PFM) crowns among patients with special colored teeth].

PURPOSE: To evaluate the roll of ShadeEye-NCC, a computer-aided colorimeter, in Porcelain-Fused-to-Metal crowns among patients with special colored Teeth. METHODS: The first step was to choose the proper patients. The next was to use the colorimeter to measure the base shade of tooth and fabricate the PFM crowns according to the recipe given by the colorimeter. At last, the effects of the PFM crowns were evaluated subjectively by patients and doctor. RESULTS: The satisfaction rates of patients and doctor were 83.7% and 81.4% respectively, there was no significant difference between the two rates. CONCLUSIONS: The computer-aided colorimeter can offer good base shade recipe for fabricating PFM crowns of patients with special colored teeth.

[In vitro study on the cytotoxicity of strontium substituted hydroxyapatite].

OBJECTIVE: To evaluate the cytotoxicity of strontium substituted hydroxyapatite. METHODS: Cell Relative Growth Rate(RGR) method, MTT assay and Flow Cytometry(FCM) method were used, and the strontium substituted hydroxyapatite contained different strontium concentration(0%,1%,5%,10%,100%). RESULTS: It was found that there's no apparent cytotoxicity of all the strontium substituted hydroxyapatite,but the cytotoxicity increased as the strontium concentration raised. As the FCM method appeared, there was no apparent difference between the pure hydroxyapatite and 1%,5% strontium substituted hydroxyapatite. CONCLUSION: Strontium substituted hydroxyapatite has good biocompatibility, and 10%,100% strontium substituted hydroxyapatite has weak cytotoxicity.