BACKGROUND:NovaMin is a kind of bioactive glass, and its active ingredients react with saliva to form hydroxyapatite crystals, which deposit on the surface of the teeth and can close the exposed dentinal tubules. It can be used for the treatment of dentin hypersensitivity.
OBJECTIVE:To study the effect of toothpaste containing NovaMin on tooth hypersensitivity patients after subgingival scaling and root planing surgery.
METHODS:According to inclusion and exclusion criteria, 96 patients were picked out from 543 patients to participate in the experiment. In compliance with the principle of randomized, double-blind, comparison, 98 subjects were randomly divided into two groups:experiment group in which the toothpaste containing NovaMin was used, and control group in which the toothpaste without NovaMin was used. Visual analog scale scoring was used to evaluate the degree of sensitivity to air stimulus respectively before and 4 weeks after al ergy experiment.
RESULTS AND CONCLUSION:Total y 88 patients completed the experiment. After treatment with toothpaste for 4 weeks, visual analog scale scores in the experiment group decreased from 4.25±1.87 at baseline to 2.53±1.22 by air stimulus, and visual analog scale scores in the control group decreased from 4.03±1.92 at baseline to 3.63±1.45. The visual analog scale scores in the experiment group and control group both reduced, and the difference was with statistics significance (P<0.05). Compared with the control group, visual analog scale scores in the experiment group decreased more significantly. It showed that the toothpaste containing NovaMin has significant effect on dentin hypersensitivity after subgingival scaling and root planing surgery.

BACKGROUND: Bone implant materials have been previously reported to be not coincident between inducing velocity of new bone formation and degradation velocity itself; therefore, the materials could not be completely degraded but formed into foreign substances. A novel artificial bone implant material, characterizing by well biocompatibUity, biodegradation, and biomechanics, is focused in biomaterials field recently.OBJECTIVE: To study the biodegredation of a novel bionic scaffold with nanostructure, i.e., poly (3-hydroxybutyrate-co-3-hydroxyvalerata)/sol gel bioactive glass (PHBV/SGBG), in vivo. DESIGN, TIME AND SETTING: A controlled animal experiment was performed at Animal Experimental Center of the Third Hospital affiliated to Sun Yat-sen University from May 2005 to October 2006. MATERIALS: PHBV/SGBG was provided by Materials Institute of South China University of Technology, and ethylene oxide was sterilized for preparation.METHODS: Eight hybrid dogs were used to make models of Ubia diaphyseal defect, having two defects on both left and right sides. The tibia diaphyseal defects at proximal part were considered as the control group, and those were not performed with any treatment; while, the tibia diaphyseal defects at distal part were considered as the experimental group, and PHBV/SGBG was fully implanted into the defect regions. Every two dogs were sacrificed at different time points of 2, 4, 8, and 12 weeks, respectively. MAIN OUTCOME MEASURES: In vivo biodogradation and osteogenesis were monitored under optic microscopy and electron microscope.RESULTS: The PHBV/SGBG scaffold had well biodegradation and rapid degradation velocity, and it began to degrade at two weeks after operation. The PHBV/SGBG scaffold was almost replaced by new bone tissues at 8 weeks after operation and completely degraded at 12 weeks after operation. In addition, the PHBV/SGBG scaffold had a good ability to induce new bone formation from edge to center. Whereas, surface depression in the defect region was still visible in the control group, cortical bone was not formed in embedded region of soft tissue; furthermore, electron microscopy demonstrated that calcium salt deposition was increased in the bone defect region, and the structure was tight; however, the defect was not completely repaired, and some voids were still visualized.CONCLUSION: The novel bionic scaffold, PHBV/SGBG, degrades fast in vivo to generate new bone tissues. The new bone regenerate accompanied by a fitting degradation of the novel bionic scaffold that achieve complete repair.

BACKGROUND: Poly hydroxybutyrate-hydroxyvalerate (PHBV) has been used to construct bioprosthetic heart valve. It remains unclear whether it can be used as membrane for guided bone regeneration. OBJECTIVE: To investigate the biocompatibility of PHBV membrane and evaluate its efficiency of promoting bone regeneration in vivo. METHODS: Effects of 100%, 75%, 50%, 25% PHBV extract solution on relative growth rate of dog bone marrow mesenchymal stem cells were measured by MTT method and cytotoxicity of the biomaterials was evaluated. Bone defects were made on distal bilateral tibias and treated with PHBV membrane; the proximal bilateral tibias undergoing reduction of periosteal flap and were used as control. RESULTS AND CONCLUSION: The toxicity gradation of PHBV membranes was grade 0-1. That is, they were not toxic to growth and proliferation of bone marrow mesenchymal stem cells. New bone regeneration was observed in the defects covered with PHBV membranes at week 2 post-surgery. The defects covered with PHBV membranes were filled with mature bone at week 12 post-surgery. The bone repair in experimental groups was earlier and better than that in control groups. Results demonstrated that PHBV membrane, which has no cytotoxicity to mesenchymal stem cells in a wide range of extract concentration, could be a promising biopolymer membrane for guided bone regeneration.

BACKGROUND: The shape and amount of bone regenerated depend on the existence and maintenance of hypolemmal space. Collapse and reduction of hypolemmal space will greatly inhibit bone regeneration. Therefore, the key to success of induced bone regeneration is to select membrane material.OBJECTIVE: This study is designed to investigate the feasibility of poly (hydroxybutyrate-hydroxyvalerate) (PHBV) membrane for guiding bone regeneration.DESIGN, TIME AND SETTING: This study, a self-control animal experiment, was performed at the Laboratory Animal Center, Third Hospital Affiliated to Sun Yat-sen University between May 2005 and October 2006.MATERIALS: PHBV membrane, (10×10×0.3)mm, was provided by Research of Biomaterials, College of Material Science and Engineering, South China University of Technology. Eight healthy hybrid dogs, aged 1 year old, weighing 10-12kg, were included for model of tibial defects.METHODS: Four bone defects were made on bilateral tibias in each dog. Bilateral proximal bone defects of all dogs were included as control group and only subjected to periosteal flap reduction. Bilateral distal bone defects of all dogs were included as experimental group and covered by PHBV membrane. Samples were harvested at weeks 2, 4, 8, and 12 post-surgery.MAIN OUTCOME MEASURES: In vivo degradation performance and ossific capability of PHBV copolymer as well as energy-dispersive X-ray analysis and elemental quantitative assay in bone defect regions.RESULTS: In the experimental group, at week 8 post-surgery, PHBV copolymer membrane had been gradually degraded, different sizes of hollows formed on its surface, bone defect surface was smooth and flat, and X-ray results showed increased bone density in the bone defect regions; at week 12 post-surgery, the PHBV copolymer was still not degraded completely, but bone defect regions had been completely fused with normal bone. Energy-dispersive X-ray analysis and elemental quantitative assay results demonstrated in the experimental group, peaks of Ca and P atom number of newly formed bone were predominant, and peaks of impurity were few. With time going, element Ca and P levels in the newly formed bone were increased, the ratio for Ca and P atoms approximated to that in the normal bone. There was significant difference between the. experimental group and the control group (P<0.05).CONCLUSION: PHBV copolymer membrane is a promising ideal natural membrane material for guiding bone regeneration.

BACKGROUND:Pore diameter,size and porosity of biomaterials are important for cell attachment,infiltration and growth.OBJECTIVE:To primarily evaluate the biocompatibility of novel bionic scaffold of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/sol gel bioactive glass (PHBV/SGBG) with nanostructure in vitro.DESIGN,TIME AND SETTING:Cell-material experiment was performed at the Central Laboratory of Third Hospital of Sun Yat-sen University from March to September 2006.MATERIALS:PHBV/SGBG was provided by the Institute of Materials Science and Engineering,South China University of Technology;bone marrow stroma cells (MSCs) were prepared by our team.METHODS:The standard concentration of PHBV/SGBG extracting solution should be 10 mL/ cm2 of the ratio of culture solution to material surface.PHBV/SGBG was immersed into the complete culture solution and incubated in 5% CO2 at 37 ℃ for 2-3 days.The extracting solution was drawn and stored under sterile condition.In addition,PHBV/SGBG extracting solution of 8,4,2,1,0.5,0.25 and 0.125 times of standard concentration was prepared.MAIN OUTCOME MEASURES:PHBV/SGBG ultrastructure was observed by scanning electron microscopy;PHBV/SGBG porosity was measured by routine measurement.MTT methods were used as a quantitative assessment for cytotoxicity of the biomaterials.Adherence and spreading of MSCs on the surface of specimen was observed using direct contact cultivation.RESULTS:The PHBV/SGBG was porous,with connecting pores under electron microscopy.Nanometer SGBG particles were imbedded or encapsulated in pore wall of PHBV,with the porosity ＞90%.The toxicity gradation of the novel bionic scaffold ranked from grade 0 to 1 at 1,3,5 days of culture.MSCs slightly attached and grew on the surface of the biomaterials,and proliferated rapidly.Obvious cell processes stretched into the micro-pores structure.CONCLUSION:The novel bionic scaffold of PHBV/SGBG has excellent cellular affinity,possibly due to the porous structure,with no cytotoxicity to MSCs.