The influences of sucrose, citric acid and sodium bicarbonate on the adhesion of 3 kinds of adhesives / 实用口腔医学杂志

Objective:To study the influences of sucrose,citric acid and sodium bicarbonate on the adhesion of 3 kinds of adhesives.Methods:60 extracted tooth and 60 zirconia blocks (3 mm × 3 mm × 3 mm) were randomly divided into 3 groups (n =20),namely PULPDENT group,3M ESPE RelyxTM Veneer group and RelyxTM Luting group.Then,the samples of each group fell into 4 subgroups(n=5),namely subgroup A for artificial saliva,subgroup B for 10％ sucrose,subgroup C for 0.2％ citric acid,and subgroup D for 0.03 ％ sodium bicarbonate.After completing the adhesion of the specimens with corresponding adhesives,the specimens of subgroups A,B,C and D were submerged into artificial saliva(the control),sucrose,citric acid and sodium bicarbonate solutions for 2 times/day and 5 min/time,respectively.For the rest of time,all the specimens were submerged in artificial saliva.3 months later,shear bond strength of the specimens was tested,the fracture surface was observed under SEM,20 × microscope,and the fracture model was observed by stereoscopic microscope.SPSS 17.0 software was adopted for statistical analysis of the data.Results:The bond strength of PULPDENT,3M ESPE RelyxTM Veneer groups were higher than that of RelyxTM Luting group(P ＜ 0.05);the bond strength of subgroups B,C and D was lower than that of subgroup A(P ＜0.05);and the difference between the remaining groups was not statistically significant(P ＞0.05).SEM observation displayed that in group RelyxTM Luting,subgroups B,C and D showed increased crack depth,width and length when compared with subgroup A;there was no obvious difference between the remaining groups and the control group;in groups PULPENT,3M ESPE RelyxTM Veneer and RelyxTM Luting,all samples in their subgroups showed interface failure.Conclusion:Compared with PULPDENT and 3M ESPE RelyxTM Veneer adhesive,RelyxTM Luting is more susceptible to the influence of sucrose,citric acid and sodium bicarbonate,so it is not suitable for bonding zirconia blocks.

The influence of disposing the shoulder by the dental pneumatic ultrasonic hand-piece on the edge sealing prop-erty of the zirconium dioxide crown / 实用口腔医学杂志

15 extracted premolars were selected and randomly divided into 3 groups, with 5 in each group. MANI TF-13 bur、TR13-EF bur and the dental pneumatic ultrasonic hand-piece were respectively used to dispose the shoulder. 15 Zirconium dioxide full crowns were made. The shoulder marginal microleakage was observed by staining method. Dental pneumatic ultrasonic hand-piece showed the best anti-mic-roleakage effect in shoulder refinement.

The influence of the different polishing methods on the marginal sealing property of the computer aided design and computer aided manufacture zirconium dioxide full crown / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the influence of different polishing methods on marginal microleakage of zirconium dioxide full crown.</p><p><b>METHODS</b>Thirty extracted premolars were selected and randomly divided into three groups, A, B and C, with 10 in each group. Group A was prepared with MANI TF-13 bur completely without the treatment of shoulder. The shoulder of group B was polished with MANI TR13-EF bur after the preparation using MANI TF-13. The shoulder of group C was polished with the dental pneumatic ultrasonic hand-piece of KaVo SONICflex after the preparation using MANI TF-13 bur. Five specimens after preparation were selected in each group. Fifteen CAD/CAM zirconium dioxide full crowns have been made. The crowns were bonded using PULPDENT resin cement, and the root canals were sealed using nail polish, and apical foramen were closed using flow resin. The test-pieces have been immersed in a 3% solution of methylene blue for 24 h. The condition of shoulder marginal microleakage was observed using light stereomicroscopy and evaluated in classification index. The remaining specimens in each group were used for roughness test and scanning electron microscope(SEM) experiment. The marginal microleakage situations of specimens in three groups was analyzed by SPSS 17.0. The enamel surface of different polishing methods was observed using SEM.</p><p><b>RESULTS</b>The specimens in group C demonstrated the least marginal microleakage, and those in group B showed an intermediate level of marginal microleakage, and those in group A characterized the most serious marginal microleakage (total, χ2=44.610, P<0.01; among the different groups, P<0.05). The roughness experiment showed that specimens in group C achieve the smoothest results ([0.27±0.03] μm). Preparation shoulder polished using the dental pneumatic ultrasonic hand-piece demonstrated the best result under the SEM among the three groups.</p><p><b>CONCLUSIONS</b>The anti-microleakage effectiveness of dental pneumatic ultrasonic hand-piece in shoulder refinement is better than ordinary shoulder treatment.</p>

Effect of bisphosphonate on osteoclast differentiation and tartrate-resistant acid phosphatase / 中国组织工程研究

BACKGROUND:Tartrate-resistant acid phosphatase is a specific marker for osteoclast differentiation and bone resorption, which is a sign of osteoclast maturity. OBJECTIVE:To study the effect of alendronate on tartrate-resistant acid phosphatase related to osteoclast differentiation and bone resorption. METHODOsteoclasts were cultured by mouse monocyte-macrophage cellline-RAW264.7. The cells were divided into two groupcontrol group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor;alendronate group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor+10-7 mol/L alendronate. Osteoclastogenesis and resorption function of osteoclasts were examined at 7 days of culture. Gene expression of tartrate-resistant acid phosphatase was detected by immunofluorescence method. Western blot assay was used to detect protein expression of tartrate-resistant acid phosphatase. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase positive multinuclear cells were observed and resorption lacunae formed in two groups. Control group showed the higher number of tartrate-resistant acid phosphatase positive multinuclear cells and larger size of resorption lacunae than the alendronate group (P<0.01). Immunofluorescence showed expression of tartrate-resistant acid phosphatase was higher in the control group than the alendronate group (P<0.01);furthermore, the protein expression of tartrate-resistant acid phosphatase was also lower in the alendronate group than the control group (P<0.01). These findings indicate that bisphosphonates could strongly inhibit osteoclastogenesis and its resorption function by inhibiting protein expression of tartrate-resistant acid phosphatase.

Bisphosphonate effects on capthesin K and bone resorption function during osteoclast differentiation / 中国组织工程研究

BACKGROUND:Studies have shown that bisphosphonates inhibit osteoclast resorption, but whether cathepsin K, a key cytokine of bone resorption, plays an effect has rarely been reported. OBJECTIVE:To study the effect of bisphosphonate on capthesin K and bone resorption function during osteoclast differentiation. METHODS:Osteoclasts were cultured by mouse monocyte-macrophage cellline-RAW264.7. The cells were divided into two groups:control group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor;alendronate group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor+10-7 mol/L alendronate. Osteoclastogenesis and resorption function of osteoclasts were examined at 7 days of culture and gene expression of capthesin K was detected by immunofluorescence method at 72 hours of culture. Western blot assay was used to detect capthesin K protein expression at 72 hours of culture. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase positive multinuclear cells were observed and resorption lacunae formed in two groups. Control group showed the higher number of tartrate-resistant acid phosphatase positive multinuclear cells and larger size of resorption lacunae than the alendronate group (P<0.01). Immunofluorescence showed expression of capthesin K was higher in the control group than the alendronate group (P<0.01);furthermore, the protein expression of capthesin K was also lower in the alendronate group than the control group (P<0.01). These findings indicate that bisphosphonates could strongly inhibit osteoclastogenesis and its resorption function by inhibiting gene expression of capthesin K.

Advance in fiber post surface treatment technology / 中国组织工程研究

BACKGROUND:How to improve effective connection strength between fiber post and resin, to reduce the failure rate of repairing, has become the focus of current researches. Without surface treatment, the fiber post surface bonding strength is relatively low, is prone to appear adhesive failure, so the surface treatment of fiber post to increase the fiber post-resin bonding strength is the key to achieve a successful repair. OBJECTIVE:To review the progress of fiber post surface treatment technology in the crown restoration. METHODS: A computer-based retrieval was performed among CNKI and PubMed databases between 2003 and 2013, by using the key words of fiber-reinforced post, surface treatment, bond strength in English and Chinese. The recent literatures concerned with the fiber post surface treatment were extensively reviewed, 32 ones were summarized and analyzed. RESULTS AND CONCLUSION: The failure of bonding between fiber post and resin is a major problem in fiber posts restoration techniques. In recent years, scholars try to use a variety of methods for processing fiber post surface, the fiber post-resin bonding strength is significantly improved. Mechanical or (and) chemical treatment on the surface of fiber post can significantly improve fiber post-resin bonding strength, which could increase the success rate of the crown restoration. Among them, H2O2+silicane coupling agent achieved the best effects. However, long-term clinical observations are needed to verify these methods.

Effect of alendronate on expressions of osteoprotegerin and receptor activator of nuclear factor κB ligand in mouse osteoblasts / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of alendronate on the expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in mouse osteoblasts.</p><p><b>METHODS</b>Mouse calvarial osteoblasts cultured in vitro were identified by alkaline phosphatase (ALP) staining and immunofluorescence assay of OPG and RANKL expressions. The second passage of the osteoblasts were treated with different concentrations of alendronate (10(-4) to 10(-7) mol/L) for 48 h, and the changes in OPG and RANKL mRNA and protein expressions were examined using real-time PCR and Western blotting, respectively.</p><p><b>RESULTS</b>The isolated osteoblasts were positive for ALP and expressed OPG and RANKL. Real-time PCR and Western blotting showed that at the concentration of 1×10(-4) mol/L, alendronate caused an obvious down-regulation of OPG and RANKL expressions in the cells, whereas at lower concentrations, alendronate increased the expressions of both genes with the highest expressions occurring after treatment with 1×10(-5) mol/L.</p><p><b>CONCLUSION</b>High concentrations of alendronate (>1×10(-4) mol/L) decrease the expressions of OPG and RANKL, whereas low concentrations (1×10(-5) to 1×10(-7) mol/L) increase their expressions in mouse osteoblasts cultured in vitro.</p>

Construction and selection of effective mouse Smad6 recombinant lenti-virus interference vectors / 生物医学工程学杂志

This experiment was designed to construct mouse Smad6 recombinant RNA interference vectors and determine their interference effects on bone marrow mesenchymal stem cells (BMSCs). Three recombinant Smad6 RNA interference vectors were constructed by molecular clone techniques with a lenti-virus vector expressing green fluorescent protein (GFP), and the correctness of recombinant vectors was verified by DNA sequencing. Mouse BMSCs were used for transfection experiments and BMP-2 was in use for osteogenic induction of MSCs. The transfection efficiency of recombinant vectors was examined by Laser confocal scanning microscope and the interference effect of recombinant vectors on Smad6 gene expression was determined by real-time RT-PCR and Western blot, respectively. Three Smad6 recombinant RNA interference vectors were successfully constructed and their correctness was proved by DNA sequencing. After transfection, GFPs were effectively expressed in MSCs and all of three recombinant vectors gained high transfection efficiency (> 95%). Both real-time PCR and Western blot examination indicated that among three recombinant vectors, No. 2 Svector had the best interference effect and the interference effect was nearly 91% at protein level. In conclusion, Mouse recombinant Smad6 RNA interference (RNAi) vector was successfully constructed and it provided an effective tool for further studies on BMP signal pathways.