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| 1 | Calcium phosphate cements for bone engineering and their biological properties显示文摘Calcium phosphate cements(CPCs) are frequently used to repair bone defects. Since their discovery in the 1980 s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability,bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs,including 3 D printing, injectability, stem cell delivery, growth factor and drug delivery, and prevascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis. | Hockin HK Xu Ping Wang Lin Wang Chongyun Bao Qianming Chen Michael D Weir Laurence C Chow Liang Zhao Xuedong Zhou Mark A Reynolds | 2017 | Bone Research2017,5,4: | 14 |
| 2 | Effects of quaternary ammonium chain length on the antibacterial and remineralizing effects of a calcium phosphate nanocomposite显示文摘Composites containing nanoparticles of amorphous calcium phosphate(NACP)remineralize tooth lesions and inhibit caries.A recent study synthesized quaternary ammonium methacrylates(QAMs)with chain lengths(CLs)of 3–18 and determined their effects on a bonding agent.This study aimed to incorporate these QAMs into NACP nanocomposites for the first time to simultaneously endow the material with antibacterial and remineralizing capabilities and to investigate the effects of the CL on the mechanical and biofilm properties.Five QAMs were synthesized:DMAPM(CL3),DMAHM(CL6),DMADDM(CL12),DMAHDM(CL16),and DMAODM(CL18).Each QAM was incorporated into a composite containing 20%NACP and 50%glass fillers.A dental plaque microcosm biofilm model was used to evaluate the antibacterial activity.The flexural strength and elastic modulus of nanocomposites with QAMs matched those of a commercial control composite(n 5 6;P.0.1).Increasing the CL from 3 to 16 greatly enhanced the antibacterial activity of the NACP nanocomposite(P,0.05);further increasing the CL to 18 decreased the antibacterial potency.The NACP nanocomposite with a CL of 16 exhibited biofilm metabolic activity and acid production that were 10-fold lesser than those of the control composite.The NACP nanocomposite with a CL of 16 produced 2-log decreases in the colony-forming units(CFU)of total microorganisms,total streptococci,and mutans streptococci.In conclusion,QAMs with CLs of 3–18 were synthesized and incorporated into an NACP nanocomposite for the first time to simultaneously endow the material with antibacterial and remineralization capabilities.Increasing the CL reduced the metabolic activity and acid production of biofilms and caused a 2-log decrease in CFU without compromising the mechanical properties.Nanocomposites exhibiting strong anti-biofilm activity,remineralization effects,and mechanical properties are promising materials for tooth restorations that inhibit caries. | Ke Zhang Lei Cheng Michael D Weir Yu-Xing Bai Hockin HK Xu | 2016 | International Journal of Oral Science2016,8,1: | 13 |
| 3 | Bone tissue engineering via nanostructured calcium phosphate biomaterials and stem cells显示文摘Tissue engineering is promising to meet the increasing need for bone regeneration. Nanostructured calcium phosphate(CaP) biomaterials/scaffolds are of special interest as they share chemical/crystallographic similarities to inorganic components of bone. Three applications of nano-CaP are discussed in this review:nanostructured calcium phosphate cement(CPC); nano-CaP composites; and nano-CaP coatings. The interactions between stem cells and nano-CaP are highlighted, including cell attachment, orientation/morphology, differentiation and in vivo bone regeneration. Several trends can be seen:(i) nano-CaP biomaterials support stem cell attachment/proliferation and induce osteogenic differentiation, in some cases even without osteogenic supplements;(ii) the influence of nano-CaP surface patterns on cell alignment is not prominent due to non-uniform distribution of nano-crystals;(iii) nano-CaP can achieve better bone regeneration than conventional CaP biomaterials;(iv) combining stem cells with nano-CaP accelerates bone regeneration, the effect of which can be further enhanced by growth factors; and(v) cell microencapsulation in nano-CaP scaffolds is promising for bone tissue engineering. These understandings would help researchers to further uncover the underlying mechanisms and interactions in nano-CaP stem cell constructs in vitro and in vivo, tailor nano-CaP composite construct design and stem cell type selection to enhance cell function and bone regeneration, and translate laboratory findings to clinical treatments. | Ping Wang Liang Zhao Jason Liu Michael D Weir Xuedong Zhou Hockin H K Xu | 2014 | Bone Research2014,2,3: | 11 |
| 4 | Toward dental caries: Exploring nanoparticle-based platforms and calcium phosphate compounds for dental restorative materials显示文摘Millions of people worldwide suffer from a toothache due to tooth cavity,and often permanent tooth loss.Dental caries,also known as tooth decay,is a biofilm-dependent infectious disease that damages teeth by minerals loss and presents a high incidence of clinical restorative polymeric fillings(tooth colored fillings).Until now,restorative polymeric fillings present no bioactivity.The complexity of oral biofilms contributes to the difficulty in developing effective novel dental materials.Nanotechnology has been explored in the development of bioactive dental materials to reduce or modulate the activities of caries-related bacteria.Nano-structured platforms based on calcium phosphate and metallic particles have advanced to impart an anti-caries potential to restorative materials.The bioactivity of these platforms induces prevention of mineral loss of the hard tooth structure and antibacterial activities against caries-related pathogens.It has been suggested that this bioactivity could minimize the incidence of caries around restorations(CARS)and increase the longevity of such filling materials.The last few years witnessed growing numbers of studies on the preparation evaluations of these novel materials.Herein,the caries disease process and the role of pathogenic caries-related biofilm,the increasing incidence of CARS,and the recent efforts employed for incorporation of bioactive nanoparticles in restorative polymer materials as useful strategies for prevention and management of caries-related-bacteria are discussed.We highlight the status of the most advanced and widely explored interaction of nanoparticle-based platforms and calcium phosphate compounds with an eye toward translating the potential of these approaches to the dental clinical reality. | Abdulrahman A.Balhaddad Anmar A.Kansara Denise Hidan Michael D.Weir Hockin H.K.Xu Mary Anne S.Melo | 2019 | Bioactive Materials2019,4,1: | 9 |
| 5 | A novel protein-repellent dental composite containing 2-methacryloyloxyethyl phosphorylcholine显示文摘Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure.To date,there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment.The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine(MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption,bacteria attachment,biofilm growth,and mechanical properties.Composites were synthesized with 0(control),0.75%,1.5%,2.25%,3%,4.5%and 6%of MPC by mass.A commercial composite was also tested as a control.Mechanical properties were measured in three-point flexure.Protein adsorption onto the composite was determined by the microbicinchoninic acid method.A human saliva microcosm biofilm model was used.Early attachment at 4 h,biofilm at 2 days,live/dead staining and colony-forming units(CFUs) of biofilms grown on the composites were investigated.Composites with MPC of up to 3%had mechanical properties similar to those without MPC and those of the commercial control,whereas 4.5%and 6%MPC decreased the mechanical properties(P<0.05).Increasing MPC from 0 to 3%reduced the protein adsorption on composites(P<0.05).The composite with 3%MPC had protein adsorption that was 1/12 that of the control(P<0.05).Oral bacteria early attachment and biofilm growth were also greatly reduced on the composite with 3%MPC,compared to the control(P<0.05).In conclusion,incorporation of MPC into composites at 3%greatly reduced protein adsorption,bacteria attachment and biofilm CFUs,without compromising mechanical properties.Protein-repellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries.The protein-repellent method might be applicable to other dental materials. | Ning Zhang Chen Chen Mary AS Melo Yu-Xing Bai Lei Cheng Hockin HK Xu | 2015 | International Journal of Oral Science2015,7,2: | 8 |
| 6 | One-year water-ageing of calcium phosphate composite containing nano-silver and quaternary ammonium to inhibit biofilms显示文摘Dental composites are commonly used restorative materials; however, secondary caries due to bio?lm acids remains a major problem. The objectives of this study were(1) to develop a composite containing quaternary ammonium dimethacrylate(QADM),nanoparticles of silver(NAg), and nanoparticles of amorphous calcium phosphate(NACP), and(2) to conduct the ?rst investigation of the mechanical properties, bio?lm response and acid production vs water-ageing time from 1 day to 12 months.A 4 × 5 design was utilized, with four composites(NACP-QADM composite, NACP-NAg composite, NACP-QADM-NAg composite,and a commercial control composite), and ?ve water-ageing time periods(1 day, and 3, 6, 9, and 12 months). After each waterageing period, the mechanical properties of the resins were measured in a three-point ?exure, and antibacterial properties were tested via a dental plaque bio?lm model using human saliva as an inoculum. After 12 months of water-ageing, NACP-QADMNAg had a ?exural strength and elastic modulus matching those of the commercial control(P40.1). Incorporation of QADM or NAg into the NACP composite greatly reduced bio?lm viability, metabolic activity and acid production. A composite containing both QADM and NAg possessed a stronger antibacterial capability than one with QADM or NAg alone(Po0.05). The anti-bio?lm activity was maintained after 12 months of water-ageing and showed no signi?cant decrease with increasing time(P40.1). In conclusion, the NACP-QADM-NAg composite decreased bio?lm viability and lactic acid production, while matching the loadbearing capability of a commercial composite. There was no decrease in its antibacterial properties after 1 year of water-ageing.The durable antibacterial and mechanical properties indicate that NACP-QADM-NAg composites may be useful in dental restorations to combat caries. | Lei Cheng Ke Zhang Chen-Chen Zhou Michael D Weir Xue-Dong Zhou Hockin HK Xu | 2016 | International Journal of Oral Science2016,8,3: | 8 |
| 7 | Advanced smart biomaterials and constructs for hard tissue engineering and regeneration显示文摘Hard tissue repair and regeneration cost hundreds of billions of dollars annually worldwide, and the need has substantially increased as the population has aged. Hard tissues include bone and tooth structures that contain calcium phosphate minerals.Smart biomaterial-based tissue engineering and regenerative medicine methods have the exciting potential to meet this urgent need. Smart biomaterials and constructs refer to biomaterials and constructs that possess instructive/inductive or triggering/stimulating effects on cells and tissues by engineering the material's responsiveness to internal or external stimuli or have intelligently tailored properties and functions that can promote tissue repair and regeneration. The smart material-based approaches include smart scaffolds and stem cell constructs for bone tissue engineering; smart drug delivery systems to enhance bone regeneration; smart dental resins that respond to pH to protect tooth structures; smart pH-sensitive dental materials to selectively inhibit acid-producing bacteria; smart polymers to modulate biofilm species away from a pathogenic composition and shift towards a healthy composition; and smart materials to suppress biofilms and avoid drug resistance. These smart biomaterials can not only deliver and guide stem cells to improve tissue regeneration and deliver drugs and bioactive agents with spatially and temporarily controlled releases but can also modulate/suppress biofilms and combat infections in wound sites. The new generation of smart biomaterials provides exciting potential and is a promising opportunity to substantially enhance hard tissue engineering and regenerative medicine efficacy. | Ke Zhang Suping Wang Chenchen Zhou Lei Cheng Xianling Gao Xianju Xie Jirun Sun Haohao Wang Michael D.Weir Mark A.Reynolds Ning Zhang Yuxing Bai Hockin H.K.Xu | 2018 | Bone Research2018,6,4: | 6 |
| 8 | Inhibition of CCL2 by bindarit alleviates diabetes-associated periodontitis by suppressing inflammatory monocyte infiltration and altering macrophage properties显示文摘Diabetes-associated periodontitis(DP)aggravates diabetic complications and increases mortality from diabetes.DP is caused by diabetes-enhanced host immune-inflammatory responses to bacterial insult.In this study,we found that persistently elevated CCL2 levels in combination with proinflammatory monocyte infiltration of periodontal tissues were closely related to DP.Moreover,inhibition of CCL2 by oral administration of bindarit reduced alveolar bone loss and increased periodontal epithelial thickness by suppressing periodontal inflammation.Furthermore,bindarit suppressed the infiltration of proinflammatory monocytes and altered the inflammatory properties of macrophages in the diabetic periodontium.This finding provides a basis for the development of an effective therapeutic approach for treating DP. | Zongshan Shen Shuhong Kuang Min Zhang Xin Huang Jiayao Chen Meiliang Guan Wei Qin Hockin H.K.Xu Zhengmei Lin | 2021 | Cellular & Molecular Immunology2021,18,9: | 6 |
| 9 | Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates显示文摘Antibacterial adhesives are promising to inhibit biofilms and secondary caries.The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives,and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time.Six quaternary ammonium methacrylates with chain lengths of 3,6,9,12,16 and 18were synthesized and incorporated into Scotchbond Multi-Purpose.Streptococcus mutans bacteria were cultured on resin to form biofilms.Confocal laser scanning microscopy was used to measure biofilm thickness,live/dead volumes and live-bacteria percentage vs.distance from resin surface.Biofilm thickness was the greatest for Scotchbond control;it decreased with increasing chain length,reaching a minimum at chain length 16.Live-biofilm volume had a similar trend.Dead-biofilm volume increased with increasing chain length.The adhesive with chain length 9 had 37%live bacteria near resin surface,but close to 100%live bacteria in the biofilm top section.For chain length 16,there were nearly 0%live bacteria throughout the three-dimensional biofilm.In conclusion,strong antibacterial activity was achieved by adding quaternary ammonium into adhesive,with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16.Antibacterial adhesives typically only inhibited bacteria close to its surface;however,adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm.Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries. | Han Zhou Michael D Weir Joseph M Antonucci Gary E Schumacher Xue-Dong Zhou Hockin H K Xu | 2014 | International Journal of Oral Science2014,6,2: | 5 |
| 10 | Effect of anti-biofilm glass–ionomer cement on Streptococcus mutans biofilms显示文摘Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial glass–ionomer cements(GIC) containing a quaternary ammonium monomer(dimethylaminododecyl methacrylate, DMADDM), and to investigate their effect on material performance and antibacterial properties. Different mass fractions(0, 1.1% and 2.2%) of DMADDM were incorporated into the GIC. The flexure strength, surface charge density, surface roughness and fluoride release were tested. A Streptococcus mutans biofilm model was used. Exopolysaccharides(EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm matrix. In addition, biofilm metabolic activity, lactic acid metabolism and the expression of glucosyltransferase genes gtf B, gtf C and gtf D were measured. GIC containing 1.1% and 2.2% DMADDM had flexural strengths matching those of the commercial control(P40.1). DMADDM was able to increase the surface charge density but reduced surface roughness(Po0.05). The incorporation of 1.1% and 2.2% DMADDM elevated the release of fluoride by the GIC in the first 2 days(Po0.05). The novel DMADDM-modified GIC significantly reduced biofilm metabolic activity(Po0.05) and decreased lactic acid production(Po0.05). The quantitative polymerase chain reaction(q PCR) results showed that the expression of gtf B, gtf C and gtf D decreased when mass fractions of DMADDM increased(Po0.05). EPS staining showed that both the bacteria and EPS in biofilm decreased in the DMADDM groups. The incorporation of DMADDM could modify the properties of GIC to influence the development of S. mutans biofilms. In this study, we investigated the interface properties of antibacterial materials for the first time. GIC containing DMADDM can improve material performance and antibacterial properties and may contribute to the better management of secondary caries. | Su-Ping Wang Yang Ge Xue-Dong Zhou Hockin HK Xu Michael D Weir Ke-Ke Zhang Hao-Hao Wang Matthias Hannig Stefan Rupf Qian Li Lei Cheng | 2016 | International Journal of Oral Science2016,8,2: | 5 |
| 11 | Effects of water-aging for 6 months on the durability of a novel antimicrobial and protein-repellent dental bonding agent显示文摘Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The objectives of this study were to synthesize a novel bioactive dental bonding agent containing dimethylaminohexadecyl methacrylate(DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine(MPC) to inhibit biofilm formation at the tooth-restoration margin and to investigate the effects of water-aging for 6 months on the dentin bond strength and protein-repellent and antibacterial durability. A protein-repellent agent(MPC) and antibacterial agent(DMAHDM) were added to a Scotchbond multi-purpose(SBMP) primer and adhesive. Specimens were stored in water at 37 °C for 1, 30, 90, or 180 days(d).At the end of each time period, the dentin bond strength and protein-repellent and antibacterial properties were evaluated. Protein attachment onto resin specimens was measured by the micro-bicinchoninic acid approach. A dental plaque microcosm biofilm model was used to test the biofilm response. The SBMP + MPC + DMAHDM group showed no decline in dentin bond strength after water-aging for 6 months, which was significantly higher than that of the control(P < 0.05). The SBMP + MPC + DMAHDM group had protein adhesion that was only 1/20 of that of the SBMP control(P < 0.05). Incorporation of MPC and DMAHDM into SBMP provided a synergistic effect on biofilm reduction. The antibacterial effect and resistance to protein adsorption exhibited no decrease from 1 to 180 d(P > 0.1). In conclusion, a bonding agent with MPC and DMAHDM achieved a durable dentin bond strength and long-term resistance to proteins and oral bacteria. The novel dental bonding agent is promising for applications in preventive and restorative dentistry to reduce biofilm formation at the tooth-restoration margin. | Ning Zhang Ke Zhang Michael D.Weir David J.Xu Mark A.Reynolds Yuxing Bai Hockin H.K.Xu | 2018 | International Journal of Oral Science2018,10,3: | 4 |
| 12 | Primer containing dimethylaminododecyl methacrylate kills bacteria impregnated in human dentin blocks显示文摘Antibacterial dimethylaminododecyl methacrylate(DMADDM) was recently synthesized. The objectives of this study were to:(1)investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and(2) compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate(QADM).Scotchbond Multi-Purpose(SBMP) bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested: SBMP control primer P, P+2.5% DMADDM, P+5% DMADDM, P+7.5% DMADDM, P+10% DMADDM, and P+10% QADM.S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units(CFU) and inhibition zones were measured. The bacterial inhibition zone of P+10% DMADDM was 10 times that of control primer(Po0.05). CFU in dentin with P+10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups(P40.1). In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promising for use in bonding agents as well as in other restorative and preventive materials to inhibit bacteria. | Chen Chen Lei Cheng Michael D Weir Nancy J Lin Sheng Lin-Gibson Xue-Dong Zhou Hockin HK Xu | 2016 | International Journal of Oral Science2016,8,4: | 4 |
| 13 | Induced Pluripotent Stem Cell-derived Mesenchymal Stem Cell Seeding on Biofunctionalized Calcium Phosphate Cements显示文摘Induced pluripotent stem cells(iPSCs)have great potential due to their proliferation and differentiation capability.The objectives of this study were to generate iPSC-derived mesenchymal stem cells(iPSC-MSCs),and investigate iPSC-MSC proliferation and osteogenic differentiation on calcium phosphate cement(CPC)containing biofunctional agents for the first time.Human iPSCs were derived from marrow CD34+cells which were reprogrammed by a single episomal vector.iPSCs were cultured to form embryoid bodies(EBs),and MSCs migrated out of EBs.Five biofunctional agents were incorporated into CPC:RGD(Arg-Gly-Asp)peptides,fibronectin(Fn),fibronectin-like engineered polymer protein(FEPP),extracellular matrix Geltrex,and platelet concentrate.iPSC-MSCs were seeded on five biofunctionalized CPCs:CPC-RGD,CPC-Fn,CPC-FEPP,CPC-Geltrex,and CPC-Platelets.iPSC-MSCs on biofunctional CPCs had enhanced proliferation,actin fiber expression,osteogenic differentiation and mineralization,compared to control.Cell proliferation was greatly increased on biofunctional CPCs.iPSC-MSCs underwent osteogenic differentiation with increased alkaline phosphatase,Runx2 and collagen-I expressions.Mineral synthesis by iPSC-MSCs on CPC-Platelets was 3-fold that of CPC control.In conclusion,iPSCs showed high potential for bone engineering.iPSC-MSCs on biofunctionalized CPCs had cell proliferation and bone mineralization that were much better than traditional CPC.iPSC-MSC-CPC constructs are promising to promote bone regeneration in craniofacial/orthopedic repairs. | WahWah TheinHan Jun Liu Minghui Tang Wenchuan Chen Linzhao Cheng Hockin H.K.Xu | 2013 | Bone Research2013,1,4: | 3 |
| 14 | 磷酸钙骨水泥复合物/脐带间充质干细胞凝胶构建组织工程骨显示文摘目的构建新型可注射强化型磷酸钙骨水泥复合物/脐带间充质干细胞凝胶组织工程骨,探讨其力学性能,细胞活性和成骨作用。方法选用第四代hUCMSCs,1.2%海藻酸钠水凝胶构建hUCMSCs水凝胶微球。高温煅烧钙/磷比约为1.9的磷酸氢钙和碳酸钙混合物,按摩尔质量比以1:1混合制备CPC粉末。15%Chitosan,8mm长度可吸收纤维用于提高CPC复合物力学强度。实验组分为四组:(1)单纯hUCMSCs微球;(2)CPC+hUCMSCs微球;(3)CPC+chitosan+hUCMSCs微球;(4)CPC+chitosan+可吸收纤维+hUCMSCs微球,分别检测力学性能,细胞活性和成骨作用。结果新型组织工程骨力学性能显著增强,抗弯曲强度提高到(11.7±2.1)MPa,弹性模量提高到(2.0±0.4)GPa,断裂功提高到(1.65±0.66)kj/m2(P<0.05)。hUCMSCs的ALP活性第7天时明显增高,第14天时达峰,第21天时有所减弱,各组间比较无明显统计学差异(P>0.1)。第7天时,所有实验组中的hUCMSCs均见少量矿物合成。第14天和第21天时,矿物合成数量明显增多。hUCMSCs中ALP基因表达培养第1天最低,第4天达峰,第8天时稍减弱。OC基因表达第8天达峰。结论构建完成新型可注射强化型磷酸钙骨水泥/脐带间充质干细胞凝胶构建组织工程骨。水凝胶微球中hUCMSCs在CPC中具有良好的成骨作用。CPC-chitosan-可吸收纤维组织工程骨力学性能满足松质骨力学要求,支持水凝胶微球中hUCMSCs的细胞活性和成骨作用。为组织工程骨研究和临床应用提供新思路和新方法。 | 赵亮 Hockin Xu 王健 史占军 | 2012 | 中华关节外科杂志(电子版)2012,6,2: | 3 |
| 15 | Novel rechargeable calcium phosphate nanoparticle-containing orthodontic cement显示文摘White spot lesions(WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate(NACP) with long-term calcium(Ca) and phosphate(P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACPrechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release.The rechargeable cement consisted of pyromellitic glycerol dimethacrylate(PMGDM) and ethoxylated bisphenol A dimethacrylate(EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength(SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release(P40.1). Specimens after one recharge treatment(e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as '1 min 3 times') exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles(P40.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times43 min 2 times41 min 2 times46 min 1 time43 min 1 time41 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets. | Xian-Ju Xie Dan Xing Lin Wang Han Zhou Michael D Weir Yu-Xing Bai Hockin HK Xu | 2017 | International Journal of Oral Science2017,9,1: | 3 |
| 16 | Dental remineralization via poly(amido amine) and restorative materials containing calcium phosphate nanoparticles显示文摘Tooth decay is prevalent,and secondary caries causes restoration failures,both of which are related to demineralization.There is an urgent need to develop new therapeutic materials with remineralization functions.This article represents the first review on the cutting edge research of poly(amido amine)(PAMAM) in combination with nanoparticles of amorphous calcium phosphate (NACP).PAMAM was excellent nucleation template,and could absorb calcium (Ca) and phosphate (P) ions via its functional groups to activate remineralization.NACP composite and adhesive showed acid-neutralization and Ca and P ion release capabilities.PAMAM +NACP together showed synergistic effects and produced triple benefits: excellent nucleation templates,superior acidneutralization,and ions release.Therefore,the PAMAM+NACP strategy possessed much greater remineralization capacity than using PAMAM or NACP alone.PAMAM+NACP achieved dentin remineralization even in an acidic solution without any initial Ca and P ions.Besides,the long-term remineralization capability of PAMAM+NACP was established.After prolonged fluid challenge,the immersed PAMAM with the recharged NACP still induced effective dentin mineral regeneration.Furthermore,the hardness of predemineralized dentin was increased back to that of healthy dentin,indicating a complete remineralization.Therefore,the novel PAMAM+NACP approach is promising to provide long-term therapeutic effects including tooth remineralization,hardness increase,and caries-inhibition capabilities. | Kunneng Liang Suping Wang Siying Tao Shimeng Xiao Han Zhou Ping Wang Lei Cheng Xuedong Zhou Michael D.Weir Thomas W.Oates Jiyao Li Hockin H.K.Xu | 2019 | International Journal of Oral Science2019,11,3: | 3 |
| 17 | Quaternary ammonium-induced multidrug tolerant Streptococcus mutans persisters elevate cariogenic virulence in vitro显示文摘Dental caries are the most prevalent chronic infections in the oral cavity, and Streptococcus mutans acts as the main cariogenic bacterial species. Antibacterial quaternary ammonium compounds(QAs) have been developed to preve Fnt or treat dental caries.However, there is no report on the tolerance of S. mutans to QAs. In this study, we investigated the development of S. mutans persistence induced by a novel dental caries defensive agent, dimethylaminododecyl methacrylate(DMADDM), for the first time.Typical biphasic killing kinetics for persisters were observed in both S. mutans planktonic and biofilm cultures challenged by DMADDM at concentrations of 20 and 200 μg·m L^(-1), respectively. The persisters tolerated six other antibiotics with different antibacterial mechanisms, while only daptomycin and vancomycin could slightly reduce the persister numbers in planktonic cultures. The distribution of persisters in DMADDM-treated biofilms was similar to that in the untreated control, except that the total biomass and biofilm height were significantly reduced. A higher exopolysaccharides(EPS):bacteria ratio was observed in DMADDM-treated biofilms. Persisters in biofilms significantly upregulated gtf gene expression, indicating an increase in the bacteria's ability to produce EPS and an elevated capability of cariogenic virulence. Carbon source metabolism was significantly reduced, as related metabolic genes were all downregulated in persisters. Concentrations of 0.1 m M, 1 m M and 10 m M of extra glucose significantly reduced the number of persisters both in planktonic and biofilm conditions. The formation of noninheritable and multidrug tolerant persisters induced by DMADDM suggested that drug tolerance and new persistent eradication strategies should be considered for oral antibacterial agents. | Ya-Ling Jiang Wei Qiu Xue-Dong Zhou Hao Li Jun-Zhuo Lu Hockin HK Xu Xian Peng Ming-Yun Li Ming-Ye Feng Lei Cheng Biao Ren | 2017 | International Journal of Oral Science2017,9,4: | 2 |
| 18 | The response of diatom central carbon metabolism to nitrogen starvation is different from that of green algae and higher plants显示文摘 | HOCKIN N L MOCK T | | 0,,01: | 1 |
| 19 | Calcium phosphate cement containing resorbable fibers for short-term reinforcement and macroporosity显示文摘 | HOCKIN H K X JANET B Q | 2002 | Biomaterials2002,23,: | 1 |
| 20 | Effects of differentwhiskers on the reinforcement of dental resin composites 显示文摘 | Hockin H K Xu Janet B Quinn douglas T Smith | 2003 | Dental Materials2003,19,: | 1 |