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Nano-mechanical characterisation of CAD/CAM materials

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Nano-mechanical characterisation of CAD/CAM materials

Effect of Preheat Temperatures on Mechanical Properties and Polymerization Contraction Stress of Dental Composites

第十二次全国口腔材料学术会第五届口腔材料专委会换届会议

作者： michael swain University of Sydney

CAD/CAM materials especially some of the more recently developed ceramic-polymer systems have become increasingly complex with the presence of multiple *** further complicate the situation the arrangements between the various components ranges from simple multiphase composites in a common resin matrix to interpenetrating network *** the present study a traditional CAD/CAM all-ceramic block(Mark Ⅱ by Vita Zahnfabrik) and three relative new ceramic polymer CAD/CAM materials(Enamic by Vita,Lava Ultimate by 3 M and Cerasmart by GC) are investigated using nano-indentation and an AFM based nano-probe *** the case of the Mark Ⅱ material the E modulus and Hardness of the crystalline and glass phases was *** measurements were made for the 3 ceramic-polymer composites but even with the lowest load used it was not possible to determine the precise properties of the various *** with the AFM nano-probe with less than 20 nm diameter contact at picoN loads it was possible to quantify and readily visualise the various phases *** issue with the AFM based nano-probe is the ability to calibrate the tip geometry and also determine the contact depth at picoN loads that are *** approach using micro and nano tip geometries provides a basis whereby the restorative CAD/CAM materials can be more critically compared with the hierarchical structure of enamel so as to better develop dental materials that more closely match the natural tooth enamel.

关键词： CAD/CAM materials Nano-mechanical characterization

来源： cnki会议评论

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Materials Sciences and Applications 2013年第6期4卷 374-385页

作者： Pavinee P. Didron Ayman Ellakwa michael V. swain Biomaterials Research Unit Faculty of Dentistry University of Sydney Sydney Australia Department of General Dentistry Faculty of Dentistry Srinakharinwirot University Bangkok Thailand Department of Tooth Conservation Faculty of Dentistry University of Sydney Sydney Australia Faculty of Dentistry Tanta University Tanta Egypt

Objectives: The purpose of this study was to investigate the effect of preheat temperatures on polymerization contraction stress and mechanical properties of three resin composites. Methods: Three resin composites (Filtek Supreme XT, GC Kalore, and Gradia Direct X) at room temperature, 37°C, and 60°C were investigated. Stress development and maximum contraction stress of the composites were evaluated. Directly after preheating, samples were light-cured for 40 seconds and the force recorded for 15 minutes. Subsequent calculations were done to account for the system’s compliance and to obtain the shrinkage stress of the composites. In addition, composite discs (5 mm? and1 mmthick) were light-cured for 40 seconds at the preheat temperature. Hardness, elastic modulus, and creep of composites were investigated using a nano-indentation system (UMIS 2000). The results were analyzed using Two-way Analysis of Variance (2-way ANOVA) and Tukey’s Post-Hoc test (α = 0.05). Results: The results indicated that preheating composites to 37°C and 60°C increased the polymerization contraction forces, but did not significantly affect hardness, elastic modulus, and creep behaviour of the materials. Analysis of the contraction force upon allowing for thermal contraction indicated only a minor influence of preheat temperature. Significance: Preheating composites, upon allowing for system thermal contraction, showed a slight increase of the polymerization contraction stress but did not significantly affect the composites’ mechanical properties.

关键词： Preheating Dental Composites Polymerization Shrinkage Contraction Stress Nanoindentation Hardness

Periodontal Health among Type 2 Diabetes Patients Treated with Different Dental Restorations

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Open Journal of Stomatology 2021年第8期11卷 278-296页

作者： Mohammad Albakry michael Vincent swain Abdo Abdul-Razzaq Falah Alshammary Waleed Asiri Restorative Dental Sciences Faculty of Dentistry University of Najran Najran KSA Biomaterials Science Research Unit School of Aerospace Mechanical and Mechatronic Engineering Biomechanics Engineering The University of Sydney Sydney New South Wales Australia Preventive Dental Sciences Faculty of Dentistry University of Najran Najran KSA Preventive Dental Sciences Faculty of Dentistry University of Hail Hail KSA

Background: Diabetes increases periodontal disease risk and its complications, which are worsened with age or faulty restorations. Aim: Evaluate periodontal health among patients with diabetes treated with different dental restorations. Materials and Methods: This comparative cross-sectional study was conducted at the faculty of dentistry, Najran University, KSA, from March 2018 to February 2020. It included 260 diabetics, treated with different dental restorations, divided into four groups, each comprising 65 patients aged 45 - 60 years: Group 1 (G1), no restorations (control group);Group 2 (G2), Class II amalgam restorations;Group 3 (G3), Class II composite resin restorations;and Group 4 (G4), three-unit posterior metal ceramic prostheses. The Ages of all restorations ranged from 8 to 10 years. All groups were assessed for the Plaque Index (PI) and Gingival Index (GI), Overhangs Rate (OR), Alveolar Bone Loss (ABL) (the latter two using panoramic X-ray). HbA1c and duration of participants were also assessed and compared. Results: The mean HbA1c results of the groups ranged from 8.1% to 9.5%, and their mean diabetes durations ranged from 7.2 to 12 years. All the groups showed worse periodontal scores, ranging from 2.45 - 2.95 for PI and 2.25 - 2.8 for GI. G2 had higher scores than G1 and G3 (p p p p = 0.987). The highest value was observed in G4, which was significantly higher than other groups (p Conclusion: The worse periodontal parameters among subjects treated with either three-unit metal ceramic or Class II amalgam restorations indicated severe periodontal de

关键词： Diabetes Mellitus Alveolar Bone Loss Plaque Index Dental Restoration

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荧光原位杂交在滑膜肉瘤诊断中的应用

中华病理学杂志 2007年第4期36卷 275-276页

作者：殷敏智张忠德 Vida Petrovic michael swain 周中和上海交通大学医学院附属新华医院上海儿童医学中心病理科 200127 Murdoch Children's Research Institute Australian Department of Pathology Royal Children's Hospital of Melbourne Australian

滑膜肉瘤是儿童及青少年期常见的软组织肿瘤，约占软组织恶性肿瘤的2％～10％。好发于大关节周围，也可见于其他关节、软组织，还可发生于肺、前列腺、肾等脏器。组织学可分为双相分化型、单相纤维型、单相上皮型、低分化型H0，其中前2... 详细信息

滑膜肉瘤是儿童及青少年期常见的软组织肿瘤，约占软组织恶性肿瘤的2％～10％。好发于大关节周围，也可见于其他关节、软组织，还可发生于肺、前列腺、肾等脏器。组织学可分为双相分化型、单相纤维型、单相上皮型、低分化型H0，其中前2种最常见。由于其形态多样，发病部位广泛，免疫组织化学染色又缺乏特异的抗体，有时会造成病理诊断的困难。细胞和分子遗传学研究发现，90％以上的滑膜肉瘤存在特异的t（X；18）（p11．2；q11．2），导致位于18号染色体SYT基因易位，和位于X染色体上SSX基因产生SYT—SSX融合基因。目前国内检测该融合基因均使用逆转录-聚合酶链反应（RT—PCR）。我们收集儿童滑膜肉瘤4例，探讨运用荧光原位杂交（FISH）法对甲醛固定、石蜡包埋组织检测其融合基因的可行性。

关键词：荧光原位杂交滑膜肉瘤病理诊断逆转录-聚合酶链反应免疫组织化学染色软组织恶性肿瘤软组织肿瘤 18号染色体

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饰瓷对磨牙***双层全瓷冠断裂类型的影响

口腔医学研究 2011年第2期27卷 97-100页

作者：潘娱 michael V swain 马骁张新平赵克中山大学光华口腔医学院.附属口腔医院修复科.口腔医学研究所广东广州510055 澳大利亚悉尼大学牙科学院及悉尼牙科医院华南理工大学材料科学与工程学院

目的:通过抗折破坏实验研究饰瓷对磨牙***双层全瓷冠断裂强度和断裂类型的影响,为减少临床双层全瓷修复体崩瓷提供实验依据。方法:制作单层全瓷冠(IPS *** Press)和双层全瓷冠(IPS *** Press/Ce-ram)共40个(每组20个),粘接于树脂代型后... 详细信息

目的:通过抗折破坏实验研究饰瓷对磨牙***双层全瓷冠断裂强度和断裂类型的影响,为减少临床双层全瓷修复体崩瓷提供实验依据。方法:制作单层全瓷冠(IPS *** Press)和双层全瓷冠(IPS *** Press/Ce-ram)共40个(每组20个),粘接于树脂代型后进行抗折破坏实验并记录断裂强度值;体视显微镜和扫描电子显微镜下观察断裂类型;能谱分析饰瓷-核瓷界面化学元素构成。结果:单层全瓷冠断裂强度值[(2665.4±759.2)N]与双层全瓷冠[(1431.1±404.3)N]间差异有统计学意义(P=0.000)。饰瓷内部及饰瓷-核瓷界面缺陷催生裂纹造成饰瓷崩裂是双层全瓷冠断裂的主要模式。结论:饰瓷对磨牙***双层全瓷冠断裂强度和断裂类型均有影响;饰瓷内部及饰瓷-核瓷界面缺陷是全瓷冠断裂的主要原因,提高饰瓷断裂强度及减少界面缺陷可减少因崩瓷造成的修复体失败。

关键词：牙修复体牙瓷料力学牙修复失效

Role of Mechanical Stimuli in Oral Implantation

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Journal of Biosciences and Medicines 2014年第4期2卷 63-68页

作者： Wei Li Daniel Lin Junning Chen Zhongpu Zhang Zhipeng Liao michael swain Qing Li School of Aerospace Mechanical and Mechatronic Engineering The University of Sydney Sydney Australia

Prosthetic implantation has been a prevalent surgical procedure in dentistry. Insertion of dental implant significantly changes local oral conditions and leads to the surrounding bone to remodel to a new morphology. To predict how the bone responds such a biomechanical change, finite element analysis (FEA) based remodeling simulation has proven effective. For a range of mechanical stimuli, which should be used remains controversial arguable? This paper aims to compare how the different mechanical stimuli, including mechostat model (effective strain), daily stress and strain energy density (SED) affect the predictions of bone remodeling.

关键词： Dental Implant Bone Remodeling Mechanobiology Finite Element Mechanical Stimulus

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新型美学陶瓷用于牙修复体的优与劣

中华口腔医学研究杂志（电子版） 2014年第6期8卷 22-22页

作者： michael V.swain 潘娱澳大利亚悉尼大学牙学院生物材料实验室深圳市人民医院

陶瓷材料应用于口腔修复已有五十余载。理想的牙科陶瓷可高度模拟天然牙釉质和牙本质。然而．天然牙釉质是一种梯级结构材料（hierarchy material）．即以不同微观单位观察呈现不同机械强度和韧性。研究结果显示。牙釉质具有超越任何现... 详细信息

陶瓷材料应用于口腔修复已有五十余载。理想的牙科陶瓷可高度模拟天然牙釉质和牙本质。然而．天然牙釉质是一种梯级结构材料（hierarchy material）．即以不同微观单位观察呈现不同机械强度和韧性。研究结果显示。牙釉质具有超越任何现有牙科陶瓷的增韧能力。氧化锆陶瓷近年来广泛应用于临床，但修复体设计、粘接、打磨等方面的缺陷及氧化锆本身的低温老化行为常导致修复失败。

关键词：牙修复体陶瓷材料天然牙釉质氧化锆陶瓷美学牙科陶瓷口腔修复结构材料

The future of wireless capsule endoscopy

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World Journal of Gastroenterology 2008年第26期14卷 4142-4145页

作者： Paul swain Department of Surgical Oncology and Technology London University (Imperial College)London NW3 1TNUnited Kingdom

We outline probable and possible developments with wireless capsule endoscopy. It seems likely that capsule endoscopy will become increasingly effective in diagnostic gastrointestinal endoscopy. This will be attractive to patients especially for cancer or varices detection because capsule endoscopy is painless and is likely to have a higher take up rate compared to conventional colonoscopy and gastroscopy. Double imager capsules with increased frame rates have been used to image the esophagus for Barrett's and esophageal varices. The image quality is not bad but needs to be improved if it is to become a realistic substitute for flexible upper and lower gastrointestinal endoscopy. An increase in the frame rate, angle of view, depth of field, image numbers, duration of the procedure and improvements in illumination seem likely. Colonic, esophageal and gastric capsules will improve in quality, eroding the supremacy of flexible endoscopy, and become embedded into screening programs. Therapeutic capsules will emerge with brushing, cytology, fluid aspiration, biopsy and drug delivery capabilities. Electrocautery may also become possible. Diagnostic capsules will integrate physiological measurements with imaging and optical biopsy, and immunologic cancer recognition. Remote control movement will improve with the use of magnets and/or electrostimulation and perhaps electromechanical methods. External wireless commands will influence capsule diagnosis and therapy and will increasingly entail the use of real-time imaging. However, it should be noted that speculations about the future of technology in any detail are almost always wrong.

关键词： Wireless Capsule Endoscopy Future Complementary oxide silicone Charge coupled device Therapy Screening Colonoscopy Biopsy Cancer Electrocautery

Steganography based on quotient value differencing and pixel value correlation

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CAAI Transactions on Intelligence Technology 2021年第4期6卷 504-519页

作者： Reshma Sonar Gandharba swain Department of Computer Science and Engjneetttig Koneru Lakshtnaiah Education FoundationGunturAndhra PradeshIndia

Pixel value differencing(PVD)steganography techniques produce imperceptible *** PVD-based techniques have a fkll-off boundary problem(FOBP).To avoid FOB£a steganographic scheme is presented that combines the quotient value difference(QVD)with pixel value correlation(PVC).It performs data embedding in two stages on 3 x 3 size pixel *** first stage of the embedding procedure performs QVD and remainder substitution on five *** five pixels are central pixel and it*s neighbours on the left,right,upper,and lower *** on the new values of these five pixels,the PVC embedding procedure is applied on the remaining four corner pixels of the *** experimental results are found to be *** hiding capacity is high that is 3.92 bits per byte with an acceptable peak signal-to-noise ratio value.A security check was performed using two tests:(i)a regular-singular(RS)test,(ii)a pixel difference histogram(PDH)*** experimental outcomes demonstrate that PDH curves of the stego-images do not have a zigzag shape,that means the PDH test could not detect this steganography ***,the RS curves show that the RS test could not detect this steganography technique.

关键词： technique. PDH value