Titanium dioxide and modified titanium dioxide by silver nanoparticles as an anti biofilm filler content for composite resins

Objective

The aim of this study was to evaluate the antibacterial activity of a composite resin modified by TiO₂ and TiO₂/Ag nanoparticles and their influence over different properties.

纯钛阳极氧化伴水热处理后羟基磷灰石薄涂层种植体的实验研究

目的：了解阳极氧化伴水热处理后纯钛种植的体内成骨效应。方法：36枚纯钛种植体采用4种表面处理,随机植入12只兔股骨内,分别在术后4周、8周、16周取出带种植体骨块制作磨片,观察界面新生骨情况以及抛光、水热处理种植体术后8周的界面超微结构,行表面能谱分析。结果：术后8周,阳极氧化伴水热处理种植体表面编码骨的转化和成熟较快,至16周时界面几乎无编织骨和剥脱的羟基磷灰石碎片,种植体表面的钙,磷含量在种植后增加,抛光种植体表面钙、磷含量增加不明显。结论：纯钛经阳极氧化伴水热处理后,可以加快种植表现编织骨转化为板层骨,从而可能促进种植区的早期愈合,薄涂层特有的优越性尚待进一步研究。     

预阳极氧化和水热沉积复合法制备纯钛表面羟基磷灰石涂层

目的：研究阻止金属离子向体液中游离和改善纯钛的生物相容性。方法：采用预阳极氧化及水热沉积复合法对纯钛试件进行生物改性。用X射线衍射(XRD)及SEM和SEM附带的能谱(EOS)对涂层的组成和结构进行分析。结果：预氧化后，纯钛表面生成了致密的纯锐钛矿型二氧化钛薄膜，它可诱导骨样羟基磷灰石的形成，促进细胞的黏附和生长，还能阻止内层金属离子的溶出。结论：水热沉积后在致密的二氧化钛薄膜上生成了结晶状态完好、均匀多孔的骨样羟基磷灰石涂层，可提高纯钛植入体的生物相容性和生物活性。     

Nitrogen doped titanium dioxide as an aesthetic antimicrobial filler in dental polymers

ObjectiveTo develop an aesthetic resin composite using a nitrogen-doped titanium dioxide (NTiO₂) filler that possesses antimicrobial properties against cariogenic bacteria.MethodsN-TiO₂ powder was manufactured by calcining commercial TiO₂ with urea. Free radical release from the N-TiO₂ powder under visible light irradiation was analysed using UV-Vis spectrophotometry. The N-TiO₂ powder was incorporated into a dental resin and the photocatalytic activity assessed using a dye under both visible light and dark conditions. Using XTT assay to measure the cellular metabolic activity, the antibacterial properties of the N-TiO₂ /resin composite discs were tested using Streptococcus mutans.ResultsDoping nitrogen of TiO₂ resulted in a band gap shift towards the visible light spectrum, which enabled the powder to release reactive oxygen species when exposed to visible light. When incorporated into a dental resin, the N-TiO₂/resin composite still demonstrated sustained release of reactive oxygen species, maintaining its photocatalytic activity and showing an antibacterial effect towards Streptococcus mutans under visible light conditions.SignificanceN-TiO₂ filled resin composite shows great promise as a potential aesthetic resin based adhesive for orthodontic bonding.     

含银离子羟基磷灰石表面涂层的钛板对6种牙周致病菌的体外抑菌作用

目的 探讨含银离子羟基磷灰石表面涂层的钛板对于牙周致病菌的体外抑菌作用.方法 对比普通羟基磷灰石表面钛板与含银离子羟基磷灰石表面钛板的抗菌能力,采用平板菌落计数法比较2种材料对6种常见牙周致病菌的体外抑菌作用,包括:A.牙龈卟啉单胞菌(ATCC,33277),B.牙龈卟啉单胞菌381,C.牙髓卟啉单胞菌(ATCC,34...     

钛种植体SLA表面HA涂层对骨髓源成骨细胞生物学特性的影响

目的:探讨表面喷砂和酸蚀(SLA)处理后羟基磷灰石(HA)涂层的钛种植体(HA-SLA-Ti),对骨髓源成骨细胞(MOOBs)生物学特性的影响。方法:应用离子束辅助沉积技术(IBAD)在SLA处理的钛种植体(SLA-Ti)表面制备HA涂层,将MOOBs分别接种于HA-SLA-Ti和SLA-Ti表面,观察其生长情况,并对2组MOOBs增殖指数、碱性磷酸酶活性、骨钙素含量以及骨桥蛋白基因(opn)mRNA相对表达量进行比较。结果:MOOBs在HA-SLA-Ti表面生长良好,其细胞增殖指数、碱性磷酸酶活性以及骨钙素含量明显高于SLA-Ti组;且opnmRNA相对表达量是SLA-Ti组的3.25倍。结论:应用IBAD技术在钛种植体SLA表面制备HA涂层,可明显促进MOOBs的增殖及其成骨表型的表达,是一种有应用前景的种植体表面处理方法。     

不同电压阳极氧化处理对金属钛表面形态和羟基磷灰石沉积作用的研究

目的探讨不同电压阳极氧化对二氧化钛(TiO2)纳米管形貌的影响及不同形貌TiO2纳米管体外沉积羟基磷灰石能力的差异。方法控制阳极氧化的电压(10V、20V、30V和40V),在钛基底表面制备不同结构TiO2纳米管,利用扫描电子显微镜观察纳米管的形貌。配置模拟体液(SBF),将未经阳极氧化处理的对照组及各试验组试件分别浸泡在SBF中3d、7d和14d,利用扫描电子显微镜观察各试件表面羟基磷灰石沉积状况,通过X射线光电子能谱分析(XPS)对钛试件表面沉积物进行定性、定量分析。结果随着氧化电压的增加,TiO2纳米管管径逐渐增大。随着在SBF中浸泡时间增加,沉积物增多。浸泡相同时间,60nmTiO2纳米管(氧化电压为30V)表面羟基磷灰石沉积物最多。结论阳极氧化的电压可以影响TiO2纳米管的形貌,浸泡模拟体液的时间与钛试件表面形貌均会影响羟基磷灰石的沉积。提示纳米管管径为60nm时,钛试件在模拟体液中促进羟基磷灰石沉积的能力最佳。     

Effect of titanium dioxide nanoparticle reinforcement on flexural strength of denture base resin: A systematic review and meta-analysis

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In vitro precision of fit of computer-aided design and computer-aided manufacturing titanium and zirconium dioxide bars

Objectives

Optical scanners combined with computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide high accuracy in the fabrication of titanium (TIT) and zirconium dioxide (ZrO) bars. The aim of this study was to compare the precision of fit of CAD/CAM TIT bars produced with a photogrammetric and a laser scanner.

Methods

Twenty rigid CAD/CAM bars were fabricated on one single edentulous master cast with 6 implants in the positions of the second premolars, canines and central incisors. A photogrammetric scanner (P) provided digitized data for TIT-P (n = 5) while a laser scanner (L) was used for TIT-L (n = 5). The control groups consisted of soldered gold bars (gold, n = 5) and ZrO-P with similar bar design. Median vertical distance between implant and bar platforms from non-tightened implants (one-screw test) was calculated from mesial, buccal and distal scanning electron microscope measurements.

Results

Vertical microgaps were not significantly different between TIT-P (median 16 μm; 95% CI 10–27 μm) and TIT-L (25 μm; 13–32 μm). Gold (49 μm; 12–69 μm) had higher values than TIT-P (p = 0.001) and TIT-L (p = 0.008), while ZrO-P (35 μm; 17–55 μm) exhibited higher values than TIT-P (p = 0.023). Misfit values increased in all groups from implant position 23 (3 units) to 15 (10 units), while in gold and TIT-P values decreased from implant 11 toward the most distal implant 15.

Significance

CAD/CAM titanium bars showed high precision of fit using photogrammetric and laser scanners. In comparison, the misfit of ZrO bars (CAM/CAM, photogrammetric scanner) and soldered gold bars was statistically higher but values were clinically acceptable.     

Chlorhexidine delivery system from titanium/polybenzyl acrylate coating: evaluation of cytotoxicity and early bacterial adhesion

Objectives

The formation of biofilms on titanium dental implants is one of the main causes of failure of these devices. Streptococci are considered early colonizers that alter local environment favouring growing conditions for other colonizers. Chlorhexidine (CHX) is so far the most effective antimicrobial treatment against a wide variety of Gram-positive and Gram-negative organisms as well as fungi. This study was designed to develop a CHX delivery system appropriate for healing caps and abutments, with suitable drug release rate, effective as antimicrobial agent, and free of cytotoxic effects.

Methods

Polybenzyl acrylate (PBA) coatings with and without CHX (Ti/PBA and Ti/PBA-CHX, respectively) and different drug loads (0.35, 0.70, and 1.40%, w/w) were assayed. The cytotoxic effect of CHX released from the different substrates on UMR106 cells was tested by alkaline phosphatase specific activity (ALP), and microscopic evaluation of the cells. Non-cytotoxic drug load (0.35%, w/w) was selected to evaluate the antimicrobial effectiveness of the system using a microbial consortium of Streptococcus species.

Results

The kinetic profile of CHX delivered by Ti/PBA-CHX showed an initial fast release rate followed by a monotonic increase of delivered mass over 48 h. The number of attached bacteria decreased in the following order: Ti > Ti/PBA > Ti/PBA-0.35.

Conclusions

PBA-0.35 coating is effective to inhibit the adhesion of early colonizers on Ti without any cytotoxic effect on UMR-106 cells.     

不同固化剂比例对锆基钛用包埋料物理性能的影响

目的:研究加入不同比例固化剂对氧化锆基钛用包埋料物理性能的影响。方法:将砂A与粉B按13∶7的比例充分混合成粉料C,将C与黏结剂D按7.5∶1之比混合,分别按14∶1、14.5∶1、15∶1的黏结剂与固化剂之比添加固化剂E调和,分别包埋预先制作好的片状(10mm×10mm×0.8mm)蜡熔模12片,铸造成纯钛铸件。观察浆料的操作性、型壳表面状态、铸件颜色、完整性、边缘清晰程度,依据实验结果确定配方。在1、3、5、7d分别取黏结剂D测定动力黏度、密度、pH值。结果:14∶1配比组的材料固化过快,无法操作;15∶1配比组固化时间较长,铸圈有回溶现象,铸件变形;14.5∶1配比组初凝时间合适,焙烧后型壳表面无裂纹,浇注腔完整光滑,铸件表面喷砂后呈金属色。黏结剂1、3、5、7d的动力黏度、密度、pH值无显著差异。结论:黏结剂与固化剂按14.5∶1之比混合后包埋蜡熔模、铸造,能得到优良的钛铸件;实用环境下黏结剂在7d内性能指标无明显差异。     

In vitro and in vivo studies of anti-bacterial copper-bearing titanium alloy for dental application

Objective

A novel copper-bearing titanium alloy (Ti–Cu) was fabricated for dental application that is expected to efficiently restrain the growth of bacteria and discourage biofilm formation. The aim of this study was to investigate both the antibacterial activity and biofilm inhibition of Ti–Cu alloy in vitro, and the antibacterial effect of Ti–Cu implant in early stage of peri-implantitis in vivo.

In vitro performance of zirconia and titanium implant/abutment systems for anterior application

Objectives

To investigate the type of failure and fracture resistance behaviour of different zirconia and titanium implant/abutment systems for anterior application.

Methods

Eight groups of implant–abutment combinations (n = 8/system) were restored with identical full-contour zirconia crowns. The systems represented one-piece and multi-piece zirconia (Z) or titanium (T) implants/abutments with different types of connection (screwed = S, bonded = B). The following combinations (implant–abutment-connection) were investigated: ZZS, ZZB, ZZZB (three-piece), ZTS, TTS, TTS reference, and Z (one-piece, 2×). To simulate clinical anterior loading situations the specimens were mounted into the chewing simulator at an angle of 135° and subjected to thermal cycling (2 × 3000 × 5°/55 °C) and mechanical loading (1.2 × 10⁶ × 50 N; 1.6 Hz). Fracture resistance and maximum bending stress were determined for all specimens that survived ageing. Data were statistically analyzed with the Kolmogorov–Smirnov-test and one-way ANOVA (α = 0.05). Survival performance was calculated with the Kaplan–Meier Log-Rank test.

Results

Independent of the material combinations screwed systems showed partly failures of the screws during simulation (ZZS: 3×, ZTS: 8×, TTS: 3×). Screw failures were combined with implant/abutment fractures of zirconia systems. Zirconia one-piece implants and the reference system did not show any failures, and only one specimen of the systems with a bonded connection (ZZZB) fractured. Mean (±standard deviation) fracture forces and maximum bending stresses differed significantly (p = 0.000) between 187.4 ± 42.0 N/250.0 ± 56.0 N/mm² (ZZZB) and 524.3 ± 43.1 N/753.0 ± 61.0 N/mm² (Z).

Conclusions

Both material (zirconia or titanium) and the type of connection influenced failure resistance during fatigue testing, fracture force, and maximum bending stress.

Clinical significance

Different material combinations for implants and abutments as well as different types of connection achieved acceptable or even good failure and fracture resistance that may be satisfactory for anterior clinical application.     

Suitability evaluation of sol–gel derived Si-substituted hydroxyapatite for dental and maxillofacial applications through in vitro osteoblasts response

Si-hydroxyapatite (Si-HAP) has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute.

Objective

The aim of this investigation was to study the effect of Si substitution into the hydroxyapatite matrices and evaluate the biocompatibility effects of Si-HAP material in vitro with human osteoblasts.

Methods

Silicon-substituted hydroxyapatite (Si-HAP) bioceramic materials were prepared by incorporating small amounts of silicon into the structure of hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HAP] through a sol–gel method. A series of silicon substitutions ranging from 0, 1, 3 and 5 mol%, which are comparable to the measured silicon contents in natural bone, were performed.

Results

Single-phase Si-HAP was obtained upon calcining the as-prepared powders up to 800 °C since no secondary phases, such as tricalcium phosphate (TCP), tetracalcium phosphate (TeCP) or calcium oxide (CaO), were identified by X-ray diffraction analysis. The effects of silicon-substituted hydroxyapatite (Si-HAP) materials towards the responses of human osteoblast-like (HOB) cells were investigated and compared with pure hydroxyapatite.

Significance

The Si-HAP indicated a significant increase in cell growth density with culture time irrespective of the amount of Si substituted in HAP. A high Si content (5 mol%) appears to promote rapid bone mineralization, since large amount of calcium phosphate minerals started to develop across the ECM by day 31 for a sample containing 5 mol% Si. On the other hand, a high Si content may result in fast dissolution of the material, owing to a decrease of HAP crystallite size, which might not be ideal for cell attachment for prolonged time periods. An optimum level of Si appears to exist at 3 mol%, which balances these effects.     

In vitro degradation of a biodegradable polylactic acid/magnesium composite as potential bone augmentation material in the presence of titanium and PEEK dental implants

Objective

The aim of this study was to assess the degradation behavior by measuring the H₂ release of a biodegradable composite consisting of a polylactic acid matrix reinforced with 30% wt. spherical magnesium microparticles (PLA/Mg) as potential bone augmentation material in combination with dental implants of either titanium or polyetheretherketone (PEEK) in order to evaluate the potential influence of the titanium dental implants on the corrosion behavior of the Mg particles within the PLA matrix.

Surgical guide and CAD/CAM prebent titanium plate for sagittal split ramus osteotomy in the correction of mandibular prognathism

This study was designed to introduce and evaluate the clinical use of a surgical guide and a CAD/CAM prebent titanium plate for sagittal split ramus osteotomy (SSRO) in the correction of mandibular prognathism. We studied 14 patients who had been diagnosed, and treated by bilateral SSRO with the guide, during the period July 2015–January 2016. Surface deviations of distal segments from simulation until the end of the operation were measured on a coloured map. Deviations of position and orientation of the condyle and proximal segment from before to after operation, and those from simulation until the end of the operation, were measured with a 3-dimensional vector. All patients were followed up for at least a year. The coloured map showed that the mean (SD) distances were 0.40 (0.25) mm between the simulated and postoperative distal segments. The 3-dimensional vector showed that the mean values of mediolateral, anteroposterior, and superior-inferior translations of the condyles were less than 1 mm (p < 0.02) from before the operation until the end, and from simulation to the end of the operation, and the mean value of pitching for proximal segments was less than 1° (p < 0.02) from simulation to the end of the operation. At the one year follow-up, the occlusions were stable. Based on accurate diagnosis and simulation, this guide takes the distal segment precisely to its planned position, and the condyle and proximal segment are well-controlled. This is a useful tool, which is comparatively easy to make and operate.     

CAD/CAM supported production process of standardized enamel and dentin tooth discs with different thicknesses for in vitro material testing

ObjectiveThe production of similar specimens for material testing is very difficult and crucial. This has much influence on the results of an experiment. With CAD design and new printing technologies it is possible to create individual devices to produce specimens for different testing situations. In this study different devices were designed for the standardized production of tooth discs for testing with bonded materials.MethodsThe different devices were designed using optimized CAD for 3D printing. After the design, the different parts of the devices were printed using a desktop SLA 3D printer with high precision. Three different tools were needed for the generation of a standardized disc. After the production, the different devices were tested on natural teeth.ResultsIt is possible to generate very precise tools for the creation of round tooth discs. 40 tooth discs divided into 4 groups with a thickness of 2.0 mm, 2.5 mm, 3.0 mm and 3.5 mm and a constant diameter of 5 mm were produced. For all groups the median of the diameter and thickness was under +/−0.05 mm and the lower and the upper quartile were all under +/−0.06 mm.SignificanceWith this new approach the creation of very precise and uniform tooth discs is possible. The whole process for the creation of the tooth discs was standardized.     

Hybrid nickel hexacyanoferrate/polypyrrole composite as mediator for hydrogen peroxide detection and its application in oxidase-based biosensors

The synthesis and electrochemical characterization of a new organic/inorganic hybrid material was performed by combining polypyrrole and a hexacyano metalate (nickel hexacyanoferrate (NiHCNFe)) aiming to obtain an electrocatalyst for H₂O₂ reduction in the presence of either Na⁺ or K⁺ ions. The use of this material as a redox mediator in an oxalate biosensor based on the immobilization of oxalate oxidase enzyme was also discussed. The electrochemical properties of the hybrid material were investigated by using impedance measurements and compared with those of the nickel hexacyanoferrate film alone. The electrocatalytic properties of the hybrid for reducing H₂O₂, in the presence of both Na⁺ and K⁺ ions, are higher than those of the NiHCNFe film due to the presence of polypyrrole chains that enhances the electronic conductivity of the material.     

Molecularly imprinted poly[tetra(o-aminophenyl)porphyrin] as a stable and selective coating for the development of voltammetric sensors

Molecularly Imprinted poly[tetra(o-aminophenyl)porphyrin] is presented as an electrosynthesized coating for the development of selective microsensors. A carbon fiber microelectrode has been modified with this covering by cyclic voltammetry in the potential range from −0.15 to 1.0 V (scan rate 50 mV s⁻¹) obtaining a microsensor able to recognize the template molecule. To carry out this study dopamine was chosen as model to work with, since this molecule presents electroactivity as it can be oxidized on carbon electrodes. The MIP sensor presented a linear response to the dopamine concentration in the range from 10⁻⁶ to 10⁻⁴ M with good repeatability (RSD 6.22%). The selectivity shown by the microsensor was found to be excellent as it was able to differentiate between different catecholamines. A method has been developed for the determination of dopamine in brain tissue samples using the MIP microsensor.