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Fabrication and deformation behaviour of multilayer Al2O3/Ti/TiO2 nanotube arrays

Baradaran S, Basirun WJ, Zalnezhad E, Hamdi M, Sarhan AA, Alias Y

J Mech Behav Biomed Mater, 2013 Apr;20:272-82.
PMID: 23453827 DOI: 10.1016/j.jmbbm.2013.01.020

In this study, titanium thin films were deposited on alumina substrates by radio frequency (RF) magnetron sputtering. The mechanical properties of the Ti coatings were evaluated in terms of adhesion strength at various RF powers, temperatures, and substrate bias voltages. The coating conditions of 400W of RF power, 250°C, and a 75V substrate bias voltage produced the strongest coating adhesion, as obtained by the Taguchi optimisation method. TiO2 nanotube arrays were grown as a second layer on the Ti substrates using electrochemical anodisation at a constant potential of 20V and anodisation times of 15min, 45min, and 75min in a NH4F electrolyte solution (75 ethylene glycol: 25 water). The anodised titanium was annealed at 450°C and 650°C in a N2 gas furnace to obtain different phases of titania, anatase and rutile, respectively. The mechanical properties of the anodised layer were investigated by nanoindentation. The results indicate that Young's modulus and hardness increased with annealing temperature to 650°C.

Matched MeSH terms: Materials Testing
Fulltext Synthesis of silver nanoparticle-decorated hydroxyapatite nanocomposite with combined bioactivity and antibacterial properties

Bee SL, Bustami Y, Ul-Hamid A, Lim K, Abdul Hamid ZA

J Mater Sci Mater Med, 2021 Aug 23;32(9):106.
PMID: 34426879 DOI: 10.1007/s10856-021-06590-y

Combination of bioactive material such as hydroxyapatite (HAp) with antibacterial agents would have great potential to be used as bone implant materials to avert possible bacterial infection that can lead to implant-associated diseases. The present study aimed to develop an antibacterial silver nanoparticle-decorated hydroxyapatite (HAp/AgNPs) nanocomposite using chemical reduction and thermal calcination approaches. In this work, natural HAp that was extracted from chicken bone wastes is used as support matrix for the deposition of silver nanoparticles (AgNPs) to produce HAp/AgNPs nanocomposite. XRD, FESEM-EDX, HRTEM, and XPS analyses confirmed that spherical AgNPs were successfully synthesized and deposited on the surface of HAp particles, and the amount of AgNPs adhered on the HAp surface increased with increasing AgNO3 concentration used. The synthesized HAp/AgNPs nanocomposites demonstrated strong antibacterial activity against Staphylococcus aureus bacteria, where the antibacterial efficiency is relied on the amount and size of deposited AgNPs. In addition, the in vitro bioactivity examination in Hank's balanced salt solution showed that more apatite were grown on the surface of HAp/AgNPs nanocomposite when AgNO3 concentration used >1 wt.%. Such nanocomposite with enhanced bioactivity and antibacterial properties emerged as a promising biomaterial to be applied for dentistry and orthopedic implantology.

Matched MeSH terms: Materials Testing
Fabrication and preliminary in vitro evaluation of ultraviolet-crosslinked electrospun fish scale gelatin nanofibrous scaffolds

Beishenaliev A, Lim SS, Tshai KY, Khiew PS, Moh'd Sghayyar HN, Loh HS

J Mater Sci Mater Med, 2019 May 24;30(6):62.
PMID: 31127374 DOI: 10.1007/s10856-019-6264-4

This study aimed to explore a potential use of fish scale-derived gelatin nanofibrous scaffolds (GNS) in tissue engineering due to their biological and economical merits. Extraction of gelatin was achieved via decalcification, sonication and lyophilization of mixed fish scales. To fabricate nano-scale architecture of scaffolds analogous to natural extracellular matrix, gelatin was rendered into nanofibrous matrices through 6-h electrospinning, resulting in the average diameter of 48 ± 12 nm. In order to improve the water-resistant ability while retaining their biocompatibility, GNS were physically crosslinked with ultraviolet (UV) irradiation for 5 min (UGN5), 10 min (UGN10) and 20 min (UGN20). On average, the diameter of nanofibers increased by 3 folds after crosslinking, however, Fourier transform infrared spectroscopy analysis confirmed that no major alterations occurred in the functional groups of gelatin. A degradation assay showed that UGN5 and UGN10 scaffolds remained in minimum essential medium for 14 days, while UGN20 scaffolds degraded completely after 10 days. All UGN scaffolds promoted adhesion and proliferation of human keratinocytes, HaCaT, without causing an apparent cytotoxicity. UGN5 scaffolds were shown to stimulate a better growth of HaCaT cells compared to other scaffolds upon 1 day of incubation, whereas UGN20 had a long-term effect on cells exhibiting 25% higher cell proliferation than positive control after 7 days. In the wound scratch assay, UGN5 scaffolds induced a rapid cell migration closing up to 79% of an artificial wound within 24 h. The current findings provide a new insight of UGN scaffolds to serve as wound dressings in the future. In the wound scratch assay, UGN5 induced a rapid cell migration closing up to 79% of an artificial wound within 24 h.

Matched MeSH terms: Materials Testing
Flexibility and hardness of dental stainless steel wrought wires used in Thailand

Benjakul P, Cheunarrom C, Ongthiemsak C

J Oral Sci, 2001 Mar;43(1):15-9.
PMID: 11383631

Stainless steel wrought wires used as clasp arms for removable partial dentures in Thailand were compared with those used in some other countries (in the as-received condition) in terms of flexibility, Vickers microhardness and composition. The results showed that there were significant differences (P< or =0.05) among the wires. A Japanese stainless steel wire (SK) was obviously different from the others. It had the lowest proportional limit and microhardness, but its flexibility was almost the same. The chemical composition of each wire was not greatly different. The wires were about 18-20 wt% chromium and 8-9 wt% nickel, except for the SK wire, which had about 12 wt% nickel.

Matched MeSH terms: Materials Testing
Fulltext Development and characterization of novel porous 3D alginate-cockle shell powder nanobiocomposite bone scaffold

Bharatham BH, Abu Bakar MZ, Perimal EK, Yusof LM, Hamid M

Biomed Res Int, 2014;2014:146723.
PMID: 25110655 DOI: 10.1155/2014/146723

A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects.

Matched MeSH terms: Materials Testing
From concept to patient--biomaterials solutions to medical problems

Bonfield W

Med J Malaysia, 2004 May;59 Suppl B:1.
PMID: 15468788
Matched MeSH terms: Materials Testing*
Physicomechanical properties of sintered scaffolds formed from porous and protein-loaded poly(DL-lactic-co-glycolic acid) microspheres for potential use in bone tissue engineering

Boukari Y, Scurr DJ, Qutachi O, Morris AP, Doughty SW, Rahman CV, et al.

J Biomater Sci Polym Ed, 2015;26(12):796-811.
PMID: 26065672 DOI: 10.1080/09205063.2015.1058696

An injectable poly(DL-lactic-co-glycolic acid) (PLGA) system comprising both porous and protein-loaded microspheres capable of forming porous scaffolds at body temperature was developed for tissue regeneration purposes. Porous and non-porous (lysozyme loaded) PLGA microspheres were formulated to represent 'low molecular weight' 22-34 kDa, 'intermediate molecular weight' (IMW) 53 kDa and 'high molecular weight' 84-109 kDa PLGA microspheres. The respective average size of the microspheres was directly related to the polymer molecular weight. An initial burst release of lysozyme was observed from both microspheres and scaffolds on day 1. In the case of the lysozyme-loaded microspheres, this burst release was inversely related to the polymer molecular weight. Similarly, scaffolds loaded with 1 mg lysozyme/g of scaffold exhibited an inverse release relationship with polymer molecular weight. The burst release was highest amongst IMW scaffolds loaded with 2 and 3 mg/g. Sustained lysozyme release was observed after day 1 over 50 days (microspheres) and 30 days (scaffolds). The compressive strengths of the scaffolds were found to be inversely proportional to PLGA molecular weight at each lysozyme loading. Surface analysis indicated that some of the loaded lysozyme was distributed on the surfaces of the microspheres and thus responsible for the burst release observed. Overall the data demonstrates the potential of the scaffolds for use in tissue regeneration.

Matched MeSH terms: Materials Testing
Fulltext Feasibility of using latex examination gloves as dental dam: a tensile strength study

Budi Aslinie Md Sabri, Nur Hidayah Mohd Radzi, Fatimatuz Zahira Abdul Hadi, Ikmal HishamIsmai

Compendium of Oral Science, 2015;2(1):6-13.
MyJurnal

Objective: To evaluate feasibility of hand gloves as a rubber dam isolation alternative, in respect of physical properties. Materials and Methods: A randomized controlled trial study design was used. Three types of gloves were tested with two types of a rubber dam used as the control group. Cut-out pattern of dumb-bell shapes were made from 35 samples for each type of groups and tensile strength were tested using Universal Testing Machine and the Trapezium X software. All tests for physical requirements were performed in accord-ance with American Society for Testing and Materials D412, Standard Test Methods for Vulcanized Rubber and Thermoplastic Rubbers and Thermoplastic Elastomers-Tension. Findings were analyzed by analysis of vari-ance (ANOVA) and differences were compared using a Tukey-Kramer interval calculated at the 0.05 signifi-cance level. Results: Heavy gauge rubber dam has the highest Mean (calculated at the 0.05 significance level) except for maximum stress calculated at entire area. Medium-gauge rubber dam has significantly higher tensile strength (44.5075 N/mm2) when compared to heavy-gauge rubber dam (35.7787 N/mm2) although it was 0.09mm thinner. Discovery 2020 Powder Free Latex Examination Gloves with tensile strength value of 28.5922 N/mm2 (±3.27366) is more than the minimum requirement specified by American Federal Specification ZZ-R90B Rubber Dam (Dental, 1985) (4000 pounds per square inch or 27.6 N/mm2). For all variable tested, all groups are significantly different from each other. The mean square between the groups was quite large. Conclusion: This study shows that there are significant differences between the physical strength of latex gloves when com-pared to rubber dam. However, the comparison between thickness and tensile strength among various rubber dam, did not correspond proportionately. Only one type of rubber gloves met the minimum requirement but that is just one aspect. In view of these mixed results, more research is needed before we can conclude that it is feasable that we use hand gloves to replace rubber dam.

Matched MeSH terms: Materials Testing
Effect of hydrofluoric acid (HF) concentration to pores size diameter of silicon membrane

Burham N, Hamzah AA, Majlis BY

Biomed Mater Eng, 2014;24(6):2203-9.
PMID: 25226919 DOI: 10.3233/BME-141032

This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface.

Matched MeSH terms: Materials Testing
Fulltext Systematic mechanical evaluation of electrospun gelatin meshes

Butcher AL, Koh CT, Oyen ML

J Mech Behav Biomed Mater, 2017 May;69:412-419.
PMID: 28208112 DOI: 10.1016/j.jmbbm.2017.02.007

Electrospinning is a simple and efficient process for producing sub-micron fibres. However, the process has many variables, and their effects on the non-woven mesh of fibres is complex. In particular, the effects on the mechanical properties of the fibre meshes are poorly understood. This paper conducts a parametric study, where the concentration and bloom strength of the gelatin solutions are varied, while all electrospinning process parameters are held constant. The effects on the fibrous meshes are monitored using scanning electron microscopy and mechanical testing under uniaxial tension. Mesh mechanical properties are relatively consistent, despite changes to the solutions, demonstrating the robustness of electrospinning. The gel strength of the solution is shown to have a statistically significant effect on the morphology, stiffness and strength of the meshes, while the fibre diameter has surprisingly little influence on the stiffness of the meshes. This experimental finding is supported by finite element analysis, demonstrating that the stiffness of the meshes is controlled by the volume fraction, rather than fibre diameter. Our results demonstrate the importance of understanding how electrospinning parameters influence the pore size of the meshes, as controlling fibre diameter alone is insufficient for consistent mechanical properties.

Matched MeSH terms: Materials Testing*
Fulltext Effect of sandblasting, silica coating, and erbium: Yttrium-Aluminum-Garnet laser treatment on the shear bond strength of self-adhesive resin cement to alumina ceramics

Caglar I, Ates SM, Boztoprak Y, Aslan YU, Duymus ZY

Niger J Clin Pract, 2018 Aug;21(8):1000-1007.
PMID: 30074001 DOI: 10.4103/njcp.njcp_300_17

Objective: The aim of this study was to investigate the different surface treatments on the bond strength of self-adhesive resin cement to high-strength ceramic.
Materials and Methods: Ninety aluminum oxide ceramic (Turkom-Ceramic Sdn. Bhd., Kuala Lumpur, Malaysia) specimens were produced and divided into nine groups to receive the following surface treatments: control group, no treatment (Group C), sandblasting (Group B), silica coating (Group S), erbium: yttrium-aluminum-garnet (Er:YAG) laser irradiation at 150 mJ 10 Hz (Group L1), Er:YAG laser irradiation at 300 mJ 10 Hz (Group L2), sandblasting + L1 (Group BL1), sandblasting + L2 (Group BL2), silica coating + L1 (Group SL1), and silica coating + L2 (Group SL2). After surface treatments, surface roughness (SR) values were measured and surface topography was evaluated. Resin cement was applied on the specimen surface, and shear bond strength (SBS) tests were performed. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparisons at a significance level of P < 0.05.
Results: Group S, SL1, and SL2 showed significantly increased SR values compared to the control group (P < 0.05); therefore, no significant differences were found among the SR values of Groups B, BL1, BL2, L1, and L2 and the control group (P > 0.05). Group S showed the highest SBS values, whereas the control group showed the lowest SBS values.
Conclusion: Silica coating is the most effective method for resin bonding of high strength ceramic, but Er:YAG laser application decreased the effectiveness.

Matched MeSH terms: Materials Testing
Graphene oxide increases PMMA's resistance to fatigue and strength degradation

Cahyanto A, Martins MVS, Bianchi O, Sudhakaran DP, Sililkas N, Echeverrigaray SG, et al.

Dent Mater, 2023 Sep;39(9):763-769.
PMID: 37400298 DOI: 10.1016/j.dental.2023.06.009

OBJECTIVES: to characterize the effects of graphene oxide (GO) on polymethyl methacrylate's (PMMA) reliability and lifetime. The hypothesis tested was that GO would increase both Weibull parameters and decreased strength degradation over time.
METHODS: PMMA disks containing GO (0.01, 0.05, 0.1, or 0.5 wt%) were subjected to a biaxial flexural test to determine the Weibull parameters (m: modulus of Weibull; σ0: characteristic strength; n = 30 at 1 MPa/s) and slow crack growth (SCG) parameters (n: subcritical crack growth susceptibility coefficient, σf0: scaling parameter; n = 10 at 10-2, 10-1, 101, 100 and 102 MPa/s). Strength-probability-time (SPT) diagrams were plotted by merging SCG and Weibull parameters.
RESULTS: There was no significant difference in the m value of all materials. However, 0.5 GO presented the lowest σ0, whereas all other groups were similar. The lowest n value obtained for all GO-modified PMMA groups (27.4 for 0.05 GO) was higher than the Control (15.6). The strength degradation predicted after 15 years for Control was 12%, followed by 0.01 GO (7%), 0.05 GO (9%), 0.1 GO (5%), and 0.5 GO (1%).
SIGNIFICANCE: The hypothesis was partially accepted as GO increased PMMA's fatigue resistance and lifetime but did not significantly improve its Weibull parameters. GO added to PMMA did not significantly affect the initial strength and reliability but significantly increased PMMA's predicted lifetime. All the GO-containing groups presented higher resistance to fracture at all times analyzed compared with the Control, with the best overall results observed for 0.1 GO.

Matched MeSH terms: Materials Testing
Designing Calcium Silicate Cements with On-Demand Properties for Precision Endodontics

Cahyanto A, Rath P, Teo TX, Tong SS, Malhotra R, Cavalcanti BN, et al.

J Dent Res, 2023 Dec;102(13):1425-1433.
PMID: 37861249 DOI: 10.1177/00220345231198185

Calcium silicate (C3S) cements are available in kits that do not account for patients' specific needs or clinicians' preferences regarding setting time, radiopacity, mechanical, and handling properties. Moreover, slight variations in powder components and liquid content affect cement's properties and bioactivity. Unfortunately, it is virtually impossible to optimize several cement properties simultaneously via the traditional "one variable at a time" strategy, as inputs often induce trade-offs in properties (e.g., a higher water-to-powder ratio [W/P] increases flowability but decreases mechanical properties). Herein, we used Taguchi's methods and genetic algorithms (GAs) to simultaneously analyze the effect of multiple inputs (e.g., powder composition, radiopacifier concentration, and W/P) on setting time, pH, flowability, diametral tensile strength, and radiopacity, as well as prescribe recipes to produce cements with predicted properties. The properties of cements designed with GAs were experimentally tested, and the results matched the predictions. Finally, we show that the cements increased the genetic expression of odonto/osteogenic genes, alkaline phosphatase activity, and mineralization potential of dental pulp stem cells. Hence, GAs can produce cements with tailor-made properties and differentiation potential for personalized endodontic treatment.

Matched MeSH terms: Materials Testing
Biomimetic growth of bone-like apatite via simulated body fluid on hydroxyethyl cellulose/polyvinyl alcohol electrospun nanofibers

Chahal S, Chalal S, Fathima SJ, Yusoff MB

Biomed Mater Eng, 2014;24(1):799-806.
PMID: 24211966 DOI: 10.3233/BME-130871

In this study, randomly oriented hydroxyethyl cellulose/polyvinyl alcohol (HEC/PVA) nanofibers were fabricated by electrospinning. The blend solutions of HEC/PVA with different weight ratio of HEC to PVA were prepared using water as solvent to fabricate nanofibers. These nanofibrous scaffolds were coated with bone-like apatite by immersing into 10x simulated body fluid (SBF) for different time periods. The morphology and structure of the nanofibers were characterized by SEM, FTIR and DSC. FESEM-EDS and FTIR analysis were used to confirm the deposition of apatite on the surface of nanofibers. The results of this study suggest that this apatite coated nanofibrous scaffolds could be a suitable biomaterial for bone tissue engineering.

Matched MeSH terms: Materials Testing
Plasma polymerized carvone as an antibacterial and biocompatible coating

Chan YW, Siow KS, Ng PY, Gires U, Yeop Majlis B

Mater Sci Eng C Mater Biol Appl, 2016 Nov 01;68:861-871.
PMID: 27524089 DOI: 10.1016/j.msec.2016.07.040

Antibacterial coating is important to prevent the colonization of medical devices by biofilm forming bacteria that would cause infection and sepsis in patients. Current coating techniques such as immobilization of antimicrobial compounds, time-releasing antibiotic agents and silver nanoparticles, require multiple processing steps, and they have low efficacy and low stability. We proposed a single-step plasma polymerization of an essential oil known as carvone to produce a moderately hydrophobic antibacterial coating (ppCar) with an average roughness of <1nm. ppCar had a static water contact angle of 78°, even after 10days of air aging and it maintained its stability throughout 24h of LB broth immersion. ppCar showed promising results in the live-dead fluorescence assay and crystal violet assay. The biofilm assay showed an effective reduction of E. coli and S. aureus bacteria by 86% and 84% respectively. ppCar is also shown to rupture the bacteria membrane for its bactericidal effects. The cytotoxicity test indicated that the coating is not cytotoxic to the human cell line. This study would be of interest to researcher keen on producing a bacteria-resistance and biocompatible coating on different substrates in a cost-effective manner.

Matched MeSH terms: Materials Testing
Use of waste gypsum to replace natural gypsum as set retarders in portland cement

Chandara C, Azizli KA, Ahmad ZA, Sakai E

Waste Manag, 2009 May;29(5):1675-9.
PMID: 19131236 DOI: 10.1016/j.wasman.2008.11.014

The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.

Matched MeSH terms: Materials Testing
Fulltext Engineering electrospun multicomponent polyurethane scaffolding platform comprising grapeseed oil and honey/propolis for bone tissue regeneration

Chao CY, Mani MP, Jaganathan SK

PLoS One, 2018;13(10):e0205699.
PMID: 30372449 DOI: 10.1371/journal.pone.0205699

Essential oils play an important role in reducing the pain and inflammation caused by bone fracture.In this study, a scaffold was electrospun based on polyurethane (PU), grape seed oil, honey and propolis for bone tissue-engineering applications. The fiber diameter of the electrospun PU/grape seed oil scaffold and PU/grape seed oil/honey/propolis scaffold were observed to be reduced compared to the pristine PU control. FTIR analysis revealed the existence of grape seed oil, honey and propolis in PU identified by CH band peak shift and also hydrogen bond formation. The contact angle of PU/grape seed oil scaffold was found to increase owing to hydrophobic nature and the contact angle for the PU/grape seed/honey oil/propolis scaffold were decreased because of hydrophilic nature. Further, the prepared PU/grape seed oil and PU/grape seed oil/honey/propolis scaffold showed enhanced thermal stability and reduction in surface roughness than the control as revealed in thermogravimetric analysis (TGA) and atomic force microscopy (AFM) analysis. Further, the developed nanocomposite scaffold displayed delayed blood clotting time than the pristine PU in the activated prothrombin time (APTT) and partial thromboplastin time (PT) assay. The hemolytic assay and cytocompatibility studies revealed that the electrospun PU/grape seed oil and PU/grape seed oil/honey/propolis scaffold possess non-toxic behaviour to red blood cells (RBC) and human fibroblast cells (HDF) cells indicating better blood compatibility and cell viability rates. Hence, the newly developed electrospun nanofibrous composite scaffold with desirable characteristics might be used as an alternative candidate for bone tissue engineering applications.

Matched MeSH terms: Materials Testing/methods
Comparative evaluation of the effectiveness of desensitizing agents in dentine tubule occlusion using scanning electron microscopy

Chen CL, Parolia A, Pau A, Celerino de Moraes Porto IC

Aust Dent J, 2015 Mar;60(1):65-72.
PMID: 25721280 DOI: 10.1111/adj.12275

Dentine hypersensitivity (DH) occurs on exposed dentine and is dependent on the patency of dentinal tubules. This study compared the effectiveness of red propolis extract (RPE), calcium sodium phosphosilicate (Novamin) and arginine-calcium carbonate (ACC) in occluding dentine tubules.

Matched MeSH terms: Materials Testing
Fulltext Shape Optimization for Additive Manufacturing of Removable Partial Dentures--A New Paradigm for Prosthetic CAD/CAM

Chen J, Ahmad R, Suenaga H, Li W, Sasaki K, Swain M, et al.

PLoS One, 2015;10(7):e0132552.
PMID: 26161878 DOI: 10.1371/journal.pone.0132552

With ever-growing aging population and demand for denture treatments, pressure-induced mucosa lesion and residual ridge resorption remain main sources of clinical complications. Conventional denture design and fabrication are challenged for its labor and experience intensity, urgently necessitating an automatic procedure. This study aims to develop a fully automatic procedure enabling shape optimization and additive manufacturing of removable partial dentures (RPD), to maximize the uniformity of contact pressure distribution on the mucosa, thereby reducing associated clinical complications. A 3D heterogeneous finite element (FE) model was constructed from CT scan, and the critical tissue of mucosa was modeled as a hyperelastic material from in vivo clinical data. A contact shape optimization algorithm was developed based on the bi-directional evolutionary structural optimization (BESO) technique. Both initial and optimized dentures were prototyped by 3D printing technology and evaluated with in vitro tests. Through the optimization, the peak contact pressure was reduced by 70%, and the uniformity was improved by 63%. In vitro tests verified the effectiveness of this procedure, and the hydrostatic pressure induced in the mucosa is well below clinical pressure-pain thresholds (PPT), potentially lessening risk of residual ridge resorption. This proposed computational optimization and additive fabrication procedure provides a novel method for fast denture design and adjustment at low cost, with quantitative guidelines and computer aided design and manufacturing (CAD/CAM) for a specific patient. The integration of digitalized modeling, computational optimization, and free-form fabrication enables more efficient clinical adaptation. The customized optimal denture design is expected to minimize pain/discomfort and potentially reduce long-term residual ridge resorption.

Matched MeSH terms: Materials Testing
Fabrication and evaluation of bacterial nanocellulose/poly(acrylic acid)/graphene oxide composite hydrogel: Characterizations and biocompatibility studies for wound dressing

Chen XY, Low HR, Loi XY, Merel L, Mohd Cairul Iqbal MA

J Biomed Mater Res B Appl Biomater, 2019 08;107(6):2140-2151.
PMID: 30758129 DOI: 10.1002/jbm.b.34309

Graphene oxide (GO) is a potential material for wound dressing due to its excellent biocompatibility and mechanical properties. This study evaluated the effects of GO concentration on the synthesis of bacterial nanocellulose (BNC)-grafted poly(acrylic acid) (AA)-graphene oxide (BNC/P(AA)/GO) composite hydrogel and its potential as wound dressing. Hydrogels were successfully synthesized via electron-beam irradiation. The hydrogels were characterized by their mechanical properties, bioadhesiveness, water vapor transmission rates (WVTRs), water retention abilities, water absorptivity, and biocompatibility. Fourier transform infrared analysis showed the successful incorporation of GO into hydrogel. Thickness, gel fraction determination and morphological study revealed that increased GO concentration in hydrogels leads to reduced crosslink density and larger pore size, resulting in increased WVTR. Thus, highest swelling ratio was found in hydrogel with higher amount of GO (0.09 wt %). The mechanical properties of the composite hydrogel were maintained, while its hardness and bioadhesion were reduced with higher GO concentration in the hydrogel, affirming the durable and easy removable properties of a wound dressing. Human dermal fibroblast cell attachment and proliferation studies showed that biocompatibility of hydrogel was improved with the inclusion of GO in the hydrogel. Therefore, BNC/P(AA)/GO composite hydrogel has a potential application as perdurable wound dressing. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2140-2151, 2019.

Matched MeSH terms: Materials Testing

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