Custom-made Mold Research Articles

Development of Synthetic Lumbar Vertebrae using Custom-made Mould for Orthopaedics Training: Micro-Structural Analysis

Human vertebrae composed of cortical and cancellous bone are crucial to provide the structural support of human framework and protect the organs underneath. Vertebrae from the Lumbar 3 (L3) was selected for fabrication because it is the most commonly used for surgical training. The use of human vertebrae in the orthopaedic studies is necessary to investigate various complications such as vertebral compression fracture and to propose the most suitable medical intervention for the treatment. However, investigations of cortical and cancellous material properties and composition have been limited. Therefore, the main objective of this study was to design a custom-made mould for synthetic lumbar vertebrae using moulding techniques that could exhibit the same anatomical structure as real vertebrae. Then, this study was carried out to establish a process of cortical and cancellous synthetic bone development. Lastly, this study was done to compare the morphological properties of synthetic bone produced with human bone. Utilizing Polyurethane (PU) as the main material was used for the fabrication, where it could inhibit the morphological properties that could mimic the human bone. The methods to fabricate the vertebrae also varied from static mould and rotational mould. The fabricated lumbar produced was tested for the morphological properties, targeting the pore diameter, was performed using Scanning Electron Microscopy (SEM). From this study, it was identified that the analysis of pore diameter from specimen of Ratio 3 from rotational mould depicts the smallest pore diameter and standard deviation, 1.5 ± 0.3 mm. While this specimen has the smallest value, the results were still higher when compared to the pore diameter of human trabecular bone (which ranges from 0.3 mm to 0.6 mm). In conclusion, the use of silicone custom-made moulds could provide synthetic vertebrae with an anatomical structure mimicking real human vertebrae.

Experimental study on instability failure of rock mass with rough joints under one-side constraint compression

The development of rough joints parallel to the free surface in the surrounding rock will lead to instability and failure of the surrounding rock, and the occurrence of rockburst, plate cracking, and other disasters. This paper used a custom-made mold, 3D-printing technology, acoustic emission (AE) equipment, and digital image correlation (DIC) to systematically analyze the fracture characteristics and instability process of rock sample with different roughness joints under one-side constraint compression. The results showed that, in the same sample group, the peak stress gradually increases with the increase in the distance between the joint and the free surface, and that the peak stress and strain at the same distance of the joint will decrease first and then increase as the roughness increases. The energy storage limit of the sample with joints 10 mm away from the free surface was greater than that for 5 mm, the energy dissipation ratio before the peak strength of specimens decreases as the roughness increases. The smooth-jointed specimens have higher resistance to deformation under one-side constraint compression, and the failure pattern of that specimen can be tensile type. However, as roughness increases, shear cracks gradually appear along the joint convex position, and the damage degree will be increased. The closer the joint is to the free surface, the more broken the specimen will be. The AE events within the same sample group increased with the increase in the distance between the joint and the free surface, and the cumulative AE counts increased with the increase in roughness when the joint space position was the same.

Rheological and Sensorial Characteristics of the Reformed Ras Cheese Made Using Cheese Trims and Different Starches

The objective was to study the technological suitability of using the Ras cheese trims and starch as casein stabilizer in making novel reformed Ras cheese (RRC) product and to evaluate the effect of two levels of corn, potato, and rice starches whether at the native form or pregelatinized, on the rheological and sensorial properties of that reformed Ras cheese which was supposed to be very close to conventional Ras cheese. Cheese trims were shredded, and table salt was added and kept at 25°C for 24 h. Starch was added in the form of whipped transparent paste, then the mixture was cooked without emulsifying salts to 75°C for 5 minutes at 120 rpm, the cooking temperature was then lowered until reaching 55°C at the same stirring speed, and then, the mixing speed was raised to 1400 rpm for another 1 minute. The molten cheese mass was poured into custom-made moulds. The height from which the cheese was poured into moulds was adapted to be 50 cm from the bottom of the mould. The samples were allowed to set at 5°C for 24 hours. The obtained results indicated that increasing the starch level significantly decreased the values of dry matter, protein, lactose, titratable acidity, water activity (aw), consistency coefficient ( K ), flow behavior index ( n ), Tan δ, hardness, springiness, melt distance, and shredding efficiency and increased the values of ash, pH, critical strain, adhesiveness, and sliceability. The starch source had no significant effect on critical strain, K , Tan δ, and sliceability. The rice starch RRCs were distinguished with the highest significant values of aw, n , cohesiveness, springiness, flavour, and total sensorial scores. The potato starch RRCs had the lowest hardness, fracturability, shreddability, and total sensorial score, as well as the highest melt distance, free oil, and adhesiveness. The corn starch RRCs were characterized with the lowest aw, n , springiness, body, and texture scores, as well as the highest hardness, fracturability, and shreddability. The pregelatinized starch RRCs were associated with increased aw, critical strain, n , Tan δ, fracturability, springiness, melt distance, shredding efficiency, sliceability, and all sensorial characteristics except appearance. The native starch RRCs were characterized with the highest pH, hardness, adhesiveness, free oil, and appearance score values.

Effect of Polydopamine on Bonding Characteristics of Mineral Trioxide Aggregate to Resin Composite.

The success of vital pulp therapy is crucial to preserve the integrity of the teeth and to enable an uninterrupted root formation in a young permanent tooth. This warrants placement of an intact permanent seal immediately in contact with the pulp capping material. Mineral trioxide aggregate (MTA) sets by hydration and deters placement of an immediate permanent resin composite restoration over it. The aim of this in vitro study is to evaluate the wettability, surface morphology and shear bond strength (SBS) of polydopamine (PDA)-pretreated MTA to resin composite (RC). The contact angle (CA) and morphological changes caused by self-etch (SE) adhesive on untreated and PDA-pretreated MTA was analyzed using contact angle meter and scanning electron microscope (SEM) respectively. To evaluate SBS, 144 MTA samples were prepared using a custom-made mold of 5 mm diameter and 3 mm height. The samples were randomly divided into two groups of 72 samples each based on whether their surface was pretreated with PDA or not. Under each group, nano-hybrid RC restoration was done either immediately or after a delay of 3 h, 24 h and 96 h. SBS of the MTA/resin composite assembly was tested in a universal testing machine. CA values were analyzed using One-way analysis of variance and Games-Howell Post Hoc test. Mann-Whitney test and Friedman post-hoc Dunn test were used to analyze SBS values. SE adhesive made a significantly lesser mean CA with PDA-pretreated MTA (27.20°+-2.28) compared to untreated MTA (34.22°+-1.45, p<0.05). SEM micrographs showed that while etching with SE primer eroded the surface characteristics, PDA coating minimized the erosive effect of the acidic primer and preserved the original crystalline plate-like structure of MTA. At all tested time intervals, PDA pretreatment significantly increased the SBS of MTA to RC, compared to untreated control. Immediate bond strength of PDA pretreated MTA (26.30+-7.60 MPa) was equivalent to the SBS value achieved at 96 h with untreated MTA (27.82+-2.96 MPa). Within the limitations of this in vitro study, it can be concluded that PDA pretreatment of MTA surface improved its wettability, prevented loss of surface integrity following etching and increased the SBS of RC to MTA. (EEJ-2022-11-144).

The Effect of Varying Dentin Chroma and Enamel Thickness on the Color of A2 Double-layered Resin Composite.

To evaluate chroma (C*) and overall color of double-layered (DL) resin composite (RC) restorations with various dentin shades and enamel thicknesses. Enamel specimens were fabricated using custom-made molds to replicate VITA shade tabs with variant enamel thicknesses (0.5, 0.7, and 1.0 mm) (n=7) from two RC: Clearfil-Majesty (CM) shade (A2), and Vit-l-escence (VL), shade (pearl-neutral). Dentin specimens (shades A1, A2, and A3) were fabricated using custom molds corresponding to the enamel molds. Each enamel specimen was paired with three different dentin specimens. L*a*b* parameters were measured with VITA Easyshade-V. Color difference between DL specimens and the A2 VITA shade tab were calculated with the CIEDE2000 formula. Relationships among enamel thickness, ΔE00, C* of dentin layer, C* of DL, and change in chroma were assessed by Spearman rank correlations. ΔE00 was compared among groups using one-way analysis of variance with Tukey post-hoc adjustment for all possible pairwise group comparisons (experiment-wise α=0.05). There was no statistical difference among C* of DL specimens (p=0.65, 0.53) for CM and VL, respectively. Combinations of enamel thickness/ dentin shade had a significant difference in ΔE00 (p>0.05). No significant correlation was observed among enamel thickness and C* of dentin, and C* of the DL (p>0.05). Significant correlations were observed between ΔE00 of the VL DL and C* DL (r=-0.8, p<0.001); and ΔE00 of CM DL and enamel thickness (r=0.5, p<0.001). Enamel thickness did not affect C* of the dentin layer. Unlike VL RC, variations in dentin shades with CM produced a closer match to the A2 shade tab. Enamel is recommended to be 0.7 mm or less.

Color difference between the vita classical shade guide and composite veneers using the dual-layer technique.

BackgroundThe purpose of this in vitro study was to evaluate the color difference between the Vita Classical Shade Guide and composite veneers using the dual-layer technique. Material and MethodsThirty samples were fabricated using a custom-made mold (Easy Layering Shade Guide Kit, 3M) using two resin composites: Filtek Supreme Ultra (3M); and Estelite Omega (Tokuyama) (n=3). The composite veneers were made by layering the different enamel and body or dentin shades from each composite. The color measurements were taken using a spectrophotometer (Vita Easyshade V®, Vita Zahnfabrik). The ΔE00 between the Vita Classical Shade Guide (Vita Zahnfabrik) and the composite veneers were calculated using the CIEDE2000 formula. ResultsFor the composite veneers using Filtek Supreme Ultra, the best match for A1 Vita shade was achieved layering either EA1 with DA2 or DA3; EA2 with DA1 or DA2 (ΔE00= 1.53 ~ 1.96 ± 0.4). For A2 Vita shade the best match would be EA3 with DA3 or EA3 with DA2 (ΔE00= 1.40 ~ 1.85 ± 0.1); or for A3 Vita shade the best match would be EA3 with DA2 2.50±(0.6). For the composite veneers using Estelite Omega, the were no best match for neither A1, A2 or A3 Vita shade (ΔE00> 2.5). ConclusionsThe combination of enamel and dentin shades from Filtek Supreme Ultra provided acceptable color match for A1, A2 and A3 shades from the Vita Shade Guide, while Estelite Omega did not provide acceptable color match for any of the Vita Shade Guide standard shades tested. Key words:Color, color matching, optical properties, resin composite, layering.

Assessment of Streptococcus mutans biofilms on orthodontic adhesives over 7 days

The purpose of this study was to compare the metabolism of Streptococcus mutans biofilms after 1-7days of growth on different orthodontic adhesives. Specimens of 6 commercial orthodontic adhesives were fabricated in custom-made molds and polymerized using a light-emitting diode light-curing unit. Bioluminescent S mutans (UA159:JM10) biofilms were grown on ultraviolet-sterilized specimens for 1, 3, 5, and 7days (n=18 biofilms/d/product) in anaerobic conditions at 37°C. The metabolism of biofilms (relative luminescence unit [RLU]) was measured 0, 2, 4, and 6minutes after exposure to D-luciferin solution using a microplate reader. A linear mixed-effects model was used to analyze the logarithm of RLU (log RLU). The model included fixed effects of products, days, and minutes. Tukey-Kramer post-hoc tests were then performed on the significant predictors of log RLU (α=0.05). Days (P<0.0001) and minutes (P<0.0001) were independent predictors of log RLU, but the products were not (P=0.5869). After adjusting for minutes, the log RLU was analyzed with a post-hoc test, and all differences between days were significant with the exceptions of day 3 from day 5 (P=0.0731) and day 5 from day 7 (P=0.8802). After adjusting for day, log RLU was analyzed with a post-hoc test and all differences in minutes were significant. No significant differences in the metabolism of S mutans biofilms were observed among the 6 orthodontic adhesives. Biofilms that were grown for 3days demonstrated the highest levels of biofilm metabolism as evidenced by higher mean log RLU values relative to 1, 5, and 7-day growth durations.

Fabrication of Hierarchical Multilayer Poly(Glycerol Sebacate urethane) Scaffolds Based on Ice-Templating

In this study, it was demonstrated that ice-templating via freeze drying with custom-made moulds, in combination with air brushing, allows for the fabrication of poly(glycerol sebacate urethane) (PGSU) scaffolds with hierarchical multilayer microstructures to replicate various native soft tissues. The PGSU scaffolds were either monolayered but exhibited an anisotropic microstructure, or bilayered and trilayered, with each layer showing different microstructures. By using freeze drying with custom-made moulds, the ice crystals of the solvent were grown unidirectionally, and after freeze-drying, the scaffolds had an anisotropic microstructure, mimicking tissues such as tendon and skeletal muscle. The anisotropic PGSU scaffolds were also examined for their tensile strength, and a range of mechanical properties were obtained by altering the reactants’ molar ratio and polymer concentration. This is of importance, since soft tissues exhibit different mechanical properties depending on their native location and functionality. By combining freeze drying with airbrushing, scaffolds were fabricated with a thin, non-porous layer on top of the porous layers to allow three-dimensional cell co-culture for tissues such as skin and oral mucosa. These results show that fabrication techniques can be combined to produce PGSU scaffolds with tailored hierarchical microstructures and mechanical properties for multiple tissue engineering applications.

Resin Transfer molding of High-Fluidity Polyamide-6 with modified Glass-Fabric preforms

In Resin Transfer Molding (RTM), resin precursors of thermoset or, more recently, thermoplastic polymers are generally employed, raising issues related to the chemical reaction taking place during and after part processing. In this study, already polymerized polyamide-6 with low melt-viscosity (~30 Pa·s at 280 °C), is injected at low pressure (<30 bar) in a custom-made mold, so as to impregnate glass fabric preforms via in-plane impregnation. Composite plates were produced using interply spacers acting as flow-enhancers. A three-step impregnation strategy, involving fast in-plane resin injection, a successive saturation step through transverse flow, followed by further micro-saturation caused by the collapse of the spacers, ensured industrially relevant impregnation kinetics. The influence of the spacer, the saturation time, pressure and temperature on the process kinetics and part quality were evaluated with three-point bending tests as well as microstructural analyses. Optimum processing parameters were identified and scaled up for a given part geometry.

Designer Cranioplasty at Budget Prices: A Novel Use of 3D Printing Technology

Abstract Background Cranioplasty using synthetic materials for restoration of the exact shape of the skull has always remained a challenge until the development of 3D printing technology. However, the high-cost of available 3D printed implants limits their extensive use. Objectives To study the effectiveness of a low-cost, 3D-printed template for molding the polymethyl methacrylate (PMMA) (bone cement) in order to achieve exact contours of the skull specific to each patient. Materials and Methods 10 cranioplasties have been performed between July 2018 to December 2019 in a variety of craniotomy defects using bone cement flaps shaped using custom-made molds. The mold was 3D-printed and based on each patient’s CT images in digital imaging and communications in medicine (DICOM). Miniplates and screws were used to fix the flap. Postoperatively, clinical and radiological evaluation were done to assess patient satisfaction and accuracy of contour achieved. Results Patient satisfaction as well as accuracy of contouring, as seen on postoperative CT scans, were excellent. There were no notable complications on follow-up. Conclusion PMMA cranioplasty flap, contoured using a 3D-printed mold, is a very cost-effective alternative for restoration of skull contour for various craniotomy defects.Polymethyl methacrylate (PMMA) molded to form the exact shape of lost calvarium using 3D printed plastic templates is a smart and economical solution.

Effect of different cleaning methods on resin bond strength of contaminated monolithic zirconia

The present study evaluated the effects of cleaning methods on resin bond strength to contaminated monolithic zirconia. A total of 180 bar-shaped monolithic zirconia specimens (12 mm × 4 mm × 1.2 mm) were abraded with aluminum oxide and divided into nine groups (n = 10). The control group (Cnt) comprised non-contaminated or cleaned monolithic zirconia specimens. Half of the remaining samples were contaminated with saliva (S) and the other half with a silicone disclosing agent (F; Fit checker). The bonding surfaces of the specimens were cleaned with water (Sw and Fw), 0.5% sodium hypochlorite (NaOCl) solution (Sh and Fh), 37% phosphoric acid gel (Sa and Fa), or plasma treatment (Sp and Fp). The bars were luted end-to-end on the bonding surfaces using a self-adhesive resin cement with a custom-made stainless-steel mold. After 72 h of water storage, the bond strength was measured using a four-point bending test. Data were analyzed using two-way ANOVA and Tukey’s test. The Cnt group showed the highest four-point bending strength (p < .05). There were no significant differences among the groups subjected to the cleaning methods, except the NaOCl groups (p > .05). These findings indicate that the cleaning protocol for saliva- or fit checker-contaminated monolithic zirconia ceramics must be taken into account to ensure zirconia–resin cement bond strength resistance. The plasma treatment that an alternative cleaning method for decontamination did not affect the bond strength between monolithic zirconia and resin cement.

Comparative evaluation of compressive and flexural strength, fluoride release and bacterial adhesion of GIC modified with CPP-ACP, bioactive glass, chitosan and MDPB.

Background. This study evaluated the incorporation of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), calcium sodium phosphosilicate bioactive glass (BAG), chitosan (CH), and methacryloyloxydodecylpyridinium bromide (MDPB) on the compressive and flexural strength, fluoride (F‒ ) release, and bacterial adhesion of conventional glass-ionomer cement (C-GIC). Methods. Modifications were implemented by adding CPP-ACP, BAG, and CH to the glass powder, while MDPB-GIC was prepared by incorporating MDPB to the liquid of C-GIC. Custom-made molds were used for specimen preparation. Compressive and flexural strengths were evaluated using a universal testing machine. F‒ release was calculated with Erichrome cyanide reagent, using UV-spectrophotometry, at two time intervals of 24 hours and seven days. For bacterial adhesion, the test specimens were exposed to the bacterial suspension of Streptococcus mutans and Lactobacillus acidophilus for 4 hours, and the adherent bacteria were quantified using colorimetry as the optical density (OD). Results. The incorporation of MDPB increased the flexural strength of C-GIC, with no effect on its compressive strength. CH significantly improved the compressive and flexural strength; modifications with CPP-ACP, BAG, and MDPB significantly improved the flexural strength of C-GIC. While MDPB-GIC released significantly higher F‒ at 24 hours, CPP-ACP- and BAG-modified GICs were comparable to C-GIC on day 7. C-GIC exhibited the highest bacterial adhesion, and MDPB-GIC showed the least. The data were analyzed with one-way (ANOVA), and pairwise comparisons were made with Tukey HSD tests. Conclusion. Hence, it can be concluded that the incorporation of CPP-ACP, BAG, and CH improved the mechanical properties of C-GIC, whereas MDPB improved the resistance of C-GIC to bacterial adhesion.

Discoloration of Resin Composites Induced by Coffee and Tomato Sauce and Subjected to Surface Polishing: An In Vitro Study

BackgroundThe purpose of this study is to evaluate and compare color stability of 3 resin based restorative materials when immersed into staining media at 0, 3, 30, 45, 60, and 75 days, and to assess the efficacy of surface polishing in reducing possible discoloration.Material/MethodsNinety composite discs were prepared in a custom-made mold (5 mm diameter and 2 mm thick) from 3 different light cured composites (Filtek™ Z250, Harmonize™, and G-aenial). Color differences of all specimens were measured by a spectrophotometer according to the CIE L*a*b* system. After baseline color measurements, 30 discs from each composite group were randomly divided into 3 subgroups of 10 specimens each. Subgroups (n=10) were immersed for 75 days into different staining solutions: coffee, tomato sauce, and distilled water (control). Solutions were changed every week and color measurements were repeated every 15 days. At day 75, color measurements of the specimens were performed before and after surface polishing with aluminum oxide discs. The experimental data were statistically evaluated using repeated measures one-way ANOVA test followed by Tukey’s multiple pairwise comparison with a significance level of 5%.ResultsOf the 3 composites, G-aenial reported the highest color change deviation when immersed into coffee (ΔE=8.674), and tomato sauce (ΔE=7.737) at day 75, followed by Harmonize that also exhibited a significant difference for coffee (ΔE=4.7) and tomato sauce (ΔE=3.8) when compared to distilled water. While Filtek™ Z250 did not show any significant difference between the 3 storage solutions (P>0.05).Only G-aenial had significant color change (P<0.05) after polishing with aluminum oxide discs for all tested samples, whereas Filtek™ Z250 and Harmonize presented no significant difference after surface polishing (P>0.05).ConclusionsUnder the tested experimental conditions, Filtek™ Z250, among the 3 resin-based composites, exhibited the highest color stability when subjected to coffee and tomato sauce as well. Whereas, G-aenial presented the highest color deviation when immersed in both staining media.Surface polishing effectively reduced coffee and tomato sauce discolorations for G-aenial’s specimens and had no significant effect regarding Filtek™ Z250 and Harmonize.

A novel sample design for determining color compatibility between layered resin composite and vita shade guides.

To compare the color of double-layered (DL) resin-composite (RC) samples with variant enamel-thicknesses (ET) to their corresponding shade-tabs from VITA classical (VC) and 3D-Master (V3DM). A2-DL samples (N = 30) fabricated using three pairs of custom-made molds with an ET of 0.5, 0.7, and 1.0 mm. Shades were selected according to the manufacturer's instructions of two RC brands: Clearfil-Majesty (CM), and Vita-l-essence (VL). A spectrophotometer measured CIE L*a*b* color parameters. We used ΔE 00 to calculate color differences among DL samples, VC, and V3DM shade-tabs. The data were analyzed using Spearman correlation coefficient, one-way ANOVA, and Tukey test (∝=0.05). ΔE 00 between DL samples A2 and 2M2 shade tabs were all greater than the predetermined 50:50% acceptability threshold (ΔE 00 = 6.6-10.4). Depending on the shade tabs compared, the ΔE 00 among CM and VL ET subgroups were statistically different (P < .001). ET and L* were negatively correlated for CM and VL. For CM, ΔE 00 and L* correlated on the A2 shade tab, whereas for VL, ΔE 00 , and ET correlated on the 2M2 shade tab (P < .05). The DL samples produced unacceptable color matches to their corresponding shade. An enamel layer thickness of 0.7 mm corresponded to the lowest ΔE 00 . The use of V3DM for RC shade selection should be investigated. Understanding color interaction between RC layers is important to achieve consistent results in esthetic clinical procedures. The thickness of the enamel layer can critically alter the overall shade for a given RC shade and brand. This variation is difficult for the clinician to predict and negatively impacts patient satisfaction, increasing overall procedure costs, and decreasing efficiency. This color interaction study aims to facilitate consistency in shade reproduction.

Cell physiological effects of glass ionomer cements on fibroblast cells

The cytotoxicity of glass ionomer cements (GICs) was investigated using a novel, cost-effective, easy-to-perform and standardized test. GIC rings were made using in-house designed, custom-made moulds under sterile conditions; 10 with Fuji Equia and 10 with Fuji Triage capsules, placed in direct contact with primary human gingival fibroblasts (HGF) and immortalized human fibroblasts (HFF1). On day 1, 4, 14 and 21, an AlamarBlue® (resazurin) assay was completed towards determining the effects of the GICs on metabolic activities of the cells, whilst cell morphology was examined by light microscopy. The influence of the compounds released from the GIC rings on cell physiological effects (viability, proliferation and adhesion) during 24 h incubation was further investigated by impedimetry.Result trends obtained from this battery of techniques were complementary. At 100 v/v% concentration, the released compounds from Equia were strongly cytotoxic, while at lower concentration (0, 4, 20 v/v%) they were not cytotoxic. In contrast, Triage elicited only slightly transient cytotoxicity.The method proposed has been proved as being efficient, reliable and reproducible and may be useful in quick testing of the cytotoxicity of similar biomaterials by using an immortalized cell line.

Prosthetic rehabilitation of a microtia patient by adhesive retained auricular prosthesis: A dental technique.

Introduction: Auricular deformity can be emotionally traumatising and affects social behavior of an individual. In such cases, aesthetically acceptable prosthesis serves as a viable alternative technique to surgical reconstruction.&#x0D; Case description: Impression of the auricular defect was taken by light and regular body of poly vinyl siloxane impression material. Wax sculpting was challenging due to the bulgy remnant of the defected ear. The wax pattern was made very thin to accommodate and mask the remnant without compromising the aesthetic. Trial on the patientwas done for correction of the contours, angulation, height and width according to the normal contralateral ear. The intrinsic coloration of a Room Temperature Vulcanizing silicone was done and poured in a custom-made three-piece mold. Before the final issue of the auricular prosthesis, extrinsic coloration was done based on the surrounding area of the defect.&#x0D; Discussion: Fabrication of adhesive retained prosthesis is challenging in patients with large deformed soft tissue who refuse to undergo surgical repair. A modified wax sculpting was done to overcome this challenge. Medical grade silicone was the choice of material because of its flexibility, biocompatibility and life like appearance.&#x0D; Conclusion: Replacement of missing ear is a difficult and multi-step task in which extensive array of materials and techniques need to be employed. This fabrication technique is alternative to surgical repair with the utilization of available and economical materials.&#x0D; Bangladesh Journal of Medical Science Vol.18(2) 2019 p.437-439

Fracture toughness of glass ionomers measured with two different methods

Glass Ionomer Cements (GICs) are brittle materials with low fracture toughness and strength. Therefore, understanding the fracture toughness is an important parameter to know, due to GICs being promoted for load-bearing restorations. Also, little is known about the effects of artificial saliva (AS) on fracture toughness of GICs. This project aimed to study the effects of storage and compare two different fracture toughness test methods, namely: Compact-Tension test and 4-point bending test. Samples were made from a Zinc-reinforced-GIC (ChemFil), High viscosity bulk-fill-GIC (HV) with and without LC-coating (EQUIA), Resin-Modified GIC (RM-GIC) (Riva-LC), HV-RMGIC (Riva-HV-LC) and flowable bulk-fill Giomer (Beautifil-Bulk Flowable) using a custom-made mould. Specimens were stored in either AS or distilled-water (DW) for 7 or 30 days. After storage, specimens were tested for fracture toughness. Results were analysed with Analysis of variance (ANOVA), Mann-Whitney and Weibull statistics. ANOVA showed a significant difference (P < 0.05) between methods, however the same trend among materials was observed in both methods. Some materials showed significantly higher values for samples stored in DW and others revealed the same trend but were not significant. Significantly higher (P < 0.05) mean fracture toughness values were observed for materials stored for 30 days. Since both fracture toughness test methods revealed the same fracture toughness strength order among materials, either test appears appropriate. GICs maturation led to a difference between 7 and 30-day results. The AS used had a high ionic strength compared to DW, which may have led to increased solubility of GICs and consequently to the reduced fracture toughness values. The results revealed that coating the GIC has a protective effect against storage media.

Treatment of non-melanoma superficial skin cancer with custom-made wax moulds using Iridium-192 high-dose-rate brachytherapy source

AbstractIntroductionIn non-melanoma skin cancer—that is, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)—brachytherapy treatment is preferred over surgical excision because of cosmetic reasons, acceptability and preference of patients.Material and methodsMoulds are prepared of wax to match the size of the lesion. This represents the area to be considered in treatment planning. A total of 85 patients who had either SCC or BCC were treated, and all these patients were classified on the basis of age, gender and origin.ResultsPatients were treated with 39 Gy in 13 fractions (biological effective dose=50·7 Gy). In 52 BCC patients, treatment achieved excellent cosmetic results in 49 cases, with 17 of these patients experiencing Grade-1 skin reactions related to treatment in the first 24 weeks of follow-up. A single patient experienced Grade-II hyper-pigmentation reaction in the third week. In 33 SCC patients, treatment achieved excellent cosmetic results in 28 cases, with 17 of these patients experiencing Grade-I reaction in the first 36 weeks after treatment. Among the remaining four patients, only one developed Grade-II hypo-pigmentation and one patient experienced tumour recurrence near the primary site. The overall outcome efficacy of the treatment was 98·8%.FindingsThe treatment outcome not only enhances our confidence in brachytherapy but also improves the patient’s satisfaction regarding cosmetic results and curative output achieved by avoiding a surgical procedure for non-melanoma skin cancers.

Successful conjunctival socket expansion in anophthalmic patients until the age of 2 years: an outpatient procedure.

PurposeTo report the results of a simple outpatient method for soft tissue socket expansion in young children with congenital anophthalmos.MethodsSeventeen congenital anophthalmic sockets of 15 infants of a mean age of 4.2±4.4 months were fitted with specially designed serial solid acrylic shapes or hydrogel expanders using cyanoacrylate for eyelids closure when using the latter.ResultsAt the age of 2 years, the mean horizontal eyelid length increased from a mean of 11.6±4.5 to 19.4±4.6 mm and the volume of the last expander from a mean of 0.6±0.2 to 2.0±0.3 cm2. The specially designed acrylic shapes could be a substitute to the custom-made molds, which require general anesthesia.ConclusionSuccessful increase in the horizontal eyelid length as well as the conjunctival socket volume could be achieved by a simple outpatient procedure without the need for repeated hospitalization and general anesthesia in these infants.

Combined T2 and diffusion-weighted MR imaging with template prostate biopsies in men suspected with prostate cancer but negative transrectal ultrasound-guided biopsies

PurposeTransperineal template prostate (TPB) biopsy has been shown to improve prostate cancer detection in men with rising PSA and previous negative TRUS biopsies. Diagnostic performance of this approach especially MR imaging and using reliable reference standard remains scantly reported.Materials and methodsA total of 200 patients, who were previously TRUS biopsy negative, were recruited in this study. All the participants had at least 28-core TPB under general anesthetic within 8 weeks of previous negative TRUS biopsies. In 15 men undergoing laparoscopic radical prostatectomy, prostate specimens were sectioned using custom-made molds and analyzed by experienced pathologist as a feasibility study.ResultsIn total, 120 of 200 patients (60 %) had positive TPB biopsy results. All of these men had at least one negative biopsy from transrectal route. T2 diffusion-weighted MR imaging showed no lesion in almost one-third of these men (61/200; 30.5 %). Out of these, 33 (33/61; 54 %) showed malignancy on TPB including high-grade tumors (>Gleason 7). Out of 15 patients underwent surgery with a total of 52 lesions (mean 3.5) on radical prostatectomy histology analyses, TPB detected 36 (70 %) lesions only. Some of these lesions were Gleason 7 and more mostly located in the posterior basal area of prostate.ConclusionsTransperineal template biopsy technique is associated with significantly high prostate cancer detection rate in men with previous negative TRUS biopsies, however compared to radical prostatectomy histology map, a significant number of lesions can still be missed in the posterior and basal area of prostate.