Instron Universal Testing Machine Research Articles

Biodeterioration Field Test and Mechanical Properties of Maesopsis eminii Wood Treated with Boron Preservative and Plant Oils

Boron preservatives have insecticidal and fungicidal effects. The leaching problem of boron preservative-treated wood can be overcome using oil treatment. This study evaluated the resistance in a biodeterioration field test and the mechanical properties of manii wood (Maesopsis eminii Engl.) treated with boric acid and plant oils. Manii wood samples were impregnated in two stages with boric acid and vegetable oils (neem, tamanu, and candlenut oils). The impregnation process was performed in a chamber at a pressure of 7 kg cm−2 for approximately 4 h. Next, the sample was heated at temperatures of 60 °C, 120 °C, and 180 °C. The biodeterioration field test was conducted in ground contact for 100 days. In addition, mechanical tests in terms of modulus of elasticity (MOE), modulus of rupture (MOR), and hardness were conducted using an Instron universal testing machine. The test results prove that the combination of boric acid preservation with neem, tamanu, or candlenut oil treatment increases the resistance of manii wood to subterranean termites, especially when the treatment is accompanied by heating at 120 °C. The combination treatment of boric acid and plant oils also increases the MOE, MOR, and hardness values of manii wood.

Gadolinium oxide Nanoparticles Infusion in Heat-Cured Acrylic Denture Base Material: Impact on Glass Transition Temperature and Mechanical Strength Enhancement

Introduction: Nano dentistry has paved the way for advanced therapeutic opportunities in various dental disciplines, particularly in the improvement of oral health. One area of focus is the enhancement of mechanical properties of dental materials, such as acrylic resins commonly used in denture base materials. Various strategies, including chemical corrections and the addition of particles, have been explored to augment the mechanical qualities. This study investigates the impact of incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture materials. Materials and Methods: The denture base was processed using a standardized approach, with the addition of Gadolinium oxide nanoparticles during the monomer phase. A total of 120 specimens were fabricated. 30 specimens for each test using 10 specimens for each nanoparticle concentration (Control 0%, 1%, and 1,5% nanoparticles). The nanoparticles were dispersed using sonication to ensure uniform distribution. The study assessed properties such as glass transition temperature using a differential scanning calorimeter, impact strength and transverse strength utilizing an Instron universal testing machine, and surface roughness via profilometer measurements. Scanning electron microscope also utilized. One way ANOVA was used to determine the mean differences. Results: The study revealed significant improvements in glass transition temperature, impact strength, and transverse strength. The peak values were often seen in the 1.5% wt. group. Surface roughness, however, showed non-significant changes with nanoparticle additions, possibly due to the minimal involvement of nanoparticles on the outer surface. Conclusion: Incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture base materials demonstrated notable enhancements in key mechanical properties. The findings suggest that nanoparticle additions contribute to increased strength and rigidity, as evidenced by improvements in impact and transverse strength. However, surface roughness remained largely unaffected. This study contributes valuable insights into the potential benefits of nanotechnology in optimizing dental materials for improved clinical performance and patient outcomes.

Evaluation of the Fracture Resistance of Different Designs of All-Resin Post and Core Systems: An In Vitro Study.

Introduction There is a growing demand for post and core systems that offer both ease of use and efficiency. Recently introduced dual-cure build-up and post cement materials exhibit properties similar to dentin. The objective of this laboratory experiment is to compare the fracture resistance among three distinct post and core systems and identify the locations of failures within each group. Material and methods This in vitro experimental study involved 30 epoxy resin-based blocks (Endo Training Bloc J, Dentsply Sirona, Ballaigues, Switzerland) divided into three groups: The first group was a post space preparation and restoration with a fiber post (RelyX™ Fiber Post, 3M ESPE, Saint Paul, Minnesota, United States) 1.6 mm in diameter and 10 mm in length (Group A) where core build-up and cementation were performed using a dual-cure build-up and cement for endodontic post resin material (Core X Flow, Dentsply DeTrey, Konstanz, Germany). The second group was a post space preparation and restoration using a dual-cure build-up and cement for endodontic post resin material, 10 mm in length filled with resin but without fiber post placement (Group B). The third group was where post space and core were filled and restored with a dual-cure build-up and cement for endodontic post resin material, 5 mm in length and without fiber post placement (Group C). Subsequently, samples were mounted and tested using a universal testing machine (Instron, Canton, Massachusetts, United States), and the fracture site was located. Results Significant differences were identified among the three groups, indicating the impact of both post length and type on fracture resistance (p-value <0.05). Group B exhibited the highest mean compressive strength resistance and maximum load at 899.3330 (N), followed by Group C at 848.9690 (N) and Group A at 751.9620 (N). The predominant failures in the samples were core fractures or debonding of the core material. Conclusion All-resin posts demonstrated high fracture resistance, unlike fiber posts which displayed inferior fracture resistance.

Effectiveness of Different Etching Agents on Enamel Surface and Shear Bond Strength: An In Vitro Evaluation.

Background Enamel etching is of utmost importance during the orthodontic bonding procedure. Phosphoric acid, hydrofluoric acid, and citric acid are used in specific concentrations to create surface irregularities on enamel surfaces, enhancing the bond strength of the orthodontic attachment. Therefore, it is essential to evaluate the type of etchant for reliable orthodontic bracket bonding with minimal damage to the enamel surface. Aims and objectives This study aimed to investigate the morphological changes on the enamel surface after treatment with different surface etchants, assess the depth of penetration, and evaluate the shear bond strength (SBS) of orthodontic brackets. Materials and methods One hundred and one extracted premolar teeth were used to investigate morphological changes on the enamel surface treated with 37% phosphoric acid, 11% hydrofluoric acid, and 20% citric acid. It was evaluated on a scanning electron microscope (Jeol Scientific Equipment, Jeol Limited, Akishima, Japan), and the SBS of brackets on enamel treated with different etching agents was evaluated using an Instron Universal Testing Machine (UTM; Instron Model: 5982, Universal Testing Systems, Norwood, MA). Group A had 60 test samples. Group B had 40 test samples. One control without any acid etching was used in both groups. Subgroup A1 (n = 30) was evaluated for surface characteristics of acid-etched enamel. Subgroup A2 was assessed for the penetration depth of various etchants. Group B (n = 40) was tested for SBS. The results were tabulated and analyzed using IBM SPSS Statistics, version 20.0 (IBM Corp., Armonk, NY). Post hoc Tukey HSD test and one-way analysis of variance were used to assess SBS and penetration depth of etchants (P ≤ 0.05). Pearson's correlation test was used to correlate SBS, etching pattern, and penetration depth. The chi-square test was used to test the frequency of types of etching patterns. Results Intergroup correlations between etching depth, etching pattern evaluated on SEM, and SBS evaluated on the UTM showed a high statistical correlation between etching depth & SBS, etching depth & etching pattern, and SBS & etching pattern between A1, A2, and group B (P ≤ 0.001). A highly significant negative correlation between SBS & etching pattern (P = 0.42) was observed among intra-group correlation. Non-significant correlations were found between etching depth & SBS and etching depth & etching pattern within the 20% citric acid etch group (P = 0.370 and 0.141, respectively). Conclusion Penetration depth obtained was highest with 11% hydrofluoric acid, followed by 37% phosphoric acid and20% citric acid. In addition, 11% hydrofluoric acid showed the highest bond strength. Acid etching showed better penetration depth and bond strength than control.

Multifunctional Nanocomposite Membranes Containing TiO2 Developed by Air-Jet-Spun Fibers for Tissue Engineering

The incorporation of inorganic nanoparticles (NP) into nanofibrous polymeric membranes (NPM) is an attractive approach to developing multifunctional nanocomposites. The purpose of this study was to incorporate titanium dioxide (TiO2) NP into NPM to enhance the overall properties. Polycaprolactone (PCL) membranes with TiO2-NP (0.2 wt%) was fabricated by means of the Air-Jet Spinning (AJS) technique. The physicochemical characterization of the PCL-TiO2-NPM was performed by X-ray powder diffraction (XRD), the morphology was observed under scanning electron microscopy (SEM), and tensile strength and Young’s moduli were evaluated using an INSTRON Universal Testing Machine. In-vitro biocompatibility was evaluated in terms of cell adhesion and cell proliferation using human fetal osteoblasts. The results obtained demonstrated that TiO2-NP added to the PCL-NPM increases the values of tensile strength and Young’s moduli (p < 0.008 and p < 0.043) with respect to PCL-NPM without TiO2-NP. XRD exhibited the characteristic peaks of PCL at 21.3° and 23.7° and of TiO2 at 36°. The SEM micrographs revealed a random distribution with interconnected micropores. Cell adhesion and proliferation increased according to the time of the culture; only after the first period of cell culture was there a significant difference in cell proliferation (p < 0.05). The possible potential application of this PCL-PNM by Air-Jet Spinning (AJS) in tissue engineering could favor bone regeneration due that the addition of TiO2-NP.

To evaluate the effect of different enamel conditioning procedures on the shear bond strength of new metal bracket on previously debonded tooth surface - An in-vitro study

To evaluate the efficacy of different enamel conditioning methods while bonding a new bracket on a previously de-bonded site, and assess the difference in shear bond strength and ARI score if any. 125 human-extracted premolars were selected. 250 premolar brackets were procured. 125 brackets were bonded on the buccal surface of the premolars using different enamel conditioning methods (bonding sequence 1) and was followed by debonding using the Instron Universal testing machine (Debonding procedure I).The remaining 125 brackets were bonded (Bonding sequence II) on the same teeth after the removal of residual adhesive. Bonding sequence II was followed by debonding (Debonding procedure II), shear bond strength calculation, and ARI score calculation. There was a significant difference in SBS between the 5 groups after initial debonding. SEP group (group 4) showed the highest SBS followed by acid etching groups (groups 3, 2, and 1). The sandblasting group (group 5) had the lowest shear bond strength value. After the second debonding, SBS was found to be highest in Group 3 {37% o-phosphoric acid (Bonding I) sandblasting (Bonding II)} followed by Group 4 {SEP (Bonding I and Bonding II)}, group 2 {acid etching (Bonding I) SEP (Bonding II)}, and group 1 (acid etching in both bonding sequences). Group 5 (sandblasting in both sequences) had the least SBS. Non-significant differences were found in ARI score of the five groups. Self-etching primer group had highest SBS and sandblasting group had least SBS after first debond. The SBS of new brackets after two debonding procedures significantly decreased but was still found to be above the required bond strength. SEP and sandblasting can be used as a substitute to acid etching technique in second time bonding of brackets as these groups had higher SBS after second debond.

Effect of surface finish and resin cement on the bond strength to CAD-CAM ceramics for interim resin-bonded prostheses

Statement of problemResin-bonded prostheses, including interim resin-bonded prostheses, are effective in preserving tooth structure compared with other types of fixed dental prostheses for the replacement of missing teeth. However, loss of retention remains a notable concern with these types of prostheses. PurposeThe purpose of this in vitro study was to investigate the influence of glass-ceramic type, resin type, and surface finish on the shear bond strength (SBS) to the CAD-CAM ceramics used to fabricate interim resin-bonded prostheses. Material and methodsEighty 10×2-mm glass-ceramic disks were fabricated by using a diamond saw (IsoMet 1000), 40 from feldspathic porcelain blocks (Vita Mark II) and 40 from lithium disilicate blocks (IPS e.max CAD). Half of the specimens in each group were left with a dull or matte surface finish after cutting, while the other half were glazed with an add-on glaze (VitaAkzento Plus Glaze Spray and IPS e.max CAD Glaze Spray, respectively). The disks were mounted in acrylic resin, and each group was subdivided into 2, with 1 receiving a photopolymerized resin cement (RelyX Veneer) and the other receiving a flowable composite resin (Filtek Supreme Ultimate Flow) to form 2.38×2-mm cylinders. SBS was determined using a universal testing machine (Instron 4411) in accordance with the International Organization for Standardization (ISO) 29022:2013 standard, and failure modes were analyzed by using a stereomicroscope with ×40 magnification. The data were analyzed with a 3-way analysis of variance and Tukey post hoc analysis. The chi-squared test was used to analyze the failure mode (α=.05 for all tests). ResultsCeramic type, resin type, and surface finish significantly impacted SBS (P<.001, P=.003, P<.001, respectively). Lithium disilicate showed higher SBS than feldspathic porcelain, and flowable composite resin exhibited higher SBS than resin cement. Glazed surfaces displayed lower SBS compared with the dull or matte surfaces. The combinations among the 3 materials also impacted SBS (P=.03). In addition, the combinations between ceramic type and surface finish affected SBS (P<.001), regardless of resin cement type. No other combinations affected the SBS (P>.05). The mode of failure was different among the groups (P<.001). In comparison with all other groups, cohesive failures were most prevalent in feldspathic porcelain with a dull or matte surface finish, regardless of the resin type used. ConclusionsThe SBS to glass-ceramics was influenced by ceramic material, resin cement type, and surface finish. Flowable composite resin showed higher SBS than resin cement. A dull or matte surface finish exhibited greater bond strength than a glazed surface. Lithium disilicate had higher SBS than feldspathic porcelain.

Determination of Needle Penetration Force and Pump Pressure for the Development of an Automated Trunk Injection System for HLB-Affected Citrus Trees

Highlights An equation was developed for estimating the needle penetration force required for trunk injection. A method to determine the required pump pressure for citrus tree trunk injection was developed. This information can be used for the development of a drill-free, pressurized, automated trunk injection system. Abstract. Targeted precisemanagement of intravascular diseases such as citrus Huanglongbing (HLB) involves the application of therapeutics via trunk injection.Although trunk injection has proven more effective than foliar spray and soil drenching, multiple studies have highlighted limitations for large-scale commercial tree crop applications because of the manual process involved, emphasizing the need for an automated injection system.The design of a trunk injection mechanism to efficiently dispense aqueous therapeutic materials to the trunk of HLB-affected citrus trees requires the characterization of the hydraulic properties of the trunk and the determination of the penetration force of a dispensing needle. This study developed an equation for estimating penetration force at maximum depth based on the needle diameter, depth of penetration, and specific gravity of the wood tissue, and presents a method for estimating injection pump pressure. Trunk hydraulic conductance was measured using a hydraulic conductance flow meter, and needle insertion and removal force were measured using a force gauge in an Instron universal testing machine. The average maximum force was 2517, 3739, and 5387 N for dowel pins 4.76, 6.35, and 7.93 mm in diameter at a 12 mm penetration depth. Average specific conductivity was 2.45, 0.34, and 0.15 kgs-1m-1MPa-1for trunk segments 0–12.7, 12.7–26.7, and 26.7–40.6 cm above the ground, with a corresponding estimated pump pressure of 0.14, 0.99, and 2.31 MPa, respectively. Keywords: Automated trunk injection, Drill-free, Huanglongbing, Plant diseases.

Effect of Surface Treatments with Plasma and Chemical Bond on Shear Bond Strength of Acrylic Denture Teeth to Flexible and Heat-Cured Denture Base Material: An In Vitro Study

Introduction: We aimed to evaluate the shear bond strength of acrylic denture teeth to flexible and heat-cured denture base material after surface treatments with argon plasma, chemical bonding agent (PALFIQUE universal), and combination. Methods: A total of 80 incisor acrylic denture teeth were treated with a argonplasma, chemical bond (PALFIQUE universal bond), and a combination with 10 samples for each group. The neck (gingival portion) of teeth was cut at a 45° angle, and the teeth were attached to heat-cured acrylic resin and flexible denture base material. All the specimens were stored in artificial saliva for 7 days in an incubator (37 °C). A shear bond strength test was conducted using an Instron universal testing machine. Data were analyzed by the analysis of variance (ANOVA) and the Tukey’s honest significant difference post hoc test using R 4.2.3. Results: A statistically significant difference was found among study groups regarding the type of base, surface treatment with bond, plasma, and combination of bond and plasma (P &lt; 0.00). The Tukey’s test showed that in a heat-cured base, the difference between the control and surface treatment with bond was not significant (P &gt; 0.05). Also, in the flexible base group, the difference between the control and surface treatment with plasma was not significant (P = 0.162). Conclusion: In heat-cured denture-base group, the shear bond strength increased significantly with the combination of surface treatment with argon plasma and a chemical bonding agent (PALFIQUE universal). In the flexible denture-base group, the shear bond strength increased significantly with use of a surface treatment with a chemical bonding agent (PALFIQUE universal).

Prevention of White Spot Lesion during Orthodontic Treatment: A Novel Bioactive Glass Nanobioadhesive

Objectives: The objective of this study is to evaluate the ability of the bioactive glass (BAG)-Bonds to inhibit the demineralization surrounding the orthodontic brackets when being exposed to an in vitro caries challenge and also simultaneously evaluate the physical and mechanical properties in order to be accepted as an orthodontic bonding agent. Materials and Methods: Preparation of mesoporous bioactive glass (MBG) used an improved sol-gel method, combining with sacrificial liquid template to MBGs with controllable particle size. Tetraethyl orthosilicate, triethyl phosphate, calcium nitrate tetrahydrate, ethanol absolute, ethyl acetate, hexadecyltrimethylammonium bromide, deionized water, and ammonium hydroxide were used. The microstructure was analyzed using a field emission gun-based scanning electron microscope (SEM). The debonding and adhesion characteristics were analyzed using an Instron Universal Testing Machine. Results: SEM analysis shows that the prepared MBG particles possess spherical morphology with generally uniform size. Novel orthodontic bonding material (BG) provides adequate mechanical and physical properties in order to be accepted as an orthodontic bonding agent since its bond strength both at the time of bonding and after 6 months in simulated salivary conditions is significantly higher than conventional bonding resin (TBXT). The bond strength was also evaluated both initially at the time of bonding as well as 6 months after being kept in simulated salivary conditions. Conclusion: These novel adhesives result in reduced demineralization surrounding orthodontic brackets and possess optimal physical and mechanical properties to be accepted as an orthodontic adhesive.

Niobium oxyhydroxide as a bioactive agent and reinforcement to a high-viscosity bulk-fill resin composite.

The present in vitro study incorporated niobium oxyhydroxide fillers into an experimental high-viscosity bulk-fill resin composite to improve its mechanical performance and provide it a bioactive potential. Scanning electron microscopy synthesized and characterized 0.5% niobium oxyhydroxide fillers, demonstrating a homogeneous morphology that represented a reinforcement for the feature. Fillers were weighed, gradually added to the experimental resin composite, and homogenized for one minute, forming three groups: BF (experimental high-viscosity bulk-fill resin composite; control), BF0.5 (experimental high-viscosity bulk-fill resin composite modified with 0.5% niobium oxyhydroxide fillers), and BFC (commercial bulk-fill resin composite Beautifil Bulk U, Shofu; positive control). In total, 10 specimens/groups (8 × 2 × 2 mm) underwent flexural strength (FS) tests in a universal testing machine (Instron) (500N). Resin composites were also assessed for Knoop hardness (KH), depth of cure (DoC), degree of conversion (DC), elastic modulus (E), and degree of color change (ΔE). The bioactive potential of the developed resin composite was evaluated after immersing the specimens into a simulated body fluid in vitro solution and assessing them using a Fourier-transformed infrared spectroscope with an attenuated total reflectance accessory. One-way ANOVA, followed by the Tukey's test (p<0.05), determined FS, DC, KH, and ΔE. For DoC, ANOVA was performed, which demonstrated no significant difference between groups (p<0.05). The high-viscosity bulk-fill resin composite with 0.5% niobium oxyhydroxide fillers showed promising outcomes as reinforcement agents and performed well for bioactive potential, although less predictable than the commercial resin composite with Giomer technology.

Effect of Ceramic Thickness on the Bond Strength to Resin-Luting Agents before and after Thermal Cycling.

This study investigated microshear bond strength (µSBS) of two (2) dual-cured resin-luting agents (RelyX™ Ultimate and RelyX™ U200) when photoactivated through varying thicknesses of lithium disilicate, with or without thermal cycling. Discs of IPS e.max Press of 0.5, 1.5, and 2 mm in thickness were obtained. Elastomer molds (3.0 mm in thickness) with four cylinder-shaped orifices 1.0 mm in diameter, were placed onto the ceramic surfaces and filled with resin-luting agents. A Mylar strip, glass plate, and load of 250 grams were placed over the filled mold. The load was removed and the resin-luting agents were photoactivated through the ceramics using a single-peak LED (Radii Plus.) All samples were stored in distilled water at 37oC for 24 h. Half of the samples were subjected to thermal cycling (3,000 cycles; 5ºC and 55ºC). All samples were then submitted to µSBS test using a universal testing machine (Instron 4411) at a crosshead speed of 0.5 mm/min. Data were submitted to three-way ANOVA and Tukey post-hoc test (α=0.05). The mean µSBS at 24 h was significantly higher than after thermal cycling (p<0.05). No statistical difference was found between resin-luting agents (p > 0.05). The mean µSBS for groups photoactivated through 0.5 mm ceramic were significantly higher than 1.5 mm and 2.0 mm (p < 0.05). In conclusion, increased ceramic thicknesses reduced the bond strength of tested resin-luting agents to lithium disilicate. No differences were found between resin-luting agents. Thermal cycling reduced the bond strength of both resin-luting agents.

The Influence of Thickness on the Mechanical Behaviors of 3D Printing Resins for Orthodontic Retainers

This study aimed to evaluate the mechanical behaviors of thermoformed and 3D‐printed retainers with different thicknesses. Thermoformed retainers (Duran) and 3D‐printed retainers (Dental LT Clear V2 and NextDent Ortho Flex) were fabricated at thicknesses of 0.5, 0.75, and 1 mm. Five samples of each material were subjected to compression, tensile, and flexural testing with the universal testing machine (Instron Ltd., Buckinghamshire, England). The results revealed that the mechanical behaviors were significantly influenced by thickness in each type of material. The increased thickness tended to increase strength and modulus in all three tests. However, Dental LT Clear V2 and Duran showed that flexural strength and modulus were inversely related to thickness. The compressive test revealed significantly greater compressive resistance in 3D‐printed groups, except for the NextDent Ortho Flex at 0.5 mm. The tensile test showed that Dental LT Clear V2 at all thicknesses demonstrated significantly higher tensile strength and modulus, while NextDent Ortho Flex was significantly lowest at any thickness in tensile and flexural properties. In conclusion, the thickness significantly influenced the mechanical behaviors of the 3D‐printed retainers. The 0.75 mm thickness of Dental LT Clear V2 could be considered as an alternative to fabricated retainers due to its similar mechanical properties compared with the thermoformed material.

Correlation between shear bond strength and degree of conversion of four orthodontic adhesives.

Background and objective: The study aims to assess the correlation between degree of monomer conversion (DC) and shear bond strength (SBS) of the different adhesives. The objective of the present study was to determine the efficiency of four orthodontic adhesives regarding shear bond strength (SBS), debonding characters and degree of conversion (DC) and to correlate SBS to the DC. Methods: Forty human upper first premolars, divided into four Groups (n = 10) were bonded with metal brackets using four different adhesives. Brackets were debonded in shear on an Instron universal testing machine with a crosshead speed of 1 mm per minute. The mode of bond failure was determined by the adhesive remnant index (ARI) index and the DC was determined by Fourier transform infrared spectroscopy (FTIR) analysis. Result: There was a statistically significant difference between the SBS of only Transbond XT and Orthobond plus color change adhesive while the two remaining adhesives showed no significant difference. All groups of adhesives showed a cohesive type of bond failure according to the ARI results. A statistically significant lower percentage of DC was noted for Orthobond plus (63 %) than Transbond XT (70.2 %) but it was within the accepted range reported in the literature (55-75%). Pearson’s correlation was significantly positive between SBS and DC for Smart Ortho, Heliosit Orthodontic and Orthobond Plus adhesives and insignificantly positive for Transbond XT. Conclusion: Within the limitations of this in vitro study it can be concluded that the Transbond plus color change has significantly higher fluoride release as well as recharge properties when compared to other ortho-adhesive materials. Keywords: Orthodontic Adhesive, Shear Bond Strength, Degree of conversion

Chitosan-Reinforced Gelatin Microspheres-Modified Glass Ionomer Cement (GIC): A Novel Bone Alloplast Graft Material Synthesis and an In Vivo Analysis.

Aim and objective The study aimed to assess and evaluate the efficacyof glass ionomer modified with chitosan-reinforced gelatin microspheres on bone formation. Materials and methods The study involved three groups: Group I comprised plain glass ionomer cement; Group II comprised glass ionomer cement/gelatin (70:30 wt%); in Group III, glass ionomer cement/gelatin/chitosan (70:30%) scaffold were made into discs; the gelatin microspheres were synthesized by oil emulsion method. The synthesized scaffold was subjected to the following in vitro testing, Instron Universal Testing Machine (UTM), U3000, (Instron Corporation, Norwood, Massachusetts, United States) to assess compressive strength, scanning electron microscope(SEM) examination, and biocompatibility testing using hemocompatibility assay. The material was then testedin vivo; male Wistar albino rats, a total of nine animals, were utilized for this purpose. Three animals were used in each group; a femoral defect model was the model of choice for the experiment and the animals were observed for a period of four weeks, following which the animals were sacrificed and sent for histopathological analysis. Results The compression testing was carried out using UTM; test group I was 33 MPa, test group II was 2.3 MPa, and test group III was 25.75 MPa. SEM (JSM-IT800 Schottky Field Emission NANO SEM (JEOL, Tokyo, Japan)) analysis was done to observe the porosity of the fabricated scaffold with the average measurement of0.12 ± 0.2 μm in test group II and 0.29 ± 0.4μm in test group III. Hemocompatibility reports noted 0.4-0.8% lysis for the synthesized scaffolds. Histopathology staining of the femur defects showed that group III favoured bone formation. One-way analysis of variance (ANOVA) and post hoc Bonferroni test was done on the data. The optical density values of the alizarin red stained slide showed statistical significance for group III. Conclusion In conclusion, the synthesized scaffolds are biocompatible, distribution of porosity andpore characteristics in the glass ionomer cement/gelatin/chitosan group is better than that of the glass ionomer cement/gelatin group. The glass ionomer cement/gelatin/chitosan group had better compressive strength and induced more bone formation compared to the other test group and the control. Thus, the novel glass ionomer modified with chitosan-reinforced gelatin microspheres has optimal properties to be used as a bone graft material.

Measuring the Shear Bound Strength on Acrylic Resin Veneer to Metal Surface of Nickel (A Comparative Study)

The bound strength of metal resin interface of prosthesis is a key factor in determining the service ability of that prosthesis. The main objective of this study was to determine the effect of different surface treatment on the shear bond strength of Ni-Cr alloy (CB-Blando 72 alloy) and heat cured acrylic veneer resin (Vertex). Thirty disc shaped samples from base plate wax were prepared, the diameter of disc was (8 mm x 4.5 mm). After casting the metal, the samples were cleaned, finished and polished by silicon carbide abrasive paper with grit size (600 μm) and then the profilometer was u sed to determine the surface roughness of samples. Then the sa mples were divided in to three groups, each group contain (10) sa mples. The first group rece ived no treatment and serve as control .The Second group received micro mechanical treatment using 250 μm Al2o3 .The third group recived micro mechanical treatment using 400 μm Al2o3. The acrylic was prepared as a round shape (8 μm) in diameter and (2 μm) in thickness, which was placed on the metal surface treatment, the acrylic was fabricated in the same conventional way for construction veneer resin. Then all samples was tested the shear bond strength by using Instron universal testing machine .The result from this study showed that, the first group was give low shear bond strength while the second group showed that the air abrasion with 250 μm Al2o3 give the highest shear bond values when compared with the third group which air abrasive with 400 μm Al2o3.

Effect of Surface Textures and Fabrication Methods on Shear Bond Strength Between Titanium Framework and Auto-Polymerizing Acrylic Repair Resin.

The aim of the study was to evaluate the effect of airborne particle abrasion (using different sizes of alumina particles) on the shear bond strength (SBS) between cast and milled titanium metal frameworks and auto-polymerizing acrylic repair resin. Forty flat cylindrical titanium disks were divided into two main divisions: cast and milled titanium. The two divisions were further subdivided into four groups based on metal surface treatment. Three particle sizes of aluminum oxide air abrasive powders (50µm, 110µm, and 250µm) were used for metal surface treatment by airborne particle abrasion. One group was the control group with no surface treatment. Auto-polymerizing acrylic repair resin was applied to all titanium disks. The specimens were subjected to SBS testing using a universal testing machine (Instron Corporation, Norwood, Massachusetts, United States). Surface evaluation was performed using a scanning electron microscope. One-way ANOVA was used for statistical analysis. The results showed a significant increase in SBS after airborne particle abrasion of both milled and cast titanium groups (p<0.001). The SBS was directly proportional to the size of the aluminum oxide particles. The milled titanium group showed higher SBS values than the cast group when the surface was not treated with alumina particles (p < 0.001) and when the surface was treated with the smaller particle sizes of 50 µm, whereas the cast group demonstrated higher SBS values than the milled group (p < 0.01) when the particle size was increased to 110 µm and 250 µm. It could be concluded that SBS between titanium metal frameworks and auto-polymerizing repair acrylic resin was directly related to the size of the alumina airborne particle abrasives. The fabrication method of the titanium frameworkalso influenced the SBS as the untreated milled frameworks demonstrated favorable SBS values compared to the untreated cast frameworks.

Comparative Evaluation of Compressive Strength of Self-cure, Dual-cure, and Light-cure Glass Ionomer Cements in a Simulated Oral Environment: An In Vitro Study.

In primary dentition, glass ionomer cements (GICs) have unique benefits as a restorative material. Various types of GICs are available in the market. In pediatric dentistry, the choice of GI materials is generally focused on handling convenience with adequate consideration for mechanical qualities, including compressive strength to withstand occlusal stresses in the oral environment. To evaluate the compressive strength of self-cure, dual-cure, and light-cure GI-based cements using a universal testing machine. The study population comprised 30 cylindrical restorative blocks for compressive strength assessment. The restorative materials used for the studies were self-cure GIC (ChemFil Rock and GC Fuji IX GP Fast GIC), dual-cure GIC (Equia Forte and Ionolux GIC), and light-cure GIC (GC Fuji II LC and Ketac N 100 GIC). The cylindrical blocks were prepared using prefabricated Teflon mold measuring 4 mm diameter and 6 mm height from respective restorative materials and divided into three major groups and were subdivided into six groups comprising two materials in each group. Using an Instron universal testing machine, compressive strength was assessed. Data obtained were tabulated, and statistical analysis was done using Statistical Package for the Social Sciences (SPSS v22.0) software. On individual comparison of GI-based types of cement, Ketac N100 GIC showed the highest compressive strength, and Fuji IX GP Fast GIC showed the least compressive strength. Light-cure GIC exhibited the highest compressive strength in comparison to dual-cure and self-cure GICs with regard to the nature of curing. Chandru TP, Chandran S, Peedikayil FC, et al. Comparative Evaluation of Compressive Strength of Self-cure, Dual-cure, and Light-cure Glass Ionomer Cements in a Simulated Oral Environment: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(5):707-710.

Evaluation of Physical Properties of Denture Base Resins Containing Silver Nanoparticles of Aloe barbadensis Miller, Morinda citrifolia, and Boesenbergia rotunda and Its Anti-microbial Effect: An In Vitro Study.

Introduction The denture bases fabricated from polymethylmethacrylate (PMMA) have some disadvantages, such as surface prone to microbial growth and biofilm accumulation, which contributes to the onset and dissemination of infections among denture wearers. Therefore, the purpose of this in vitro study was to evaluate the flexural strength, hardness, and antimicrobial effect of denture base resin incorporated with 0.05% and 0.1% silver nanoparticles (AgNPs) of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root). Materials and methods A total of 84 PMMAsamples were used and were divided into three groups. Flexural strength tests were performed on Group 1 PMMAblocks. Group 2 involved hardness testing of PMMAblocks, whereas Group 3 involved antimicrobial activity. Each group was subsequently split into seven subgroups with differing concentrations of AgNPs: Sub Group 1: control (no AgNPs),Sub Group 2: 0.05% aloe vera AgNPs, Sub Group 3: 0.1% aloe vera AgNPs, Sub Group 4: 0.05% noni AgNPs, Sub Group 5: 0.1% of noni AgNPs,Sub Group 6: 0.05%finger root AgNPs, and Sub Group 7: 0.1% finger root AgNPs.The flexural strength was evaluated usinga universal testing machine (Instron 8801). Surface hardness was measured using a Vickers tester (Tukon 1102). For the antimicrobial activity analysis, the samples were incubated in a suitable culture broth containing Candida albicans for 24 hours. Microbial colony count (colony-forming unit (CFU)/mL) was estimated to evaluate the microbial adhesion to the surface of the denture base materials. Statistical analysis The flexural strength, hardness, and CFU between the groups were analyzed using one-way analysis of variance (ANOVA) followed by multiple comparisons with Tukey's honest significant difference (HSD) test (α=0.05). The level of statistical significance was determined at p<0.05. Results It was observed that the mean flexural strength was maximum in PMMA incorporated with 0.05% of aloe vera AgNPs and least in PMMA incorporated with 0.1% noni AgNPs. It was seen that a steady loss in flexural strength is observed from 0.05% to 0.1%. The mean hardness was maximum in PMMA incorporated with 0.1% of noni AgNPs and least in PMMA incorporated with 0.05% aloe vera AgNPs. It was also found that the hardness was directly proportional to the number of nanoparticles. With an increase in the weight percentage of nanoparticles, a steady increase in hardness was seen in all the test groups. In our study, the results showed that finger root 0.1% showed the least CFU with a significant reduction of C. albicans adherence; therefore, it indicates higher anti-fungal activity. Aloe vera 0.05% showed the lowest inhibition of C. albicans,suggesting the least anti-fungal activity. Conclusion Within the limitations of this study, It can thus be concluded that the addition of AgNPs incorporated with plant extracts of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root) can alter the flexural strength, hardness, and microbial adhesion of PMMA. In our study, it can be concluded that flexural strength increases with the addition of AgNPs of 0.5% concentration after which a steady loss is seen. However, the hardness and antimicrobial activity increased with an increase in the concentration of AgNPs in all three plant extracts.

Characteristics laminates composite bamboo

The main plants in Indonesian people's plantations are apus bamboo (Gigantochloa apus), wulung bamboo (Gigantochloa atroviolacea) and tutul bamboo (Bambusa maculat). Apart from being used as a craft material, bamboo is also suitable for boards in the form of laminated composites bamboo which are usually called laminated bamboo boards. One of the main criteria for laminated bamboo boards is their good adhesion, which is determined by their shear performance (shear strength). The shear strength of laminated bamboo boards is influenced by several factors such as the type of bamboo used, adhesive/matrix type and laminate configuration. This research used three variations of bamboo species: Gigantochloa apus (GA), Gigantochloa atroviolacea (GV) and Bambusa maculat (BM). The matrix/adhesive used is phenol resorcinol formaldehyde (PRF). The bamboo laminated composite arrangement or horizontal configuration is assembled into a three-layer structure using a hand lay up technique. Testing to determine the performance of bamboo laminated composites, with a shear test, using an Instron universal testing machine (UTM) (serial number CP105207), maximum load cell 100 kN with 8 Kg. The results show that the type of bamboo has an effect on the shear performance of bamboo laminate composites. The BM, GV, GA bamboo, respectively, have better performance, greater shear strength.