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"Materials Testing - methods"
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Successful reading assessments and interventions for struggling readers : lessons from literacy space
\"Each struggling reader has a unique combination of strengths and areas that require targeted instruction. Through their work with teachers and children in an after school tutoring program, the authors have identified six types of struggling readers and offer suggestions for assessment and instruction for each type of struggling reader. The book shares lessons learned from the tutoring program that are applicable to the classroom. Suggestions of how teachers can outreach and involve parents, caregivers, and families is included\"-- Provided by publisher.
Book
The Effect of Thermocycling on Interfacial Bonding Stability of Self-Etch Adhesives: OCT Study
Objective. The aim of this study was to monitor the behavior of interfacial gaps formed under different bonded polymeric restorations before and after thermocycling (TC), using swept-source optical coherence tomography (SS-OCT) and confirming the obtained findings with confocal laser scanning microscopy (CLSM). Materials and Methods. Cylindrical class I cavities were prepared in twenty noncarious human premolar teeth (1.5 mm depth×3.5 mm diameter) and divided randomly into two groups: TS and SN, according to the adhesive system (n=10). In the TS group, one-step self-etch adhesive Clearfil Tri-S Bond Plus (Kuraray Noritake Dental, Japan) was used, followed by composite restoration using Estelite Sigma Quick (Tokuyama Dental, Japan). In the SN group, the cavities were restored with the two-step self-etch/composite silorane-based resin restoration system (3M ESPE, USA). All specimens were restored in bulk filling technique and cured in accordance with the manufacturers’ instructions. Both groups were imaged under SS-OCT after 24 h and recorded as controls. Then, each group was subjected to thermal challenge using the TC machine (5–55°C) and B-scans were recorded at different TC intervals (2600, 5200, and 10000). In order to confirm the SS-OCT findings, additional specimens were prepared, scanned, and sectioned for CLSM observation. Results. B-scans demonstrated white clusters at the tooth-resin interface that corresponded to the gap location on CLSM images. The TS group showed significantly less gap formation than the SN group before and after TC (p<0.001). Conclusions. An optimal composite adaptation can be achieved when the bonded restoration comprises a combination of an adhesive containing 10-MDP monomer and a considerable highly filled composite.
Journal Article
Reading success for all students : using formative assessment to guide instruction and intervention
\"Help for reading teachers in continuous monitoring, assessment and instruction that targets students' problem areas This vital resource offers classroom teachers and literacy coaches practical assessments that can be used to evaluate key areas in students' reading performance. These assessments will provide information that can be directly used for planning instruction. Specific instructional techniques and activities are linked to each of the assessments so that teachers know exactly how to teach necessary skills. Tests and other evaluative devices are aligned with Common Core State Standards and state frameworks. Offers a proven model for monitoring and assessing students Assessments and instructional strategies are easy to implement as part of any curriculum Practical strategies are modeled on a tested approach for helping students work through their problem areas \"-- Provided by publisher.
Book
The critical bond strength of orthodontic brackets bonded to dental glass–ceramics
ObjectivesTo evaluate the critical bond strength (σ) of ceramic and metal brackets to a lithium disilicate-based glass–ceramic.Materials and methodsTwo hundred and forty ceramic specimens (IPS e-max CAD) were randomly distributed in 12 experimental groups (n = 20). Two ceramic brackets (monocrystalline, BCm; and polycrystalline, BCp) and a metal bracket (BM) were bonded to glass–ceramic specimens after one of the following surface treatments: HF—hydrofluoric acid applied for 60 s; S—silane applied for 3 min; HFS—HF followed by S; and MDP—application of an adhesive containing a phosphate monomer (MDP). All brackets were bonded to the treated glass–ceramic using a resin cement, stored in 37 °C water for 48 h before shear bond strength testing. Optical (OM) and scanning electron (SEM) microscopies were used for fractographic analysis. Data was statistically analyzed using Kruskal–Wallis and Student–Newman–Keuls (α = 0.05).ResultsBCm bonded to glass–ceramic treated with either HFS or HF showed the highest median σ values, respectively, 10.5 MPa and 8.5 MPa. In contrast, the BCp bonded to glass–ceramic treated with MDP showed the lowest median σ value (0.8 MPa), which was not statistically different from other MDP-treated groups.ConclusionsThe failure mode was governed by the glass–ceramic surface treatment, not by the bracket type. Quantitative (σ values) and qualitative (fracture mode) data suggested a minimum of 5 MPa for brackets bonded to glass–ceramic, which is the lower critical limit bond strength for a comprehensive orthodontic treatment.Clinical relevanceBonding brackets to glass–ceramic requires micromechanical retention.
Journal Article
Can Fiber Application Affect the Fracture Strength of Endodontically Treated Teeth Restored with a Low Viscosity Bulk-Fill Composite?
Objective. The aim of this study is to evaluate the effects of different fiber insertion techniques and thermomechanical aging on the fracture resistance of endodontically treated mandibular premolar teeth restored using bulk-fill composites. Materials and Methods. Eighty human mandibular premolar teeth were randomly divided into eight groups: Group IN, Group BF, Group PRF1, Group PRF2, Group IN-TMA, Group BF-TMA, Group PRF1-TMA ,and Group PRF2-TMA. Group IN (intact) and Group IN-TMA (intact but subjected to thermomechanical aging) served as control groups. In the other six groups, endodontic treatment was performed and standardized mesio-occluso-distal (MOD) cavities were prepared. In BF, PRF1, and PRF2, the cavities were restored with bulk-fill composite only, bulk-fill/Ribbond, and bulk-fill/additional Ribbond, respectively. In BF-TMA, PRF1-TMA, and PRF2-TMA, the teeth were subjected to thermomechanical aging after the restorations. All of the teeth were fractured on the universal testing machine. Fracture surfaces were analyzed with a stereomicroscope. Results. Control groups showed significantly higher fracture strengths than tested groups (P<0.05). No statistically significant difference was observed among the tested groups (P>0.05). Most of the favorable fractures were seen in PRF1, PRF2, and PRF2-TMA. Most of the unfavorable fractures were seen in BF-TMA. Conclusions. Although fiber insertion with different techniques did not increase the fracture strength of teeth restored with bulk-fill composites, it increased the favorable fracture modes. Thermomechanical aging did not change the fracture strength of the groups.
Journal Article
Clinical efficacy of ceramic versus resin-based composite endocrowns in Chinese adults: study protocol for a randomized controlled trial
Background
Endocrown restoration is widely used to restore endodontically treated teeth. However, the clinical effects of different computer-aided design/computer-aided manufacturing (CAD/CAM) materials for endocrown restoration are not clear. The primary objective of this trial is to compare the clinical efficacy of resin-based bloc and ceramic endocrowns for restoring endodontically treated teeth.
Methods
The proposed resin-based bloc and ceramic endocrown assessment trial is a parallel group-designed randomized controlled trial. We will recruit 156 adults between 18 and 75 years old with a minimum of one such molar. The inclusion criteria were good oral hygiene habits, root apex of molar without evident damage, receipt of standard endodontic treatment, need for endocrown restoration, and only one endocrown restoration performed per patient. Patients participating in another study or those with systemic diseases, disabilities, or known allergies to used materials will be excluded. All patients will be randomized and restored with resin-based bloc and ceramic endocrown according to a random number table. Clinical evaluations will be performed at baseline and after treatment at 6, 12, and 24 months, in accordance with the modified Federation Dentaire Internationale (FDI) criteria, by two independent evaluators. The primary outcome is marginal adaptation; secondary outcomes include wear, tooth integrity, fracture of material and retention, marginal staining, and patient view. All data will be analyzed by an independent statistician. Signed rank-sum tests will be used for intragroup comparisons. Wilcoxon rank-sum tests will be used for intergroup comparisons. Hierarchical logistic regression will be used to adjust the baseline and other important indicators.
Discussion
This study will investigate endocrowns of two CAD/CAM materials for endodontically treated molars. The results may help clinicians choose the better CAD/CAM material option and explain to patients the advantages and disadvantages of these two materials with evidence-based support. For patients, the results may lead to improvement in long-term restoration.
Trial registration
ClinicalTrials.gov
NCT04033380
. Registered on 24 July 2019
Journal Article
Effectiveness of Menghini-Type Needles for Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Pancreatic Masses
BackgroundCutting needles are thought to be effective as biopsy needles. A few types of cutting needles are available for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), and the Menghini-type needle is an end-type cutting needle.AimsA prospective randomized controlled trial was conducted to compare the results of EUS-FNA using a Menghini-type needle (needle M) versus a conventional needle (needle S).MethodsThe main eligibility criteria were as follows: patients with a pancreatic mass referred for EUS-FNA, ≥ 20 years old, and a performance status < 4. The primary outcome was the sample quality. The secondary outcomes were factors associated with the sample quality, diagnostic accuracy, and adverse events.ResultsA total of 97 patients were enrolled in this study. The sample quality for total puncture with needle M (92.8%) was significantly higher than that with needle S (81.4%) (p = 0.0305). The tumor size (p = 0.033) and type of needle (p = 0.031) were significant factors associated with adequate tissue collection in univariate and multivariate analyses (odds ratio [OR] 2.71; 95% confidence interval [CI] 1.12–6.54; p = 0.027 for tumor size, and OR 2.93; 95% CI 1.23–8.21; p = 0.0153 for type of needle). The diagnostic accuracy of each needle was 88.7% (86/97) with needle M and 73.2% (71/97) with needle S. Adverse events occurred in 2 of the 97 patients (0.02%).ConclusionA Menghini-type needle was able to obtain core tissue for histology more effectively than a conventional aspiration needle.Trial Registration NumbersUMIN registration number of 000020668.
Journal Article
Polyetheretherketone (PEEK) for medical applications
Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical properties favorable for bio-medical applications. Polyetheretherketone forms: PEEK-LT1, PEEK-LT2, and PEEK-LT3 have already been applied in different surgical fields: spine surgery, orthopedic surgery, maxillo-facial surgery etc. Synthesis of PEEK composites broadens the physicochemical and mechanical properties of PEEK materials. To improve their osteoinductive and antimicrobial capabilities, different types of functionalization of PEEK surfaces and changes in PEEK structure were proposed. PEEK based materials are becoming an important group of biomaterials used for bone and cartilage replacement as well as in a large number of diverse medical fields. The current paper describes the structural changes and the surface functionalization of PEEK materials and their most common biomedical applications. The possibility to use these materials in 3D printing process could increase the scientific interest and their future development as well.
Journal Article
Methacrylate peak determination and selection recommendations using ATR-FTIR to investigate polymerisation of dental methacrylate mixtures
Investigation of polymerisation kinetics using ATR-FTIR systems is common in many dental studies. However, peak selection methods to calculate monomer-polymer conversion can vary, consequently affecting final results. Thus, the aim of this study is to experimentally confirm which method is less prone to systematic errors. Three commercial restorative materials were tested–Vertise Flow (VF), Constic and Activa Bioactive Restorative Kids. Firstly, Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) (Spectrum One, Perkin-Elmer, UK) spectra of monomers were acquired—10-methacryloyloxy decyl dihydrogen phosphate (10-MDP), bisphenol-A glycidyl dimethacrylate (Bis-GMA), 2-hydroxyethyl methacrylate (HEMA), triethyelene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) to investigate proportionality of methacrylate peak heights versus concentration. Spectral changes upon light exposure of 2 mm discs of the restorative materials (irradiated for 20 s, LED curing unit 1100–1330 mW/cm 2 ) were assessed to study polymerisation kinetics ( n = 3), with continuous acquisition of spectra, before, during and after light exposure. Peak differences and degrees of conversion (D C %) were calculated using 1320/1336, 1320/1350 and 1636/1648 cm -1 as reaction/reference peaks. Inferential statistics included a MANOVA and within-subjects repeated measures ANOVA design (5% significance level). Proportionality of methacrylate peak height to concentration was confirmed, with the 1320/1352 cm -1 peak combination showing the lowest coefficient of variation (8%). Difference spectra of the polymerisation reaction showed noise interference around the 1500–1800 cm -1 region. Across the different materials, D C % results are highly dependent upon peak selection ( p <0.001), with higher variability associated to the 1636 cm -1 . Significant differences in the materials were only detected when the 1320 cm -1 peak was used ( p <0.05). Within the same materials, methods were significantly different for Constic and Activa ( p <0.05). It is possible to conclude that the 1320 cm -1 peak is more adequate to assess polymerisation of methacrylates and is therefore recommended.
Journal Article
Biocompatibility of cardiopulmonary bypass circuit with new polymer Senko E-Ternal Coating
The aim of this study was to compare the biocompatibility of a new Senko E-Ternal coating (SEC) for cardiopulmonary bypass (CPB) circuits with the well-established poly-2-methoxyethyl acrylate (PMEA) coating.
Forty patients undergoing aortic valve replacement were randomly assigned to either an SEC-coated group (n = 20) or a PMEA-coated group (n = 20). Clinical data and the following markers were analyzed: platelet count, platelet factor (PF) 4, fibrinogen, fibrinogen degradation products (FDPs), antithrombin III (AT III), thrombin-antithrombin complex (TAT), plasminogen, complement hemolytic activity (CH50), complement 3 (C3) and interleukin-6 (IL-6). Blood samples were obtained at five time points in both groups.
CPB time, aortic cross-clamp time and blood loss and transfusion were similar in both groups. There were no significant differences between the groups in terms of platelet count, PF4 and all coagulation and fibrinolytic parameters (FDP, AT III, TAT, and plasminogen) at any time points. Inflammatory markers (CH50, C3 and IL-6) were also similar in both groups at all time points.
The SEC-coated circuit demonstrated equivalent biocompatibility to the PMEA-coated circuit. SEC-coated circuits are, therefore, favorably comparable to PMEA-coated circuits for clinical use in CPB.
Journal Article