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Journal of Oleo Science 2024Herein, we evaluated friction dynamics of human skin treated with polyacrylic acid aqueous solutions or gel creams using a sinusoidal motion friction evaluation system...
Herein, we evaluated friction dynamics of human skin treated with polyacrylic acid aqueous solutions or gel creams using a sinusoidal motion friction evaluation system to demonstrate the effect of treatment with polymer aqueous solutions on human skin. A polymer aqueous solution or gel cream was applied to the inner forearms of 10 subjects to evaluate temporal changes in friction force under sinusoidal motion. Water content, skin viscoelasticity, and transepidermal water loss were also simultaneously measured to determine the effects on skin conditions. When human skin was treated with the polymer aqueous solution, the friction coefficient immediately after treatment was 0.69-0.99 and the delay time δ, a normalized parameter of the time difference in the delayed response of friction to the movement of the contact probe divided by the friction time T for one round trip, was 0.171-0.179, which was greater than that of untreated skin. This increase was caused by the swelling and softening of the stratum corneum caused by the penetration of water in the polymer aqueous solution, which increased true contact area between the skin and contact probe. A significant difference was observed in the friction coefficient of the skin immediately after treatment with different polymer aqueous solutions. Among polymers (P1-P4), P4, which has a low-salt resistance and low yield stress, had the lowest friction coefficient because of collapsing of the polymer network structures by shearing and reduced viscosity owing to salts on human skin. The skin treated with a gel cream also exhibited a greater friction coefficient than the untreated skin immediately after treatment and 90 min later. This phenomenon can be caused by the occlusive effect of the oil in the gel cream.
Topics: Humans; Friction; Water; Viscosity; Solutions; Acrylic Resins; Skin; Elasticity; Adult; Female; Male; Polymers; Skin Cream; Gels; Water Loss, Insensible
PubMed: 38945920
DOI: 10.5650/jos.ess24036 -
Dental Materials Journal Jun 2024This study investigated the usefulness of a dental laboratory polymerization unit with light-emitting diode (LED) as a light source. The depth of cure (n=15), water...
This study investigated the usefulness of a dental laboratory polymerization unit with light-emitting diode (LED) as a light source. The depth of cure (n=15), water absorption and solubility (n=9) of two indirect composite materials (Cesead N and Solidex Hardura) were evaluated by five dental laboratory polymerization units (LED Cure Master, Twinkle LED, α-Light V, α-Light II, and Hyper LII). Statistical analysis was performed by one-way ANOVA and Tukey test or non-parametric tests. Comparison of light sources for curing depth showed that metal halide had the highest value, followed by the LED group with similar values, and halogen lamps with the lowest value. The water absorption and solubility of the composite specimens polymerized with the three LED laboratory polymerization units were within the ISO recommended limit.
PubMed: 38945865
DOI: 10.4012/dmj.2023-260 -
Dental Materials Journal Jun 2024Laboratory evidence has shown that 45S5 bioglass can help in dental remineralization, so its incorporation into resin-modified glass ionomer cement (RMGIC) has been...
Laboratory evidence has shown that 45S5 bioglass can help in dental remineralization, so its incorporation into resin-modified glass ionomer cement (RMGIC) has been studied. This randomized clinical trial aimed to determine the efficacy of RMGIC enriched with 10% 45S5 bioglass (RMGIC/45S5) in preventing the progression of moderate caries lesions. Sixty-six permanent molars with moderate caries lesions, were randomly sealed with RMGIC or RMGIC/45S5. After 1, 3-6 months, patients' oral health, material behavior, and caries evolution were evaluated. Chi-square and Fisher's exact test was employed. After one month, the RMGIC showed higher total retention and better clinical performance compared to RMGIC/45S5, both showed a predominance of sealed teeth or without caries progression. After 6 months, no materials retention, quality and caries progression difference was observed for both materials. Short-term clinical follow-up reveals worse retention and quality of RMGIC/45S5, only after 6 months no clinical/microscopic differences are observed between the materials.
PubMed: 38945864
DOI: 10.4012/dmj.2023-261 -
The Journal of Prosthetic Dentistry Jun 2024Artificial intelligence has been used to enhance the digitalized workflow, especially when undergoing complex oral rehabilitations. However, the reliability of real-time...
STATEMENT OF PROBLEM
Artificial intelligence has been used to enhance the digitalized workflow, especially when undergoing complex oral rehabilitations. However, the reliability of real-time jaw motion registration devices is unclear, and no standard measurement method of the sagittal condylar inclination (SCI) and Bennett angle (BA) has been established.
PURPOSE
The purpose of this clinical study was to compare and evaluate the reliability of the SCI and BA values recorded by using 2 different digital devices.
MATERIAL AND METHODS
A total of 17 participants, aged between 20 and 30 years (10 women and 7 men) were included in the study. For each participant, the Cadiax Compact 2 and MODJAW tracking devices were used to measure the SCI and BA values at 3 mm and 5 mm of condylar displacement during 3 separate recording sessions. The intraclass correlation coefficient (ICC) was used to assess the reliability of the recordings. Comparisons between the devices were performed with the Wilcoxson rank-sum test (α=.05). The Bland-Altman plot was used to evaluate the quantitative agreement between the 2 devices.
RESULTS
All ICC intrarater reliability values for Cadiax and MODJAW were higher than 0.90. Both at 3 and 5 mm, the SCI measurements were higher for MODJAW registrations than for those recorded by Cadiax. The Bland-Altman plot showed that the SCI values were higher for MODJAW than for Cadiax by 5.9 (95% CI 3.9 to 8.2) and that the BA differences between the MODJAW and the Cadiax were not consistent with the measured value.
CONCLUSIONS
Excellent reliability was found with the MODJAW and Cadiax recordings. The SCI and BA values for MODJAW measurements were higher at 3 mm and 5 mm than those acquired with Cadiax. MODJAW showed higher values than Cadiax, and the discrepancies were more pronounced for 3 mm than for 5 mm of condylar displacement, highlighting the need for precision in measurements at lower ranges of motion.
PubMed: 38945794
DOI: 10.1016/j.prosdent.2024.05.014 -
Dental Materials : Official Publication... Jun 2024To assess the effects of different aging protocols on chemical, physical, and mechanical properties of an experimental ATZ composite compared to a zirconia.
OBJECTIVES
To assess the effects of different aging protocols on chemical, physical, and mechanical properties of an experimental ATZ composite compared to a zirconia.
METHODS
Disc-shaped specimens were obtained through uniaxial pressing of commercial powders (Tosoh), ATZ comprised of 80%ZrO/20%AlO (TZ-3YS20AB) and 3Y-TZP (3Y-SBE). The specimens of each material were divided into different groups according to the aging protocol: immediate, autoclave aging and hydrothermal reactor aging. The aging protocols were performed at 134 ºC for 20 h at 2.2 bar. Crystalline evaluations were performed using X-Ray Diffraction. The nanoindentation tests measured the elastic modulus (Em) and hardness (H). Biaxial flexural strength was performed, and Weibull statistics were used to determine the characteristic strength and Weibull modulus. The probability of survival was also determined. The Em and H data were analyzed by one-way ANOVA and Tukey test.
RESULTS
Diffractograms revealed the presence of monoclinic phase in both materials after aging. The hydrothermal reactor decreased the Em for ATZ compared to its immediate condition; and the H for both ATZ and 3Y-TZP regarding their immediate and autoclave aging conditions, respectively. The aging protocols significantly increased the characteristic strength for ATZ, while decreased for 3Y-TZP. No difference regarding Weibull modulus was observed, except for 3Y-TZP aged in reactor. For missions of up to 500 MPa, both materials presented a high probability of survival (>99 %) irrespective of aging condition.
SIGNIFICANCE
The synthesized ATZ composite exhibited greater physical and microstructural stability compared to 3Y-TZP, supporting potential application of the experimental material for long-span reconstructive applications.
PubMed: 38945742
DOI: 10.1016/j.dental.2024.06.023 -
Dental Materials : Official Publication... Jun 2024This study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM),...
The effect of photoinitiator type and filler load on physicochemical and mechanical properties of experimental light-cured resin cements through lithium disilicate ceramics of different shades and thicknesses.
OBJECTIVE
This study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of lithium disilicate ceramics.
METHODS
Lithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV-vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05).
RESULTS
Thicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05).
SIGNIFICANCE
The luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.
PubMed: 38945741
DOI: 10.1016/j.dental.2024.06.020 -
ACS Biomaterials Science & Engineering Jun 2024In addition to transmitting and carrying genetic information, RNA plays an important abiotic role in the world of nanomaterials. RNA is a natural polyanionic...
In addition to transmitting and carrying genetic information, RNA plays an important abiotic role in the world of nanomaterials. RNA is a natural polyanionic biomacromolecule, and its ability to promote osteogenesis by binding with other inorganic materials as an osteogenic induction agent was discovered only recently. However, whether it can promote osseointegration on implants has not been reported. Here, we investigated the effect of the RNA-containing coating materials on peri-implant osseointegration. Total RNA extracted from rat muscle tissue was used as an osteogenic induction agent, and hyaluronic acid (HA) was used to maintain its negative charge. In simulated body fluids (SBF), in vitro studies demonstrated that the resulting material encouraged calcium salt deposition. Cytological experiments showed that the RNA-containing coating induced greater cell adhesion and osteogenic differentiation in comparison to the control. The results of animal experiments showed that the RNA-containing coating had osteoinductive and bone conduction activities, which are beneficial for bone formation and osseointegration. Therefore, the RNA-containing coatings are useful for the surface modification of titanium implants to promote osseointegration.
PubMed: 38943625
DOI: 10.1021/acsbiomaterials.4c00133 -
Journal of X-ray Science and Technology Jun 2024Typical propagation-based X-ray phase contrast imaging (PB-PCI) experiments using polyenergetic sources are tested in very ideal conditions: low-energy spectrum (mainly...
BACKGROUND
Typical propagation-based X-ray phase contrast imaging (PB-PCI) experiments using polyenergetic sources are tested in very ideal conditions: low-energy spectrum (mainly characteristic X-rays), small thickness and homogeneous materials considered weakly absorbing objects, large object-to-detector distance, long exposure times and non-clinical detector.
OBJECTIVE
Explore PB-PCI features using boundary conditions imposed by a low power polychromatic X-ray source (X-ray spectrum without characteristic X-rays), thick and heterogenous materials and a small area imaging detector with high low-detection radiation threshold, elements commonly found in a clinical scenario.
METHODS
A PB-PCI setup implemented using a microfocus X-ray source and a dental imaging detector was characterized in terms of different spectra and geometric parameters on the acquired images. Test phantoms containing fibers and homogeneous materials with close attenuation characteristics and animal bone and mixed soft tissues (bio-sample models) were analyzed. Contrast to Noise Ratio (CNR), system spatial resolution and Kerma values were obtained for all images.
RESULTS
Phase contrast images showed CNR up to 15% higher than conventional contact images. Moreover, it is better seen when large magnifications (>3) and object-to-detector distances (>13 cm) were used. The influence of the spectrum was not appreciable due to the low efficiency of the detector (thin scintillator screen) at high energies.
CONCLUSIONS
Despite the clinical boundary condition used in this work, regarding the X-ray spectrum, thick samples, and detection system, it was possible to acquire phase contrast images of biological samples.
PubMed: 38943421
DOI: 10.3233/XST-230425 -
Nigerian Journal of Clinical Practice Jun 2024Apically extruded debris can be affected by some features of the file systems such as kinematics or metallurgic properties.
BACKGROUND
Apically extruded debris can be affected by some features of the file systems such as kinematics or metallurgic properties.
AIMS
This in vitro study aimed to evaluate the effect of movement kinematics (reciprocation or rotation) and heat-treated alloys (C.Wire) on the amount of debris extrusion.
METHODS
Seventy-two mesiobuccal root canals were assigned into three experimental groups related to the single-file system used (n = 24): two rotational; One Shape (Conventional Ni-Ti), One Curve (C.Wire), and one reciprocating; and One Reci (C.Wire). The file systems were used according to the advisable speed and torque according to the manufacturers' suggestion. The weight of debris was calculated by subtracting the preweights from postweights of Eppendorf tubes. Kruskall-Wallis and Mann-Whitney U tests were used to analyze the data (P = 0.05).
RESULTS
One Shape produced the greatest amount of extruded debris compared with One Curve (P < 0.001) and One Reci (P < 0.001), respectively. No statistical difference was found between One Curve and One Reci concerning amount of apical debris extrusion (P = 0.489).
CONCLUSION
Metallurgical properties of files may affect apical debris extrusion. Alloy type is an important factor in the amount of debris extrusion. File kinematics does not affect apical debris extrusion.
Topics: Humans; Alloys; Root Canal Preparation; Hot Temperature; Biomechanical Phenomena; In Vitro Techniques; Materials Testing; Equipment Design; Nickel; Dental Pulp Cavity
PubMed: 38943303
DOI: 10.4103/njcp.njcp_889_23 -
Nigerian Journal of Clinical Practice Jun 2024This study aims to assess the diagnostic accuracy of an artificial intelligence (AI) system employing deep learning for identifying dental plaque, utilizing a dataset...
OBJECTIVES
This study aims to assess the diagnostic accuracy of an artificial intelligence (AI) system employing deep learning for identifying dental plaque, utilizing a dataset comprising photographs of permanent teeth.
MATERIALS AND METHODS
In this study, photographs of 168 teeth belonging to 20 patients aged between 10 and 15 years, who met our criteria, were included. Intraoral photographs were taken of the patients in two stages, before and after the application of the plaque staining agent. To train the AI system to identify plaque on teeth with dental plaque that is not discolored, plaque and teeth were marked on photos with exposed dental plaque. One hundred forty teeth were used to construct the training group, while 28 teeth were used to create the test group. Another dentist reviewed images of teeth with dental plaque that was not discolored, and the effectiveness of AI in detecting plaque was evaluated using pertinent performance indicators. To compare the AI model and the dentist's evaluation outcomes, the mean intersection over union (IoU) values were evaluated by the Wilcoxon test.
RESULTS
The AI system showed higher performance in our study with a precision of 82% accuracy, 84% sensitivity, 83% F1 score, 87% accuracy, and 89% specificity in plaque detection. The area under the curve (AUC) value was found to be 0.922, and the IoU value was 76%. Subsequently, the dentist's plaque diagnosis performance was also evaluated. The IoU value was 0.71, and the AUC was 0.833. The AI model showed statistically significantly higher performance than the dentist (P < 0.05).
CONCLUSIONS
The AI algorithm that we developed has achieved promising results and demonstrated clinically acceptable performance in detecting dental plaque compared to a dentist.
Topics: Humans; Artificial Intelligence; Adolescent; Child; Dental Plaque; Female; Male; Sensitivity and Specificity; Deep Learning
PubMed: 38943301
DOI: 10.4103/njcp.njcp_862_23