The use of hybrid fibre-reinforced Self-compacting concrete (HFR-SCC) has escalated recently due to its significant advantages in contrast to normal concrete such as increased ductility, crack resistance, and eliminating the need for compaction etc. The process of determining residual strength properties of HFR-SCC after a fire event requires rigorous experimental work and extensive resources. Thus, this study presents a novel approach to develop equations for reliable prediction of compressive strength (cs) and flexural strength (fs) of HFR-SCC using gene expression programming (GEP) algorithm. The models were developed using data obtained from internationally published literature having eight inputs including water-cement ratio, temperature, fibre content etc. and two output parameters i.e., cs and fs. Also, different statistical error metrices like mean absolute error (MAE), coefficient of determination ( R 2 ) and objective function (OF) etc. were employed to assess the accuracy of developed equations. The error evaluation and external validation both approved the suitability of developed models to predict residual strengths. Also, sensitivity analysis was performed on the equations which revealed that temperature, water-cement ratio, and superplasticizer are some of the main contributors to predict residual compressive and flexural strength.

Acrylic resins are widely used as the main components in removable orthodontic appliances. However, poor oral hygiene and maintenance of orthodontic appliances provide a suitable environment for the growth of pathogenic microorganisms. In this study, strontium-modified phosphate-based glass (Sr-PBG) was added to orthodontic acrylic resin at 0% (control), 3.75%, 7.5%, and 15% by weight to evaluate the surface and physicochemical properties of the novel material and its in vitro antifungal effect against Candida albicans (C. albicans). Surface microhardness and contact angle did not vary between the control and 3.75% Sr-PBG groups (p > 0.05), and the flexural strength was lower in the experimental groups than in the control group (p < 0.05), but no difference was found with Sr-PBG content (p > 0.05). All experimental groups showed an antifungal effect at 24 and 48 h compared to that in the control group (p < 0.05). This study demonstrated that 3.75% Sr-PBG exhibits antifungal effects against C. albicans along with suitable physicochemical properties, which may help to minimize the risk of adverse effects associated with harmful microbial living on removable orthodontic appliances and promote the use of various materials.

The study investigates the bending strength of tracks of box headers beyond AISI, which considers the capacity of individual channels alone. Both experimental and FEM are used, and the results are compared to AISI. The findings highlight tracks\' significant role in the overall bending capacity. AISI is found to be conservative by 34% to 152%. Failure mode is different from code theoretical expectations for a single channel. Fastener close spacing marginally improves the capacity, while side fasteners offer significant enhancement, but track widening limits this enhancement. A modification to AISI is proposed considering track strength, with outcomes showing good accuracy.

Experimental light-curing pattern resins were fabricated to produce pattern resin materials with adequate dimensional stability. The light-curing pattern resins consisted of poly(n-butyl methacrylate) or poly(iso-butyl methacrylate) (PiBMA) polymers and methacrylate monomers. The physical properties, amount of residual ash after burning, Vickers hardness, flexural strength, and volumetric polymerization shrinkage of each material were determined. The data obtained for the prepared resins were compared with those of a commercially available pattern resin, Palavit G (PG). A lower amount of residual ash was observed for some of the prepared resins than for PG. The Vickers hardness and flexural strength values of all experimental resins were lower than those of PG. The volumetric polymerization shrinkage of all the experimental resins based on PiBMA was lower than that of PG. These results suggest that acrylic light-curing resin materials based on PiBMA may be useful for patterning and indexing during soldering.

UNASSIGNED: Recently, a group of universal single-shade resin-based composites (RBCs) has been developed to simplify the process of shade selection. Excellent mechanical and physical properties are crucial for the ultimate success and clinical longevity of restorations. Therefore, evaluating the properties of the single-shaded RBCs is imperative. This study aimed to determine the flexural strength (FS) and degree of conversion (DC) of universal single-shade RBCs.
UNASSIGNED: In this study, four commercial RBCs were used; three universal single-shade RBCs; Omnichroma (OC), Charisma® Diamond ONE (CD), and Vittra APS Unique (VU), and a conventional nanohybrid composite Filtek™ Z250 XT (FT) which was used as a control. Sixty composite beams and 40 composite discs were used for FS and DC, respectively. A universal test machine with a three-point bending test was used to measure the FS, whereas the DC was measured using a Fourier-transform infrared spectrometer (FTIR). Three fractured specimens from each resin composite group were qualitatively analyzed using scanning electron microscopy.
UNASSIGNED: ANOVA was used to compare the mean values of FS and DC among the four RBCs (OC, CD, VU, and FT). Highly significant differences were observed in the mean FS and DC values (F = 673.043, p < 0.001 and F (=782.4, p < 0.0001), respectively. The highest FS was observed in the CD group, followed by FT and VU groups; the lowest value was observed in the OC group. In addition, a statistically significant difference was identified in DC values. The highest DC value was observed in VU, followed by OC and CD, and the lowest DC value was observed in FT.
UNASSIGNED: Universal single-shade RBCs demonstrated a good FS, except for OC, which exhibited a significantly low FS. The DC of the universal single-shade RBCs was higher than that of the conventional nanohybrid composite restorative material.

OBJECTIVE: Occurrence of denture stomatitis and prosthesis breakage are common problems faced by elderly people wearing removable dentures. To overcome this, several attempts are made to improve the denture material by addition of antimicrobials without compromising original properties. The aim of the study was to evaluate flexural strength and microhardness of self-cured polymethyl methacrylate (PMMA) denture base resin after addition of Vaccinium macrocarpon (commonly called as cranberry), extract as antimicrobial, at varying proportions.
METHODS: Experimental in vitro study.
METHODS: Frozen cranberry fruits were subjected to extraction process in the presence of aqueous solvents. Lyophilized extract was added in proportions of 0, 0.5, 1.0, 1.5, and 2.0 dry wt/wt % into polymer of self-cure PMMA denture base resin. Based on cranberry inclusion, the study comprised one control (0%) and four test groups (0.5%-2%) with total of 100 samples. A three-point bending test for flexural strength was done for fifty study samples (n = 10). Surface of fractured samples was analyzed using a scanning electron microscope (SEM). Microhardness was determined using Vickers hardness test.
METHODS: One-way statistical ANOVA test was done to find the difference between groups, followed by Tukey\'s post hoc test for multiple pairwise comparison.
RESULTS: Flexural strength ranged from 66.80 to 69.28 MPa, and a statistically insignificant difference was observed between groups (P > 0.05). SEM evaluation showed uniformly dispersed strands of cranberry extract in PMMA matrix. With higher concentration, less voids were seen. Vickers microhardness value significantly decreased from 15.96 in the control group to 14.57 with 2% cranberry addition (P < 0.05).
CONCLUSIONS: Incorporation of cranberry extract into self-cure PMMA denture base resin, up to 2 dry wt %, did not decline the flexural strength. However, there was a significant decrease in Vickers microhardness values when compared against the control group (0% cranberry inclusion).

OBJECTIVE: Evaluate the efficacy of denture cleaners on the adhesion of Candida albicans and their effects on the surface, optical, and mechanical properties of resins for conventional, milled, and 3D-printed denture bases.
METHODS: A total of 240 resin samples were made, 120 for testing Candida albicans adhesion, optical stabilities (ΔE00), roughness (Ra), hydrophilicity (°), surface free energy (Owens-Wendt) and 120 samples for testing Candida albicans adhesion, surface microhardness (Knoop), flexural strength and modulus of elasticity in a three-point test, in which they were divided into 3 groups of denture resin (n = 40) and subdivided into 5 cleaners of dentures (n = 8). Data were evaluated by two-way ANOVA and Tukey\'s test for multiple comparisons (α = 0.05).
RESULTS: Denture cleaners with an alkaline solution and dilute acid composition were those that showed the greatest effectiveness in reducing Candida albicans (P < 0.001), however 1% NaOCl significantly affected the properties of the resins (P < 0.05). Denture 3D-printed showed that the surface microhardness was significantly lower for all cleansers (P < 0.05).
CONCLUSIONS: Listerine demonstrated superior efficacy in reducing Candida albicans with minimal effect on denture properties, whereas 1% NaOCl had a significant negative impact on the properties. The mechanical properties were significantly lower in 3D-printed resin than in other resins for all denture cleansers.
CONCLUSIONS: Denture base materials are being sold to adapt to the CAD/CAM system, increasing the number of users of dentures manufactured with this system. Despite this, there is little investigation into denture cleaners regarding the adhesion capacity of microorganisms and the optical, surface and mechanical properties of dentures, thus requiring further investigation.

BACKGROUND: In dentistry, glass-ionomer cements (GICs) are extensively used for a range of applications. The unique properties of GIC include fluoride ion release and recharge, chemical bonding to the tooth\'s hard tissues, biocompatibility, a thermal expansion coefficient like that of enamel and dentin, and acceptable aesthetics. Their high solubility and poor mechanical qualities are among their limitations. E-glass fibers are generally utilized to reinforce the polymer matrix and are identified by their higher silica content.
OBJECTIVE: The purpose of the study was to assess the impact of adding (10 wt% and 20 wt%) silane-treated E-glass fibers to traditional GIC on its mechanical properties (compressive strength, flexural strength, and surface hardness) and solubility.
METHODS: The characterization of the E-glass fiber fillers was achieved by XRF, SEM, and PSD. The specimens were prepared by adding the E-glass fiber fillers to the traditional GIC at 10% and 20% by weight, forming two innovative groups, and compared with the unmodified GIC (control group). The physical properties (film thickness and initial setting time) were examined to confirm operability after mixing. The evaluation of the reinforced GIC was performed by assessing the compressive strength, flexural strength, hardness, and solubility (n = 10 specimens per test). A one-way ANOVA and Tukey tests were performed for statistical analysis (p ≤ 0.05).
RESULTS: The traditional GIC showed the least compressive strength, flexural strength, hardness, and highest solubility. While the GIC reinforced with 20 wt% E-glass fibers showed the highest compressive strength, flexural strength, hardness, and least solubility. Meanwhile, GIC reinforced with 10 wt% showed intermediate results (P ≤ 0.05).
CONCLUSIONS: Using 20 wt% E-glass fiber as a filler with the traditional GIC provides a strengthening effect and reduced solubility.

This study aimed to evaluate the flexural strength (FS), surface wear, and optical properties of 3D-printed dental resins subjected to different post-printing conditions. A total of 240 specimens (2 × 2 × 25 mm³) were 3D-printed using resin materials for permanent (VaresoSmile Crown Plus) VSC and temporary (VaresoSmile Temp) VST restorations. Specimens underwent five post-printing conditions: no post-printing cure; post-cured in a Form Cure curing unit; Visio Beta Vacuum; Ivoclar Targis; or heat-cured (150 °C) for 30 min. Each group of specimens (n = 24) was tested either directly after post-curing, after 24 h of dry storage, or following hydrothermal accelerated aging in boiling water for 16 h. The three-point bending test was used to evaluate the FS. The two-body wear test was performed on 50 disc-shaped specimens (n = 5/group). Surface gloss and translucency were measured for permanent VSC specimens (n = 5/group). SEM/EDS and statistical analyses were performed. The Form Cure device yielded the highest FS and lowest wear depth (p < 0.05). Hydrothermal aging significantly reduced FS. There were no statistical differences in FS and wear values between materials subjected to same post-printing conditions. VSC groups exhibited similar optical properties across different post-printing treatments. Post-printing treatment conditions had a significant impact on the FS and wear of the 3D-printed resin, while optical properties remained unaffected.

This paper shows the three-point bending strength analysis of a composite material consisting of polyamide doped with chopped carbon fiber and reinforced with continuous carbon fiber produced by means of the material extrusion (MEX) additive manufacturing technique. For a comparison, two types of specimens were produced: unreinforced and continuous fiber-reinforced (CFR) with the use of carbon fiber. The specimens were fabricated in two orientations that assure the highest strength properties. Strength analysis was supplemented by additional digital image correlation (DIC) analysis that allowed for the identification of regions with maximum strain within the specimens. The utilization of an optical microscope enabled a fractographic examination of the fracture surfaces of the specimens. The results of this study demonstrated a beneficial effect of continuous carbon fiber reinforcement on both the stiffness and strength of the material, with an increase in flexural strength from 77.34 MPa for the unreinforced composite to 147.03 MPa for the composite reinforced with continuous carbon fiber.