Improvement of Biological Effects of Root-Filling Materials for Primary Teeth by Incorporating Sodium Iodide.

Therapeutic iodoform (CHI3) is commonly used as a root-filling material for primary teeth; however, the side effects of iodoform-containing materials, including early root resorption, have been reported. To overcome this problem, a water-soluble iodide (NaI)-incorporated root-filling material was developed. Calcium hydroxide, silicone oil, and NaI were incorporated in different weight proportions (30:30:X), and the resulting material was denoted DX (D5~D30), indicating the NaI content. As a control, iodoform instead of NaI was incorporated at a ratio of 30:30:30, and the material was denoted I30. The physicochemical (flow, film thickness, radiopacity, viscosity, water absorption, solubility, and ion releases) and biological (cytotoxicity, TRAP, ARS, and analysis of osteoclastic markers) properties were determined. The amount of iodine, sodium, and calcium ion releases and the pH were higher in D30 than I30, and the highest level of unknown extracted molecules was detected in I30. In the cell viability test, all groups except 100% D30 showed no cytotoxicity. In the 50% nontoxic extract, D30 showed decreased osteoclast formation compared with I30. In summary, NaI-incorporated materials showed adequate physicochemical properties and low osteoclast formation compared to their iodoform-counterpart. Thus, NaI-incorporated materials may be used as a substitute for iodoform-counterparts in root-filling materials after further (pre)clinical investigation.

Cytotoxicity and proinflammatory cytokine expression induced by interim resin materials in primary cultured human dental pulp cells.

STATEMENT OF PROBLEM: Acrylic resin materials for interim restoration may adversely affect pulp tissue during the polymerization phase. PURPOSE: The purpose of this in vitro study was to determine the cytotoxic and proinflammatory cytokine production effects induced by interim resin materials in primary cultured human dental pulp cells (hDPCs). MATERIAL AND METHODS: Five interim resin materials were evaluated: 3 types of chemically activated products, 1 light-activated product, and 1 computer-aided design and computer-aided manufacturing (CAD-CAM) product. After obtaining eluates from interim resin materials that either were in the process of polymerizing or were already polymerized, these extracts were cocultured with hDPCs under serially diluted conditions (50%, 25%, 12.5%, 6.25%, and 3.125%) for 24 hours with positive (1% phenol) and negative (distilled water) controls. A cell viability assay with tetrazolium was used to evaluate toxic effects on the cells, and images of both live and dead cells were captured using confocal microscopy. Proinflammatory cytokine levels were measured using cytokine antibody arrays. All experiments were independently repeated 3 times, and data were analyzed using 1-way ANOVA and post hoc Tukey honest significant differences test (α=.05). RESULTS: Cell viabilities less than 70% were observed from the eluates of the 3 chemically activated products under the 50% conditions. Among the chemically activated products, the adverse effects were significantly greater with eluates derived from the polymerizing phase compared than those that had already polymerized, as shown by confocal microscopy images of live and dead cells. However, the light-activated and CAD-CAM-fabricated products did not adversely affect the hDPCs. Significantly increased levels of proinflammatory cytokines were not detected in 12.5% of extract from polymerizing compared with distilled water control. CONCLUSIONS: The 50% eluates derived from chemically activated interim resin during the polymerizing phase were cytotoxic to hDPCs and may adversely affect pulp tissue. Recommendations such as excess washing are necessary during fabrication.

Technique for fabricating individualized dentures with a gingiva-shade composite resin.

More natural dental esthetics have been sought by patients who wear conventional complete or partial dentures. Recently, gingiva-shade composite resins (GSCRs) have become available for replicating soft tissue for both fixed and removable prostheses. The technique presented is for fabricating individualized complete dentures. First the acrylic resin is mixed with a coloring agent and processed to modify the base shade of the denture. GSCRs are light polymerized onto a prepared space on the buccal surfaces of denture base to replicate the appearance of gingival tissues including blood vessels. The technique provides an outstanding natural, gingiva-like, appearance and allows complete dentures to harmonize with the individual patient's surrounding oral tissues.

Inclusion of phytogenic blends in different nutrient density diets of meat-type ducks.

A total of 160 1-day-old ducklings (average initial body weight of 53 g), were used in a 42-d feeding trial to evaluate the effects of reducing nutrient density of diets, and supplementing the diets with a phytogenic blend (quillaja, anise, and thyme) on their growth, carcass quality, and nutrient digestibility. After checking body weight on d 1, the birds were sorted into pens with 5 birds/pen and 8 pens/treatment. The treatments were: T1, Basal diet; T2, T1+150 ppm phytogenic blend; T3, T1-(1% CP, 0.04% Lys, 0.05% Met+Cys, 0.02% Ca, and 0.02% P, and 50 kcal ME); T4, T3+150 ppm phytogenic blend. The results indicated that reducing nutrient density of the diets had an adverse effect (P<0.05) on body weight gain (BWG) on d 1 to 21, d 21 to 42, and the overall experimental period. Supplementing the diets with the phytogenic blend improved (P<0.05) BWG and feed conversion ratio (FCR) on d 21 to 42 and the overall experimental period. Feed intake was not affected by treatments. Low nutrient density diets increased (P<0.05) the cooking loss percentage of breast meat. Supplementing the diets with the phytogenic blend decreased (P<0.05) the lightness of breast meat. The percentage of drip loss was influenced (P<0.05) by nutrient density and the phytogenic blend on d 1 and d 7. The relative weights of breast meat, abdominal fat, gizzard, liver, spleen, and bursa of Fabricius, pH, and TBARS values were not affected by the treatments. The digestibility of dry matter, energy, nitrogen, ADF, and NDF was decreased (P<0.05) by reducing nutrients density of the diets, but addition of the phytogenic blend alleviated (P<0.05) the negative effects of lowering the nutrient density. The results indicated that the ducks fed high nutrient density diets supplemented with the phytogenic blend showed higher BWG and nutrient digestibility and lower FCR, cooking loss, drip loss, and TBARS value, without any negative effect on meat quality and relative organs weights.

Strength-limiting damage and defects of dental CAD/CAM full-contour zirconia ceramics.

OBJECTIVE: This study aimed to compare the four-point flexural strength of CAM-milled and sintered (as-sintered, AS) specimens with those of high-polished (HP) specimens using chairside polishing systems to simulate clinical surface conditions. METHODS: Seven full-contour zirconia CAM/CAM blanks with various yttria contents (3, 4, 5 mol%) including three high-translucent groups (5Y) were selected to prepare flexural specimens. The bend bar specimens (2.0 × 4.0 × 25.0 mm3) were fabricated by using STL file and dental CAM machine with the respective zirconia blanks (98 mm ϕ and 10-14 mm in height). Twelve bar specimens were machined from one zirconia puck and a total of 24 specimens were prepared from each group. The pre-sintered bar specimens were sintered by using a dental zirconia furnace at 1530-1550 °C for 2 h according to the instructions. All sintered specimens were divided into two groups: as-sintered (AS) group and high-polished (HP) groups (n = 12). HP groups were subjected to polishing one surface of specimens using a three-step polishing system and finally finished with diamond polishing. After cleaning and drying, the flexural strength of all specimens was determined by a fully articulating four-point flexure fixture consisting of a 1/4-point test configuration with an inner/outer span of 10/20 mm. Statistical differences between AS and HP groups were conducted with Weibull analysis. The fractured surfaces of zirconia specimens were observed using a field emission SEM and EDS to detect failure origins. RESULTS: The mean AS flexural strength values were significantly lower than those of HP counterparts. However, Weibull moduli expressing the reliability of HP groups were generally decreased although not significantly in comparison to their AS. The fracture of the AS specimens mostly originated from extrinsic CAM-milling defects, while the HP specimens were fractured from intrinsic subsurface or volume defects including pores, large grain clusters, inclusions, and corner-located critical flaws. Two high-translucent (5Y) zirconia groups were not affected in their strength and reliability after polishing, whereas one 5Y zirconia significantly increased its strength but significantly lowered its reliability. SIGNIFICANCE: The extrinsic and intrinsic strength-limiting defects should be considered in evaluating the flexural strength and reliability of dental CAD/CAM zirconia ceramics for full-contour restorations. For the materials tested in this study, more optimized processing of blanks and milling protocols of pre-sintered zirconia blanks should be developed including post-sintering surface finishing to reduce the flaw population regulating strength and reliability which will affect the survivability of dental zirconia prostheses.

Mechanophysical and Anti-Adhesive Properties of a Nanoclay-Containing PMMA Denture Resin.

Poly(methyl methacrylate) (PMMA) is commonly used for dental dentures, but it has the drawback of promoting oral health risks due to oral bacterial adhesion. Recently, various nanoparticles have been incorporated into PMMA to tackle these issues. This study aims to investigate the mechanophysical and antimicrobial adhesive properties of a denture resin by incorporating of nanoclay into PMMA. Specimens were prepared by adding 0, 1, 2, and 4 wt % surface-modified nanoclay (Sigma) to self-polymerizing PMMA denture resin. These specimens were then evaluated using FTIR, TGA/DTG, and FE-SEM with EDS. Various mechanical and surface physical properties, including nanoindentation, were measured and compared with those of pure PMMA. Antiadhesion experiments were conducted by applying a Candida albicans (ATCC 11006) suspension to the surface of the specimens. The antiadhesion activity of C. albicans was confirmed through a yeast-wall component (mannan) and mRNA-seq analysis. The bulk mechanical properties of nanoclay-PMMA composites were decreased compared to those of pure PMMA, while the flexural strength and modulus met the ISO 20795-1 requirement. However, there were no significant differences in the nanoindentation hardness and elastic modulus. The surface energy revealed a significant decrease at 4 wt % nanoclay-PMMA. The antiadhesion effect of Candida albicans was evident along with nanoclay content in the nanocomposites and confirmed by the reduced attachment of mannan on nanoclay-PMMA composites. mRNA-seq analysis supported overall transcriptome changes in altering attachment and metabolism behaviors on the surface. The nanoclay-PMMA materials showed a lower surface energy as the content increased, leading to an antiadhesion effect against Candida albicans. These findings indicate that incorporating nanoclay into PMMA surfaces could be a valuable strategy for preventing the fungal biofilm formation of denture base materials.

Hierarchically porous surface of HA-sandblasted Ti implant screw using the plasma electrolytic oxidation: Physical characterization and biological responses.

The surface topological features of bioimplants are among the key indicators for bone tissue replacement because they directly affect cell morphology, adhesion, proliferation, and differentiation. In this study, we investigated the physical, electrochemical, and biological responses of sandblasted titanium (SB-Ti) surfaces with pore geometries fabricated using a plasma electrolytic oxidation (PEO) process. The PEO treatment was conducted at an applied voltage of 280 V in a solution bath consisting of 0.15 mol L-1 calcium acetate monohydrate and 0.02 mol L-1 calcium glycerophosphate for 3 min. The surface chemistry, wettability, mechanical properties and corrosion behavior of PEO-treated sandblasted Ti implants using hydroxyapatite particles (PEO-SB-Ti) were improved with the distribution of calcium phosphorous porous oxide layers, and showed a homogeneous and hierarchically porous surface with clusters of nanopores in a bath containing calcium acetate monohydrate and calcium glycerophosphate. To demonstrate the efficacy of PEO-SB-Ti, we investigated whether the implant affects biological responses. The proposed PEO-SB-Ti were evaluated with the aim of obtaining a multifunctional bone replacement model that could efficiently induce osteogenic differentiation as well as antibacterial activities. These physical and biological responses suggest that the PEO-SB-Ti may have a great potential for use an artificial bone replacement compared to that of the controls.

Evaluation of Human Platelet Lysate as an Alternative to Fetal Bovine Serum for Potential Clinical Applications of Stem Cells from Human Exfoliated Deciduous Teeth.

In recent years, there has been a surge in demand for and research focus on cell therapy, driven by the tissue-regenerative and disease-treating potentials of stem cells. Among the candidates, dental pulp stem cells (DPSCs) or human exfoliated deciduous teeth (SHED) have garnered significant attention due to their easy accessibility (non-invasive), multi-lineage differentiation capability (especially neurogenesis), and low immunogenicity. Utilizing these stem cells for clinical purposes requires careful culture techniques such as excluding animal-derived supplements. Human platelet lysate (hPL) has emerged as a safer alternative to fetal bovine serum (FBS) for cell culture. In our study, we assessed the impact of hPL as a growth factor supplement for culture medium, also conducting a characterization of SHED cultured in hPL-supplemented medium (hPL-SHED). The results showed that hPL has effects in enhancing cell proliferation and migration and increasing cell survivability in oxidative stress conditions induced by H2O2. The morphology of hPL-SHED exhibited reduced size and elongation, with a differentiation capacity comparable to or even exceeding that of SHED cultured in a medium supplemented with fetal bovine serum (FBS-SHED). Moreover, no evidence of chromosome abnormalities or tumor formation was detected. In conclusion, hPL-SHED emerges as a promising candidate for cell therapy, exhibiting considerable potential for clinical investigation.

Development of an Injectable Biphasic Hyaluronic Acid-Based Hydrogel With Stress Relaxation Properties for Cartilage Regeneration.

Biomimetic stress-relaxing hydrogels with reversible crosslinks attract significant attention for stem cell tissue regeneration compared with elastic hydrogels. However, stress-relaxing hyaluronic acid (HA)-based hydrogels fabricated using conventional technologies lack stability, biocompatibility, and mechanical tunability. Here, it is aimed to address these challenges by incorporating calcium or phosphate components into the HA backbone, which allows reversible crosslinking of HA with alginate to form interpenetrating networks, offering stability and mechanical tunability for mimicking cartilage. Diverse stress-relaxing hydrogels (τ1/2; SR50, 60-2000 s) are successfully prepared at ≈3 kPa stiffness with self-healing and shear-thinning abilities, favoring hydrogel injection. In vitro cell experiments with RNA sequencing analysis demonstrate that hydrogels tune chondrogenesis in a biphasic manner (hyaline or calcified) depending on the stress-relaxation properties and phosphate components. In vivo studies confirm the potential for biphasic chondrogenesis. These results indicate that the proposed stress-relaxing HA-based hydrogel with biphasic chondrogenesis (hyaline or calcified) is a promising material for cartilage regeneration.

Cyclic stretch induced epigenetic activation of periodontal ligament cells.

Periodontal ligament (PDL) cells play a crucial role in maintaining periodontal integrity and function by providing cell sources for ligament regeneration. While biophysical stimulation is known to regulate cell behaviors and functions, its impact on epigenetics of PDL cells has not yet been elucidated. Here, we aimed to investigate the cytoskeletal changes, epigenetic modifications, and lineage commitment of PDL cells following the application of stretch stimuli to PDL. PDL cells were subjected to stretching (0.1 Hz, 10 %). Subsequently, changes in focal adhesion, tubulin, and histone modification were observed. The survival ability in inflammatory conditions was also evaluated. Furthermore, using a rat hypo-occlusion model, we verified whether these phenomena are observed in vivo. Stretched PDL cells showed maximal histone 3 acetylation (H3Ace) at 2 h, aligning perpendicularly to the stretch direction. RNA sequencing revealed stretching altered gene sets related to mechanotransduction, histone modification, reactive oxygen species (ROS) metabolism, and differentiation. We further found that anchorage, cell elongation, and actin/microtubule acetylation were highly upregulated with mechanosensitive chromatin remodelers such as H3Ace and histone H3 trimethyl lysine 9 (H3K9me3) adopting euchromatin status. Inhibitor studies showed mechanotransduction-mediated chromatin modification alters PDL cells behaviors. Stretched PDL cells displayed enhanced survival against bacterial toxin (C12-HSL) or ROS (H2O2) attack. Furthermore, cyclic stretch priming enhanced the osteoclast and osteoblast differentiation potential of PDL cells, as evidenced by upregulation of lineage-specific genes. In vivo, PDL cells from normally loaded teeth displayed an elongated morphology and higher levels of H3Ace compared to PDL cells with hypo-occlusion, where mechanical stimulus is removed. Overall, these data strongly link external physical forces to subsequent mechanotransduction and epigenetic changes, impacting gene expression and multiple cellular behaviors, providing important implications in cell biology and tissue regeneration.

Materials and extracellular matrix rigidity highlighted in tissue damages and diseases: Implication for biomaterials design and therapeutic targets.

Rigidity (or stiffness) of materials and extracellular matrix has proven to be one of the most significant extracellular physicochemical cues that can control diverse cell behaviors, such as contractility, motility, and spreading, and the resultant pathophysiological phenomena. Many 2D materials engineered with tunable rigidity have enabled researchers to elucidate the roles of matrix biophysical cues in diverse cellular events, including migration, lineage specification, and mechanical memory. Moreover, the recent findings accumulated under 3D environments with viscoelastic and remodeling properties pointed to the importance of dynamically changing rigidity in cell fate control, tissue repair, and disease progression. Thus, here we aim to highlight the works related with material/matrix-rigidity-mediated cell and tissue behaviors, with a brief outlook into the studies on the effects of material/matrix rigidity on cell behaviors in 2D systems, further discussion of the events and considerations in tissue-mimicking 3D conditions, and then examination of the in vivo findings that concern material/matrix rigidity. The current discussion will help understand the material/matrix-rigidity-mediated biological phenomena and further leverage the concepts to find therapeutic targets and to design implantable materials for the treatment of damaged and diseased tissues.

Influence of thermo-mechanical aging on fracture resistance and wear of digitally standardized chairside computer-aided-designed/computer-assisted-manufactured restorations.

OBJECTIVES: To investigate the influence of thermal cycling and mechanical loading (TCML) aging on fracture resistance and wear behavior of various chairside computer-aided-designed/computer-assisted-manufactured (CAD/CAM) premolar crowns cemented on standardized tooth abutments. METHODS: Eighty chairside CAD/CAM crowns were prepared using lithium disilicate (IPS e.max CAD; EM), zirconia-infiltrated lithium silicate (Celtra Duo; CD), polymer-infiltrated ceramic network (Vita Enamic; VE), and resin nanoceramics (Cerasmart; CS) (n = 20). The specimens were divided into two groups (n = 10). In one group, they were subjected to TCML: thermocycling (6000 cycles in distilled water at 5-55 °C) and mechanical loading (50 N for 1.2 × 106 cycles), while in control group they were stored in distilled water (37 °C for 24 h). The fracture load, height loss, and volume wear of the crowns were measured after TCML. Fractography was performed on fractured specimens. Data were analyzed using analysis of variance and multiple comparison tests (α=0.05). RESULTS: The mean fracture loads of EM and CD were significantly higher than those of EC and CS (p<0.05). There was no significant change in the fracture load of any CAD/CAM crowns after TCML (p>0.05). CS exhibited a significantly higher volume wear than the other materials investigated. The wear tracts of all TCML crowns acted as failure origins during the fracture test. CONCLUSIONS: The fracture resistance of glass-ceramic CAD/CAM crowns was significantly higher than that of resin composite crowns. A 5-year TCML aging did not affect the fracture resistance of CAD/CAM crowns investigated. However, TCML treatment produces a larger wear track in CS than in other materials. CLINICAL SIGNIFICANCE: Appropriate chairside CAD/CAM restorative material should be selected for successful clinical practice after considering the fracture and wear resistance of the crowns.

The Effects of Thermocycling on the Physical Properties and Biocompatibilities of Various CAD/CAM Restorative Materials.

The purpose of this study is to evaluate the changes in physical properties and biocompatibilities caused by thermocycling of CAD/CAM restorative materials (lithium disilicate, zirconia reinforced lithium silicate, polymer-infiltrated ceramic network, resin nanoceramic, highly translucent zirconia). A total of 225 specimens were prepared (12.0 × 10.0 × 1.5 mm) and divided into three groups subjected to water storage at 37 °C for 24 h (control group), 10,000 cycles in distilled water at 5-55 °C (first aged group), and 22,000 cycles in distilled water at 5-55 °C (second aged group) [(n= 15, each]). The nanoindentation hardness and Young's modulus (nanoindenter), surface roughness (atomic force microscopy (AFM)), surface texture (scanning electron microscopy (FE-SEM)), elemental concentration (energy dispersive spectroscopy (EDS)) and contact angle were evaluated. The morphology, proliferation and adhesion of cultured human gingival fibroblasts (HGFs) were analyzed. The data were analyzed using one-way ANOVA and Tukey's test (p < 0.05). The results showed that the nanoindentation hardness and Young's modulus were decreased after thermocycling aging. Cell viability and proliferation of the material decreased with aging except for the highly translucent zirconia. Zirconia-reinforced lithium silicate exhibited significantly lower cell viability compared to other materials. The surface roughnesses of all groups increased with aging. Cell viability and Cell adhesion were influenced by various factors, including the surface chemical composition, hydrophilicity, surface roughness, and topography.

Effects of ultraviolet weathering aging on the color stability and biocompatibility of various computer-aided design and computer-aided manufacturing glass-ceramic materials.

OBJECTIVES: This study assessed the changes in color stability and biocompatibility of computer-aided design and computer-aided manufacturing (CAD-CAM) glass-ceramics after ultraviolet weathering (UW) aging. METHODS: A total of 300 plate-shaped specimens (12.0 × 14.0 × 1.5 mm3) were prepared using a leucite-reinforced glass-ceramic (IPS Empress CAD; E), a lithium disilicate (IPS e.max CAD; M), and two zirconia-reinforced lithium silicate (Celtra Duo; C, Vita Suprinity; V) glass-ceramics. Specimens were divided into three groups (n = 25, each), subjected to water storage at 37 °C for 24 h (control group), or UW aging at 150 kJ/m2 (first-aged group) or 300 kJ/m2 (second-aged group). The color stability, mechanical and surface properties, and biocompatibility of the CAD-CAM glass-ceramics were investigated experimentally, followed by statistical analysis. RESULTS: The brightness and redness or greenness were reduced in all groups after aging. After the first aging, V exhibited the largest color change and E exhibited the smallest color change. After the second aging, E exhibited the highest nanoindentation hardness and Young's modulus. The surface roughness was the highest for V after the first aging. Furthermore, the hydrophilicity of the materials increased after aging process. The cell proliferation/viability of human gingival fibroblasts was the highest in E before and after aging. Almost all cells survived for all groups based on a live/dead assay. CONCLUSIONS: Leucite-reinforced glass-ceramic exhibit the highest color stability and biocompatibility after aging. The color stability and biocompatibility of CAD-CAM glass-ceramics depend on the aging process and material type. CLINICAL SIGNIFICANCE: Various CAD-CAM glass-ceramics exhibit adequate color stability after UW aging. The leucite-reinforced glass-ceramics exhibit the highest color stability, cell proliferation, and viability after aging. The color stability, mechanical and surface properties, and biocompatibility of the glass-ceramics depend on the aging process and material type.

Delivery of Induced Neural Stem Cells Through Mechano-Tuned Silk-Collagen Hydrogels for the Recovery of Contused Spinal Cord in Rats.

Neural stem cells (NSC) have tremendous potential for therapeutic regeneration of diseased or traumatized neural tissues, including injured spinal cord. However, transplanted NSC suffer from low cell survival and uncontrolled differentiation, limiting in vivo efficacy. Here, this issue is tackled by delivery through silk-collagen protein hydrogels that are stiffness-matched, stress-relaxing, and shear-thinning. The mechanically-tuned hydrogels protect NSC reprogrammed from fibroblasts (iNSC) initially from injection shear-stress, and enhance long-term survival over 12 weeks. Hydrogel-iNSC treatment alleviates neural inflammation, with reduced inflammatory cells and lesions than NSC-only. The iNSC migrate from the hydrogel into surrounding tissues, secrete up-regulated neurotrophic factors, and differentiate into neural cell subtypes, forming synapses. More serotonergic axons are observed in the lesion cavity, and locomotor functions are improved in hydrogel-iNSC than in iNSC-only. This study highlights the ability of mechanically-tuned protein hydrogels to protect iNSC from the injection stress and severe inflammatory environment, allowing them to differentiate and function to recover the injured spinal cord.

Physicochemical, Biological, and Antibacterial Properties of Four Bioactive Calcium Silicate-Based Cements.

Calcium silicate-based cement (CSC) is a pharmaceutical agent that is widely used in dentistry. This bioactive material is used for vital pulp treatment due to its excellent biocompatibility, sealing ability, and antibacterial activity. Its drawbacks include a long setting time and poor maneuverability. Hence, the clinical properties of CSC have recently been improved to decrease its setting time. Despite the widespread clinical usage of CSC, there is no research comparing recently developed CSCs. Therefore, the purpose of this study is to compare the physicochemical, biological, and antibacterial properties of four commercial CSCs: two powder-liquid mix types (RetroMTA® [RETM]; Endocem® MTA Zr [ECZR]) and two premixed types (Well-Root™ PT [WRPT]; Endocem® MTA premixed [ECPR]). Each sample was prepared using circular Teflon molds, and tests were conducted after 24 h of setting. The premixed CSCs exhibited a more uniform and less rough surface, higher flowability, and lower film thickness than the powder-liquid mix CSCs. In the pH test, all CSCs showed values between 11.5 and 12.5. In the biological test, cells exposed to ECZR at a concentration of 25% showed greater cell viability, but none of the samples showed a significant difference at low concentration (p > 0.05). Alkaline phosphatase staining revealed that cells exposed to ECZR underwent more odontoblast differentiation than the cells exposed to the other materials; however, no significant difference was observed at a concentration of 12.5% (p > 0.05). In the antibacterial test, the premixed CSCs showed better results than the powder-liquid mix CSCs, and ECPR yielded the best results, followed by WRPT. In conclusion, the premixed CSCs showed improved physical properties, and of the premixed types, ECPR exhibited the highest antibacterial properties. For biological properties, none of these materials showed significant differences at 12.5% dilution. Therefore, ECPR may be a promising material with high antibacterial activity among the four CSCs, but further investigation is needed for clinical situations.

Physicochemical, Pre-Clinical, and Biological Evaluation of Viscosity Optimized Sodium Iodide-Incorporated Paste.

This study aimed to investigate the impact of different viscosities of silicone oil on the physicochemical, pre-clinical usability, and biological properties of a sodium iodide paste. Six different paste groups were created by mixing therapeutic molecules, sodium iodide (D30) and iodoform (I30), with calcium hydroxide and one of the three different viscosities of silicone oil (high (H), medium (M), and low (L)). The study evaluated the performance of these groups, including I30H, I30M, I30L, D30H, D30M, and D30L, using multiple parameters such as flow, film thickness, pH, viscosity, and injectability, with statistical analysis (p < 0.05). Remarkably, the D30L group demonstrated superior outcomes compared to the conventional iodoform counterpart, including a significant reduction in osteoclast formation, as examined through TRAP, c-FOS, NFATc1, and Cathepsin K (p < 0.05). Additionally, mRNA sequencing showed that the I30L group exhibited increased expression of inflammatory genes with upregulated cytokines compared to the D30L group. These findings suggest that the optimized viscosity of the sodium iodide paste (D30L) may lead to clinically favorable outcomes, such as slower root resorption, when used in primary teeth. Overall, the results of this study suggest that the D30L group shows the most satisfactory outcomes, which may be a promising root-filling material that could replace conventional iodoform-based pastes.

Ranking and selection of dental restorative composite materials using FAHP-FTOPSIS technique: An application of multi criteria decision making technique.

In the present investigation, the optimal formulations of dental restorative composite materials were designed using hybrid FAHP (Fuzzy Analytic Hierarchy Process)-FTOPSIS (Fuzzy Technique for Order of Preference by Similarity to Ideal Solution) methodology of statistical techniques. The dental composite was composed of an organic matrix and different types and ratios of inorganic filler. The various performance defining attributes (PDAs) such as compressive strength, flexural strength, depth of cure, and polymerization shrinkage were taken into account to evaluate the optimal formulation of dental restorative composite materials. The weight criteria of PDAs was evaluated by the FAHP; PDA-1 (0.084, 0.083, 0.083), PDA-2 (0.084, 0.095, 0.102), PDA-3 (0.079, 0.097, 0.110), PDA-4 (0.084, 0.108, 0.124), PDA-5 (0.084, 0.091, 0.093), PDA-6 (0.062, 0.083, 0.113), PDA-7 (0.070, 0.081, 0.098), PDA-8 (0.058, 0.071, 0.090), PDA-9 (0.073, 0.074, 0.092), PDA-10 (0.070, 0.076, 0.089), and PDA-11 (0.157, 0.135, 0.098), respectively. The FTOPSIS is used to determine the rank of alternatives as DHZ4 > DHZ8 > DHZ0 > DHZ6 > DHZ2. The Hybrid FAHP-FTOPSIS technique was significant in ranking analysis of different dental restorative composite materials under conflicting PDAs.

Investigating the Effects of Conditioned Media from Stem Cells of Human Exfoliated Deciduous Teeth on Dental Pulp Stem Cells.

Pulp regeneration has recently attracted interest in modern dentistry. However, the success ratio of pulp regeneration is low due to the compromising potential of stem cells, such as their survival, migration, and odontoblastic differentiation. Stem cells from human exfoliated deciduous teeth (SHED) have been considered a promising tool for regenerative therapy due to their ability to secrete multiple factors that are essential for tissue regeneration, which is achieved by minimally invasive procedures with fewer ethical or legal concerns than those of other procedures. The aim of this study is to investigate the potency of SHED-derived conditioned media (SHED CM) on dental pulp stem cells (DPSCs), a major type of mesenchymal stem cells for dental pulp regeneration. Our results show the promotive efficiency of SHED CM on the proliferation, survival rate, and migration of DPSCs in a dose-dependent manner. Upregulation of odontoblast/osteogenic-related marker genes, such as ALP, DSPP, DMP1, OCN, and RUNX2, and enhanced mineral deposition of impaired DPSCs are also observed in the presence of SHED CM. The analysis of SHED CM found that a variety of cytokines and growth factors have positive effects on cell proliferation, migration, anti-apoptosis, and odontoblast/osteogenic differentiation. These findings suggest that SHED CM could provide some benefits to DPSCs in pulp regeneration.

Photocatalytic effect-assisted antimicrobial activities of acrylic resin incorporating zinc oxide nanoflakes.

To overcome the deficiency of the antimicrobial effect of polymer, zinc oxide nanoparticles have been widely utilized as advanced nanofillers due to their antimicrobial and photocatalytic activity. However, the underlying antimicrobial mechanism has not been fully understood apart from topological and physical characteristics. In this study, we prepared zinc oxide nanoparticles-based acrylic resin to explore its antimicrobial mechanism under controlled mechanophysical conditions by using silane-treated zinc oxide nanoflakes (S-ZnNFs). S-ZnNFs incorporated acrylic resin (poly(methyl methacrylate), PMMA) composites up to 2 wt% were selected based on comparable mechanophysical properties (e.g., roughness, wettability, strength and hardness), possibly affecting antimicrobial properties beyond the zinc oxide nanoparticle effect, to bare PMMA. Antimicrobial adhesion results were still observed in 2 wt% S-ZnNFs incorporated PMMA using Candida albicans (C. albicans), one of the fungal infection species. In order to confirm the antimicrobial effects by photocatalysis, we pre-exposed the UV light on 2 wt% S-ZnNF composites before cell seeding, revealing synergetic antimicrobial effect via additional reactive oxygen species (ROS) generation to C. albicans over zinc oxide nanoparticle-induced one. RNA-seq analysis revealed distinguished cellular responses between zinc oxide nanoparticles and UV-mediated photocatalytic effect, but both linked to generation of intracellular ROS. Thus, the above data suggest that induction of high intracellular ROS of C. albicans was the main antimicrobial mechanism under controlled mechanophysical parameters and synergetic ROS accumulation can be induced by photocatalysis, recapitulating a promising use of a S-ZnNFs or possibly zinc oxide nanoparticles as intracellular-ROS-generating antimicrobial nanofillers in acrylic composite for biomedical applications.