Effects of various beverages on characteristics of provisional restoration materials.

OBJECTIVE: To investigate the effect of common beverages on four currently used provisional restoration materials: Protemp®4, Integrity®, polymethyl methacrylate (PMMA) block, and acrylic resin. Flowable resin composite is included as a control group. MATERIALS AND METHODS: Each material was formed into disks of 10-mm diameter and 4-mm thickness (N = 40) by loading the material into acrylic molds. The exposed surface in the mold was covered using a glass slide to prevent an oxygen inhibition layer, and polymerization then proceeded. The solidified disks were placed in distilled water for 24 h. These samples (n = 8) were then immersed for 14 days in one of four different beverages: water, orange juice, cola, and coffee. Changes in color dimension, hardness, and roughness were observed and then analyzed using two-way repeated analysis of variance. RESULTS: The provisional materials had more obvious changes in all three color dimensions than the flowable resin composite. Integrity showed the biggest changes, followed by acrylic resin and PMMA block, whereas Protemp had the smallest changes. The hardness of all the materials significantly decreased after immersion in any of the beverages for 14 days. There were no changes in surface roughness when the materials were immersed in distilled water. The surface roughness of the PMMA block significantly decreased in orange juice whereas that of Integrity and acrylic resin significantly increased in cola. CONCLUSION: Different kinds of provisional materials had different degrees of staining due to their composition. Moisture had a significant influence on the hardness of materials, and the acidity of cola significantly roughened the surface of the provisional materials.

Assessing the effect of Artemisia sieberi extracts on surface roughness and candida growth of digitally processed denture acrylic materials.

BACKGROUND: Denture stomatitis, frequently encountered, is generally addressed symptomatically, with limited exploration of preventive approaches involving antifungal medicinal plants. OBJECTIVE: This study assessed the impact of Artemisia sieberi extracts on the candida growth of conventional and digitally processed acrylic materials. METHOD: Thirty acrylic resin discs (3 mm thickness × 10 mm diameter) were prepared by conventional or CAD/CAM technology (milling and 3D printing). The resin discs were exposed to simulated brushing, thermocycling, and immersion in Artemisia sieberi extract for 8 hours. The surface roughness of the discs was assessed at baseline and after immersion in Artemisia sieberi extract. Candida growth was quantified through colony-forming units (CFU/mL). Data was analyzed using SPSS v.22 (α⩽ 0.05). RESULTS: Irrespective of the material type, the post-immersion surface roughness was significantly higher compared to pre-immersion values (p< 0.05). Candida growth was significantly higher in conventional acrylic materials than digitally fabricated acrylics (p< 0.05). At × 3, Ra and CFU were found to be moderately positive and non-significantly correlated (R= 0.664, p= 0.149). At × 4, Ra and CFU were found to be weak positive and non-significantly correlated (R= 0.344, p= 0.503). CONCLUSION: Artemisia sieberi extracts had a notable impact on digitally fabricated denture acrylics, reducing candida albicans growth compared to conventional heat-cured acrylic. This suggests a potential role for these extracts in improving denture hygiene and preventing denture stomatitis, particularly in the context of digitally fabricated dentures.

Antimicrobial activity of essential oils against biofilms formed in dental acrylic resin: a systematic review of in vitro studies.

This study aimed to answer the question formulated according to the PICO strategy: 'Which essential oils show antimicrobial activity against biofilms formed on dental acrylic resin?' composed by population (dental acrylic resin), intervention (application of essential oils), comparison (denture cleansers, antifungal drugs, chlorhexidine, and oral mouthwashes), and outcome (antibiofilm activity). In vitro experimental studies evaluating the activity of EOs on biofilm formed on acrylic resin were included. PRISMA guidelines were followed, and the search was performed in the PubMed, Science Direct, Embase, and Lilacs databases and in the gray literature using Google Scholar and ProQuest in December 2023. A manual search of the reference lists of the included primary studies was performed. Of the 1467 articles identified, 37 were selected for full-text reading and 12 were included. Twelve EOs were evaluated, of which 11 showed activity against Candida spp., 3 against Staphylococcus aureus, and 1 against Pseudomonas aeruginosa. The EOs of Cymbopogon citratus, Cinnamomum zeylanicum, and Cymbopogon nardus showed higher action than chlorhexidine, C. nardus higher than Listerine, C. citratus higher than nystatin, and Melaleuca alternifolia higher than fluconazole and nystatin. However, chlorhexidine was more effective than Lippia sidoides and Salvia officinalis, sodium hypochlorite was more effective than L. sidoides, nystatin was more effective than Zingiber officinale, Amphotericin B more effective than Eucalyptus globulus and M. alternifolia. In conclusion, the EOs of C. zeylanicum, C. citratus, C. nardus, and M. alternifolia showed antimicrobial activity to reduce biofilm on dental acrylic resin.

Evaluating the color stability of temporary crowns fabricated by 3-dimensional printing and manual methods.

This in vitro study aimed to compare the color stability of temporary crowns fabricated by 3-dimensional (3D) printing with that of crowns fabricated with 2 manual methods. An impression was made of a prepared central incisor, from which 90 dies were fabricated. The dies were randomly assigned to 3 groups (n = 30) based on crown fabrication method: 3D printing, automix bis-acryl resin, or powder-and-liquid polymethyl methacrylate. All specimens were immersed in a coffee, soft drink, or distilled water solution for 1 week (n = 10 per subgroup). Color change was measured using a spectrophotometer and the International Commission on Illumination's CIE L*a*b* method, and the values were converted to the National Bureau of Standards (NBS) index for assessment and comparison. When color change was assessed according to fabrication method, the highest (mean [SD]) ΔE* value was reported for the automix specimens (3.39 [2.86]), and the lowest was recorded for the powder-and-liquid specimens (2.05 [2.33]) (P < 0.05; Kruskal-Wallis test). The difference between ΔE* values of the 3D printing group (2.46 [1.75]) and the powder-and-liquid group was not statistically significant. When color change was assessed according to the immersion solution, the coffee solution showed a significantly higher (mean [SD]) ΔE* value (5.04 [2.67]) than the soft drink (1.43 [0.92]) and distilled water (3.41 [7.93]) solutions (P < 0.05; Kruskal-Wallis test). The color changes associated with the 3 methods were statistically equal in terms of the NBS index ranges, most frequently falling in the range of very minor to acceptable change. The powder-and-liquid method seems to be most suitable for fabricating temporary prostheses for long-term use.

Pharmacokinetic Study of Ultrasmall Superparamagnetic Iron Oxide Nanoparticles HY-088 in Rats.

BACKGROUND AND OBJECTIVE: HY-088 injection is an ultrasmall superparamagnetic iron oxide nanoparticle (USPIOs) composed of iron oxide crystals coated with polyacrylic acid (PAA) on the surface. The purpose of this study was to investigate the pharmacokinetics, tissue distribution, and mass balance of HY-088 injection. METHODS: The pharmacokinetics of [55Fe]-HY-088 and [14C]-HY-088 were investigated in 48 SD rats by intravenous injection of 8.5 (low-dose group), 25.5 (medium-dose group), and 85 (high-dose group) mg/100 µCi/kg. Tissue distribution was studied by intravenous injection of 35 mg/100 µCi/kg in 48 SD rats, and its tissue distribution in vivo was obtained by ex vivo tissue assay. At the same time, [14C]-HY-088 was injected intravenously at a dose of 25.5 mg/100 µCi/kg into 16 SD rats, and its tissue distribution in vivo was studied by quantitative whole-body autoradiography. [14C]-HY-088 and [55Fe]-HY-088 were injected intravenously into 24 SD rats at a dose of 35 mg/100 µCi/kg, and their metabolism was observed. RESULTS: In the pharmacokinetic study, [55Fe]-HY-088 reached the maximum observed concentration (Cmax) at 0.08 h in the low- and medium-dose groups of SD rats. [14C]-HY-088 reached Cmax at 0.08 h in the three groups of SD rats. The area under the concentration-time curve (AUC) of [55Fe]-HY-088 and [14C]-HY-088 increased with increasing dose. In the tissue distribution study, [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes of both female and male rats. In the mass balance study conducted over 57 days, the radioactive content of 55Fe from [55Fe]-HY-088 was primarily found in the carcass, accounting for 86.42 ± 4.18% in females and 95.46 ± 6.42% in males. The radioactive recovery rates of [14C]-HY-088 in the urine of female and male rats were 52.99 ± 5.48% and 60.66 ± 2.23%, respectively. CONCLUSIONS: Following single intravenous administration of [55Fe]-HY-088 and [14C]-HY-088 in SD rats, rapid absorption was observed. Both [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes. During metabolism, the radioactivity of [55Fe]-HY-088 is mainly present in the carcass, whereas the 14C-labeled [14C]-HY-088 shell PAA is eliminated from the body mainly through the urine.

Cryptocarya moschata extract decreases single and mixed biofilms on acrylic resins.

OBJECTIVE: This study proposed to assess the effect of Cryptocarya moschata extract on single and mixed biofilms formed on denture base and reline acrylic resin. MATERIALS AND METHODS: Single and mixed biofilms of Candida albicans and Streptococcus mutans were formed on the samples and treated with C. moschata extract; Nystatin solution at 100,000 IU/mL or Penicillin antibiotic solution at 100,000 IU/mL; or PBS solution. Antimicrobial activity was analyzed by counting colony-forming units, metabolism assay, assessment of protein components of the biofilm matrix, and of cell viability using confocal laser scanning microscopy (CLSM). Data were submitted to ANOVA and Tukey's post-test (α = 0.05). RESULTS: Cryptocarya moschata extract reduced cell viability of C. albicans and S. mutans single and mixed biofilms formed on samples. For all types of biofilms in the C. moschata group, there was a log reduction of the biofilm, proven by the Alamar Blue assay. Analyzing the extracellular matrix protein components, groups treated with the extract exhibited a lower level of fluorescence compared to the PBS groups. Reduction in thickness biofilm and viable cells was perceptible in the C. moschata group when assessing through CLSM. CONCLUSION: Cryptocarya moschata extract reduced the single and mixed biofilms of C. albicans and S. mutans on acrylic resins.

Development and characterization of films from Campomanesia xanthocarpa and commercial citrus pectins with different degrees of methyl-esterification.

In this study, pectins from commercial citrus and isolated from gabiroba (Campomanesia xanthocarpa) fruits, were obtained with different degrees of methyl-esterification (DM) and applied in the films. The DM ranged from 0 % to 62.5 % and the gradual de-esterification process was confirmed by mono-dimensional analysis (1H NMR). In order to investigate the influence of DM values in pectin film properties, PCP (DM: 62.5 %); PCP-5 (DM: 37.4 %); PCP-15 (DM: 19.1 %), and a fully de-esterified sample PCP-35 (DM: 0 %) were selected. The functional properties of the films clearly showed that the DM and cross-linking process are necessary to obtain a material with water resistance. Furthermore, pectin isolated from the fruits of gabiroba was purified (GW-Na, DM: 51.9 %) and partially de-esterified (GW-Na-5, DM: 37.1 %). These pectins were used, for the first time, in development of films and the physical and mechanical properties were compared with films made with PCP and PCP-5 samples. GW-Na and GW-Na-5 films presented suitable properties, with reduced solubility reduced (57.1 and 26.2 %), high degree of swelling (2.14 and 2.26), low flexibility (18.05 and 6.11 MPa), respectively. High strength and rigidity (99.36 and 1040.9 MPa), for both films (GW-Na and GW-Na-5) were demonstrated, similar to that obtained by analyzed citrus pectin.

Effect of Tea Tree Oil Addition to Denture Liners Against Candida albicans and Bond Strength to Acrylic Denture Bases.

PURPOSE: To evaluate the effect of adding tea tree oil to denture liners on Candida albicans and bond strength to the acrylic denture base. MATERIALS AND METHODS: Disc-shaped specimens were fabricated from silicone-based resilient liner (Tokuyama, Molloplast), acrylic-based hard liner (GC Reline), and acrylic-based soft liner (Visco-gel). Tea tree oil (TTO) was incorporated into the liners at varying concentrations (0% [control], 2%, 5%, 8%). C albicans were counted by viable colony count, and optical density (OD) was measured with a spectrophotometer. The tensile strength to heat polymerized acrylic denture base was measured in a universal testing machine. The compliance of the data to the distribution of normality was evaluated using the Shapiro Wilk test. Two-way ANOVA, Bonferroni correction, and paired sample t test were performed (α = .05). RESULTS: The addition of TTO into liners provided a significant decrease in the OD values (P < .001). The control groups of the liners presented the highest colony counts, whereas increasing TTO decreased the results (P < .01). According to tensile bond strength test, 8% TTO addition resulted in a significant decrease for Tokuyama (P < .01) and Molloplast liners (P < .05), while 2% TTO resulted in significance for GC Reline (P < .001). CONCLUSIONS: Denture liners containing increasing percentages of TTO presented lower amounts of C albicans colonies and decreased bond strength to the denture bases. When using TTO for its antifungal properties, the amount added should be carefully selected because the tensile bond strength may be affected.

Impact of effervescent denture cleaning tablets on color and surface characteristics of additively manufactured and hand-cast splint materials.

OBJECTIVES: This study is to evaluate the color stability, surface roughness, and hardness of additively manufactured and hand-cast splint materials after a 6-month commercially available denture cleaning tablet immersion simulation. MATERIALS AND METHODS: Disc-shaped additively manufactured and hand-cast auto polymerizing acrylic resin specimens were prepared (N = 40 each). All specimens were exposed to coffee solution totally 2 days. Thereafter, all specimens were immersed into three different effervescent solutions that simulated 6 months of clinical use. The total color change (ΔE*ab), surface roughness (Ra), and Vickers hardness (Vh) were measured at baseline and after immersion protocols. A two-way ANOVA and Bonferroni's post hoc test were used for color change. The dependent t-test and ANOVA were used for roughness and hardness evaluation. RESULTS: Additively manufactured splint materials were more affected by coffee immersion. It was observed that all denture cleaning tablets induced a noticeable alteration in color of the specimens (p < 0.05). Roughness and hardness measurement changes after solution immersions were statistically significant for both splint groups (p < 0.05). On the other hand, distilled water and denture cleaning tablets created similar roughness and hardness measurements at baseline and after immersion. CONCLUSIONS: After 6 months use of tested cleaning tables, the color stability, surface roughness, and hardness of both groups were affected. The evaluation of the surface properties of splint materials could be recommended to the dentists in periodic controls during splint treatments. CLINICAL RELEVANCE: The use effervescent denture cleaning tablets altered the surface characteristics of tested splint materials over time with nonsignificant difference between each other. After 6 months, awareness should be raised about surface characteristics of splint materials.

Temporary fixed prosthesis materials and beverage colorants: an in vitro study.

The esthetic outcome of temporary prostheses, especially those in the anterior area, is of primary importance. The purpose of this in vitro study was therefore to evaluate the color stability of 3 temporary restorative materials: self-curing (SC) acrylic resin (Tempron); heat-curing acrylic resin (SR Ivocron); and polymethyl methacrylate resin blocks (Telio CAD) machined using computer-aided design/computer-aided manufacturing (CAD/CAM) technology. The heat-curing material was polymerized with either a pressure-curing technique (PT) or a flasking technique (FT). As a result, there were 4 experimental groups: SC, PT, FT, and CAD/CAM. Sixteen specimens were prepared for each group. After polymerization or milling, all specimens were polished using a diamond polishing paste, and 1 specimen from each group was exposed to Fourier-transform infrared (FTIR) and ultraviolet visible (UV-Vis) spectroscopy before immersion. The specimens were exposed to pigmented beverage agents (coffee, cola, turmeric solution, or tea), and the color change was monitored for 4 weeks using FTIR and UV-Vis spectroscopy as well as by macroscopic observation of the specimens (n = 4 per group per immersion period). The PT specimens showed the most significant color change, followed by the SC specimens. A less significant color variation was noted in the FT specimens, and insignificant change was reported in the CAD/CAM group. The solution that had the most significant staining effect was turmeric, and the CAD/CAM resin showed the greatest color stability of the tested materials. Color stability depends on the material used, the polymerization technique, the polishing steps, the pigmentation agent, and the duration of exposure to the agent.

[Preparation and in vitro property evaluation of ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocrystals].

This study aims to improve the solubility and bioavailability of daidzein by preparing the ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocrystals. Specifically, the nanocrystals were prepared with daidzein as a model drug, PEG_(20000), Carbomer_(940), and NaOH as a plasticizer, a gelling agent, and a crosslinking agent, respectively. A two-step method was employed to prepare the ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocystals. First, the insoluble drug daidzein was embedded in ß-cyclodextrin to form inclusion complexes, which were then encapsulated in the PEG_(20000)/Carbomer_(940) nanocrystals. The optimal mass fraction of NaOH was determined as 0.8% by the drug release rate, redispersability, SEM morphology, encapsulation rate, and drug loading. The inclusion status of daidzein nanocrystals was determined by Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TGA), and X-ray diffraction(XRD) analysis to verify the feasibility of the preparation. The prepared nanocrystals showed the average Zeta potential of(-30.77±0.15)mV and(-37.47±0.64)mV and the particle sizes of(333.60±3.81)nm and(544.60±7.66)nm before and after daidzein loading, respectively. The irregular distribution of nanocrystals before and after daidzein loading was observed under SEM. The redispersability experiment showed high dispersion efficiency of the nanocrystals. The in vitro dissolution rate of nanocrystals in intestinal fluid was significantly faster than that of daidzein, and followed the first-order drug release kinetic model. XRD, FTIR, and TGA were employed to determine the polycrystalline properties, drug loading, and thermal stability of the nanocrystals before and after drug loading. The nanocrystals loaded with daidzein demonstrated obvious antibacterial effect. The nanocrystals had more significant inhibitory effects on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa than daidzein because of the improved solubility of daidzein. The prepared nanocrystals can significantly increase the dissolution rate and oral bioavailability of the insoluble drug daidzein.

Anti-fungal efficacy of Miswak Extract (Salvadora Persica) and commercial cleaner against Candida albicans on heat cured polymethylmethacrylate denture base.

AIM: The aim of the study was to compare the antifungal efficacy between commercial cleaner (Corega) and Miswak extract (Salvadora persica) against Candida albicans on heat cured Polymethyl methacrylate (PMMA) acrylic denture base resin. MATERIALS AND METHODS: Forty-eight samples of heat cured PMMA acrylic denture base resin were fabircated in the study. The sterile acrylic resin specimens were immersed in standardized cell suspension of Candida albicans and incubated for 60 min at 370°C for cell adhesion and 2 h at 370°C for biofilm formation. After 24 h biofilm was evaluated by cell viability (CFUs) on SDA and cell counting of Candida albicans under light microscope at 400× magnification. The fungicidal effect of commercial cleaner and Miswak extract on Candida albicans biofilm was then evaluated by colony-forming units on SDA and cell counting under light microscope at 400× magnification. RESULTS: Screening test agar disk-diffusion assay showed mean inhibitory zone of 3 mm for commercial cleaner as compared to Miswak extract, which showed mean inhibitory zone of 2 and 1 mm for different concentrations. Broth microdilution method showed 31 mg/ml MIC and 62.5 mg/ml Minimal Fungicidal Concentration (MFC) values for commercial cleaner as compared to Miswak extract that showed 125 mg/ml MIC and 250 mg/ml MFC values against Candida albicans. A significant difference (p < 0.05) was observed between pre and post treatment of both commercial cleaner and Miswak extract, for CFUs and cell count for Candida albicans. CONCLUSION: Commercial denture cleaner (Corega) showed better antifungal (C albicans) activity than Miswak extract (Salvadora persica) on heat cured PMMA acrylic denture base resin.

Comparison of antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against Candida albicans adherent to acrylic denture base resin: An in vitro study.

Aim: One of the main factors responsible for the development of Candida albicans on the surface of denture is improper maintenance of dentures. Denture hygiene can be achieved by regular cleansing of dentures using an appropriate denture cleanser. The aim of the study is to evaluate the antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against C. albicans adherent to the surface of denture base resin. Settings and Design: This was an in vitro experimental study. Materials and Methods: Twenty-four Acrylic resin samples of dimension 10-mm radius and 2-mm thickness was randomly divided into two groups. The denture base resin was coated with C. albicans. The colonies present on the surface of each denture base resin were evaluated by serial dilution method. Group A was treated with commercially available denture cleanser and Group B was treated with extract of seaweed T. conoides. The colonies were then evaluated using serial dilution. Statistical Analysis Used: The colony count values obtained by serial dilution were tabulated. These values were statistically analysed using t-test. Results: Reduction of colony count is more in T. conoides than commercially available Fittydent; the difference was statistically significant with a mean difference of 65 at dilution 10-2 and 29.25 at dilution 10-3 using t-test with P < 0.001. Conclusion: Within the limitations of this in vitro study, it was proved that the extract of T. conoides seaweed and commercially available denture cleanser Fittydent was effective in reducing the colony count of C. albicans. T. conoides seaweed is statistically significant than commercially available Fittydent.

Impact of polyacrylamide supplementation on intake, nutrient digestion and growth of lambs.

This study was conducted to evaluate the effect of polyacrylamide (PAM) supplementation on the intake, digestion, weight gain, metabolism and growth of lambs. A total of ten 30 days old male small-tailed Han lambs with a body weight of 7.7±0.5 kg were divided into two equal groups (n = 5 each) and fed a basal diet or diet supplemented with 2.0 g of PAM per kg diet. The duration of the experiment was 210 days and experimental diets were fed ad libitum throughout the experimental period. Voluntary feed intake (VFI) was measured on daily basis, while body weight was measured on every ten days of the experiment.Two digestive and metabolic trials were conducted at the lamb's age of 95 to 103 days (Trial 1) and at the age of 210 to 218 days (Trial 2). At the end of experiment, all lambs were slaughtered to determine carcass characteristics. Results of the current study showed that supplementation of PAM in the diet of lambs increased the VFI and daily body gain by 14.4% (P < 0.05) and 15.2% (P < 0.01), respectively. In Trial 1, PAM supplementation in the diet increased the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), cellulose, energy, and nitrogen retention by 7.9%, 5.4%, 6.4%, 9.6%, 4.3% and 30.3% (P < 0.01), respectively, and in Trial 2, PAM supplementation in the diet increased the digestibility of DM, OM, CP, cellulose, energy, and nitrogen retention by 9.3%, 7.9%, 7.7%, 11.6%, 6.9% and 38.5% (P < 0.01), respectively. Results of carcass parameter explored that supplementation of PAM in the diet increased the carcass, net meat and lean meat weights by 24.5%, 25.5%, and 30.6% (P < 0.01), respectively, however, PAM supplementation in the diet did not influence the contents of DM, OM, or CP in fresh liver, leg muscle, and rumen tissue; in addition, the CP contents in the Longissimus dorsi muscle was decreased by the supplementation of PAM in the diet. In summary, supplementation of 2.0 g of PAM per kg diet increased the VFI, nutrient digestibility, nitrogen retention, and carcass yield of lambs.

Action of chitosan-based solutions against a model four-species biofilm formed on cobalt-chromium and acrylic resin surfaces.

OBJECTIVE: To evaluate the anti-biofilm action of chitosan, nanoparticulate chitosan, and denture cleanser Nitradine™ against biofilms comprising Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans. BACKGROUND: Biofilm removal from removable partial dentures (RPD) is important for success in prosthetic rehabilitation. MATERIALS AND METHODS: The anti-biofilm action of the experimental chitosan-based solutions and Nitradine™ was evaluated on acrylic resin and cobalt-chromium alloy through assessing cell viability, cell metabolism, residual aggregated biofilm, and extracellular polymeric substance and biofilm morphology. RESULTS: Only chitosan reduced the viability of C. albicans on cobalt-chromium alloy surface, by 98% (a 1.7 log10 reduction in cfu). Chitosan-based solutions neither promoted substantial alteration of the metabolic activity of the four-species biofilm nor reduced the amount of the aggregated biofilm. After immersion in chitosan and nanoparticulate chitosan, viable microorganisms and extracellular polymeric substances distributed over the entire specimens' surfaces were observed. Nitradine™ reduced the viability and metabolic activity of biofilm grown on both surfaces, but it did not remove all aggregated biofilm and extracellular polymeric substances. After immersion in Nitradine™, approximately 35% of the specimens' surfaces remained covered by aggregated biofilm, mainly composed of dead cells. CONCLUSION: Although chitosan and Nitradine™ promoted changes in the viability of microorganisms, neither solution completely removed the four-species biofilm from the Co-Cr and acrylic resin surfaces. Thus, isolated use of hygiene solutions is not indicated for biofilm control on RPDs; this requires complementary mechanical removal.

Effect of multi-purpose primer on bonding of acrylic resin to cast titanium and gold alloy after airborne-particle abrasion.

PURPOSE: To clarify the effect of a multi-purpose primer combining several functional monomers on two prosthodontic materials (cast titanium and a gold alloy) after airborne-particle abrasion. METHODS: Disk-shaped adherends were prepared from cast titanium (CP Titanium JIS2) and a gold alloy (Casting Gold M.C. Type IV). A silane-containing two-liquid primer (M&C primer (MC)) and two silane-free single-liquid primers (Alloy Primer (AP) and V-Primer (VP)) were used as surface-treatment agents. The shear bond strengths were determined before and after thermocycling to evaluate the adhesive durability, and the results were compared using a non-parametric statistical analysis. The effect of airborne-particle abrasion with alumina on the titanium surface was analyzed by X-ray photoelectron spectroscopy (XPS). RESULTS: There was no significant difference in bond strength between the MC and AP before and after thermocycling, whereas VP showed significantly lower values. XPS revealed that the titanium acquired hydrophilic properties after the airborne-particle abrasion. CONCLUSIONS: The novelty of this study is that it shows that the presence/absence of the silane had no effect on the bonding of cast titanium with an acrylic resin. The study also showed that the multi-purpose primer can be used without any problems with both cast titanium and gold alloy, in combination with airborne-particle abrasion with alumina.

Determining growth inhibition of Candida albicans biofilm on denture materials after application of an organoselenium-containing dental sealant.

STATEMENT OF PROBLEM: Denture stomatitis is a chronic inflammatory condition caused by the formation of Candida albicans biofilm on denture bases. It is associated with aggravating intraoral pain, itching, and burning sensations. It can also potentiate cardiovascular diseases and aspiration pneumonia. The problem has thus far eluded efficient, toxic-free, and cost-effective solutions. PURPOSE: The purpose of this in vitro study was to investigate the effectiveness of organoselenium to inhibit the formation of C. albicans biofilm on the surface of acrylic resin denture base materials when it is either incorporated into the acrylic resin material or coated on the denture surface as a light-polymerized surface sealant. MATERIAL AND METHODS: Sixty heat-polymerized polymethyl methacrylate disks were fabricated and assigned to 4 groups (n=15): disks coated with a light-polymerized organoselenium-containing enamel surface sealant (DenteShield), disks impregnated with 0.5% organoselenium (0.5% selenium), disks impregnated with 1% organoselenium (1% selenium), and disks without organoselenium (control). C. albicans biofilm was grown on each disk which had been placed in a well of the microtiter plate containing 1-mL brain heart infusion broth inoculated with C. albicans. The plates were incubated aerobically at 37 °C for 48 hours. A confocal laser scanning microscope was used to determine the biofilm thickness, biomass, and live/dead cell ratio. Biofilm morphology was examined with scanning electron microscopy, whereas microbial viability was quantified by the spread plate method. The data were analyzed by using ANOVA and Tukey-Kramer multiple comparisons (α=.05). RESULTS: The microbial viability, biofilm thickness, biofilm biomass, and live/dead cell ratio were lower (P<.001) on disks in the test groups (DenteShield, 0.5% selenium, 1% selenium) when compared with the control group, with these variables being lowest in the 0.5% selenium and 1% selenium groups. The 0.5% selenium and 1% selenium groups did not differ significantly from each other in any of the variables (P>.05). Scanning electron microscope images showed inhibition of both biofilm growth and yeast to hyphae transition in the DenteShield, 0.5% selenium, and 1% selenium groups, with visible disruption of the biofilm morphology. CONCLUSIONS: The present study demonstrated that organoselenium, whether incorporated into or coated on the surface of an acrylic resin denture base material, has the potential to inhibit Candida albicans biofilm growth on denture surfaces and as such can be clinically useful for the prevention of denture stomatitis.

Effect of Ozonated Water on the Color Stability of Denture Teeth and Heat Polymerized Acrylic Base Resin

Abstract Objective: To determine the effect of ozonated water on the color stability of denture tooth and denture bases. Material and Methods: Thirty denture base discs consisting of 15 Acropars and 15 ProBase Hot specimens with the dimensions of 40 × 5 mm were prepared. Fifteen denture teeth in shade A1 (Ivoclar Vivadent, Schaan, Liechtenstein) were mounted in a specific acrylic jig. All specimens were immersed in three solutions (1% sodium hypochlorite, ozonated water, and distilled water) for four months (one year of clinical use). Color measurements were done with a spectrophotometer and assessed using the CIE L*a*b* colorimetric system (0, 4, 8, 12, and 16 weeks). Data were analyzed using the three-way ANOVA and Tukey test (α=0.05). Results: Tukey's post hoc test revealed a significant change in color in the Acropars denture base for the distilled water group compared to the ozonated water and 1% hypochlorite (p<0.05). Regarding the ProBase Hot denture base, significantly less color change was observed in the 1% hypochlorite group compared to the ozonated water and distilled water (p≤0.001). For the denture teeth, significantly less color change was seen in the distilled water group than in the ozonated water (p=0.015) and 1% hypochlorite (p<0.05) groups. Conclusion: The color change of denture bases and denture tooth in ozonated water are acceptable. Ozonated water can be considered a good disinfectant for cleaning dentures.

Formulation and rheological evaluation of liposomes-loaded carbopol hydrogels based on thermal waters.

The aims of this study were to develop topical liposomal hydrogels based on thermal waters (TWs) acquired in the region of Biskra (Northeast Algeria) and also to investigate their rheological properties. Liposomes containing two highly mineralized thermal waters, Baraka (BTW) and Salhine (STW), were prepared by probe sonication using phosphatidylcholine (PC) and cholesterol (Chol), plain or mixed with phosphatidylglycerol (PG). Based on their lipid composition, obtained liposomes presented vesicle sizes of 60 nm, a low polydispersity index, and various negative zeta potentials. It was noted that with increasing counterions charge in TWs the zeta potential of liposomes decreased toward neutral values.Carbopol (1%, w/w) hydrogels prepared with BTW, STW, and also demineralized water (placebo hydrogel) showed a non-Newtonian behavior, pseudoplastic fluid adjusted to Carreau model. The composition of thermal waters influenced highly the rheological properties of Carbopol hydrogels. Liposomal hydrogels were prepared by dispersing liposomes in hydrogels formulated with the same encapsulated thermal water. Regardless of composition or lipid concentration of added liposomes, the viscosity and viscoelastic parameters of Carbopol hydrogels changed negligibly. Indeed, liposome composition and lipid concentration seemed to have no effect on the rheological properties of Carbopol hydrogel in the presence of an important charge of cations. Hence, hydrogels and liposomal hydrogels based on thermal waters had suitable rheological properties for topical application and delivery of minerals in the skin.

Partially hydrolyzed polyacrylamide: enhanced oil recovery applications, oil-field produced water pollution, and possible solutions.

Polymers, such as partially hydrolyzed polyacrylamide (HPAM), are widely used in oil fields to enhance or improve the recovery of crude oil from the reservoirs. It works by increasing the viscosity of the injected water, thus improving its mobility and oil recovery. However, during such enhanced oil recovery (EOR) operations, it also produces a huge quantity of water alongside oil. Depending on the age and the stage of the oil reserve, the oil field produces ~ 7-10 times more water than oil. Such water contains various types of toxic components, such as traces of crude oil, heavy metals, and different types of chemicals (used during EOR operations such as HPAM). Thus, a huge quantity of HPAM containing produced water generated worldwide requires proper treatment and usage. The possible toxicity of HPAM is still ambiguous, but its natural decomposition product, acrylamide, threatens humans' health and ecological environments. Therefore, the main challenge is the removal or degradation of HPAM in an environmentally safe manner from the produced water before proper disposal. Several chemical and thermal techniques are employed for the removal of HPAM, but they are not so environmentally friendly and somewhat expensive. Among different types of treatments, biodegradation with the aid of individual or mixed microbes (as biofilms) is touted to be an efficient and environmentally friendly way to solve the problem without harmful side effects. Many researchers have explored and reported the potential of such bioremediation technology with a variable removal efficiency of HPAM from the oil field produced water, both in lab scale and field scale studies. The current review is in line with United Nations Sustainability Goals, related to water security-UNSDG 6. It highlights the scale of such HPAM-based EOR applications, the challenge of produced water treatment, current possible solutions, and future possibilities to reuse such treated water sources for other applications.