Acrylic Discs Research Articles

Antimicrobial, Optical, and Mechanical Properties of Saliva-Contaminated Silver–Zeolite Nanoparticle-Incorporated Dental Acrylic Resins

Background and Purpose: This study aimed to evaluate the flexural strength, color change and antimicrobial effect of silver–zeolite nanoparticles (NPs) in acrylic resin materials. Methods: Fifty-six disc-shaped acrylic resin samples were divided into four groups (n = 7) according to concentrations of silver–zeolite NPs (0%, 2%, 4%, 5%). Discs were contaminated with C. albicans and S. mutans. The antimicrobial effect was tested by inoculating contaminated discs on Tryptic soy agar (TSA), Sabouraud Dextrose Agar (SDA), Tryptic soy broth (TSB), and Sabouraud dextrose broth (SDB). Forty rectangular 65 × 10 × 2.5 mm acrylic resin specimens were also classified into four groups (n = 10) according to concentrations of silver–zeolite NPs. For the color change, L, a, and b values of rectangular specimens were examined with a spectrophotometer. A three-point bending test was also performed using a Devotrans device to determine the flexural bond strength of rectangular specimens. Scanning electron microscope analysis (SEM/EDX analysis) was also performed. Results: In this study, the antimicrobial effect increased with the concentration of silver–zeolite NPs added to acrylic resin discs. In our study, adding 2% silver–zeolite NPs was more effective against C. albicans. The antimicrobial effect against S. mutans increased with concentration of silver–zeolite NPs (<0.001). The colonization of C. albicans was significantly reduced by silver–zeolite NPs. A significant increase was observed in the color change as the nanoparticle percentage ratio increased (p < 0.001). The flexural strength values of the groups containing 2% and 4% nanoparticles were found to be clinically acceptable. Conclusions: The study showed that bacterial and fungal colonization is significantly reduced by adding silver–zeolite nanoparticles to acrylic resin discs. Based on its antimicrobial, physical, and mechanical properties, we recommend adding 2% silver–zeolite nanoparticles to the acrylic resin material for optimal results.

Reduction of Multispecies Biofilms on an Acrylic Denture Base Model by Antimicrobial Photodynamic Therapy Mediated by Natural Photosensitizers.

The aim of this study is to investigate the antimicrobial efficacy of antimicrobial photodynamic therapy (PDT) using natural photosensitizers (curcumin, riboflavin, and phycocyanin) and light-emitting diode (LED) irradiation against multispecies biofilms in an acrylic denture base model. Forty-five acrylic specimens were fabricated using heat-curing acrylic resin. The specimens were then infected with a mixed culture of bacterial and fungal species (including Streptococcus mutans, Streptococcus sanguinis, Candida albicans, and Candida glabrata) for 4 days. The acrylic discs were divided into nine groups, with each group containing five discs: control, 0.2% chlorhexidine, 5.25% sodium hypochlorite, curcumin, riboflavin, phycocyanin alone or along with LED. After treatment, the number of colony-forming units (CFUs) per milliliter was counted. In addition, the extent of biofilm degradation was assessed using the crystal violet staining method and scanning electron microscopy. All experimental groups exhibited a significant reduction in colony numbers for both bacterial and fungal species compared to the control (p < 0.001). The PDT groups exhibited a statistically significant reduction in colony counts for both bacteria and fungi compared to the photosensitizer-only groups. The results of this in vitro study show that PDT with natural photosensitizers and LED devices can effectively reduce the viability and eradicate the biofilm of microorganisms responsible for causing denture infections.

Forensic study of the mechanical properties of prosthetic materials: Submersion in mangrove environment – A pilot study

IntroductionIt is crucial for dental surgeons to use the mechanical properties of dental prosthetic materials to correlate the submersion time in a mangrove environment. ObjectiveThis study aimed to submerge dental prosthetic materials, such as acrylic resin and zirconia, contained within acrylic resin disks in a mangrove environment, and analyze the alterations in mechanical parameters, such as surface roughness and microhardness, to estimate submergence time in similar forensic situations. Materials and methodsA total of 6 specimens was embedded in acrylic resin disks numbered from 1 to 6. The materials were polished for initial parameter readings a day before submersion, and new readings were obtained 1after submersion. All specimens were subjected to surface roughness analysis, in addition to Knoop microhardness analysis for acrylic resin and Vickers microhardness analysis for zirconia. After the experiment, the data were computed for statistical comparation of the materials properties different parameters. ResultsThere was a significant increase in surface roughness and Knoop microhardness was reduced in the Acrylic Resin samples (p< 0.05); however, no statistically significant differences were observed in the roughness or Vickers microhardness values of the zirconia samples. ConclusionZirconia prosthetics were more resistant to degradation when submerged in a mangrove environment compared to acrylic resin ones; however, owing to the obstacles inherent in this study, we suggest further research on the properties of prosthetic materials submerged in mangroves or other environments, which could bolster the work of dental professionals in forensic medical institutes.

The Impact of Gastric Juice on the Surface Roughness of Surface Sealant-Treated Provisional Restorations.

Gastroesophageal reflux disease causes gastric acid to enter the oral cavity, leading to mucosal changes and deterioration of dental hard tissues and materials. The purpose of this in vitro study was to evaluate the impact of gastric juice on the surface roughness of two types of acrylics used in provisional restorations. Acrytemp ® and Temdent acrylic resin discs (10 × 2 mm) totaling 80 were manufactured and divided into eight groups (n = 10). Groups were prepared as follows: Group 1 (Temdent + Universal Polish) (control), Group 2 (Temdent + Universal Polish + Biscover LV), Group 3 (Temdent + Universal Polish + Resin Glaze), Group 4 (Temdent + Universal Polish + Fortify Plus), Group 5 (Acrytemp + Universal Polish) (control), Group 6 (Acrytemp + Universal Polish + Biscover LV), Group 7 (Acrytemp + Universal Polish + Resin Glaze), and Group 8 (Acrytemp + Universal Polish + Fortify Plus). The resin discs were immersed in distilled water for 24 h and in gastric juice (pH = 2) for additional 24 h. The initial and final roughness values of samples were measured and analyzed with non-parametric statistics including Mann-Whitney U-test for pairwise comparison, Kruskall Wallis test for comparing more than two groups, and Wilcoxon signed rank test for within-group comparison (P < 0.05). Surface roughness did not differ significantly between control groups. It notably increased for all samples with surface sealants, both initially and after gastric juice immersion (P < 0.05). Surface sealants noticeably increased the roughness of two types of acrylic resins. After immersing in gastric juice, Group 4 (Temdent + Universal Polish + Fortify Plus) showed the highest roughness, while the untreated control groups remained the smoothest.

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

Denture stomatitis, frequently encountered, is generally addressed symptomatically, with limited exploration of preventive approaches involving antifungal medicinal plants. This study assessed the impact of Artemisia sieberi extracts on the candida growth of conventional and digitally processed acrylic materials. 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). 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). 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.

Research Study on the Effects of Disinfectants on Medical Images and Medical Equipment in Infection Control Measures

In this study, we investigated the effects of various disinfectants used to prevent infectious diseases on medical images and medical equipment. First, we investigated the effect of residual disinfectant on medical images in CT, mammography (MMG), and general imaging systems. Acrylic discs with various disinfectants attached were photographed using each imaging device, and visual evaluation and changes in image signal values were evaluated. We also conducted a questionnaire survey of each manufacturer regarding cleaning methods for medical devices. With CT/MMG, residual disinfectant could be visually confirmed on the image. Although this could not be confirmed with the general imaging system, a significant difference was confirmed in the image signal values of the general imaging system through statistical analysis. This is thought to be largely due to the influence of nonlinearity in the short-time imaging range of general imaging equipment. In addition, from the responses to a questionnaire survey of each medical device manufacturer, we were able to understand detailed cleaning methods that are not covered in medical device instruction manuals.

Effects of disinfection with a vinegar-hydrogen peroxide mixture on the surface characteristics of denture acrylic resins.

This study aimed to investigate changes in the surface characteristics of two denture resins when disinfected with a vinegar-hydrogen peroxide (VHP) mixture. Microwave-polymerized or 3D printed acrylic resin disks were immersed for 900min (simulating 90 daily uses) in the following solutions (N = 10): water; 0.5% sodium hypochlorite; hydrogen peroxide and water dilution (1:1 ratio); vinegar and water dilution (1:1 ratio); and VHP mixture. Surface roughness, Knoop microhardness, surface free energy, and scanning electron microscopic images were assessed before and after the immersions. Results were compared using the 2-way ANOVA for repeated measures and Tukey test, at 5% significance. Surface roughness and microhardness did not differ (P > .05) among the solutions and times. Surface free energy and its dispersive component increased (P < .05) for all solutions. All solutions, except for water and VHP mixture, degraded microtopography. The VHP mixture was not deleterious to conventional and 3D-printed resin surfaces. Conventional and 3D printed resin dentures can be disinfected with a VHP mixture in a 1:1 ratio because this mixture does not substantially affect the surface characteristics after 90 daily immersions. On the contrary, sodium hypochlorite, hydrogen peroxide, and vinegar solutions, even in low concentrations, should be used with caution for denture disinfection because they may alter the resin microtopography over time.

Comparison of the adhesion of adhesive pastes on removable dental prostheses from different commercial companies

The use of conventional removable dental prostheses shows the lack of retention and stability, so the use of adhesives for prostheses has been generalized to improve their resistance to detachment. The adhesion of adhesive pastes in removable dental prostheses of different commercial companies was compared. The empirical component involved an in vitro experiment using two adhesive pastes: Corega and Denta Firme, applied on acrylic discs that were previously hydrated and then placed on glass slabs to measure the adhesion strength. This process involved the uniform application of 5 ml of each paste on the discs, followed by a hydration period of 8 minutes. Adhesion strength was measured using a digital scale, recording the highest value obtained during vertical debonding of the disc from the tile. This study revealed that the differences in the bond strength of the adhesive pastes evaluated for dentures are minimal. Denta Firme demonstrated the highest bond strength in the short term. It is concluded that the study failed to determine the durability of the bond strength of the pastes over time. However, the findings indicate that the use of adhesives significantly improves the retention of conventional removable or total dentures. Consequently, it is recommended that dental professionals carefully choose the most appropriate adhesive for each patient, considering individual characteristics and specific needs, in order to take full advantage of the benefits offered by these products

Influence of denture brushing on the surface properties and color stability of CAD-CAM, thermoformed, and conventionally fabricated denture base resins.

To assess the influence of denture brushing on the surface roughness, hardness, and color stability of conventional, thermoformed, and CAD-CAM denture base materials. Seven different denture base materials were included in this study; conventional heat-polymerized acrylic resin (PMMA) served as control, polyamide, acetal, two categories of milled acrylic discs (AvaDent and IvoCad), and two categories of 3D-printed resins (NextDent and FormLabs). The specimens were constructed according to manufacturers' instructions and then subjected to simulated brushing (20,000 cycles). According to the brushing method, the specimens were split into three groups, no brushing, brushing with water, and brushing with toothpaste. Surface roughness, hardness, and color change were evaluated before and after brushing. Collected data were analyzed using ANOVA, and post-hoc Tukey's tests (α = 0.05). A significant difference was noted between the surface roughness of the tested materials before and after denture brushing (p<0.05), and milled resin showed the least Ra values. Denture brushing with water significantly increased the Ra of PMMA (p = 0.004) and IvoCad (p = 0.032), while brushing using toothpaste did not show a significant increase. The brushing protocols did not alter the hardness of tested materials except that of PMMA (p = 0.001). The color stability of the tested materials showed comparable results with both brushing protocols. The tested properties showed variations between the types of denture base resins. Hardness and color stability of CAD-CAM and thermoformed denture base resins were not altered by denture brushing and showed comparable results with both brushing methods. Surface roughness was the only property that showed alteration after denture brushing.

The effect of different concentration of emodin nanoparticles, as an antibacterial agent, on the flexural resistance of acrylic resin used in orthodontics: An in vitro study

The aim of this study was to investigate the impact of emodin nanoparticles (n-Emo) on the flexural strength of acrylic resin used in orthodontics. A total of 24 acrylic resin discs were prepared according to ISO:20795-1 and divided into four groups (n=6): 0% n-Emo, 0.5% n-Emo, 1% n-Emo, and 2% n-Emo. The flexural strength of each group was measured using the Universal Testing Machine. One-way analysis of variance (ANOVA) and Tukey tests were used to analyse the data. The highest flexural strength values were observed in the groups containing 0% and 0.5% concentrations of n-Emo, while the lowest mean flexural strength was recorded in the group containing 2% concentration of n-Emo. There were significant difference in flexural strength values between the groups containing 0% with those containing 1% and 2% concentrations (P=0.045, P=0.011, respectively), as well as between those containing 0.5% and 2% concentrations of n-Emo (P=0.041). The results of the study showed that the incorporation of n-Emo had a negative impact on the flexural strength of the acrylic resin utilized in orthodontics. Nonetheless, the mean flexural strength values of all groups fell within the normal range, implying that the addition of n-Emo did not jeopardize the mechanical properties of the acrylic resin. It is therefore conceivable that the use of n-Emo as an antimicrobial agent in acrylic resin could be a promising approach to reducing enamel demineralisation and dental caries, while preserving its mechanical properties. This study was approved by the ethics committee of the Tehran University of Medical Sciences (1401-2-398-54892).

Qualitative and Quantitative Profiling of Enamel Remineralizing Potential of Fluoride Varnishes Incorporating Bioactive Glass, Dicalcium Phosphate Dihydrate, and Modified MTA: A Raman Spectroscopic Study.

To evaluate and compare for remineralization potential of enamel at three different time intervals using commercially available MI Varnish and Duraflor Halo varnish [5% sodium fluoride (NaF) varnish] incorporating bioactive glass, dicalcium phosphate dihydrate (DCPD), and biomimetically modified mineral trioxide aggregate (MTA). For the study, a buccolingual division into equal halves was done for 64 decoronated premolar crowns. Among these 64 crowns, we mounted 32 in acrylic discs to be used for microhardness and induced white spot lesions (WSLs) measuring 5 × 5 mm on the exposed enamel surface. These samples were divided into four groups of 24 each depending upon the varnish used. Varnish application was done, followed by immersion of these samples for 24 hours in artificial saliva, followed by peeling off of varnish. A pH cycling of 28 days was done after the varnish application before assessing the remineralization of the samples. Evaluation of all these samples was done at three different time intervals, baseline, after demineralization, and post remineralization for microhardness on the enamel surface. Raman spectroscopy was utilized for the measurement of phosphate (P) ion release. Sectioning of these samples to a thickness of 100 µm approximately was done to be viewed under a polarized light microscope. Bioactive glass incorporated varnish showed the highest microhardness values, mineral content levels, and least depth of lesion posttreatment. All the experimental varnish showed significant remineralizing potential with the best potency seen with bioactive glass incorporated varnish. The nonfluoride agents can be appropriately used in 2 wt% amount to augment the benefits of fluoride. Hardikar AS, Gaonkar NN, Devendrappa SN, et al. Qualitative and Quantitative Profiling of Enamel Remineralizing Potential of Fluoride Varnishes incorporating Bioactive Glass, Dicalcium Phosphate Dihydrate, and modified MTA: A Raman Spectroscopic Study. Int J Clin Pediatr Dent 2023;16(2):363-370.

Polymethylmethacrylate-Based Nanocomposites for Denture Base Fabrication: Impact of Nanoparticle Type and Concentration on the Color Change In Vitro

Background. Although the mechanical behaviors of PMMA were improved with nanoparticles addition, there is a lack of study on the color changes of nanocomposite denture base resin. This study aimed to assess and compare the color of nanocomposite denture base resin modified with different nanoparticles and concentrations. Materials and Methods. Three nanoparticles (zirconium dioxide (ZNP), titanium dioxide (TNP), and silicon dioxide (SNP)) were added to heat-polymerized acrylic resin in 3 and 7 wt% concentrations. A total of 70 acrylic discs (20 × 2 ± 0.03 mm) specimens were prepared while one without addition (control) and three main groups according to nanoparticles and two subgroups according to % (3ZNP, 7ZNP, 3TNP, 7TNP, 3SNP, and 7SNP) with total 70 acrylic discs (n = 10). Spectrophotometer was used for color change (ΔEab) followed by value conversion to National Bureau of Standards units (NBS) to relate the color alterations (ΔEab) to the clinical environment which aids in determining a threshold for clinical acceptance of the color change. ΔEab data were analyzed and compared using one- and two-way ANOVA tests followed by Bonferroni’s post hoc test (α = 0.05). Results. Two-way ANOVA showed that filler type (regardless of filler concentration) had a statistically significant effect on mean ΔEab ( P &lt; 0.001 ). Filler concentrations (regardless of filler type) showed a significant effect on mean ΔEab while the filler type and concentration interaction showed no significant effect on mean ΔEab ( P &lt; 0.001 ). One-way ANOVA in terms of filler types results showed a significant difference between mean ΔEab ( P &lt; 0.001 ), where TNP group showed the highest mean ΔEab followed by ZNP and SNP. Pair-wise comparison revealed that 3% concentration showed a significant lower mean ΔEab than 7% concentration ( P &lt; 0.001 ). Conclusion. Modification of heat-polymerized denture base resin with ZNP, TNP, or SNP causes clinically unacceptable color change. TNP produced the highest color change followed by ZNP and SNP, and the color change is concentration dependent; the color change increases as the concentration increases.

Antifungal Effect of Ginger Essential Oil Spray on Candida albicans Adhering to Self-Cure Acrylic Plates.

Objectives: The present study aimed to evaluate the efficacy of ginger essential oil spray for elimination of Candida albicans (C. albicans) adhering to self-cure acrylic plates. Materials and Methods: In this experimental study, 120 self-cure acrylic discs were contaminated with C. albicans and randomly divided into four main groups: exposure to ginger essential oil, nystatin (positive control), distilled water (negative control), and no exposure. The minimum inhibitory concentration (MIC) of ginger oil and nystatin was determined by the microdilution test. The stability ofC. albicans was determined by culturing the samples of treated acrylic plates and comparing the mean number of remaining colonies. Data were analyzed using the Kruskal-Wallis test followed by Dunn test with Bonferroni correction. P<0.05 was considered significant Results: The MIC of ginger essential oil and nystatin was found to be 1560µg/mL and 4µg/mL, respectively. The differences between the mean count of C. albicans colonies before (10175±10730.25) and after the exposure to ginger essential oil (542.86±464.81) and nystatin (257.14±247.67) was statistically significant (P<0.001). The mean number of C. albicans colonies after spraying with nystatin was not significantly different compared with ginger essential oil (P=0.204). The efficacy of nystatin and ginger essential oil at each time was significantly more than distilled water (P<0.001). At 10 and 15min, there was no significant difference between nystatin and ginger essential oil groups (P=0.05). Conclusion: Ginger essential oil spray was found to be a simple and effective method for elimination of C. albicans adhering to acrylic discs.

The Effect of Controlled Diabetic and Non-diabetic Saliva on Candida albicans Adherence to Heat Polymerized Acrylic Resin Discs

Background: Oral candidiasis is one of the most common infections in diabetic patients that may occur due to a decrease in salivary flow rate, alterations in the salivary composition, or both. This study aimed to investigate the effect of diabetic and non-diabetic saliva on Candida albicans adherence to the acrylic resin disc specimens, regardless of saliva volume. Methods: In this case-control study, the population consisted of 26 subjects in 2 groups (13 diabetic patients and 13 non-diabetic patients). In both groups, unstimulated whole saliva was collected. It was investigated for pH, salivary flow rate, and adhesion of C. albicans to polymethylmethacrylate disc. After preparing the polymethylmethacrylate discs, the samples were stored in diabetic saliva, non-diabetic saliva, and distilled water (negative control group) for 60 minutes at 37ºC. Then they were immersed in the yeast suspensions containing C. albicans and stained with gram stain. Yeast cells were counted using a light microscope. Results: The pH of unstimulated whole saliva in diabetic patients was significantly lower than in the control group. There was no significant difference between the flow rates of saliva in the two groups. Findings indicated that the adhesion of C. albicans to resin in diabetic saliva was higher than in non-diabetic saliva. Conclusion: This study showed the same amount of salivary flow rate in diabetic and non-diabetic individuals, lower pH, and higher Candida adherence to heat polymerization acrylic resin in the diabetic group.

Efficacy of Denture Cleansers on Microbial Adherence and Surface Topography of Conventional and CAD/CAM-Processed Denture Base Resins.

This study assessed the efficacy of five denture cleansers on the microbial adherence and surface topography of conventional and CAD/CAM denture base resins. Acrylic resin discs were fabricated using conventional, milling, and 3D printing methods (N = 180). The discs were contaminated with dual species of Candida albicans and Streptococcus mutans biofilm for 72 h and then disinfected with either of the denture cleansers (Fittydent cleansing tablets, 2% Chlorhexidine gluconate, 0.2% Chlorhexidine gluconate, 0.5% sodium hypochlorite, and 1% sodium hypochlorite (n = 10). Distilled water served as the control group. The colony-forming units of the microorganisms were calculated, followed by post-treatment surface roughness. Data were statistically analyzed using one-way ANOVA, paired t-test, and post hoc Tukey HSD test (α = 0.05). Among the denture cleansers, 2% Chlorhexidine gluconate, 0.5% sodium hypochlorite, and 1% sodium hypochlorite had the best cleansing effect on the resin discs and demonstrated zero growth of colonies for both the species. Comparing the material groups, the 3D-processed discs showed higher colony-forming units followed by the conventional and CAD/CAM milled group. The highest surface roughness was demonstrated by the 3D-printed discs (0.690 ± 0.08 μm), followed by the conventional (0.493 ± 0.11 μm) and the milled groups (0.301 ± 0.08 μm). The tested chemical denture cleansers affected the Candida albicans and Streptococcus mutans adhesion compared to control discs immersed in distilled water. The clinician may recommend to their patient to use 2% chlorhexidine gluconate for the disinfection of CAD/CAM PMMA denture base materials.

Antifungal effect of acrylic resin denture base containing different types of nanomaterials: A comparative study

Aim: Denture stomatitis is a frequent condition that has an influence on denture users’ oral mucosa, and it is related to the presence of Candida albicans. Silver and titanium nanoparticles are antimicrobial agents with a broad spectrum of activity. This research sought to represent and compare the antifungal properties of acrylic resins modified with two concentrations of silver nanoparticles (AgNPs) and titanium-oxide nanoparticles (TiO2 NPs) against a clinical isolate of C. albicans. Materials and Methods: One-hundred discs of acrylic resin specimens were classified into five groups based on nanoparticles’ concentration: group A: unmodified acrylic resin; groups B1 and B2: modified by adding 0.5% and 1% AgNPs to the acrylic resin powder, respectively; groups C1 and C2: modified by adding 0.5% and 1% TiO2 NPs to the acrylic resin powder, respectively. The antimicrobial efficacy of different acrylic resin discs against C. albicans clinical isolates was assessed using disc agar diffusion and elution tests (surface-plate method). The analysis of variance test was employed to evaluate the data that differentiate among means of different groups at P ≤ 0.05 significance level. Results: The bioactivity and biomass of C. albicans biofilm reduced as the nanoparticle content rises; about 0.5%, 1% of AgNPs, and 1% TiO2 NPs exhibited higher antimicrobial and antibiofilm effects against C. albicans clinical isolates caused by inhibition zone and reduction of the colony counts. Conclusion: Acrylic resins modified by adding AgNPs or TiO2 NPs exhibited antimicrobial activity against C. albicans clinical isolates.

Antibacterial properties of an acrylic resin containing curcumin nanoparticles: An in vitro study.

Background. Microbial accumulation is still a significant problem with removable acrylic appliances. This study aimed to assess the antimicrobial properties of a self-cured acrylic resin containing curcumin nanoparticles (CNPs). Methods. This in vitro study used 48 acrylic discs containing 0.5%, 1%, and 2% CNPs. The antimicrobial properties of the discs against Streptococcus mutans, Streptococcus sanguinis, Lactobacillus acidophilus, and Candida albicans were evaluated using disc agar diffusion (DAD), eluted component, and biofilm inhibition tests. The growth inhibition zones were measured, and the colonies were counted after 1, 3, and 7 days. Results. DAD test showed that none of the curcumin nanoparticle concentrations caused growth inhibition zones for any microorganisms. All the concentrations were effective against all four microorganisms in the biofilm inhibition test except 0.5% for L. acidophilus. In the eluted component test, solutions containing 2% concentration had maximum growth inhibition of all the groups at all time intervals. An increase in curcumin nanoparticle concentration from 0.5% to 1% was effective only against C. albicans. Conclusion. Generally, CNPs in all concentrations were effective against the biofilms of all four microorganisms assessed in this study. Therefore, incorporating 2% CNPs into acrylic resin seems suitable for clinical use.

Three-dimensionally printed duplicate sleeping denture

A patient presented with a treatment plan for the replacement of his maxillary complete removable denture and mandibular implant-retained complete overdenture because of excessive wear and fracture of his existing prostheses. A digital workflow was used, and his dentures were milled from a monolithic acrylic resin disk. Upon delivery of the dentures, the patient reported that he was unable to sleep without his dentures in place although he denied a diagnosis of obstructive sleep apnea. After emphasizing the recommendation to remove his dentures while sleeping, it was decided to use additive manufacturing technology because of its low cost and ability to faithfully reproduce a 3-dimensional file in various biocompatible materials. The second set of sleeping dentures were 3-dimensionally printed and delivered with minimal adjustment and at a low cost.

The Antifungal and Antibiofilm Activities of Caffeine against Candida albicans on Polymethyl Methacrylate Denture Base Material.

Background: In this study, the effect of pure caffeine was established against Candida albicans (C. albicans) using different microbiological techniques. Methods: Broth microdilution and colony forming units (CFUs) assays were used to detect the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). The Live/Dead fluorescent dyes were implemented to determine the yeast viability. Polymethyl methacrylate acrylic resin (PMMA) discs were prepared to evaluate caffeine’s effects against adherent C. albicans using microplate reader, CFUs, and scanning electron microscope (SEM). Results: caffeine’s MIC was detected around 30 mg/mL, while the MFC was considered at 60 mg/mL. In an agar-well diffusion test, the inhibition zones were wider in caffeine groups. The Live/Dead viability test verified caffeine’s antifungal effects. The optical density of the adherent C. albicans on PMMA discs were lower at 620 nm or 410 nm in caffeine groups. CFU count was also reduced by caffeine treatments. SEM revealed the lower adherent C. albicans count in caffeine groups. The effect of caffeine was dose-dependent at which the 60 mg/mL dose demonstrated the most prominent effect. Conclusion: The study reinforced caffeine’s antifungal and antibiofilm properties and suggested it as an additive, or even an alternative, disinfectant solution for fungal biofilms on denture surfaces.

Influence of Propolis Extract (Caffeic Acid Phenethyl Ester) Addition on the Candida albicans Adhesion and Surface Properties of Autopolymerized Acrylic Resin.

Background Denture stomatitis has been linked to the adhesion and proliferation of Candida albicans (C. albicans) on denture bases, which is a common and recurrent problem in denture wearers. The current study aimed to evaluate the effect of incorporating caffeic acid phenethyl ester (CAPE) into autopolymerized polymethyl methacrylate (PMMA) acrylic resin on C. albicans adhesion, surface roughness, and hardness as well as the correlation between tested properties. Methods Autopolymerized acrylic resin discs (N = 100, 50/C. albicans adhesion; 50/C. albicans surface roughness and hardness test) were fabricated in dimensions 15 × 2.5 mm, samples were categorized into 5 groups (n = 10) based on CAPE concentrations; unmodified (control), 2.5, 5, 10 and 15% wt of acrylic powder. Specimens were stored in distilled water for 48 h at 37°C. C. albicans adhesion was evaluated via direct culture method. Profilometer and Vickers hardness tester were used for surface roughness and hardness measurement. Post hoc Tukey's HSD with ANOVA test was performed to compare the difference of means amongst groups. P values were statistically significant at ≤0.05. Results The addition of 2.5% of CAPE to PMMA has significantly reduced C. albicans counts in comparison to higher CAPE concentrations (p < 0.001). As for surface roughness, it was noticed that it increased with increased CAPE concentrations (p < 0.0001). While surface hardness decreased as CAPE concentrations increased (p < 0.0001). All tested properties showed a significant difference amongst groups for C. albicans colony count and surface parameters. Conclusion The addition of 2.5% of CAPE to PMMA acrylic resin significantly decreased C. albicans count compared to higher CAPE concentrations. CAPE can be used as an adjunct in the prevention of DS by incorporating in the PMMA acrylic resin.