Acrylic Denture Base Research Articles

Influence of Nanodiamond Incorporation on The Impact Strength of Repaired Denture Base acrylic resin: An in Vitro Study

Aim. This research aims to evaluate the effects of integrating Nanodiamond on the impact strength of repaired denture base resin. Methodology. Sixty acrylic resin specimens, sized 50×6×4 mm³ with a v-notch, were created from heat-polymerized acrylic resin. Ten specimens were kept intact while the other 50 specimens were sectioned to half and prepared with 45º beveling and a 2.5mm-repair gap. Nanodiamond particles were added to autopolymerized repair resin and repaired specimens were placed in five categories (n=10) according to Nanodiamond concentrations, unmodified as a control, 0.25%, 0.5%, 0.75%, and 1%ND by weight. Each specimen half was repositioned in a metal jig, and the repair resin was applied to the repair area. Subsequently, all specimens underwent finishing, polishing, and immersion in distilled water before Charpy's impact testing. Data analysis employed Tukey's post hoc test (with significance α=0.05) and one-way ANOVA. Results. Results showed that in comparison with the control group, the impact strength of repaired denture base resin significantly increased with 0.25% and 0.5% Nanodiamond addition to repair resin (significance at P ˂0.001). While it insignificantly decreased with 0.75% and 1% Nanodiamond (P=0.108 and P=0.615) and 1% presented the lowest value of impact strength (3.48 ± 0.43 KJ/m2). Conclusion. Adding a small amount of Nanodiamond to autopolymerized repair resin demonstrated an increase in the impact strength of repaired acrylic denture base resin. The highest impact strength was recorded with 0.25%ND (6.24±0.55 KJ/m2), followed by 0.5%ND (5.93±0.21 KJ/m2), whereas 1%ND exhibited the lowest impact strength value (3.48±0.43 KJ/m2).

Effects of Combinations of Hydrogen Peroxide and Vinegar in Different Ratios on the Surface Roughness of Heat-Cure Denture Base Acrylic Resin

Background: Complete dentures are at high risk of contamination, and their disinfection is imperative to prevent cross-contamination. Also, chemical disinfecting agents can effectively eliminate microorganisms. This study aimed to assess the effect of combinations of hydrogen peroxide (HP) and vinegar in different ratios on the surface roughness of heat-cure denture base acrylic resin. Methods: This in vitro, experimental study evaluated 40 heat-cure acrylic resin specimens that were flasked and heated at 70 ° C for 9 hours for heat polymerization. The acrylic specimens were cut into small cubic pieces measuring 20×20×3 mm using a cutting machine and polished with metallographic abrasive paper. The specimens were randomized into 4 groups of control (artificial saliva) and HP and vinegar in 1:1, 1:3, and 3:1 ratios (three experimental groups). Then, they were immersed in the respective solutions for 8 hours/day for one month. Their surface roughness (Ra) was measured before and after immersion by a profilometer. The data were analyzed using a one-way analysis of variance (α=0.05). Results: The immersion of acrylic specimens in HP+vinegar in 1:1 and 1:3 ratios did not cause a significant change in their surface roughness (P>0.05). However, the surface roughness significantly decreased after immersion in HP+vinegar in a 3:1 ratio (P=0.032). Despite the reduction in the surface roughness of specimens in the 3:1 group, the difference in surface roughness was not significant among the four groups after immersion (P>0.05). Conclusion: Combinations of HP and vinegar in different ratios appear to be suitable for cleaning removable dentures due to their insignificant effects on the surface roughness of acrylic resin.

Comparative evaluation of effectiveness of chemical, mechanical and chemico-mechanical methods of denture cleaning for removal of stains from heat polymerised acrylic resin denture base - An in- vitro study

An essential quality of acrylic resin denture bases is colour stability. Over time, acrylic resin bases have a tendency to attract stains, which causes the denture base's colour to alter. These modifications sometimes make the denture less aesthetically pleasing for the wearer, which leads to patient unhappiness and higher replacement costs. The study's objective was to evaluate and compare the effectiveness of cleaning dentures using chemical, mechanical, and chemico-mechanical methods for removing stains from the heat polymerized acrylic resin denture base.A total of 120 samples of heat polymerised acrylic resin were fabricated and stained using sambhar solution for 10 days under controlled conditions. The baseline optical density of the samples was determined. The samples were then subjected to stain removal procedure by either - chemical, mechanical or chemico-mechanical method. After which the optical density was again determined. The efficiency of the three methods used was determined by the difference in the optical density after staining and post cleaning and compared with the baseline optical density measured previously. The data was analysed using One-way ANOVA test. Post hoc comparison was made by Bonferroni t-test. p<0.0.5 was considered as statistically significant. Data analysis was done using the statistical software STATA version 13.0.The results suggested that the chemico-mechanical method was the best method for stain removal from the acrylic samples. However, the mechanical method of denture cleaning was found to be equally effective. The chemical method was least effective in removing stains from the surface of heat polymerised acrylic resin. The chemico-mechanical method was 95.16% effective and the mechanical method used was 92.12% effective, proving that the chemico-mechanical was the most effective method for removing stains from the acrylic resin amongst the 3 techniques compared.

Mechanical properties of conventional versus microwave-polymerized denture base acrylic resins

New denture base acrylic resins have been introduced that are specifically formulated for microwave polymerization. Microwave polymerization is a time-efficient procedure, but few studies have evaluated how these new acrylic resin formulations compare with conventionally processed acrylic resins. The purpose of this in vitro study was to compare the stiffness and strength of denture base acrylic resins formulated for microwave polymerization with conventionally processed acrylic resin. Rectangular beams were fabricated from 2 microwave-polymerized denture base acrylic resins, microwave-specific resin (Nature-Cryl MC), resin with the option of microwave polymerization (Diamond D), and a conventionally processed resin as a control (Lucitone 199). Specimens (n=10) were stored in water for 1 week and subjected to a 3-point bend test to determine the flexural modulus (stiffness) and flexural strength before (initial properties) or after 120 000 load cycles. The load cycles, conducted between 5 and 25N at 2Hz, simulated 6 months of mastication. Data were analyzed by using 2-way ANOVA, followed by pairwise comparisons (α=.05). The initial flexural modulus (mean ±standard deviation) was conventionally processed resin, 2.65 ±0.33GPa; microwave-specific resin, 3.01 ±0.20GPa; and microwave-option resin, 2.63 ±0.04GPa. After load cycling, the mean flexural modulus was conventionally processed resin, 2.34 ±0.32GPa; microwave-specific resin, 2.69 ±0.20GPa; and microwave-option resin, 1.96 ±0.11GPa. The initial flexural strength was conventionally processed resin, 77.6 ±11.0MPa; microwave-specific resin, 83.6 ±3.5MPa; and microwave-option resin, 78.9 ±2.6MPa. After load cycling, the mean flexural strength was conventionally processed resin, 68.7 ±9.0MPa; microwave-specific resin, 73.3 ±3.3MPa; and microwave-option resin, 65.5 ±3.5MPa. Resin and loading state significantly affected the stiffness and strength (P<.01); the interaction resin×state was not significant (P≥.558). Microwave-polymerized denture base acrylic resins were comparable in stiffness and strength with conventionally processed acrylic resin. All acrylic resins decreased in stiffness and strength after load cycling. The microwave-specific resin was significantly stiffer and stronger than the other denture base acrylic resins, initially and after 120 000 load cycles.

Gadolinium oxide Nanoparticles Infusion in Heat-Cured Acrylic Denture Base Material: Impact on Glass Transition Temperature and Mechanical Strength Enhancement

Introduction: Nano dentistry has paved the way for advanced therapeutic opportunities in various dental disciplines, particularly in the improvement of oral health. One area of focus is the enhancement of mechanical properties of dental materials, such as acrylic resins commonly used in denture base materials. Various strategies, including chemical corrections and the addition of particles, have been explored to augment the mechanical qualities. This study investigates the impact of incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture materials. Materials and Methods: The denture base was processed using a standardized approach, with the addition of Gadolinium oxide nanoparticles during the monomer phase. A total of 120 specimens were fabricated. 30 specimens for each test using 10 specimens for each nanoparticle concentration (Control 0%, 1%, and 1,5% nanoparticles). The nanoparticles were dispersed using sonication to ensure uniform distribution. The study assessed properties such as glass transition temperature using a differential scanning calorimeter, impact strength and transverse strength utilizing an Instron universal testing machine, and surface roughness via profilometer measurements. Scanning electron microscope also utilized. One way ANOVA was used to determine the mean differences. Results: The study revealed significant improvements in glass transition temperature, impact strength, and transverse strength. The peak values were often seen in the 1.5% wt. group. Surface roughness, however, showed non-significant changes with nanoparticle additions, possibly due to the minimal involvement of nanoparticles on the outer surface. Conclusion: Incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture base materials demonstrated notable enhancements in key mechanical properties. The findings suggest that nanoparticle additions contribute to increased strength and rigidity, as evidenced by improvements in impact and transverse strength. However, surface roughness remained largely unaffected. This study contributes valuable insights into the potential benefits of nanotechnology in optimizing dental materials for improved clinical performance and patient outcomes.

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

To evaluate the effect of adding tea tree oil to denture liners on Candida albicans and bond strength to the acrylic denture base. 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). 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). 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.

Physico-chemical and Mechanical Assessments of a New 3D Printed PMMA-Based Acrylic Denture Base Material

Background Three-dimensional (3D) printing is progressively being applied in the dental arena due to its time-saving potential and low cost, especially for the digital preparation of acrylic resin denture bases in the treatment of edentulism. Objective This study investigated the flexural strength, surface properties, water sorption, and solubility of a new poly (methyl methacrylate) (PMMA) resin denture base fabricated with a 3D printer (test group) and compared it with a conventional heat-cured resin (control group). Materials and Methods Sixty cuboid wax samples were prepared from two groups, with a thickness of 4 mm and dimensions of 10×80 mm. Then, half of the samples in each group were thermocycled to determine the strength, surface properties, water sorption, and solubility of the samples. Two-way ANOVA and independent t-test were used at a significance level of 0.05 after the normality of data in groups was tested with the Kolmogorov-Smirnov. Results Based on the obtained results, the flexural strength was higher in heat-cured resins than in the resin fabricated with the 3D printer. However, the flexural strength values in both resins were clinically acceptable (65 MPa) based on ISO standards. There was no significant difference in the mean flexural strength in the presence or absence of thermal stress for both groups. The layered structure was observed in the samples fabricated with two groups. However, the layering structure disappeared in all cases after polishing. The layering structure had no differences in the presence or absence of thermal stress. Mass change over time was observed for all groups. In the water sorption phase, the mass increased rapidly in the first 7 days, and then the increase rate decreased until it reached an equilibrium on day 21. In the desorption phase, the mass decreased steadily in the first 7 days, and then reduction was continued until equilibrium was obtained on day 21 of the dewatering process. Conclusion The 3D printer samples had greater water sorption, and no differences were found between the solubility of 3D printer samples and heat-cured samples. Heat-cured resin exhibited enhanced water sorption after thermal cycling, and 3D-printed materials displayed no significant change.

Evaluation of flexural strength, impact strength, and surface microhardness of self-cured acrylic resin reinforced with silver-doped carbon nanotubes

BackgroundPoly-methyl methacrylate (PMMA) is a type of polymer mostly used to make denture bases. Self-cured acrylic resin (PMMA) can be used to repair a fractured acrylic denture base; however, even after repair, this area remains vulnerable. Carbon nanotubes (CNTs) could be used as a filler for polymer reinforcement. Furthermore, silver nanoparticles are efficient agents for the prevention of dental biofilm and improving their mechanical properties. The doping of CNTs with silver nanoparticles may lead to a synergistic interaction that is predicted to enhance the mechanical characteristics of the fillers.ObjectivesThe aim of the study was to assess the influnce of manual incorporation of 0.5% weight percent (%wt.) of silver doped carbon nanotubes (Ag-doped CNTs) into commercial self-cured PMMA on its flexural strength, impact strength, and surface microhardness.MethodsIn this investigation, a total of 60 specimens comprised of acrylic resin were employed. They are divided into two main groups: (a) the control group, which was made by using liquid monomer and commercial self-cured PMMA powder; and (b) the modified group, prepared by hand mixing the purchased silver-doped CNTs powder (0.5% wt.) to self-cured PMMA powder (99.5%wt.), and then the blended powder was incorporated into the liquid monomer. Flexural strength, flexural modulus, impact strength, and surface microhardness were evaluated. Independent sample t-tests were used to statistically analyze the data and compare the mean values of flexural strength, flexural modulus, impact strength, and surface microhardness (p-value ≤ 0.05).ResultsThe flexural strength of the modified groups with Ag-doped CNTs (132.4 MPa) was significantly greater than that of the unmodified (control) groups (63.2 MPa). Moreover, the flexural modulus of the modified groups with Ag-doped CNTs (3.067 GPa) was significantly greater than that of the control groups (1.47 GPa). Furthermore, the impact strength of the modified groups with Ag-doped CNTs (11.2 kJ/mm2) was significantly greater than that of the control groups (2.3 kJ/mm2). Furthermore, the microhardness of the modified groups with Ag-doped CNTs (29.7 VHN) was significantly greater than that of the control groups (16.4 VHN), (p-value = 0.0001).ConclusionThe incorporation of 0.5% wt. silver doped CNTs fillers to the self-cured acrylic resin enhanced its flexural strength, flexural modulus, impact strength, and surface microhardness.

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

This study proposed to assess the effect of Cryptocarya moschata extract on single and mixed biofilms formed on denture base and reline acrylic resin. 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). 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. Cryptocarya moschata extract reduced the single and mixed biofilms of C. albicans and S. mutans on acrylic resins.

Anticandedal Effect action of Different Concentrations of Aglycon fraction of Anthroquinon (monoanathron) isolated from Aloe vera on Heat cure Acrylic Resins

Aim of study: to investigate the effects of different concentrations of aloe vera , aglycon part (monoanathron ) against candida albicance adhere to two types of heat cure acrylic resin denture base (conventional and Hi- impact) on two periods of time (30 minutes and 8 hours).&#x0D; Materials &amp; methods: A total of 120 specimens were prepared, sixty specimens of each hot cure denture base acrylic resin material, each sixty specimens were farther divided into two subgroups of 30 specimens according to the time of immersion, each 30 specimens were farther subdivided into three 10 specimen groups according to the concentration of aleo vera used, isolation of free aglycon (Monoianthron) from anthroquinon glycoside of aloe vera plant; Candida albicans isolation and identification and preparation of candida albicans suspension; autoclaved specimens of each sub-group for both heat cure acrylic resins were placed into the tubes containing brain heart infusion plus inoculum and remained for 12 hours at 37 0C in order to favor an initial colonization of the acrylic resin surfaces, the disinfection step was performed over two periods, colony formation was then counted after incubation.&#x0D; Results: The two concentration of aloe Vera studied in the present investigation exhibited varying degree of inhibitory effect against candida albicans adherent to different type of heat cure denture base acrylic resins. The degree of inhibition varied depending on the concentration of the extract while the period of immersion has no significant effect on the number colony.&#x0D; Conclusion: with the limitation of this study it can be concluded that 100% and 75% concentrations of monoanthron aglycon part of anthroquinon isolated from aloe vera have anticandidal effect, 100%concentration has higher effect than75%. Immertion period has no effect on the anticandidal activity of the solutions.

The Effect of some Natural Products as a Denture Cleansers on some Physical Properties of Acrylic Denture Base Material

The study aims to evaluate the effect of some commercially available natural products (soda+ vinegar, soda +thymol , saturated salt solution) in relation to the commercial denture cleansers (Protifex) ,on surface roughness and hardness dimensional accuracy of acrylic denture base materials. one hundred samples were prepared from heat activated acrylic resin denture base material, they are (1cm*1cm*2mm length, width and thickness respectively). After that, half of the samples for each group were immersed for ½ hr per day in the denture cleanser, the other half of the samples immersed for 8 hr per day in the denture cleanser through one month. The denture cleansers used are three solutions prepared freshly everyday for immersion of the samples. The surface roughness of the samples were tested by using Stylus profilometer(Talysurf 10, England), while the hardness of the samples were tested by using Rockwell hardness tester (Wolpert, Germany), the mean is taken for each group and evaluated by using one way analysis of variance test, Dunnet T-test to compare the groups. The results demonstrated that there were no significant differences in the surface roughness and hardness, but with significant difference between treats of length of acrylic resin denture base material and duration of immersion at (P=0.05). All the prepared natural solutions would be accepted in relation to effect on surface roughness , dimensional accuracy, and hardness of acrylic denture base material.

A Different Approach to Analyzing the Surface Roughness of Prosthetic Dental Acrylic Resins

(1) Introduction: Apart from the polishing method, conventional or mechanized, the arithmetic mean roughness (Ra) is the most common metric to evaluate the surface roughness of denture base acrylic resins. An overview of the constraints related to this roughness parameter is highlighted in this study. This research introduces new parameters for accessing a functional analysis of surface roughness. (2) Materials and Methods: Five samples of CAD/CAM 3D-printed acrylic resins were prepared. Two polishing techniques, manual and mechanical, were applied. Surface roughness parameters were extracted from a profilometer reading: arithmetic mean height (Ra and Pa), skewness (Rsk and Psk), and kurtosis (Rku and Pku). (3) Results: Significant differences (p &lt; 0.001) were found in the Ra distribution among the study samples, in contrast with the lack of significance in Pa values. Surface roughness parameters revealed an increased coefficient of variance (CV) value due to mechanized polishing across the specimens analyzed. Skewness and kurtosis indicate a more pronounced distribution with the manual polishing technique. (4) Conclusion: This preliminary study exhibits the influence of different polishing protocols on surface roughness parameters. The primary profile, skewness, and kurtosis should be assessed for the surface characterization of acrylic resins.

Effect of Beverage Solutions on Flexural Strength of PEEK CAD –CAM, 3D Printing Denture Base and Heat Cure Acrylic Resin Denture Base Materials

This research was to evaluate the effect of distilled water (D.W.), tea, coffee, and cola on flexural strength of PEEK CAD-CAM, 3D printing and heat cure acrylic resin denture base at different durations (6, 12and 24 days). Material used in this research are PEEK, 3D printing and Heat cure acrylic resin with dimension (64 × 10 × 3.3 ±0.2 mm, ISO 20795- 1:201320) for each tested material. Total number of samples are n= (195) samples, Control samples n=15, experimental samples n=180.The control samples were non immersed in beverage media. The experimental samples were immersed in beverage media (distilled water, tea, coffee, and cola) for evaluating the flexural strength at different time which are (6, 12 and 24 days), then all collecting data were statically analyzed by spss version 25, by means of Descriptive statistics, analysis of Variance (ANOVA) and Duncan multiple range tests at p ≤ 0.05. The beverage solutions had been non significantly decreased the flexural strength and this decreasing worst as the immer sion periods increased, the most decreasing in flexural strength o f PEEK denture base was achieved in 24 immersion days in cola (252.0960 MPa ±5.19825) followed by coffee (253.4360 MPa ± 6.60975) followed by tea(253.7780 MPa ± 6.44697) followed by distilled water (254.1420 MPa ±7.41318) as comparing with control(260.2420MPa ±5.08412), the most decreasing in flexur al strength of 3D printing denture base was achieved in 24 immersion days in cola (103.1680 MPa ±12.26532) followed by coffee (105.4360 MPa ±12.36951) followed by tea (10 7.4530MPa ±11.47399) followed by distilled water (109.1320 MPa ±11.66156) as comparing with control(119.7140 MPa ± 12.25421), the most decreasing in flexural strength of heat cure acrylic resin denture base was achieved in 24 immersion days in cola (118.5640MPa ±13.06764) follow ed by coffee (122.3640MPa ± 9.78213) followed by tea( 123.5600MPa ±14.05144) followed by distilled water (126.3620 MPa ± 11.35254) as comparing with control (134.6420 MPa ± 9.79330) at p ≤ 0.05. All beverage media had been negatively aff ected the flexural strength of all experimental materials and as t he immersion periods increased the affect became worst. The aggressive effect was in cola followed by coffee followed by tea and the least effect was in D.W. beverage media. The worst immersion period was 24 then 12 and 6 days. for all tests use but this affect was non significantly.

Effect of Beverage Solutions on Surface Roughness of PEEK CAD –CAM, 3D Printing Denture Base and Heat Cure Acrylic Resin Denture Base Materials

The Aim: The aim of this research was to investigate how distilled water, tea, coffee, and cola affected the surface roughness of poly ether ether ketone CAD-CAM, 3D printing, and heat cure acrylic resin denture bases at specific intervals (6 ,12days). Materials and Methods: Disk shape 10 mm (diameter) ×2 m m (thickness), manufactured from materials used which were PEEK, 3D printing and heat cure acrylic resin. Total number of samples are n= (75) samples, control samples not immersed in beverage media n= 15, experimental samples immersed in beverage solutions (distilled water, tea, coffee and cola) n=60 for evaluating the surface roughness at (6, 12 and 24 days) .Then all collecting data were statically analyzed by spss v ersion 25, by means of descriptive statistics, analysis of variance (ANOVA) and duncan multiple range tests at p ≤ 0.05. The Results: The results revealed a significant increase in surface roughness in all beverage solutions at p ≤ 0.0 5. Conclusions: All beverage solutions had a negative effect on surface roughness of all experimental materials, the surface roughness increased. cola had the most aggressive effect followed by coffee then tea and distilled water have the least ef fect.

Comparative Evaluation to Surface Roughness of Modified Heat Cured Acrylic Resin by Zinc Oxide Nanoparticles and CAD/CAM Denture Base Materials - In Vitro Study

One of the most promising CAD/CAM approaches is milling denture base materials from highly condensed pre-polymerized resin discs. In an effort to overcome the disadvantages of acrylic resin denture base materials, nano-filler materials have been added as well as denture base chemistry adjusted to strengthen the denture base.This eliminates disadvantages associated with polymerization shrinkage compared to conventional heat-cured acrylic resin. Aim of this study: evaluate the surface roughness of PMMA acrylic resin after strengthening the denture- base by addition of zinc oxide nano-filler material to acrylic resin PMMA with concentration (1%) and compare with milled CAD/CAM and non-modified heat-cured PMMA denture base materials. Materials and methods: thirty specimens of acrylic resin PMMA were prepared and divided into three groups 10 specimens for each groups as follows; Control Group (Group1) without ZnO nanoparticles ; Group (2) with (1%) by weight of ZnO nanoparticles ; Group (3) milled CAD/CAM.Each specimen is of dimension ( 10 x 10 x 3 ) in mm and was fabricated using conventional processing method and milling the CAD/CAM blocks .Results: showed the lowest mean value was recorded by milled CAD/CAM (0.230 Ra) Then the non-significant reduction with mean value (0.312 Ra) by PMMA+ ZnO 1% and highest mean value of surface roughness was recorded by pure PMMA without additive (0.327 Ra).Conclusions: There were significant differences between control group PMMA and milled (CAD/CAM) with slight reduction of surface roughness of PMMA with (1%) Zno nanoparticles.

Colour Stability of Two Different Denture Base Resins and the Efficacy of Two Denture Cleansing Agents after Tea and Coffee Staining: An In-vitro Study

Introduction: In dentistry, colour is one of the most important dimensions of aesthetics. Due to the diverse food habits in India, stains accumulate on dentures. Various denture cleansing agents such as Fittydent and Clinsodent are widely used, emphasising the importance of patient oral hygiene. Aim: To evaluate the colour stability of heat-cure activated acrylic denture base resins {Dental Products of India (DPI) and Trevalon} after staining with tea and coffee, subsequently treated with Clinsodent, Fittydent, and distilled water (control group) as cleansing agents. Materials and Methods: This in-vitro study was conducted at Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Nagpur, in the Department of Prosthodontics, Crown and Bridge, and Implantology in collaboration with Indorama, Nagpur, Maharashtra, India, over a period of approximately 90 days (August-October 2017). Total 120 samples were prepared in-vitro study using custom-made brass metal discs measuring 10 mm by 2 mm. Trevalon and DPI heat-cure acrylic denture base resins were used for sample preparation. Baseline colour stability values were established after immersing the samples in distilled water at 37°C for 24 hours. The samples were then stained for eight hours, followed by immersion in different cleansing agents and distilled water for 12 hours. This process was repeated every 24 hours for 60 days, with the staining and cleansing agents replenished daily. Colour measurements were taken at baseline, 15th, 30th, 45th, and 60th days. Statistical analysis involved t-tests and one-way Analysis of Variance (ANOVA). Results: The DPI denture base resin exhibited a highly significant ∆E (change in energy) at 45 days (p=0.0001), while Trevalon showed significance at 60 days (p=0.0079). The difference in means was statistically significant using t-tests for independent samples, and the variance-measure analysis indicated statistical significance in the means of ∆E. The comparison of the three cleansing agents at 60 days was statistically obtained using one-way ANOVA. Conclusion: Dental Products of India (DPI) showed more colour variation than Trevalon. Tea showed a higher staining than coffee. Staining intensity increased over time, peaking at 45 days and stabilising thereafter. Clinsodent is better than Fittydent in removing stains.

Impact of adding 3% titanium oxide nanoparticles in different denture base materials on some of the biological, physical, and mechanical properties properties: In-vitro study

Background/aim Acrylic resin denture base material with all its varieties and curing techniques enormously influence their physical, biological, and mechanical properties. This study designed to evaluate and compare the impact of acrylic resin reinforcement with titanium oxide nanoparticles (TiO2NP) on physical, biological, and mechanical criteria of two dissimilar denture base materials. Materials and methods This study was constructed on 120 specimens of 2 different types of acrylic resin denture base materials. The specimens were divided equally into 2 groups (60 each), group I (heat cured acrylic resin) and group II (microwave cured acrylic resin). Each group was additionally divided into two subgroups (each 30). Subgroup A as control, while subgroup B was modified with 3% TiO2NP. Biological evaluation was performed on Enterococcus faecalis by using antimicrobial assay by agar diffusion test color stability via employing spectrophotometer, and the Modulus of elasticity through universal testing machine. Results Regarding the results of biological assessment, groups IA and IIA (control groups) revealed no inhibitory zone, while groups modified with 3% TiO2NP group IIB demonstrated significantly higher (P &lt; 0.05) inhibitory zone when compared with group IB. Concerning color stability, Regarding color stability, Group IA and IIA (control groups) demonstrated the highest color changes, while Group IB and IIB(modified groups) demonstrated the lowest color changes. In modulus of elasticity, groups IB and IIB were significantly higher (P&lt;0.05) than groups IIA and IIB. Conclusion Adding 3% TiO2NP to heat and microwave cured resins induced antibacterial characteristics against E. faecalis. Besides improvement of the evaluated mechanical (modulus of elasticity) and color stability properties.

The antimicrobial activity of an antiseptic soap against Candida Albicans and Streptococcus Mutans single and dual-species biofilms on denture base and reline acrylic resins.

To evaluate the effect of antiseptic soap on single and dual-species biofilms of Candida albicans and Streptococcus mutans on denture base and reline resins. Samples of the resins were distributed into groups (n = 9) according to the prevention or disinfection protocols. In the prevention protocol, samples were immersed in the solutions (Lifebuoy, 0.5% sodium hypochlorite solution and PBS) for 7, 14 and 28 days before the single and dual-species biofilms formation. Overnight denture disinfection was simulated. In the disinfection protocol, samples were immersed in the same solutions during 8 hours after the single and dual-species biofilms formation. Antimicrobial activity was analyzed by counting colony-forming units (CFU/mL) and evaluating cell metabolism. Cell viability and protein components of the biofilm matrix were evaluated using confocal laser scanning microscopy (CLSM). Data were submitted to ANOVA, followed by Tukey's post-test (α = 0.05) or Dunnett's T3 multiple comparisons test. In the prevention protocol, Lifebuoy solution effectively reduced the number of CFU/mL of both species. In addition, the solution decreased the cell metabolism of the microorganisms. Regarding disinfection protocol, the Lifebuoy solution was able of reduce approximately of 2-3 logs for all the biofilms on the denture base and reline resin. Cellular metabolism was also reduced. The images obtained with CLSM corroborate these results. Lifebuoy solution was effective in reducing single and dual-species biofilms on denture base and reline resins.

Effect of denture base acrylic resin containing silver nanoparticles on Candida Albicans adhesion and its release in artificial saliva

Background Candida albicans was considered a main reason of precipitate formations and decomposition of acrylic denture base; so many trials were objected to resist this microbial action and prolong the shelf life of the formulated fitting base. Aim of the work The present study aimed to adopt a new mixture of the silver nanoparticles with the PMMA denture base to get a prolonged antimicrobial protection for the formed base against Candida albicans. Statement of problem Accumulation of Candida Albicans on fitting surface of poly methyl meth-acrylate (PMMA) denture base. Purpose To evaluate the effect of denture base acrylic resin containing silver Nanoparticles (Ag NP) on Candida Albicans adhesion and its release in artificial saliva. Materials and methods Sixty round disks with dimensions of 15 mm diameter and 3 mm thickness specimens were prepared for this research. Control group A: 10 specimens were prepared from pure PMMA. Experimental group B: 50 specimens were prepared from PMMA containing 5% of Ag NP. Isolation and identification of Candida Albicans were taken from oral cavity of 10 patients by swabbing. The Specimens were immersed in artificial saliva for 3, 6, and 9 months. Microbiological test was done for specimens of each group to detect Candida Albicans accumulation at the same interval period by measuring the inhibition zone created around the disks. Specimens were taken from the artificial saliva to evaluate silver release in it by using UV-Vis Spectrophotometer Instrument ‘SHIMADZO UV-310 PC. For Spectrophotometer 1.0 cm and/or 0.2 cm matched silica cells. The amount of accumulated silver released was calculated to detect its cytotoxic effect1. Results For control group A there was no inhibition zone for Candida growth around the specimens. While for group B with Ag NP the greatest antimicrobial effect was found at zero time then was decreased gradually with increasing the time till reaching zero effect after 9 months resembling the control group. The amount of Nano silver in artificial saliva after 3 months was found to be little then it was increased gradually with increasing time. Conclusion Adding Ag NP to PMMA denture base has antimicrobial effect against Candida Albicans for only 9 months; then there was no effect as silver was released in saliva. The amount of released silver was found to be with no cytotoxic effect.

EFFECTS OF ADDITION OF CHITOSAN AND DICARBOXYLIC ACID ON PROPERTIES OF 3D PRINTABLE ACRYLIC RESIN DENTURE BASE

3D-printing has gained popularity in recent years due to the many advantages it offers over the traditional approaches for instance this technology reduces the time a dentist needs to create and fit dentures to just 2–3 sessions. Fumaric, maleic, and adipic acids with the percentage (0.1 wt.%) were added to chitosan solution (2 wt.%) and the final composite was added to the 3D printable acrylic resin. The specimens were examined for several chemical analyses (XRD, SEM, FTIR) and mechanical tests (impact strength and surface hardness tests), where the total number (115) of specimens used in the study was specimens divided into five groups. In chemical analysis, one specimen was constructed for each modified group and one specimen was used as the control group (3d printable resin without addition (non-modified) for each test. For mechanical tests ten specimens were constructed for each modified group and ten specimens were used as the control group (3d printable resin without addition (non-modified) for each test. The results of chemical analysis showed improvement in the properties of modified 3d printable acrylic denture base resin, additionally the mechanical test results showed that the (Fumaric acid and Maliec acid with Chitosan) specimens have the highest properties in comparison with other specimens, while the lowest properties were for specimens of 3D printable acrylic resin with chitosan. The chemical and mechanical properties of the modified 3D-printed denture base are improved when chitosan is modified with dicarboxylic acids. Conversely, if chitosan alone is used to modify the 3D-printed polymers, the mechanical and chemical properties would be decreased.