Determination of the effective anticandidal concentration of denture cleanser tablets on some denture base resins

Antimicrobial activity of cleanser tablets against S. mutans and C. Albicans on different denture base materials

BACKGROUND

In this study, the antimicrobial activity of three different cleanser tablets on S. mutans and C. albicans adhesion to PMMA, polyamide and 3D printed resin was investigated.

METHODS

40 samples were prepared for PMMA (SR Triplex Hot), polyamide (Deflex) and 3D printed resin (PowerResins Denture) materials and divided into four subgroups for cleansers (Aktident™, Protefix™, Corega™ tablets and distilled water) (n = 5). After the surface preparations were completed, the samples were immersed separately in tubes containing the prepared microorganism suspension and incubated at 37˚C for 24 h. After the incubation, the samples were kept in the cleanser solutions. The samples were then transferred to sterile saline tubes. All the tubes were vortexed and 10 µl was taken from each of them. Sheep blood agar was inoculated for colony counting. The inoculated plates were incubated for 48 h for S. mutans and 24 h for C. albicans. After incubation, colonies observed on all plates were counted. Statistical analyses were done with three-way ANOVA and Tukey's multiple comparison test.

RESULTS

Polyamide material registered the highest colony count of S. mutans, whereas PMMA registered the lowest. Significant differences in S. mutans adherence (p = 0.002) were found between the three denture base materials, but no such difference in C. albicans adherence (p = 0.221) was identified between the specimens. All three cleanser tablets eliminated 98% of S. mutans from all the material groups. In all these groups, as well, the antifungal effect of Corega™ on C. albicans was significantly higher than those of the other two cleanser tablets.

CONCLUSIONS

According to the study's results, it may be better to pay attention to surface smoothness when using polyamide material to prevent microorganism retention. Cleanser tablets are clinically recommended to help maintain hygiene in removable denture users, especially Corega tablets that are more effective on C. albicans.

Anti-biofilm effectiveness of protocols for cleaning complete dentures in hospitalized patients: a randomized controlled trial

BACKGROUND

Denture biofilm acts as a potential reservoir for respiratory pathogens, considerably increasing the risk of lung infections, specifically aspiration pneumonia, mainly 48h after hospital admission. The establishment of a straightforward, affordable, and applicable hygiene protocol in a hospital environment for the effective control of denture biofilm can be particularly useful to prevent respiratory infections or reduce the course of established lung disease.

OBJECTIVES

To evaluate the anti-biofilm effectiveness of denture cleaning protocols in hospitalized patients.

METHODOLOGY

The maxillary complete dentures (MCDs) of 340 hospitalized participants were randomly cleaned once using one of the following 17 protocols (n=20): brushing with distilled water, toothpaste, or neutral liquid soap (controls); immersion in chemical solutions (1% sodium hypochlorite, alkaline peroxide, 0.12% or 2% chlorhexidine digluconate), or microwave irradiation (650 W for 3 min) combined or not with brushing. Before and after the application of the protocols, the biofilm of the intaglio surface of the MCDs was evaluated using two methods: denture biofilm coverage area (%) and microbiological quantitative cultures on blood agar and Sabouraud Dextrose Agar (CFU/mL). Data were subjected to the Wilcoxon and Kruskal-Wallis tests (α=0.05).

RESULTS

All 17 protocols significantly reduced the percentage area of denture biofilm and microbial and fungal load (P<0.05). The highest percentage reductions in the area of denture biofilm were observed for 1% hypochlorite solution with or without brushing and for 2% chlorhexidine solution and microwave irradiation only in association with brushing (P<0.05). The greatest reductions in microbial and fungal load were found for the groups that used solutions of 2% chlorhexidine and 1% hypochlorite and microwave irradiation, regardless of the association with brushing (P<0.05).

CONCLUSIONS

A single immersion for 10 min in 1% sodium hypochlorite, even in the absence of brushing, proved to be a straightforward, rapid, low-cost, and effective protocol for cleaning the dentures of hospitalized patients.

Strategies for Preventing and Treating Oral Mucosal Infections Associated with Removable Dentures: A Scoping Review

Oral infections occur due to contact between biofilm rich in Candida albicans formed on the inner surface of complete dentures and the mucosa. This study investigated historical advances in the prevention and treatment of oral mucosal infection and identified gaps in the literature. Bibliographic research was conducted, looking at PubMed, Embase, Web of Science, and Scopus, where 935 articles were found. After removing duplicates and excluding articles by reading the title and abstract, 131 articles were selected for full reading and 104 articles were included. Another 38 articles were added from the gray literature. This review followed the PRISMA-ScR guidelines. The historical period described ranges from 1969 to 2023, in which, during the 21st century, in vitro and in vivo studies became more common and, from 2010 to 2023, the number of randomized controlled trials increased. Among the various approaches tested are the incorporation of antimicrobial products into prosthetic materials, the improvement of oral and denture hygiene protocols, the development of synthetic and natural products for the chemical control of microorganisms, and intervention with local or systemic antimicrobial agents. Studies report good results with brushing combined with sodium hypochlorite, and new disinfectant solutions and products incorporated into prosthetic materials are promising.

Anti-Microbial Effect of AgBr-NP@CTMAB on Streptococcus Mutans and Assessment of Surface Roughness Hardness and Flexural Strength of PMMA

Purpose

To investigate the inhibition of Streptococcus mutans (S.mutans) and its biofilm by AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) and evaluate the changes in Polymethyl methacrylate (PMMA)'s surface roughness (Ra), microhardness, and flexural strength during prolonged immersion in AgBr-NP@CTMAB for application in the denture cleaning industry.

Patients and Methods

The antibacterial activity of AgBr-NP@CTMAB against S.mutans was measured colony formation assay, OD600 and laser confocal microscopy. Changes in the specimens' values for surface roughness, microhardness, and flexural strength (MPa) were measured after immersion solutions for 180 or 360 days.

Results

The AgBr-NP@CTMAB solution exhibited a robust antibacterial effect on planktonic S. mutans, with a minimum bactericidal concentration of 5 µg/mL. The 10 µg/mL AgBr-NP@CTMAB solution efficiently inhibited S. mutans biofilm formation. (2) No significant difference in surface roughness after immersion in AgBr-NP@CTMAB (10 µg/mL and 20 µg/mL) comparing with distilled water (P > 0.05) and Polident had significantly higher than distilled water (P < 0.05). There was a significant decrease in the surface hardness of the PMMA specimens that were immersed in the Polident compared with those in distilled water (P < 0.05). While, no significant differences in surface hardness after immersion in the AgBr-NP@CTMAB (P > 0.05). The result of flexural strength suggested that there was no statistically significant difference (P < 0.05) between AgBr-NP@CTMAB as well as Polident and water.

Conclusion

AgBrNP@CTMAB can efficiently inhibit the growth of plankton S.mutans and biofilm formation, without affecting the flexural strength, microhardness, or surface roughness of PMMA. Therefore, AgBrNP@CTMAB holds promise as a new denture cleaning agent.

Different Polymers for the Base of Removable Dentures? Part II: A Narrative Review of the Dynamics of Microbial Plaque Formation on Dentures

This review focuses on the current disparities and gaps in research on the characteristics of the oral ecosystem of denture wearers, making a unique contribution to the literature on this topic. We aimed to synthesize the literature on the state of current knowledge concerning the biological behavior of the different polymers used in prosthetics. Whichever polymer is used in the composition of the prosthetic base (poly methyl methacrylate acrylic (PMMA), polyamide (PA), or polyether ether ketone (PEEK)), the simple presence of a removable prosthesis in the oral cavity can disturb the balance of the oral microbiota. This phenomenon is aggravated by poor oral hygiene, resulting in an increased microbial load coupled with the reduced salivation that is associated with older patients. In 15-70% of patients, this imbalance leads to the appearance of inflammation under the prosthesis (denture stomatitis, DS). DS is dependent on the equilibrium-as well as on the reciprocal, fragile, and constantly dynamic conditions-between the host and the microbiome in the oral cavity. Several local and general parameters contribute to this balance. Locally, the formation of microbial plaque on dentures (DMP) depends on the phenomena of adhesion, aggregation, and accumulation of microorganisms. To limit DMP, apart from oral and lifestyle hygiene, the prosthesis must be polished and regularly immersed in a disinfectant bath. It can also be covered with an insulating coating. In the long term, relining and maintenance of the prosthesis must also be established to control microbial proliferation. On the other hand, several general conditions specific to the host (aging; heredity; allergies; diseases such as diabetes mellitus or cardiovascular, respiratory, or digestive diseases; and immunodeficiencies) can make the management of DS difficult. Thus, the second part of this review addresses the complexity of the management of DMP depending on the polymer used. The methodology followed in this review comprised the formulation of a search strategy, definition of the inclusion and exclusion criteria, and selection of studies for analysis. The PubMed database was searched independently for pertinent studies. A total of 213 titles were retrieved from the electronic databases, and after applying the exclusion criteria, we selected 84 articles on the possible microbial interactions between the prosthesis and the oral environment, with a particular emphasis on Candida albicans.

Effect of Denture Cleanser on the Physico-Mechanical Properties of Injection-Molded Thermoplastic Polyamides Denture Base Material: A preliminary Study

Objectives

This study aimed to assess the color stability, surface roughness, and flexural properties of the injection-molded thermoplastic polyamide Vertex ThermoSens denture base resin following a 3-minute immersion in Polident 3-minute denture cleanser.

Methods

Sixty specimens (Vertex ThermoSens) were processed and divided into two main groups (n = 30) based on the type of test. Group 1 was further subdivided into two subgroups (n = 15): the control group immersed in distilled water (G1DW) and the test group immersed in Polident cleanser solution (G1PD). Group 2 was divided into three subgroups: a non-immersed group (G2None), a group immersed in distilled water (G2DW), and a group immersed in Polident cleanser solution (G2PD). Color change (∆E) and surface roughness measurements were conducted for group 1, and flexural modulus (E) test was performed for group 2. The CIE Lab* formula was utilized to calculate ∆E. An optical 3D surface analyzer and a three-point bending test were employed for surface roughness and E assessments, respectively. Data were subjected to statistical analysis using a paired-sample t-test for differences within each group before and after immersion. Furthermore, independent-sample t-tests and one-way ANOVA were conducted to analyze differences between groups. A significance level of P < 0.05 was considered.

Results

The results revealed a slight, statistically insignificant (P > 0.05) ∆E in all color components (L*, a*, b*) after immersion in distilled water. However, after immersion in the denture cleanser, only the L* component exhibited a statistically significant ∆E (P = 0.002), which was slight in magnitude. Additionally, a significant difference was found in the ∆E between G1DW and G1PD, with G1PD showing a higher change (P = 0.007). A significant increase in surface roughness after immersion was observed in G1PD (P = 0.017), with a notable difference between G1DW and G1PD. However, the E remained unaffected (P = 0.537).

Conclusion

Denture cleansers have the potential to modify the properties of thermoplastic polyamide resin. Further research is needed to explore the clinical implications of these observed changes on denture performance.

Effects of two novel denture cleansers on multispecies microbial biofilms, stain removal and the denture surface: an in vitro study

BACKGROUND

The continuously increasing demand for removable denture appliances and the importance of adequate denture cleaning have led to the development of various denture cleansing products. The aim of this study was to evaluate the efficacy of two novel denture cleansing agents (GE and TM) and three commonly available cleansers (0.5% sodium hypochlorite; NaClO, 0.12% chlorhexidine gluconate; CHX, and Polident®; POL) on multispecies microbial biofilm formation, stain removal and physical properties of dentures.

METHODS

The antimicrobial activities of denture cleansing agents were determined against major oral opportunistic pathogens including Streptococcus mutans, Staphylococcus aureus, Escherichia coli and Candida albicans, using time-kill assays. Multispecies microbial biofilms grown on acrylic resins for 72 h were generated to determine the antibiofilm effects of cleansing agents by confocal laser scanning microscopy (CLSM). Evaluations of the tea and coffee stain removal properties and the alterations in the physical properties of dentures were also performed. The toxicity of cleanser residues released from denture acrylics to fibroblast cells was investigated using MTT assay.

RESULTS

All denture cleansing agents tested could effectively kill oral bacteria and Candida albicans. Furthermore, after immersion for more than 3 h, the cleansers Polident®, GE and TM could efficiently penetrate and inhibit multispecies denture biofilms with effects similar to 10 min of immersion in 0.5% NaClO. However, immersion in 0.12% CHX for 20 min showed less antibiofilm activity. The NaClO solution had the highest efficacy for removing stains from the artificial teeth. Conversely, the CHX solution enhanced tea and coffee staining, and the teeth immersed in this solution showed clinically unacceptable colour changes (ΔE > 5.5). However, the colour differences of teeth stained and immersed in POL, GE and TM cleansers were in the clinically acceptable range. There was no significant difference among the POL, GE and TM cleansers in terms of stain removal efficacy. The cleansers GE and TM did not alter the surface roughness and colour of the materials, moreover the residues of both cleansers did not exhibit cytotoxicity.

CONCLUSION

Two novel denture cleansing agents containing natural products, GE and TM exhibited effective antimicrobial activity, antibiofilm and stain removal capabilities without toxicity or disturbance of the physical properties of acrylics.

Storage-related stability and antimicrobial efficacy of bottled, neutral-pH Electrolysed Oxidising Water

OBJECTIVES

Denture stomatitis is prevalent in older people and poses serious health risks. Ready-to-use (RTU) neutral-pH Electrolysed Oxidizing Water (EOW) is an effective environmental disinfectant used in residential care settings and geriatric wards. However, the influence of storage on stability and effectiveness for denture disinfection has not been established. This research investigated the storage-related stability and antimicrobial activity of RTU EOW, and its efficacy against Candida albicans biofilms formed on denture resin.

METHODS

The pH, oxidation/reduction potential (mV), available chlorine content (mg/L) and [HOCl] (mM) of RTU EOW (Envirolyte, New Zealand) solutions (n = 22) were measured from bottle opening to 28 days following storage at 4 °C, room temperature (RT) or 37 °C. Staphylococcus aureus and C. albicans cells were incubated in 80% EOW for contact times (CTs) up to 15 min and colony-forming units (cfu) determined. Minimum inhibitory concentrations (MIC90 EOW-HOCl) after CTs up to five minutes were determined for S. aureus and C. albicans reference strains and clinical isolates. C. albicans-denture resin disc biofilms were assessed after a five-minute CT with undiluted EOW by XTT-metabolic activity assay.

RESULTS

[HOCl] remained stable when RTU EOW was stored at 4 °C or RT for five months after manufacture. One-minute CT resulted in log10 cfu reductions of >6 for S. aureus and >5 for C. albicans. Mean MIC90 for five-minute CT was 37 µM (S. aureus) and 54 µM (C. albicans). Undiluted EOW reduced C. albicans biofilm metabolic activity by 86%.

CONCLUSIONS

RTU neutral-pH EOW is stable over five-months storage and is an effective denture disinfectant.

CLINICAL SIGNIFICANCE

The efficacy of the RTU neutral EOW against C. albicans isolates and biofilms formed on denture resin surfaces supports its use as a denture disinfectant and can inform future research to assess its potential for preventing denture-related oral Candida infections in the older population, especially in resource-limited communities.

Antimicrobial activity of cleansers on the cobalt-chromium surface of removable partial denture: a systematic review

This study aimed to review systematically the literature about the antimicrobial action of evaluated cleansers on the Co-Cr alloy of RPD. The search was conducted in MEDLINE/PubMed, Scopus, Lilacs, Embase and Science Direct May, 2022. The review was performed based on PRISMA guidelines and recorded in Open Science Framework. Independent reviewers performed the search, selection, extraction, and analysis of the data. The risk of bias of the in vitro and clinical trials studies was analyzed by the Joanna Briggs Institute tool. A total of 187 articles were found and 9 were included. The cleansers that showed antimicrobial action were 2% and 5.25% sodium hypochlorite, 0.12% chlorhexidine and NitrAdine effervescent tablet. Polident, Corega Tabs effervescent tablets and 5 mg/mL chitosan solution showed intermediate effects. Propolis and green tea toothpaste were not effective. Three articles presented a high risk of bias and 6, low risk. The cleansers that showed the highest antimicrobial efficacy on Co-Cr alloy were 0.12% chlorhexidine digluconate and NitrAdine and can be safely used on RPD framework.

Feasibility of microencapsulated phytochemical as disinfectant for inhibition of Candida albicans proliferation on denture base produced by digital light processing

BACKGROUNDS

A proper disinfection of denture is vital to prevent a fungal infection. A study on the feasibility of microencapsulated phytochemical as complementary disinfectant and its interaction with effervescent tablet immersion on denture base resin is lacking.

OBJECTIVES

The aim of this study was to examine the feasibility of phytochemical-filled microcapsules as disinfectant for the inhibition of Candida albicans (C. albicans) attachment on the denture base produced by digital light processing (DLP).

METHODS

54 denture base specimens uniformly mixed with or without 5wt% phytochemical-filled microcapsules were prepared using DLP. Fungal cells were inoculated onto the surfaces of the specimens, which were divided into three different disinfection treatment groups (n = 9): 1) none, 2) sterile tap water immersion for 15 min, and 3) effervescent tablet immersion for 15 min. After each treatment, the biofilm on denture surface was stained with a crystal violet solution to measure the absorbance. The number of fungal colonies was counted as colony-forming units (CFU) per mL. Morphological changes were examined by microscopy. An aligned rank transform analysis of variance was performed to analyze the interaction of presence of microcapsule and disinfection condition, with statistical significance set at P < 0.05.

RESULTS

Both for the absorbance and CFU, there was no significant interaction between the presence of microcapsules and disinfection conditions (P = 0.543 and P = 0.077, respectively). The presence of microcapsules was statistically significant (both P < 0.001), while the effect of disinfection condition was not significant (P = 0.165 and P = 0.189, respectively). Morphological changes in fungi were detected in the groups containing microcapsules, whereas undamaged hyphal structures were found in those without microcapsules, irrespective of disinfection treatments.

CONCLUSIONS

The presence of phytochemical-filled microcapsules significantly reduced the adhesion of C. albicans and inhibited its proliferation on denture surfaces, regardless of disinfection conditions.

The Influence of Cleaning Solutions on the Retention of Overdenture Attachment Systems

Dental-implant-supported reconstructions provide comfort and improvements in prosthetic function, adaptation, and stability over conventional treatment options. The objective of this study was to evaluate the effect of different denture cleansing solutions and their influence on the deterioration and loss of retention of overdenture attachments in a 12-month clinical-use simulation. In this way, ten specimens each of different brands of retentive caps made of Teflon (OT Equator^® (Rhein83, Bologna, Italy), Locator^® (Zest Anchors, Escondido, CA, USA), Kerator^® (KJ Meditech, Gwangiu, Republic of Korea), and Locator R-Tx^® (Zest Anchors, Escondido, CA, USA)) were immersed in five different cleaning solutions (Kukident^® (P&G Tech, Oxford Parkway, UK), Benfix^® (Laboratorios URGO S.L., Guipúzcoa, Spain), Corega^® (Stafford Miller, Waterford, Ireland), and Protefix^® (Neuhofer Weiche, Parchim, Germany)), and tap water was used as the control group, in a simulation that lasted 12 months. Data were analyzed using two-way ANOVA and a Tukey HSD. Furthermore, a Levene Test and Shapiro-Wilk tests were performed to assess the validation of the ANOVA assumptions. The statistical analysis was performed using R version 4.2.2 software with the significance level set to p < 0.05. There were significant statistical differences between the different manufacturers regarding the retention forces of the attachment's retentive caps (F = 322.066, p < 0.001). For the cleaning solution groups, different statistical results between Kukident^® (P&G Tech, Oxford Parkway, UK) (p < 0.05) and Benfix^® (Laboratorios URGO S.L., Guipúzcoa, Spain) (p < 0.05) were observed. There were no significant statistical differences between Corega^® (Stafford Miller, Ireland), Protefix^® (Neuhofer Weiche, Parchim, Germany), and tap water, even though the retention forces decreased in all of them.

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.

Effect of sanitizing solutions on cobalt-chromium alloys for dental prostheses: A systematic review of in vitro studies

STATEMENT OF PROBLEM

Given the wide use of cobalt-chromium (Co-Cr) alloys, especially for removable partial dentures, and the importance of chemical solutions to complement the cleaning of dental prostheses, safe disinfection products should be identified for the regular decontamination of Co-Cr dental prostheses.

PURPOSE

The purpose of this systematic review of in vitro studies was to determine the effects on the properties of Co-Cr dental alloys of the various chemical agents used to clean dental prostheses.

MATERIAL AND METHODS

In vitro studies were included based on a literature search conducted in March 2022 in the Medline/PubMed, SCOPUS, Web of Science, Virtual Health Library, and Embase databases. Independent reviewers performed the search, selection, extraction, and analysis of the data. The review was performed based on the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The quality of the included articles was evaluated by using parameters adapted from the Consolidated Standards of Reporting Trials (CONSORT) guidelines, and the risk of bias analysis was performed based on previous studies.

RESULTS

Among the 15 included studies, the chemical agents evaluated were alkaline peroxides and hypochlorites, mouthwashes containing cetylpyridinium chloride and chlorhexidine, diluted acids, and enzymes. Some peroxides produced increased ion release, surface roughness, and mass loss of the alloys. The hypochlorites were responsible for the greatest surface corrosion, yielding dark stains, rough regions, and depressions. Acetic and peracetic acids and mouthwashes containing chlorhexidine and cetylpyridinium did not produce significant changes in Co-Cr alloys. Most studies presented moderate risk of bias.

CONCLUSIONS

According to the included studies, mouth rinses containing cetylpyridinium chloride or chlorhexidine and solutions with acetic and peracetic acid could be safely used to chemically sanitize Co-Cr prostheses. Alkaline peroxides should be used with caution, and alkaline hypochlorite solutions should be avoided.

Antifungal Efficacy of Sodium Perborate and Microwave Irradiation for Surface Disinfection of Polymethyl Methacrylate Polymer

Various disinfecting agents showing variable success in disinfecting polymethyl methacrylate (PMMA) are available. The aim of our study was to evaluate the antifungal efficacy of sodium perborate (denture cleaning tablet-DC), microwave irradiation, and their combination for eradicating candida albicans (C. albicans) from polymethyl methacrylate (PMMA) denture base polymer. One hundred and sixty-eight PMMA resin specimens (30 × 30 × 15 mm) were divided into four groups, including control (no disinfection), microwave disinfection in distilled water (MW-DW), sodium perborate with distilled water (DC-DW), and a combination of MW-DC-DW (n = 10). Biofilms of C. albicans were cultured on the PMMA resin denture base specimens for 96 h. The samples were exposed to three different antifungal regimes, i.e., MW, denture cleaning agent-sodium perborate (DC) and DW, and a combination of MW-DC-DW for 1 to 5 min. Scanning electron microscopy (SEM) was performed to evaluate colony formation. The colony-forming units (CFU) among the experimental groups were assessed using ANOVA, a Kruskal–Wallis test, and a Mann–Whitney test. The mean CFU values were compared with the control for each disinfecting regime at 96 h growth time. For MW-DC-DW, the CFU were significantly low at 2 and 3 min of exposure when compared with the control (DW) (p < 0.05). For the MW-DW treated group, the CFU were significantly low at 3 min of exposure when compared with the control (DW) (p < 0.05). It was also found that for DC-DW, the CFU were significantly low at 5 minutes when compared with the control specimens (DW) (p < 0.05). Microwave disinfection in combination with sodium perborate is a more effective disinfecting regime against C. albicans than that of microwave disinfection and sodium perborate alone.

Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent

The aim was to evaluate the disinfection of E. coli, S. aureus and S. mutans cultured on Polymethyl Methacrylate (PMMA) resin polymer using microwave disinfection and sodium perborate (DC). Biofilms of E. coli, S. aureus and S. mutans were cultured on the PMMA denture base for 24, 36, 48 and 96 h. Specimens were subjected to three disinfection protocols, including microwave disinfection in distilled water (MW-DW), sodium perborate (denture cleaning tablet) with distilled water (DC-DW) and a combination of MW-DC-DW for 1 to 5 min. Colony-forming units among the study groups were analyzed using Kruskal–Wallis and Mann–Whitney tests. For E. coli and S. aureus cultured on PMMA, the MW-DC-DW group displayed complete disinfection at 2 min of exposure. However, for both bacteria, the MW-DW disinfection group showed zero CFU at 3 min. DC disinfection for E. coli and S. aureus displayed zero CFU at 5 min of exposure (p ≤ 0.05). For S. mutans, MW-DC-DW and MW-DW displayed zero CFU count at 1 min and 2 min, respectively. In DC-treated samples, CFU were significantly zero at 4 min when compared with the control at each growth time. A combination of MW irradiation with DC (sodium perborate) showed higher disinfection percentage of bacterial species on PMMA polymer denture bases compared to MW and DC alone. PMMA disinfection using DC displayed a lower antimicrobial disinfection percentage than the combined use of MW and DC as well as MW alone at 1 min or 2 min disinfection for E. coli, S. aureus and S. mutans.

Synthesis, Antifungal Activity, and Cytotoxicity of AgBr-NP@CTMAB Hybrid and Its Application in PMMA

Objective

To synthesize and determine the antifungal activity of AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) against Candida albicans (C. albicans) for use in the field of denture cleaning.

Methods

The morphology and structure of AgBr-NP@CTMAB were characterized by IR, UV-Vis, XRD and SEM. The antifungal potential of AgBr-NP@CTMAB against C. albicans was determined by colony formation assay and growth curve analysis. PMMA containing AgBr-NP@CTMAB was prepared, and the long-term antifungal efficacy was analyzed. The effect against C. albicans biofilm was analyzed by SEM and OD600 , and the color changes of the specimens were observed by stereomicroscopy after 1 week of incubation. Cytotoxicity to human oral gingival fibroblasts and oral mucosal epithelial cells was detected by Cell Counting Kit-8 (CCK-8) in vitro.

Results

The compound showed a good crystalline phase, the presence of AgBr nanoparticles and the hybridization of CTMAB+ with AgBr-NPs. AgBr-NP@CTMAB showed significant antifungal activity against C. albicans at concentrations of 10 μg/mL and 20 μg/mL. PMMA specimens containing AgBr-NP@CTMAB showed no long-term antifungal effect against C. albicans biofilm. The clearance rate of C. albicans attached to PMMA was 44.73% after soaking in 10 µg/mL AgBr-NP@CTMAB solution for 30 min and 91.35% for 8 h. There was no significant residual cytotoxicity or visual color change after soaking.

Significance

AgBr-NP@CTMAB showed promising potential treatment for denture cleaners.

Evaluation of antibacterial activity against Candida albicans according to the dosage of various denture cleansers

PURPOSE

The purpose of this study is to compare the antibacterial activity of currently purchasable denture cleansers against Candida albicans.

MATERIALS AND METHODS

This study used tablet-type denture cleansers, Polident®, Coolingdent® and Fittydent®, along with liquid denture cleansers, Hexamedine®, Listerine® and Apple vinegar®. The antibacterial activities of denture cleansers were evaluated based on the number of C. albicans and concentrations of the denture cleansers.

RESULTS

In the 0.5 × 10⁶ cfu/ml culture medium, the C. albicans' death rate of Polident® was significantly lower than those of Fittydent®, Hexamedine®, Listerine®, and Apple vinegar®(P<.05). In the 0.5 × 10⁷ cfu/, the C. albicans' death rates of Polident® and Coolingdent® were significantly lower than those of Fittydent®, Hexamedine®, Listerine® and Apple vinegar®(P<.05). The C. albicans' death rates of Polident® and Coolingdent® were significantly decreased at 0.02 g and 0.01 g. The C. albicans' death rate of Fittydent® was significantly decreased at 0.005 g (P<.05). The C. albicans' death rate of Hexamedine® was significantly decreased at 1/16 dilution. The C. albicans' death rate of Listerine® was decreased at 1/8 dilution, and the antibacterial activity of Apple vinegar® was decreased at 1/4 dilution (P<.05).

CONCLUSION

As the number of C. albicans increased, the antibacterial activities of the denture cleansers decrease. In the tablet-type denture cleanser, all denture cleansers showed 100% C. albicans' death rate when used at a dose of 1 tablet. One denture cleanser showed the same antibacterial effect with only 1/3 of a tablet. In the liquid type denture cleanser, the level of dilution required was different for each denture cleanser.

Influence of Removable Denture Cleaning Agents on Adhesion of Oral Pathogenic Microflora In Vitro: A Randomized Controlled Trial

Introduction:

Removable dentures are used by 20% of the population. These may be accompanied by denture stomatitis in 15-70% of patients. The choice of the optimal cleansing agent for removable dental prostheses is of high significance.

Aim:

The aim of our research was to study the influence of removable denture cleansing products on the adhesion of microorganisms and yeast.

Materials and Methods:

We manufactured 144 specimens of standardized round shape with a diameter of 10 mm from 4 types of modern polymeric materials used by prosthetic dentistry to produce removable dentures, 12 specimens of each material were placed into suspensions of bacterial cultures of Staphylococcus aureus, Escherichia coli, Candida albicans, then into “ClearaSept” (Test group 1), “Рrotefix active cleanser” (Test group 2), saline solution (Control group), followed by nutrient media. The adhesion index was calculated and analyzed.

Results:

There was no reliable lowering of adhesion index of Staphylococcus Aureus to all materials detected in Test group 1 (U=6, p>0.05 for Bio XS; U=8, p>0.05 for Dental D, Denotokeep Peek, Vertex Rapid Simplified). In Test group 2, the adhesion index of Staphylococcus Aureus reliably decreased to all materials compared to the Control group (U=0, p≤0.01). The adhesion index of Candida albicans and Escherichia coli to all materials in Test group 1 had a minor to moderate reliable reduction compared to the Control group (U=0, p≤0.01). Test group 2 showed a significant reliable decrease in Candida albicans and Escherichia coli adhesion index to all materials in comparison with the Control group (U=0, p≤0.01).

Conclusion:

The research showed an unreliable or minor and moderate reliable decrease in microorganisms adhesion index depending on the microorganism species after treatment of denture material specimens by antibacterial soap “ClearaSept” and a reliable significant decrease in microbial and yeast adhesion after application of Protefix active cleaner solution, which demonstrates a more significant antimicrobial effect in comparison to “ClearaSept” against Staphylococcus aureus, Escherichia coli, and Candida albicans.

Antifungal effect of tea extracts on Candida albicans

Determining whether tea extracts are effective in removing Candida albicans (C. albicans) from dentures is of interest. This study aimed to investigate the antifungal effect of tea extracts on C. albicans. One green tea (Anji white tea, AGW) and 2 oolong teas (Tie Guan Yin, TGY; Da Hong Pao, DHP) of different concentrations were tested. C. albicans suspensions were inoculated on the plates and the numbers of colony-forming units (CFU) in the culture medium were used to screen for the optimum tea extracts. Polymethyl methacrylate (PMMA) specimens that contained C. albicans biofilms were then treated with the tea extracts and the numbers of CFU were counted. The antifungal activities of the tea extracts were not significantly correlated with their catechin concentrations. Although AGW at 10.0 mg/mL and DHP at 2.5 mg/mL significantly inhibited C. albicans in the culture medium, the extracts failed to exert inhibitory effects against C. albicans biofilms on the PMMA surfaces.

Effects of two peroxide enzymatic denture cleaners on Candida albicans biofilms and denture surface

Objective

To compare the antifungal action of two commercially available denture cleaning agents to that of standard clinical solutions, and determine their effects on the polymethyl methacrylate (PMMA) acrylic resin denture surface.

Methods

Candida albicans growth was analyzed by colony forming assay, and the methyl thiazolyl tetrazolium (MTT) assay was used to evaluate biofilm formation and cell adhesion. The morphology and roughness of PMMA acrylic resin surface was measured by scanning electron microscopy (SEM) images and stylus method.

Results

Clene®, Polident® and 3% NaHCO₃ solutions showed significantly greater antifungal effects in terms of both inhibiting growth and biofilm formation. In addition, Clene® solution prevented adhesion of C. albicans on cell culture plates compared to filter-sterile tap water, whereas other reagents did not have an inhibitory effect. One-month immersion in the different cleaning reagents significantly inhibited fungal adhesion on the PMMA surface Clene®, Polident® and 3% NaHCO₃ showed greater effect compared to PBS and filter-sterile tap water. Finally, none of the cleansing agents significantly affected the morphology and roughness of the PMMA surface.

Conclusion

Clene®, Polident® and 3% NaHCO₃ solutions can inhibit C. albicans growth and biofilm formation to some extent on cell culture plates, and significantly inhibit fungal adhesion on the PMMA surface without affecting surface morphology and roughness.