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.

Evaluation of the Empower model of care for partial denture clients in a public oral health care setting

OBJECTIVE

To evaluate the effectiveness of the Empower model of care (EMC) on reducing the addition of teeth to removable partial dentures (RPD).

METHODS

Data reports were generated through the Titanium electronic database to retrieve all clients at Monash Dental Services (MHDS) who participated in the EMC or received an RPD prior to the implementation of EMC was assessed over a two-year period to determine if they had additional teeth added to their partial dentures (PD). A logistic regression was performed testing whether a combination of socio-demographic and clinical variables, provided a multivariate explanation of the EMC outcome.

RESULTS

Prior to EMC, 2034 patients attended MHDS requiring RPDs with 363 returning to have teeth added. From 2018 to 2020, 38 of 584 participants in EMC returned to have teeth added to their PDs. Those in the 'High' risk group were two times more likely to return requiring additional teeth (OR = 1.99; 95%CI:1.31-3.02); each additional year of age increased the odds of requiring additional teeth (OR = 1.03; 95%CI:1.02-1.04). Participants of the EMC were more than two times less likely to require additional teeth (OR = 0.42; 95%CI:0.29-0.59). The variance in requiring additional teeth accounted for using the full model was 9.1% (η2  = 0.091).

CONCLUSIONS

This analysis confirms the effectiveness of the EMC. This approach assists denture wearers to maintain good oral health and provides an effective way of managing public health funds by reducing denture repairs and additions. © 2023 Australian Dental Association.

Denture care and oral health-related quality of life among complete denture wearers in Eastern Province of Saudi Arabia

INTRODUCTION

This study aimed to evaluate denture care and hygiene and oral health-related quality of life (OHRQoL) among complete denture (CD) wearers in the Eastern Province of Saudi Arabia.

METHODOLOGY

This cross-sectional study was conducted on CD wearers in the Eastern Province of Saudi Arabia. A pre-tested questionnaire was administered among study participants. Questionnaire was divided in three sections: (1) patients' demographic data, (2) awareness and maintenance of CD and (3) OHRQoL. Independent sample t-test and one-way ANOVA test were performed.

RESULTS

The study included data of 300 participants with 71% of males and 28% of females. Majority of participants (82.7%) cleaned CD daily, removed CD while sleeping (88.0%) and knew that unhygienic dentures can cause oral infection (92.7%). Only 19.3% used denture cleansing tables, 41% used toothpaste, and 60.7% rinsed CD with water. Regarding OHIP-DENT domains, highest score was for functional limitation domain (2.20 ± 1.67) and the lowest for handicap domain (0.94 ± 1.09). The mean OHIP-DENT score of the sample was 12.02 ± 8.52. Females (p = 0.006), participants below 65 years of age (p = 0.029), non-Saudis (p = 0.042), those with university education (p = 0.030) and low monthly income (p = 0.045) and participants who visited dentist due to problem with CD (p = 0.041) demonstrated significantly higher mean OHIP-DENT score.

CONCLUSION

Majority of participants demonstrated appropriate denture care behaviours because they were aware of the importance of denture care and hygiene. Female gender, age below 65 years, non-Saudi nationality, university education, low monthly income and visiting dentist due to problem were related to poor OHRQoL.

Denture Plaque Biofilm Visual Assessment Methods: A Systematic Review

Denture plaque, a biofilm that develops on denture surfaces, could contribute to many oral and systemic afflictions. Hence, a quantitative assessment of denture plaque is important to evaluate the denture hygiene of denture wearers, particularly to prevent plaque biofilm-associated diseases. The aim of this systematic review, therefore, was to review and summarize the visual denture hygiene assessment methods using denture plaque indices and with planimetries published in the literature. English language studies published up to March 2022 in four electronic databases, PubMed, Medline, Embase, and Cochrane Library, were searched, followed by a manual search of Google Scholar by two assessors. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) whenever possible. Details of the visual assessment methods, including the types of denture assessed, its materials and its surfaces, as well as the use of a disclosing agent, were the main outcomes. Of 492 screened studies, 74 were included per the inclusion and exclusion criteria. Of these, 60 studies utilized various denture plaque indices while 18 used planimetries. 43 out of 60 studies with indices and 17 out of 18 studies with planimetries used disclosing agents for visual evaluation of plaque. A total of 21 indices were described in the included studies, of which seven graded a divided denture surface, while the remainder graded entire denture surface. Of the 18 planimetric assessments, one study quantified squares of the disclosed plaques on denture images, 16 studies quantified such pixels with computer programs, and a single study quantified points, pixels, and contour of plaque areas. In summary, denture plaque indices appear to be popular in denture plaque assessment due to their simplicity. Computerized planimetric assessment, though more time-consuming, provides a more accurate assessment of plaque load as it is less prone to subjectivity and assessor errors.

Assessing the efficacy of gutiferone E in photodynamic therapy for oral candidiasis

The rise in antifungal resistance and side effects of conventional treatments drive the search for innovative therapies like Photodynamic Therapy (PDT). This study explored the efficacy of PDT mediated by gutiferone, an isolated compound from red propolis, for candidiasis treatment. Multiple evaluation methods were employed, including determining the minimum inhibitory concentration (MIC) via broth microdilution, quantifying biomass using crystal violet detachment, and cell counting through total plate count. PDT mediated by gutiferone was also assessed in five groups of mice, followed by histopathological examination and agar plating of lingual tissue samples. Among the seven Candida species tested, gutiferone displayed efficacy against C. albicans, C. glabrata, and C. tropicalis, with MIC values of 1000 μg/mL. In C. tropicalis biofilms, exposure to gutiferone led to a reduction of 1.61 Log10 CFU/mL. PDT mediated by gutiferone achieved an average reduction of 3.68 Log10 CFU/mL in C. tropicalis biofilm cells, underscoring its potent fungicidal activity. Histopathological analysis revealed fungal structures, such as pseudohyphae and hyphae, in infected groups (G2) and irradiated mice. In contrast, groups treated with gutiferone or subjected to gutiferone-assisted PDT (G5) exhibited only few blastoconidia. Furthermore, CFU/mL assessments in lingual tissue post-treatment demonstrated a significantly lower count (0.30 Log10 CFU/mL) in the G5 group compared to G2 (2.43 Log10 CFU/mL). These findings highlight the potential of PDT mediated by gutiferone as a promising alternative for managing denture stomatitis. Future research and clinical investigations offer the promise of validating its clinical applicability and improving outcomes in the treatment of oral candidiasis.

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

OBJECTIVE

To evaluate the anti-biofilm action of chitosan, nanoparticulate chitosan, and denture cleanser Nitradine™ against biofilms comprising Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans.

BACKGROUND

Biofilm removal from removable partial dentures (RPD) is important for success in prosthetic rehabilitation.

MATERIALS AND METHODS

The anti-biofilm action of the experimental chitosan-based solutions and Nitradine™ was evaluated on acrylic resin and cobalt-chromium alloy through assessing cell viability, cell metabolism, residual aggregated biofilm, and extracellular polymeric substance and biofilm morphology.

RESULTS

Only chitosan reduced the viability of C. albicans on cobalt-chromium alloy surface, by 98% (a 1.7 log10 reduction in cfu). Chitosan-based solutions neither promoted substantial alteration of the metabolic activity of the four-species biofilm nor reduced the amount of the aggregated biofilm. After immersion in chitosan and nanoparticulate chitosan, viable microorganisms and extracellular polymeric substances distributed over the entire specimens' surfaces were observed. Nitradine™ reduced the viability and metabolic activity of biofilm grown on both surfaces, but it did not remove all aggregated biofilm and extracellular polymeric substances. After immersion in Nitradine™, approximately 35% of the specimens' surfaces remained covered by aggregated biofilm, mainly composed of dead cells.

CONCLUSION

Although chitosan and Nitradine™ promoted changes in the viability of microorganisms, neither solution completely removed the four-species biofilm from the Co-Cr and acrylic resin surfaces. Thus, isolated use of hygiene solutions is not indicated for biofilm control on RPDs; this requires complementary mechanical removal.

Photodynamic therapy in the treatment of denture stomatitis: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Photodynamic therapy is widely used in dentistry, but limited evidence exists regarding its effectiveness in treating denture stomatitis. High resistance to antifungals has been reported, and photodynamic therapy could be an alternative treatment.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate whether photodynamic therapy is effective in reducing denture stomatitis.

MATERIAL AND METHODS

A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and recorded in the prospective register of systematic reviews (PROSPERO) (CRD42020205589) to answer the population, intervention, control, outcome (PICO) question: "Is photodynamic therapy effective in the treatment of denture stomatitis when compared with the use of antifungal agents?" Electronic searches were performed in databases PubMed/MEDLINE, Cochrane library, and Web of Science for articles published until February 2021 by using the following terms: (denture stomatitis OR oral candidiasis) AND (low-level light therapy OR laser therapy OR lasers OR photodynamic therapies OR photochemotherapy) AND (antifungal drugs OR antifungal agents OR antimicrobial OR treatment). Clinical trials and randomized clinical trials, studies in the English language, and studies comparing antifungal agents with photodynamic therapy were included.

RESULTS

In total, 5 articles were selected for the qualitative analysis and 3 for the meta-analysis. No significant difference was detected between antifungal therapy and photodynamic therapy in the reduction of colony-forming units on the palate. In a subgroup analysis, a significant difference was found in the reduction of colony-forming units on the palate at 15 days and at the denture surface at 30 days.

CONCLUSIONS

Photodynamic therapy is effective in the treatment of denture stomatitis, but after 30 days and 15 days, the antifungals demonstrated better performance.

Effect of Hygiene Protocols on the Mechanical and Physical Properties of Two 3D-Printed Denture Resins Characterized by Extrinsic Pigmentation as Well as the Mixed Biofilm Formed on the Surface

To assess the effect of hygiene protocols and time on the physical-mechanical properties and colony-forming units (CFU) of Candida albicans, Staphylococcus aureus, and Streptococcus mutans on 3D-printed denture resins (SmartPrint and Yller) with extrinsic pigmentation compared to conventional resin (CR). The protocols were evaluated: brushing (B), brushing and immersion in water (W), 0.25% sodium hypochlorite (SH), and 0.15% triclosan (T), simulating 0, 1, 3, and 5 years. The data were analyzed by ANOVA with repeated measurements, ANOVA (Three-way) and Tukey's post-test, generalized linear model with Bonferroni adjustment, and ANOVA (Two-way) and Tukey's post-test (α = 0.05). The protocols influenced color (p = 0.036) and Knoop hardness (p < 0.001). Surface roughness was influenced by protocols/resin (p < 0.001) and time/resin (p = 0.001), and flexural strength by time/protocols (p = 0.014). C. albicans showed interactions with all factors (p = 0.033). Staphylococcus aureus was affected by protocols (p < 0.001). Streptococcus mutans exhibited no count for SH and T (p < 0.001). Yller resin showed more color changes. The 3D-printed resins displayed lower microhardness, increased roughness, and decreased flexural strength compared to CR with all protocols in a simulated period of 5 years. The indication of printed resins should be restricted to less than 3 years.

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

PURPOSE

To assess the influence of denture brushing on the surface roughness, hardness, and color stability of conventional, thermoformed, and CAD-CAM denture base materials.

MATERIALS AND METHODS

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).

RESULTS

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.

CONCLUSION

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.

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.

Evaluation of a protocol to assess a novel artificial biofilm equivalent for dentures-A prospective clinical pilot study

OBJECTIVES

This pilot study aimed to carry out preliminary tests of the removability of an artificial biofilm equivalent (ABE) and to verify the reproducibility of the ABE testing protocol for a planned main study.

BACKGROUND

There is a lack of data to develop suitable artificial biofilm substitutes, which may be helpful to perform denture hygiene education and to carry out in vitro examinations of oral hygiene products.

MATERIALS AND METHODS

This single-group, prospective, longitudinal, interventional pilot study was conducted in Dresden (Germany) from February until December 2020. Participants were recruited who wore fully functional upper complete dentures. Denture biofilm was grown on acrylic specimens by wearing dentures for 12 h and 36 h using intraoral appliances. Acrylic specimens were coated with ABEs of three compositions: chitosan (ChS) 0.3 g, methylcellulose (MC) 1.7 g; ChS 0.2 g, MC 1.8 g; ChS 0.1 g, MC 1.9 g (labelled 1.7MC, 1.8MC and 1.9MC, respectively). All specimens underwent standardised mechanical brushing. The percentages of remaining biofilm (POB) were measured.

RESULTS

Thirty-one participants were prescreened, and eight (26%) were included. The appliances were well tolerated, and biofilm was collected. ABE was prepared and brushed as planned. Three and six brushing strokes were needed to remove 12-h and 36-h natural denture biofilm, respectively. Correspondingly, three brushing strokes were needed to remove 1.9MC ABE and six brushing strokes to remove 1.8MC and 1.7MC ABE. A reproducibility of ABE removal was indicated.

CONCLUSION

The removability of ABE and the ABE testing protocol were feasible and reproducible for conducting the future main study.

Effect of simulated brushing with dentifrices on surface roughness and the mass loss of acrylic resin: A systematic review and meta-analysis of in vitro studies

STATEMENT OF PROBLEM

Brushing with dentifrice is the most commonly used denture cleaning method. However, it can result in the mass loss of acrylic resin and an increase in surface roughness, which favors the adherence of microorganisms.

PURPOSE

The purpose of this systematic review and meta-analysis of in vitro studies was to assess the influence of simulated brushing by using dentifrices and water on surface roughness and the mass loss of acrylic resins.

MATERIAL AND METHODS

Searches were performed in PubMed, Scopus, Web of Science, Lilacs, Embase, Open Gray, and Google Scholar databases in September 2022. The study selection process, data extraction, and risk of bias analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol of this systematic review was registered in the Open Science Framework (DOI number 10.17605/OSF.IO/QD4GH). Meta-analysis was performed by using a random effects model (α=.05) in the RevMan (Cochrane Collaboration) software program.

RESULTS

A total of 14 studies were included in the qualitative synthesis and 2 studies in the quantitative synthesis. The manual toothbrush was the most analyzed (n=9), followed by the electric toothbrush (n=5) and denture brush (n=1). Denture base resin (n=8) was evaluated more than acrylic resin for the abrasiveness of toothpaste (n=6). Most studies used conventional toothpaste (n=12), whereas 6 used specific dentifrices. The period of brushing corresponding to 1 year was the most predominant (n=6). Surface roughness (n=13) was evaluated more than mass loss (n=4). In general, dentifrices resulted in greater surface roughness than water. According to meta-analysis results, brushing by using dentifrices reported higher mass loss values than brushing with distilled water (P<.05).

CONCLUSIONS

Brushing acrylic resins with dentifrice was more abrasive than brushing with water.

Effectiveness of disinfectant solutions associated or not with brushing on the biofilm control of a 3D printed-denture base resin

BACKGROUND

The formation of biofilm on denture bases is a recurrent clinical problem that favors the development of denture stomatitis. The effectiveness of a hygiene protocol in a 3D-printed denture base resin is still uncertain.

OBJECTIVE

To evaluate of the effectiveness of immersion, associated or not with brushing in a soap solution, on the biofilm control of a 3D-printed denture base resin.

METHODOLOGY

Specimens of denture base resins [Cosmos Denture (COS) and Classico (CLA/control)] were contaminated in vitro with Candida albicans and immersed in sodium hypochlorite 0.25% (SH, alkaline peroxide) AP, chlorhexidine digluconate 2% (CD or PBS-Control), associated or not with brushing with 0.78% Lifebuoy soap. Roughness was evaluated before and after brushing and immersion. The effectiveness of the protocols was assessed by CFU/mL, cellular metabolism (XTT), scanning electron microscopy (SEM), and confocal scanning laser microscopy. Data were analyzed by T student, ANOVA/Welch, and Tukey/Gomes-Howell pos-hoc tests (α = 0.05).

RESULTS

CLA showed greater roughness than COS. CFU/mL and XTT were higher in COS resin with a higher hyphae formation. Immersion in SH and CD eliminated CFU/mL and reduced XTT for both resins, associated or not with brushing. AP reduced CFU/mL only when associated with brushing.

CONCLUSIONS

The biofilm on the 3D-printed resin was thicker and presumably more pathogenic, regardless of its smoother surface. Immersions in SH 0.25% and CD 2% are effective hygiene protocols for both resins, associated or not with brushing. AP should be recommended when associated with brushing with a Lifebuoy 0.78% solution.

Antimicrobial effect of phytosphingosine in acrylic resin

This study evaluated color stability (CS), anti-adherence effect (AAE), and cell viability of microorganisms on acrylic resin (AR) surface, treated associated or not with sodium percarbonate (SP). AR specimens were prepared, and color analysis was performed before and after the treatments and the CS was calculated. For analysis of AAE, the samples were sterilized by radiation in a microwave oven. Then samples were randomly distributed: phosphate-buffered saline (PBS - control), 0.5% sodium hypochlorite (SH), phytosphingosine (PHS), and phytosphingosine + SP (PHS+Na2CO3). The specimens remained in contact with solutions for 30 minutes and were later contaminated by Candida albicans. Aliquots were seeded in Petri dishes with Sabouraud Dextrose agar and incubated at 37°C for 24 hours. After the incubation, the number of colonies was counted. The cell viability of adhered microorganisms on the AR was evaluated and 20 fields were observed under an epifluorescence microscope, and the percentage of adhered viable cells was calculated. Data were compared (One-way ANOVA, Tukey, p<.05). As for CS, PHS+ Na2CO3 (0.4±0.1) resulted in less change than PBS (0.9±0.2), similar to the other groups (SH [1.0±0.3)]; PHS [0.9±0.2)]). There was no difference for all tested solutions regarding the ability to avoid microorganism adherence (p>0.05), but PHS (11.2±4.1) resulted in a smaller area of adhered viable cells, statistically different from SH (18.2±7.6) and PBS (26.4±10.8). It was concluded that PHS resulted in lower adhered viable cells and when associated with Na2CO3, also shows a lower effect on the CS of AR.

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.

Characterization of the Oral Microbiome in Wearers of Fixed and Removable Implant or Non-Implant-Supported Prostheses in Healthy and Pathological Oral Conditions: A Narrative Review

Oral commensal microorganisms perform very important functions such as contributing to the health of the host. However, the oral microbiota also plays an important role in the pathogenesis and development of various oral and systemic diseases. The oral microbiome may be characterized by a higher prevalence of some microorganisms than others in subjects with removable or fixed prostheses, depending on oral health conditions, the prosthetic materials used, and any pathological conditions brought about by inadequate prosthetic manufacturing or poor oral hygiene. Both biotic and abiotic surfaces of removable and fixed prostheses can be easily colonized by bacteria, fungi, and viruses, which can become potential pathogens. The oral hygiene of denture wearers is often inadequate, and this can promote oral dysbiosis and the switch of microorganisms from commensal to pathogens. In light of what emerged from this review, fixed and removable dental prostheses on teeth and on implants are subject to bacterial colonization and can contribute to the formation of bacterial plaque. It is of fundamental importance to carry out the daily hygiene procedures of prosthetic products, to design the prosthesis to facilitate the patient's home oral hygiene practices, and to use products against plaque accumulation or capable of reducing oral dysbiosis to improve patients' home oral practices. Therefore, this review primarily aimed to analyze the oral microbiome composition in fixed and removable implant or non-implant-supported prostheses wearers in healthy and pathological oral conditions. Secondly, this review aims to point out related periodontal self-care recommendations for oral dysbiosis prevention and periodontal health maintenance in fixed and removable implant or non-implant-supported prostheses wearers.

Influence of Contemporary Photoactivated Disinfection on the Mechanical Properties and Antimicrobial Activity of PMMA Denture Base: A Systematic Review and Meta Analysis

PURPOSE

The present study aimed to perform a systematic review and meta-analysis to investigate the effectiveness of the contemporary photoactivated disinfection methods on the mechanical features and/or antimicrobial activity of polymethyl methacrylate (PMMA) dentures bases.

METHODS

THE FOCUSED RESEARCH QUESTION WAS: : "What is the effect of contemporary photoactivated disinfection methods as compared to conventional disinfection protocols on the mechanical features and/or antimicrobial activity of PMMA dentures bases?". An electronic literature search was carried out by the author and a senior librarian specialized in health sciences on Web of Science, PubMed, and Scopus. In vitro investigations evaluating the antimicrobial and/or mechanical effects of photoactivated disinfectants as compared to conventional chemical disinfectants on the microbes formed on PMMA denture bases were included. Meta-analysis was performed for calculating the standard mean difference (SMD) with a 95% confidence interval.

RESULTS

Four out of eight studies concluded that photoactivated disinfectants, including riboflavin-mediated photodynamic therapy (PDT), hematoporphyrin-mediated PDT, poly-L-glycolic acid loaded with methylene blue, Erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser, erbium-doped yttrium-aluminum-garnet (Er:YAG) laser, and chitosan-mediated PDT, demonstrated a significant reduction in colony-forming unit per milliliter (CFU/mL) of exposed viable colonies of Escherichia coli (E. coli), Streptococcus mutans (S. mutans), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) comparable to the conventionally used chemical disinfectants of PMMA denture bases. Contrarily, two studies concluded that the PMMA denture base colonized with C. albicans and disinfected with conventional chemical disinfectants showed the greatest anti-fungal efficaciousness. All the included studies concluded that the application of photoactivated disinfectants does not negatively impact the mechanical features of the PMMA denture bases colonized with microbes including E. coli, S. mutans, S. aureus, and C. albicans. The meta-analysis revealed statistically significant reduction in C. albicans counts (CFU/mL [Log10]) (p < 0.00001) and improvement in the flexural strength (p = 0.0002) of PMMA-based denture base after the application of conventional disinfectants, while a statistically significant improvement in the fracture strength of PMMA-based denture base was observed after the application of photoactivated disinfectants (p = 0.03).

CONCLUSION

According to the systematic review (qualitative synthesis), photoactivated disinfectants demonstrated comparable mechanical features and antimicrobial activity of PMMA dentures bases to conventional chemical disinfectants suggesting their potential to be utilized as an alternative to conventional chemical disinfectants. However, the meta-analysis (quantitative synthesis) revealed that the application of conventional disinfectants demonstrated better outcomes related to antimicrobial activity and flexural strength of PMMA-based denture based.

Scientific evidence on the efficacy of effervescent tablets for cleaning removable prostheses. A systematic review and meta-analysis

STATEMENT OF PROBLEM

Scientific evidence to determine the optimal method of cleaning and disinfecting removable prostheses is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the effectiveness of effervescent tablets in the cleaning and sanitizing of removable prostheses compared with other chemical and physical methods by assessing the reduction of biofilm, microbial levels, and material stability.

MATERIAL AND METHODS

A systematic literature search and meta-analysis was conducted in August 2021 in the MEDLINE/PubMed, Cochrane, Embase, Scopus, and Web of Science databases. Randomized and nonrandomized controlled clinical trials published in English were included without publication year limits. A total of 23 studies were included in the systematic review and 6 in the meta-analysis, which had been registered in the international prospective register of systematic reviews (PROSPERO) database (CRD42021274019). The Cochrane Collaboration tool was used to assess the risk of bias of randomized clinical trials. The physiotherapy evidence database (PEDro) scale was used to analyze the internal validity of clinical trials by assessing the quality of the data obtained. The studies included in the meta-analysis were combined by using a random-effects model with the inverse variance method. Publication bias was analyzed by using the Duvall and Tweedie trim-and-fill method.

RESULTS

With regard to biofilm reduction, the standardized mean difference estimated with the 4 studies combined in the meta-analysis was P=.012: mean difference=-1.92; 95% confidence interval=-3.45 to -0.38, indicating a "large" effect of the combination of brushing and effervescent tablet versus brushing alone. To estimate the reduction in the total bacteria levels in the 3 combined studies, a "large" effect size was obtained for the combination of brushing and using an effervescent tablet versus brushing alone, P<.001: mean difference=-4.43; 95% confidence interval=-8.29 to -0.55. Finally, when the 3 studies were combined to assess the reduction of Candida or fungal infection, a "moderate" effect size was obtained for the combination of brushing combined with the use of an effervescent tablet, P<.001: mean difference=-0.78; 95% confidence interval=-1.19 to -0.37.

CONCLUSIONS

The combination of brushing and the use of effervescent tablets versus brushing alone had a significantly higher effect on reducing biofilm and bacterial counts and a moderate effect on reducing Candida. Regarding color and dimensional stability, few studies were found, with the results depending on the concentration of the product and the immersion time of the device.

Effect of alkynyloxy derivatives of lawsone as an antifungal spray for acrylic denture base: An in vitro study

Objective

The purpose of this study was to (i) synthesize and develop an alkynyloxy derivative of lawsone as an antifungal spray and (ii) assess the antifungal spray's effectiveness in reducing the viability of Candida albicans (C. albicans) on polymethylmethacrylate (PMMA) specimens.

Methods

Lawsone methyl ether (LME) and its derivative, 2-(prop-2-ynyloxy)naphthalene-1,4-dione (compound 1) were synthesized and characterized. The synthetic compounds were screened for antimicrobial activities against C. albicans using the microtiter broth dilution method to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Compound 1 was further formulated as an antifungal spray in three concentrations (100, 200, and 400 μg/mL). C. albicans biofilms were developed for 48 h on PMMA specimens. The efficacy of using an antifungal spray for 1 and 3 min to remove biofilm was assessed using colony counting and scanning electron microscopy (SEM). Chlorhexidine gluconate (CHX), polident®, and distilled water were used as positive and negative control cleansing solutions, respectively.

Results

LME and compound 1 showed comparable inhibition against C. albicans with a MIC of 25 μg/mL and MFC of 50 μg/mL. For immediate treatment, C. albicans was not detected on PMMA specimens when expose to 2% CHX and compound 1 (100, 200, and 400 μg/mL) antifungal spray for 3 min. However, after recolonization, a small number of viable cells were observed in denture soaked in compound 1 antifungal spray for 3 min group. Following recolonization, polident® and distilled water had comparable viable cell counts of C. albicans to the no treatment group. Scanning electron microscope (SEM) images revealed that CHX, polident®, and compound 1 caused cell damage in various forms.

Conclusion

Denture spray containing synthetic alkynyloxy derivative of lawsone is a promising antifungal agent for C. albicans biofilm removal from the PMMA surface.

The stain resistant effect of an ultraviolet curable coating material on denture base resin

This study aimed to evaluate the effects of an ultraviolet (UV) curable coating material on denture base resin. The results of the three-point bending test showed no significant difference between treated and untreated specimens, suggesting that the UV curable coating material did not compromise the physical strength of denture base resin. The surface free energy measurement and the surface analysis with atomic force microscopy revealed superhydrophilicity and a regularly arranged structure on the coating surface, improving wettability. Moreover, untreated specimens were significantly discolored in the staining test. However, specimens treated with the UV curable coating material showed no significant difference in color with slight staining, suggesting excellent antifouling ability. Therefore, the UV curable coating material used in this study could contribute to simplifying hygiene without altering the physical properties of denture base resins.

Clinical applications of antimicrobial photodynamic therapy in dentistry

Given the emergence of resistant bacterial strains and novel microorganisms that globally threaten human life, moving toward new treatment modalities for microbial infections has become a priority more than ever. Antimicrobial photodynamic therapy (aPDT) has been introduced as a promising and non-invasive local and adjuvant treatment in several oral infectious diseases. Its efficacy for elimination of bacterial, fungal, and viral infections and key pathogens such as Streptococcus mutans, Porphyromonas gingivalis, Candida albicans, and Enterococcus faecalis have been investigated by many invitro and clinical studies. Researchers have also investigated methods of increasing the efficacy of such treatment modalities by amazing developments in the production of natural, nano based, and targeted photosensitizers. As clinical studies have an important role in paving the way towards evidence-based applications in oral infection treatment by this method, the current review aimed to provide an overall view of potential clinical applications in this field and summarize the data of available randomized controlled clinical studies conducted on the applications of aPDT in dentistry and investigate its future horizons in the dental practice. Four databases including PubMed (Medline), Web of Science, Scopus and Embase were searched up to September 2022 to retrieve related clinical studies. There are several clinical studies reporting aPDT as an effective adjunctive treatment modality capable of reducing pathogenic bacterial loads in periodontal and peri-implant, and persistent endodontic infections. Clinical evidence also reveals a therapeutic potential for aPDT in prevention and reduction of cariogenic organisms and treatment of infections with fungal or viral origins, however, the number of randomized clinical studies in these groups are much less. Altogether, various photosensitizers have been used and it is still not possible to recommend specific irradiation parameters due to heterogenicity among studies. Reaching effective clinical protocols and parameters of this treatment is difficult and requires further high quality randomized controlled trials focusing on specific PS and irradiation parameters that have shown to have clinical efficacy and are able to reduce pathogenic bacterial loads with sufficient follow-up periods.

Effects of long-term cinnamaldehyde immersion on the surface roughness and color of heat-polymerized denture base resin

STATEMENT OF PROBLEM

Cinnamaldehyde has been successfully used for the short-term disinfection of dentures; however, its long-term effects on the surface and color properties of denture base materials remain unknown.

PURPOSE

The purpose of this in vitro study was to evaluate the effects of simulated immersion in cinnamaldehyde for up to 5 years on the surface roughness and color parameters of a heat-polymerized denture resin.

MATERIAL AND METHODS

Eighty Ø10×5-mm disk-shaped specimens were prepared from microwave heat-polymerized polymethylmethacrylate (PMMA) and immersed in 4 solutions (n=20): TW-tap water (control), SH - 0.5% sodium hypochlorite, PX-alkaline peroxide, and CA-cinnamaldehyde (27 μg/mL). The immersion protocol simulated 104 cycles (3.5 months), 913 cycles (2.5 years), and 1825 immersion cycles (5 years) of a daily immersion cleaning protocol, with immersion times ranging from 10 to 20-minutes. Surface roughness (Sa) and the color parameters of CIELab (L∗ a∗ b∗, ΔEab), CIEDE2000 (ΔE00), and the National Bureau of Standards (NBS) were analyzed at baseline (t=0) and after the immersion cycles. The data were analyzed by 2-way analysis of variance (ANOVA) for repeated measures and the Tukey post hoc test (α=.01).

RESULTS

Sa was significantly increased in all groups after 1825 cycles compared with baseline (P<.01), regardless of the solution. Only the time factor significantly affected ΔEab, ΔE00, and NBS parameters, which were below the perceptibility and acceptability thresholds. After a simulated 5-year immersion, the surface roughness and color values of CA-treated specimens were not statistically different from those of the other groups (P>.01).

CONCLUSIONS

Cinnamaldehyde solution (27 μg/mL) produced minor effects on the surface roughness and color parameters of a heat-polymerized denture base resin similar to those of 0.5% sodium hypochlorite and alkaline peroxide after a 5-year simulated immersion.

Denture cleanliness and hygiene: an overview

Dentures are an excellent treatment modality for partial and edentate patients; however, improper denture care and hygiene can result in both decreased longevity of the prosthesis and increased risk of developing dental caries, periodontal disease and oral candidosis. Previously, it has been shown that patients and dental professionals are unaware of the different materials and methods available for optimum denture care and hygiene. This article provides an overview of the key legislation and main commercially available methods for denture cleanliness and hygiene, and serves as a basis for providing tailored denture hygiene for denture wearers.

Patients typically demonstrate poor levels of denture hygiene which impacts oral health.

Denture hygiene instructions comprise mechanical and chemical methods; both should be tailored to the denture wearer.

Denture base and denture teeth materials had different compatibility with different denture cleaning methods.

Comparison of the Effect of Denture Cleansers on Long-Term Water Sorption and Solubility of Polyetheretherketone with other Denture Base Materials

Objective: In this in vitro study, the effect of three denture cleansers (DCs) after immersion in a chemical solution applied to polyetheretherketone (PEEK) and other denture base materials (DBMs) on long-term water sorption and solubility was compared. Methods: Disk-shaped specimens (50±1.0-mm diameter and 0.5±0.1-mm thickness) were prepared from four DBMs (n=48). All specimens were randomly subdivided into four storage media groups (n=12): Corega tablet (CT), Protefix tablet (PT), 1% sodium hypochlorite (NaOCl) solution (SH), and control (distilled water, DW). Storage media were renewed thrice a day for 120 days and simulated for 1-year use of overnight immersion. Water sorption and solubility (µg/mm3) of DBMs before and after immersion in storage media were examined and obtained data were statistically analyzed using a multivariate analysis of variance, followed by multiple comparisons by a posthoc Tukey’s test (p

CLEANING OF REMOVABLE DENTAL PROSTHESES - A SYSTEMATIC REVIEW

Objectives The aim of this systematic review was to provide an overview of the scientific evidence available from prospective clinical studies regarding denture hygiene interventions. Therefore, investigations addressing the efficacy of removing microorganisms and biofilms formed on the surface of removable dental prostheses (RDPs) and denture base materials in situ and their impact on the properties of denture base materials, such as color stability, surface roughness, and dimensional stability, were included. Methods A systematic literature search was conducted from June 1975-May 2020 and included articles published in English that have been indexed in the digital archives of PubMed and Cochrane (including PubMed, Embase, ICTRP, CT.gov). A complementary manual search of the initially retrieved studies was conducted. Inclusion criteria comprised prospective clinical trials with a minimum of ten participants investigating (1) approaches and methods to remove biofilms formed on the surface of RDPs and denture base materials in situ and/or (2) the influence of these biofilms on denture base materials. A total of forty-four studies were included in this systematic review, which was registered in the PROSPERO database (CRD42020189649). Results and Conclusions Data gathered from the systematic review indicate that the combined use of chemical and mechanical denture hygiene interventions is significantly more effective than single cleaning approaches. Only limited evidence is available from clinical studies regarding the effect of denture hygiene interventions on the properties of denture base materials.

Low Concentrations of Chlorhexidine Inhibit the Formation and Structural Integrity of Enzyme-Treated Multispecies Oral Biofilms

The self-produced matrix of biofilms, consisting of extracellular polymeric substances, plays an important role in biofilm adhesion to surfaces and the structural integrity of biofilms. In dentistry, biofilms cause multiple diseases such as caries, periodontitis, and pulpitis. Disruption of these biofilms adhering to dental hard tissues may pose a major challenge since biofilms show higher tolerance to antimicrobials and antibiotics than planktonic cells. In this study, the effect of low concentrations of chlorhexidine (CHX) on enzyme-treated multispecies oral biofilm was investigated in an in vitro model. Six-species biofilms were enzymatically treated by anaerobic growth in a medium containing DNase I and proteinase K. Biofilms were exposed to a low concentration of CHX at defined time points. After 64h, biofilms were either harvested and quantified by cultural analyses or stained for confocal laser scanning microscopy (CLSM) analyses using either Live/Dead kit or different fluorescent dyes. A mixture of YoPro1 and SYTOX^™ Green, Fluorescent Brightener 28 (Calcofluor), and SYPRO^™ Ruby Protein Gel Stain was used to stain total DNA, exopolysaccharides, and extracellular proteins, respectively. Extracellular DNA (eDNA) was visualized via an indirect immunofluorescence assay (Mouse anti-DNA IgG, Goat anti-Mouse IgG, Streptavidin-Cy3). Overall, the total colony-forming units significantly decreased after combined treatment with a low concentration of CHX and enzymes compared to the group treated with CHX alone (p<0.001). These findings also apply to five species individually (Streptococcus mutans, Streptococcus oralis, Actinomyces oris, Veillonella dispar, and Candida albicans) occurring in the biofilms, with Fusobacterium nucleatum being the only exception. Furthermore, CLSM images showed less dense biofilms and a reduction in cell numbers after combined treatment compared to the group without enzymes. The combination of enzymes capable of disturbing the matrix integrity with antimicrobial agents thus appears to be a promising approach for biofilm disruption and killing.

Effect of a continuous mechanical polishing protocol on the color stainability, microhardness, mass, and surface roughness of denture base acrylic resin

STATEMENT OF PROBLEM

The acrylic resin used in dental prostheses, which is subject to changes in its properties caused by hygiene chemicals, brushing, and colored beverages, can benefit from mechanical polishing methods. However, studies evaluating whether such procedures can be performed continuously without damaging the prosthetic materials are lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of a continuous mechanical polishing protocol on the color stainability, surface roughness, microhardness, and mass of a denture base acrylic resin.

MATERIAL AND METHODS

The polishing protocol was tested in specimens submitted to one of the following conditions: immersion in coffee (CF) (n=20); toothbrushing (Br, 35 600 cycles in a brushing simulation machine) (n=20); and immersion in 1% sodium hypochlorite (HYP) (n=20). For each condition, half of the specimens were polished (aluminum oxide paste and felt wheel attached to an electric motor, 3000 rpm) at simulated biweekly intervals. Two groups (n=10) of specimens were immersed in distilled water and used as the control for the immersion groups. Thus, the present study consisted of a total of 8 groups (n=80). Before and after simulated periods of 12 and 24 months, surface roughness was evaluated by using a contact profilometer; a spectrophotometer was used to calculate color changes (ΔE₀₀); and a Knoop microdurometer and a precision balance were used to assess microhardness and mass changes. Data were compared by using 2-way mixed ANOVA. The Tukey HSD and Student t tests were used for post hoc analysis (α=.05).

RESULTS

The polishing influenced surface roughness (Br, CF, HYP: P<.001) and color stainability (Br: P=.008; CF: P<.001). Significant increase in roughness was observed for the Br and HYP groups, and the polishing significantly reduced roughness under all experimental conditions. In general, the polishing did not affect the microhardness and caused minimum wear of the acrylic resin. ΔE₀₀ values were above the clinical perceptibility threshold (ΔE₀₀>1.30) for the Br group, exceeding the clinical acceptability threshold for the CF group (ΔE₀₀= 2.51). Polishing reduced ΔE₀₀ in these groups, making values similar to those found in the groups immersed in distilled water. The color in the HYP group was not influenced by polishing.

CONCLUSIONS

In general, the tested polishing protocol reduced the deleterious effects of brushing and contact with 1% sodium hypochlorite and coffee, reducing surface roughness and color change without affecting microhardness and mass in any clinically relevant way.

Effect of educational progressive web application on patient's oral and denture knowledge and hygiene: A randomised controlled trial

This study aimed to evaluate the effect of a novel progressive web application (PWA) on the patient's oral and denture knowledge and hygiene. Fifty-two removable partial denture wearers were randomised to receive education using the PWA, or verbal instructions accompanied by demonstration of hygienic procedures. Changes in the participants' knowledge score, plaque index, gingival index and denture plaque was evaluated during a follow-up period of 3 months. The participants' acceptance of PWA was explored through usage logs and a feedback form. Both groups showed significant improvement in knowledge scores, oral and denture hygiene indices (p < 0.001) after education. The PWA group demonstrated significantly lower gingival index score than control (p = 0.008) at the third month review. In conclusion, there is potential of using mobile application in educating elderly patients and the PWA is a viable option for providing post-denture delivery instructions.

Effectiveness of Oil-Based Denture Dentifrices-Organoleptic Characteristics, Physicochemical Properties and Antimicrobial Action

Denture dentifrices must be effective and not deleterious to prosthetic devices. This study formulated and evaluated dentifrices based on oils of Copaifera officinalis, Eucalyptus citriodora, Melaleuca alternifolia, Pinus strobus, and Ricinus communis. Organoleptic characteristics (appearance, color, odor, taste), physicochemical properties (pH, density, consistency, rheological, abrasiveness, weight loss, and surface roughness) and antimicrobial (Hole-Plate Diffusion–HPD)/anti-biofilm (Colony Forming Units–CFU) action against Staphylococcus aureus, Streptococcus mutans, and Candida albicans were evaluated. Formulations were compared with water (negative control) and a commercial dentifrice (positive control). The data were analyzed by Kruskal-Wallis and Dunn tests (α = 0.05). The organoleptic and physicochemical properties were adequate. All dentifrices promoted weight losses, with high values for C. officinalis and R. communis, and an increase in surface roughness, without differing from each other. For antimicrobial action, C. officinalis and E. citriodora dentifrices were similar to positive control showing effectiveness against S. mutans and C. albicans and no dentifrice was effective against S. aureus; regarding the anti-biofilm action, the dentifrices were not effective, showing higher CFU counts than positive control for all microorganisms. The dentifrices presented satisfactory properties; and, although they showed antimicrobial action when evaluated by HPD, they showed no effective anti-biofilm action on multispecies biofilm.

Patient attitude and habits regarding removable denture home hygiene and correlation with prosthesis cleanliness: A cross-sectional study of elderly Italians

STATEMENT OF PROBLEM

With the aging population, an increasing number of patients will require removable dental prostheses. Despite the recent public efforts to improve oral healthcare, knowledge of hygiene procedures for removable dental prostheses is sparse.

PURPOSE

The purpose of this cross-sectional study was to determine, through questionnaires, the level of awareness and education of home hygiene procedures among elderly Italian individuals wearing removable dental prostheses and to correlate self-reported hygiene habits and prosthesis cleanliness, as determined by a clinical examination.

MATERIAL AND METHODS

A cross-sectional study was performed by questionnaires administered by a dental hygienist to patients attending the dental clinics (prosthodontic and periodontology clinical units) at San Paolo Hospital of Milan from January 2014 to October 2015 and who volunteered to participate. The questionnaire included demographic data and oral hygiene habits. Each participant received an intraoral and prosthesis examination performed by the same dental hygienist. The cleanliness of the removable dental prosthesis was classified according to a 3-point scoring system. Categorical variables were expressed as a percentage of study participants and compared by using the χ² test, while, for the statistical correlations between continuous and categorical variables, the point-biserial correlation calculator was used (α=.05).

RESULTS

Questionnaires were collected from 161 study participants: 92 women (mean ±standard deviation age: 76 ±7.59 years; range: 65-93 years) and 69 men (mean ±standard deviation age: 74 ±6.31 years; range: 65-86 years). A total of 239 prostheses were considered. A significant correlation was found between older participants, older removable dental prostheses, and reduced prosthesis cleanliness, correlating age ranges of participants as well as of removable dental prostheses with the degrees of prosthesis cleanliness (P=.001 and P=.004, respectively). Half the study participants (n=81; 50.3%) reported prosthesis removal during the night, while the others reported sleeping with the prosthesis in place. Some study participants (n=32; 19.9%) reported that they had never received instructions about how to clean the prosthesis. Mechanical brushing with toothbrush and toothpaste was the most common cleaning method (n=47; 29.2%), while the recommended combined cleaning method based on both mechanical brushing and immersion in dental cleanser was applied by 34 (21.1%) study participants. A similar number (n=25; 15.5%) reported at least 1 episode of denture-related stomatitis.

CONCLUSIONS

In the analyzed cohort, patient attitude and habits toward home procedures for denture hygiene resulted in poor prosthesis cleanliness. Most individuals used a toothbrush and toothpaste to clean their device, although combining mechanical and chemical cleaning is typically reported to be the optimal method.

Efficacy of low-molecular weight chitosan against Candida albicans biofilm on polymethyl methacrylate resin

BACKGROUND

Candida biofilm is a major cause of denture stomatitis. We aimed to compare the efficacy of low-molecular-weight chitosan solutions against Candida albicans biofilm on polymethyl methacrylate (PMMA) resin.

METHODS

Various types of chitosan were tested for anti-Candida activity by broth dilution. Two types were selected for further testing on 24-hour C.albicans biofilm formed on PMMA specimens. Specimens were randomly distributed among experimental groups, including 0.1% and 0.2% acetic acid, 3 and 6 mg/mL of oligomer chitosan and 30 kDa chitosan solutions, effervescent tablet (Polident), and 0.2% chlorhexidine, and immersed for 5 min to 12 h. The viability of C. albicans after cleansing were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Remaining viability was calculated into percentage relative to respective controls and analyzed using ANOVA with Tukey post-hoc tests. Live/dead fluorescence microscopy was also performed.

RESULTS

Chitosan solutions had high efficacy against C. albicans biofilm on PMMA. The mean relative viability compared to control after 12-h immersion was 6.60 ± 4.75% and 12.72 ± 6.96% for 3 and 6 mg/mL oligomer, respectively, and 11.68 ± 4.81% and 18.08 ± 6.20% for 3 and 6 mg/mL 30 kDa chitosan, respectively.

CONCLUSIONS

Low-molecular-weight chitosan solution is an effective antifungal denture cleanser that can significantly reduce C. albicans viability in biofilm on PMMA.

Surface roughness of acrylic resins used for denture base after chemical disinfection: A systematic review and meta-analysis

OBJECTIVE

This study aimed to systematically review the literature regarding the surface roughness of polymethylmethacrylate (PMMA) for denture bases, disinfected with different chemical agents and analyse the outcomes of the included studies.

BACKGROUND

Various chemical disinfection protocols to clean the removable dental prosthesis are reported in the literature, however systematic reviews analysing the outcomes in the surface roughness of the PMMA are lacking.

METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) checklist was used to structure this systematic review. The inclusion criteria were as follows: clinical trials, in vitro studies, studies in English and studies comparing the effects of chemical disinfection products on the surface roughness of PMMA. An electronic search was performed in the following databases: PubMed/MEDLINE, Scopus and Web of Science.; we also conducted a manual search for articles published in specific journals of dental prostheses and dental materials.

RESULTS

Thirteen in vitro studies in this systematic review and meta-analysis. According to the meta-analysis, the effects of 0.5% (P = .32; MD: 0.06; CI: -0.05 to 0.17; heterogeneity: P < .00001; I²  = 92%) and 1% NaOCl solutions (P = .27; MD: 0.01; CI: -0.01. to 0.03; heterogeneity: P = .03; I²  = 55%) did not statistically differ between the groups studied. Effects of alkaline peroxide were statistically significant (P = .0009; MD: 0.01; CI: 0.01-0.02; heterogeneity: P = .004; I²  = 65%), suggesting that it promotes deterioration of the PMMA surface.

CONCLUSION

The alkaline peroxide, when used as a disinfectant, generated changes on the surface roughness of PMMA and should be used with caution; however, NaOCl, even at different concentrations, caused fewer changes on the surface of the denture base.

Microbiological evaluation of an experimental denture cleanser containing essential oil of Lippia sidoides

The antimicrobial activity of an experimental solution containing essential oil of Lippia sidoides for denture cleaning was evaluated by (1) minimum inhibitory (MIC) and fungicidal/bactericidal concentration (MFC/MBC) tests against Candida albicans, Staphylococcus aureus, and Pseudomona aeruginosa; (2) the metabolic activity of C. albicans biofilm formed on flat-bottom microplates and denture base specimens based on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT); and (3) scanning electron microscopy, to evaluate the fungal biofilm morphology. The solution showed antimicrobial action against the pathogens tested (C. albicans - MIC and MFC: 19.53 µg ml^-1, S. aureus - MIC and MBC: 78.12 µg ml^-1, P. aeruginosa - MIC: 625 µg ml^-1, MBC: 2,500 µg ml^-1), reduced the metabolic activity of C. albicans biofilm up to 97%, and caused cell wall damage at low concentrations (195.3-390.6 µg ml^-1) and in short time periods (20 min). Therefore, the experimental solution has the potential to be used as an alternative in the prevention and treatment of denture-induced infections.

Effectiveness of denture microwave disinfection for treatment of denture stomatitis: A systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review was to evaluate the effectiveness of removable complete denture disinfection using microwaves for the treatment of denture stomatitis.

METHODS

This review identified studies comparing the efficacy of microwave prosthesis disinfection (I) to topical antifungal therapy (C) in the treatment of denture stomatitis (O), which included only individuals who used complete dentures and presented with denture stomatitis (P). The search was performed in six databases and identified 1524 records; after the removal of duplicates, 816 articles remained. Three articles were selected for qualitative synthesis and two for meta-analysis. Random-effects meta-analysis estimated the polled effects of microwave disinfection and antifungal therapy on the Candida counts and clinical manifestation of denture stomatitis. The GRADE approach was used to estimate the certainty of evidence.

RESULTS

All included studies reported significant reductions in Candida counts and the frequency of denture stomatitis of groups subjected to microwave disinfection of dentures and topical antifungal therapy with nystatin. Significative differences between treatments were only detected for Candida quantification in the palate, within 90 days follow-up period (SMD = 0.47, 95% CI = 0.02-0.91). Meta-analyses did not show any further differences between treatments (p > .05), considering the Candida quantification in dentures and the frequency of clinical signs of denture stomatitis. The certainty of the evidence was considered as low, according to GRADE approach.

CONCLUSION

Microwave disinfection of complete dentures can be considered as efficient as antifungal therapy for the treatment of denture stomatitis. However, further well-designed studies are necessary to confirm such evidence.

Development of practice guidelines for daily oral care in care-dependent older adults to complement the InterRAI suite of instruments using a modified Delphi approach

Aim

To develop practice guidelines for nursing assistants who provide daily oral care to older adults.

Background

The interRAI suite of instruments is internationally used in professional health care to assess the needs of care‐dependent older persons. An optimised oral health section was developed recently to identify care clients with poor oral health and hygiene. Internationally shared guidelines for daily oral care are needed to complement the optimised oral health section of the interRAI suite of instruments.

Material and methods

The modified Delphi approach started with the preparation of an initial draft. Subsequently, an online survey and a face‐to‐face discussion were conducted with international experts. Their feedback was used to revise the draft. Two additional online surveys were conducted with the experts to reach consensus agreement for each item of the revised version. The same group of experts was invited to the different study phases.

Results

The three surveys were completed by 26, 27 and 23 international experts, respectively. A group of 18 experts completed each survey, whereof a subgroup of 11 experts also took part in the face‐to‐face discussion. Experts were dental hygienists, dentists, nursing scientists, physicians and psychologists from 14 different countries. After the final survey, consensus agreement was reached for 54 of the 57 (94.7%) items, representing the final version of the guidelines.

Conclusion

Available evidence was combined with practical feedback from international experts to develop clear and concise practice guidelines for daily oral care in older adults.

Implications for practice

The guidelines will help to improve knowledge and reduce barriers of nursing assistants to provide daily oral care.

Cinnamaldehyde is a biologically active compound for the disinfection of removable denture: blinded randomized crossover clinical study

BACKGROUND

Fungal infections associated with the use of dentures, like denture stomatitis, are difficult to prevent and treat. This in situ study aimed to investigate the efficacy of cinnamaldehyde for the disinfection of complete removable dentures, and the effect on the physical and mechanical properties (Vickers microhardness, color, and surface roughness) of the acrylic resin.

METHODS

Acrylic resin disks were inserted into the dentures of a probabilistic sample of 33 complete denture users, that used cinnamaldehyde (27 μg/mL) and 0.5% sodium hypochlorite solutions in a 20 min/7-days protocol of dentures immersion in each solution, with a wash-out period of 7 days, to constitute a crossover-study. The disks were analyzed before and after the immersion, for the presence of microorganisms (CFU/mL) and by scanning electron microscope (SEM). Also, the surface roughness (Ra) and Vickers microhardness were measured, and color parameters were analyzed using the National Bureau of Standards (NBS) method. Data was analyzed by Wilcoxon and Friedman (microbiological evaluation), paired t-test (color and roughness) and independent t-test (Vickers hardness) (α = 0.05).

RESULTS

A significant reduction (P < 0.05) in the number of microorganisms was observed for each species (total microorganisms, Streptococcus mutans, and Candida spp.), with no significant differences (P > 0.05) between hypochlorite and cinnamaldehyde. There was an increase in the roughness and a decrease in the hardness of the test specimens, with no difference between the two disinfectant substances (P > 0.05). Both hypochlorite and cinnamaldehyde also caused changes in color, considered as "perceptible" by the NBS classification, but with no significant difference between disinfectant substances (P < 0.05), and under the clinically acceptable limit (ΔE ≤ 3.7).

CONCLUSION

The 27 μg/mL cinnamaldehyde solution was effective against all evaluated microorganisms and caused minor alterations in hardness, surface roughness, and color parameters, with no clinical relevance.

The relationship of oral mucosal lesions and removable prostheses: Quantitative and qualitative study

Background/Aim: The aim of this study was to determine the development and distribution of denture-related oral mucosal lesions in patients using removable prosthesis by using quantitative and qualitative research methods. Material and Methods: A 21-item structured questionnaire form was used. Then, patients were evaluated for the presence and types of oral lesions. In the qualitative phase of the study, two focus group interviews were conducted with volunteers among participants of the quantitative part. The quantitative data were first evaluated by the Kolmogorov-Smirnov test for normal distribution. Chi-square test, Mann Whitney U test, t-test and logistic regression were used for statistical evaluation. Qualitative data analysis was manually performed by the content analysis method. Results: This study included 171 subjects. When the participants were classified as lesion and non-lesion groups, cigarette use and duration of prosthesis use were higher in patients with lesions. Denture-related lesions occurred in 46.2% of the participants; prosthetic stomatitis in 23.9% of the denture-related lesions, traumatic ulcer in 12.9%, epulis fissuratum in 9.9%, and angular cheilitis in 5.8%. Of the participants with lesions 72% (n=57) had a single lesion, while 28% (n=22) had multiple lesions. The duration of prosthesis use was longer in patients with lesions (p=0.022). The main themes determined in the qualitative stage were identified as "views on prosthesis use", "features related to prosthesis care", "information sources on prosthesis" and "proposals of participants". Conclusions: Current study shows that denture-related lesions are very common. Patients should be informed in detail and adequately by physicians and specialized nurses in this regard at every stage of treatment. A universal protocol will be very helpful to ensure that patients are provided with all necessary information about wearing dentures, their maintenance and the importance of regular check-ups. Informative meetings should be organized for wider patient groups in which patients may also interactively participate in, and studies to increase oral health literacy should be conducted. The cross-sectional assessment is not enough for risk assessment due to its nature and only declaration based assessment might miss the relations. Follow-up studies combined with qualitative studies with different approaches are needed.

Practical Guidelines for Physicians in Promoting Oral Health in Frail Older Adults

Good oral health in old age is particularly important for maintaining adequate oral function, preventing pain and discomfort, controlling localized or systemic inflammation, sustaining social interaction, and preserving quality of life. Given that oral health is an integral part of general health and well-being, and that major chronic systemic and oral diseases share common risk factors, oral health prevention and promotion should be embedded within routine medical assessment and care provision. The role of medical physicians, particularly primary care physicians, geriatricians, and elderly care physicians, in community and long-term care facilities in assessing and promoting oral health in frail older adults is critical and has been emphasized in recent European recommendations. All physicians should appreciate the importance of oral health and incorporate an initial oral health screening into routine medical assessment and care. A short interview with patients and carers on current oral health practices may help to assess the risk for rapid oral health deterioration. The interview should be followed by an oral health assessment, using validated tools, for nondental health care providers. Based on these findings, the physician should decide on necessary follow-up procedures, which may include oral health counseling and/or dental referral. Oral health counseling should include advice on daily oral, mucosal, and denture hygiene; denture maintenance; dietary advice; smoking cessation; limitation of harmful alcohol consumption; management of xerostomia; and frequent dental review. To enable physicians to perform the tasks recommended in this publication, appropriate teaching at both undergraduate and postgraduate levels must be delivered in addition to provision of appropriate continuing education courses.

Severity of Candida-associated denture stomatitis is improved in institutionalized elders who consume Lactobacillus rhamnosus SP1

BACKGROUND

This study aimed to determine the effect of the consumption of a probiotic on the clinical characteristics of Candida-associated denture stomatitis (DS) and to determine the impact of a protocol of self-care measures in oral/prosthetic hygiene in institutionalized elders that wear removable prostheses (RP). The current treatment for DS is the systemic use of antifungals, as well as the replacement of these devices together with oral/prosthetic hygiene instructions.

METHODS

This study was a randomized, controlled and triple-blind trial. Thirty-six elders presenting DS of different severity and who carried RP consumed milk with/without the probiotic L. rhamnosus SP1. The prevalence and severity of DS and prevalence of Candida were determined and all participants/caregivers were trained in oral/prosthetic hygiene.

RESULTS

In both groups a decrease in the prevalence of DS was observed (P < 0.05) but only the group that consumed probiotic throughout the trial had a significant reduction in the severity of DS and reduced Candida counts (P < 0.05). Educational instruction in oral/prosthetic hygiene was relevant for the participants, regarding the prevalence of this lesion.

CONCLUSIONS

The frequent consumption of Lactobacillus rhamnosus SP1 and the establishment of a protocol of oral/prosthetic hygiene drastically reduced the severity of DS in institutionalized elders who wore RP.

Effect of Denture Cleansers on Cobalt-Chromium Alloy Surface: A Simulated Period of 5 Years' Use

PURPOSE

To compare the effect of solutions of effervescent tablets (ET), cetylpyridinium chloride (CPC), and experimental solutions of Ricinus communis on the surface of cobalt-chromium (Co-Cr) alloys.

MATERIALS AND METHODS

Fifty-five specimens of Co-Cr were prepared by the lost-wax casting method using circular patterns (∅12 × 3 mm). The specimens were randomly divided into 5 groups: deionized water (control); 2% R. communis; 10% R. communis; ET, and CPC. The surface roughness of specimens (n = 10) was evaluated before immersion (baseline), and at simulated times of ½, 1, 2, 3, 4, and 5 years, by laser confocal microscope (Sa, μm) and profilometer (Ra, μm). The surface topography and chemical composition (n = 1) was qualitatively analyzed with scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). Data were subjected to Kruskal-Wallis followed by Dunn tests, and Friedman followed by Wilcoxon tests (α = 0.05).

RESULTS

For Sa, there was no difference for the solution factor. For the time factor a significant difference was found with 2% R. communis solution among baseline and ½, 2, 3, and 5 years (p < 0.001) and with 10% R. communis solution between 1 and 2 years (p = 0.007), with decreasing roughness over time. For Ra, cetylpyridinium chloride exhibited less roughness than 10% R. communis solution in ½ (p = 0.048) and 5 years (p = 0.013). In the SEM and EDS analysis the solutions did not present deleterious effects or changes in the chemical composition on the surfaces.

CONCLUSIONS

Although a significant difference was found for the roughness, the results, below 0.2 μm, are clinically acceptable. Thus, all solutions can be used safely in removable partial denture cleaning for a period of 5 years.