Effectiveness of denture cleanser associated with microwave disinfection and brushing of complete dentures: in vivo study

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.

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 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.

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.

Impact of frequency of denture cleaning on microbial and clinical parameters - a bench to chairside approach

Objective: Robust scientific and clinical evidence of how to appropriately manage denture plaque is lacking. This two-part study (i) developed an in vitro model of denture plaque removal, and (ii) assessed effectiveness of these approaches in a randomised clinical trial.

Method: (i) a complex denture plaque model was developed using the dominant microbial genera from a recent microbiome analyses. Biofilms formed on polymethylmethacrylate were brushed daily with a wet toothbrush, then either treated daily for 5 days or only on Days 1 and 5 with Polident® denture cleanser tablets (3 min soaking). Quantitative and qualitative microbiological assessments were performed. (ii), an examiner-blind, randomised, crossover study of complete maxillary denture wearers was performed (n = 19). Either once-daily for 7 days or on Day 7 only, participants soaked dentures for 15 min using Corega® denture cleansing tables, then brushed. Denture plaque microbiological assessment used sterilized filter paper discs.

Results: The in vitro model showed daily cleaning with denture cleanser plus brushing significantly reduced microbial numbers compared to intermittent denture cleaning with daily brushing (p < 0.001). The clinical component of the study showed a statistically significant reduction in denture plaque microbial numbers in favour of daily versus weekly treatment (aerobic bacteria p = 0.0144). Both in vitro and in vivo studies showed that denture plaque biofilm composition were affected by different treatment arms.

Conclusions: This study demonstrated that daily denture cleansing regimens are superior to intermittent denture cleansing, and that cleansing regimens can induce denture plaque compositional changes. Clinicaltrials.gov registration: NCT02780661.

Assessment of Hygiene Habits in Acrylic Denture Wearers: a Cross-sectional Study

Objectives:

To assess the denture hygiene habits in a population of Lebanese denture wearers.

Materials and Methods:

One hundred and thirty-two (132) patients [71 women (53.8%) and 61 men (46.2%)] wearing their acrylic dentures for more than two years were included in this study. The hygiene methods related to their dentures were evaluated and the data obtained were analyzed statistically using the IBM^® SPSS^® statistics 20.0 (USA) statistical package.

Results:

Regardless of the cleaning technique, the big majority of our participants [123 out of 132 (93.1%)] cleaned their dentures daily. The two mostly used denture cleaning techniques were rinsing with tap water (34.1%) and brushing with toothpaste (31.8%). Nearly half of our patients (45.5%) soaked their dentures during the night; most of them with cleansing tablets dissolved in water (28.8%).

Conclusions:

Within the limitations of our study, it was concluded that in a sample of Lebanese population surveyed about denture hygiene habits, the daily frequency of denture cleaning is satisfactory, but the techniques and products used were self-estimated and, consequently, not sufficient.

Histotripsy Treatment of S. Aureus Biofilms on Surgical Mesh Samples Under Varying Pulse Durations

Prior studies demonstrated that histotripsy generated by high-intensity tone bursts to excite a bubble cloud adjacent to a medical implant can destroy the bacteria biofilm responsible for the infection. The goal of this paper was to treat Staphylococcus aureus (S. aureus) biofilms on surgical mesh samples while varying the number of cycles in the tone burst to minimize collateral tissue damage while maximizing therapy effectiveness. S. aureus biofilms were grown on 1-cm square surgical mesh samples. The biofilms were then treated in vitro using a spherically focused transducer (1.1 MHz, 12.9-cm focal length, 12.7-cm diameter) using either a sham exposure or histotripsy pulses with tone burst durations of 3, 5, or 10 cycles (pulse repetition frequency of 333 Hz, peak compressional pressure of 150 MPa, peak rarefactional pressure of 17 MPa). After treatment, the number of colony forming units (CFUs) on the mesh and the surrounding gel was independently determined. The number of CFUs remaining on the mesh for the sham exposure (4.8 ± 0.9-log₁₀) (sample mean ± sample standard deviation-log10 from 15 observations) was statistically significantly different from the 3-cycle (1.9 ± 1.5-log₁₀), 5-cycle (2.2 ± 1.1-log₁₀), and 10-cycle exposures (1 ± 1.5-log₁₀) with an average reduction in the number of CFUs of 3.1-log₁₀. The numbers of CFUs released into the gel for both the sham and exposure groups were the same within a bound of 0.86-log₁₀, but this interval was too large to deduce the fate of the bacteria in the biofilm following the treatment.

ATP Bioluminometers Analysis on the Surfaces of Removable Orthodontic Aligners after the Use of Different Cleaning Methods

Purpose. The aim was to quantify the bacteria concentration on the surface of orthodontic clear aligners using three different cleaning methods. Furthermore the objective was to validate the efficacy of the bioluminometer in assessing the bacteria concentration. Materials and Methods. Twenty subjects (six males and fourteen females) undergoing orthodontic therapy with clear aligners (Invisalign® Align Technology, Santa Clara, California) were enrolled in this study. The observation time was of six weeks. The patients were instructed to use different cleaning methods (water, brushing with toothpaste, and brushing with toothpaste and use of sodium carbonate and sulphate tablet). At the end of each phase a microbiological analysis was performed using the bioluminometer. Results. The highest bacteria concentration was found on aligners cleaned using only water (583 relative light units); a value of 189 relative light units was found on aligners cleaned with brushing and toothpaste. The lowest bacteria concentration was recorded on aligners cleaned with brushing and toothpaste and the use of sodium carbonate and sulfate tablet. Conclusions. The mechanical removal of the bacterial biofilm proved to be effective with brushing and toothpaste. The best results in terms of bacteria concentration were achieved adding the use of sodium carbonate and sulfate tablet.

Effectiveness of a Chlorhexidine Digluconate 0.12% and Cetylpyridinium Chloride 0.05% Solution in eliminating Candida albicans Colonizing Dentures: A Randomized Clinical in vivo Study

BACKGROUND

Effective denture hygiene is important for patients suffering from denture stomatitis (DS). This study aimed to evaluate the efficacy of a solution containing 0.12% chlorhexidine (CHX) digluconate and 0.05% cetylpyridinium chloride (CPC) in eliminating Candida albicans colonizing dentures.

MATERIALS AND METHODS

Forty denture wearers (11 men, 29 women; age range 40 to 80 years) with clinical evidence of DS were randomly divided into two groups, one test and one control. The dentures of the test group were treated by immersion in a solution of 0.12% CHX and 0.05% CPC while those of the control group were immersed in distilled water. Swabs were collected from the fitting surfaces of the upper dentures prior and post cleaner use and examined mycologically.

RESULTS

Reduction in the number of colony-forming units (CFU) of Candida albicans after immersion of the dentures in a solution of 0.12% CHX and 0.05% CPC was significantly greater than that of the control group.

CONCLUSION

A solution of 0.12% CHX and 0.05% CPC tested as a product of disinfection of the acrylic dentures showed significant results after immersion of 8 night hours for 4 days.