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.

Effect of various staining beverages on the color stability of CAD/CAM PMMA denture teeth: An in vitro study.

OBJECTIVE: This study aimed to compare the color change of computer-aided design (CAD)/computer-aided manufacturing (CAM) polymethyl methacrylate (PMMA) denture teeth and conventional acrylic teeth after immersion in three staining beverages (coffee, red tea, and cola) for a day, 7 days, and 30 days. MATERIALS AND METHODS: Group 1: Conventional acrylic teeth (n = 32). Group 2: Milled CAD/CAM teeth out of PMMA disc (n = 32). The specimens of each material were further divided into four subgroups: (1) Control group, distilled water (n = 16). (2) Red tea solution (n = 16). (3) Coffee solution (n = 16). (4) Cola (n = 16). The color change ( ∆ E $\unicode{x02206}E$ ) was assessed using a spectrophotometer at four time points: at the baseline (t0 ), on the 1st day (t1 ), on the 7th day (t2 ), and the 30th day (t3 ) of immersion. Kolmogorov-Smirnov test was applied, followed by performing independent samples t test, one-way analysis of variance and post-hoc Tukey tests to compare the color change values at different time points. RESULTS: The mean score of NBS values of the coffee solution indicates perceivable color change at the end of the 30th day in the conventional acrylic teeth group. It was 0.843 ± 0.395 at t1 , then increased to 1.017 ± 0.477 at t2 and to 2.259 ± 1.059 at t3 . There is a statistically significant difference (p < 0.05) in color change values between both tooth types at the end of the 30th day of immersion in red tea solution and a statistically significant difference at the end of the 7th day (p < 0.05) and the 30th day (p < 0.05) of immersion in coffee solution. CONCLUSIONS: CAD/CAM PMMA teeth are more color stable than conventional acrylic teeth after 30 days of immersion in coffee and red tea solution.

Mechanophysical and Anti-Adhesive Properties of a Nanoclay-Containing PMMA Denture Resin.

Poly(methyl methacrylate) (PMMA) is commonly used for dental dentures, but it has the drawback of promoting oral health risks due to oral bacterial adhesion. Recently, various nanoparticles have been incorporated into PMMA to tackle these issues. This study aims to investigate the mechanophysical and antimicrobial adhesive properties of a denture resin by incorporating of nanoclay into PMMA. Specimens were prepared by adding 0, 1, 2, and 4 wt % surface-modified nanoclay (Sigma) to self-polymerizing PMMA denture resin. These specimens were then evaluated using FTIR, TGA/DTG, and FE-SEM with EDS. Various mechanical and surface physical properties, including nanoindentation, were measured and compared with those of pure PMMA. Antiadhesion experiments were conducted by applying a Candida albicans (ATCC 11006) suspension to the surface of the specimens. The antiadhesion activity of C. albicans was confirmed through a yeast-wall component (mannan) and mRNA-seq analysis. The bulk mechanical properties of nanoclay-PMMA composites were decreased compared to those of pure PMMA, while the flexural strength and modulus met the ISO 20795-1 requirement. However, there were no significant differences in the nanoindentation hardness and elastic modulus. The surface energy revealed a significant decrease at 4 wt % nanoclay-PMMA. The antiadhesion effect of Candida albicans was evident along with nanoclay content in the nanocomposites and confirmed by the reduced attachment of mannan on nanoclay-PMMA composites. mRNA-seq analysis supported overall transcriptome changes in altering attachment and metabolism behaviors on the surface. The nanoclay-PMMA materials showed a lower surface energy as the content increased, leading to an antiadhesion effect against Candida albicans. These findings indicate that incorporating nanoclay into PMMA surfaces could be a valuable strategy for preventing the fungal biofilm formation of denture base materials.

Use of T-Scan III in analyzing occlusal changes in molar fixed denture placement.

BACKGROUND: This study aims to analyze the longitudinal variation of occlusal force distribution prior to and after fixed restoration for molar full-crowns with T-SCAN III which provide reference for occlusal adjustment and long-term maintenance. METHODS: We enrolled a total of 20 patients who received conventional restorative treatment for molars. The occlusion examination was conducted in 3 stages (before placement, immediately after placement, and 3 months after placement) using T-SCAN III (Tekscan South Boston, MA, USA, 10.0) to examine and measure the occlusal contact areas of the full dentition. RESULTS: The results indicated that the occlusal force distribution in the molar region of the patients changed before and after the fixed restoration, but the percentages of occlusal force in the dental arch of the molar did not differ significantly before and after the restoration (P > 0.05). Three months after the fixed restoration, the percentage of occlusal force in the restored dental arches of lateral teeth increased significantly (P < 0.05). CONCLUSION: The results of this study indicated that the occlusal forces of the patients changed with tooth movement and adaptation, which is mainly reflected in the increasing occlusal force. Quantitative occlusal force analysis using T-SCAN III occlusal analyzer can provide more objective and accurate data to effectively guide clinical occlusion adjustments.

Relationship between oral health and depression: data from the National Health Survey 2016-2017.

OBJECTIVE: To evaluate the relationship between oral health status, self-perception of oral health, and depression. METHODS: This cross-sectional study included 2953 individuals that were ≥ 18 years of age and participated in the Chilean National Health Survey (NHS), 2016-2017. Information on oral, dental, and mental health, and the presence or absence of depressive symptoms was collected. Secondary data analysis was carried out using STATA and included logistic regression models adjusted for sex, age, and educational level. The analyses factored in the expansion weights to estimate representative prevalences of the entire population. RESULTS: Participants experiencing frequent dental or prosthesis-related discomfort while speaking (OR: 1.57; 95% CI: 1.01-2.43) were related with exhibiting suspected depression. Removable upper denture users were at a higher risk of exhibiting suspected (OR: 2.04; 95% CI: 1.11-3.74) than those not using them. Participants diagnosed with depression in the past 12 months had a similar number of teeth (median = 24) compared to those without depression (median = 25) (OR: 0.99; 95% CI: 0.96-1.02). CONCLUSION: Experiencing dental or prosthesis-related difficulties in speaking is related to suspected depression or a diagnosis of depression. These findings highlight the importance of developing comprehensive healthcare approaches that consider mental health in the context of oral health.

A New Scale for Rating Oral Health-Related Quality of Life in Denture Wearers.

PURPOSE: When carrying out prosthetic rehabilitation of edentulous and partially edentulous patients, great attention is paid to the personal attitude of the patients, their satisfaction with oral health and psychosocial interaction due to tooth loss, as well as the treatment of the resulting disorders. This attention has led to the development of various instruments for examining the quality of life related to oral health. The aim of this study was to develop and validate a reliable instrument in the Serbian language suitable for measuring oral health-related quality of life in patients who have been rehabilitated with complete or partial dentures. Мaterials and Methods: The study was unicentric and cross-sectional, and assessed the reliability and validity of a newly developed instrument for measuring the oral health-related quality of life in denture wearers (OHRQoL-DW). It was conducted on a sample of 200 adults from Serbia, wearers of various types of dentures, with a mean age 66.9 ± 10.3 years and male/female ratio of 86/114 (43%/57%). RESULTS: The definitive version of the OHRQoL-DW scale with 28 items showed very good reliability, with Cronbach's alpha = 0.938. Good temporal stability of the questionnaire was demonstrated, and satisfactory results were obtained for divergent and convergent validity tests. Exploratory factorial analysis revealed four domains of oral health-related quality of life in denture wearers: physical, psychosocial, environmental and aesthetic. CONCLUSIONS: The OHRQoL-DW scale is a reliable and valid generic instrument for measuring the oral health-related quality of life in patients wearing dentures, which is one of the most important outcomes of oral health in prosthetic treatment.

[Clinical analysis of denture rehabilitation after mandibular fibula free-flap reconstruction].

OBJECTIVE: To evaluate the postoperative denture restoration and denture function in patients with mandibular defect reconstructed with vascularized free fibula flap. METHODS: In the study, 154 patients who underwent mandibular segment resection and used vascularized free fibula flap to repair mandibular defects due to inflammation, trauma and tumor from January 2015 to December 2020 were collected. These patients had common inclusion criteria which were stable occlusal relationship before operation, segmental defects of mandibular bone caused by lesions of mandible and adjacent parts (such as floor of mouth, tongue, cheek), free fibula flap used for repair and surviving after operation. Relevant data were reviewed and situation of denture restoration was followed up. A questionnaire related to denture functional evaluation had been proposed for those who had completed the denture rehabilitation. The evaluation index of denture restoration function was assigned by expert authority to obtain the denture function score. SPSS 18.0 software was used for statistical analysis of the basic information of the patients included in the study and the denture restoration of the patients. RESULTS: The rate of postoperative denture restoration in the patients with mandibular defects repaired by free fibula flap was 17.5%, and the rate of postoperative denture restoration in the patients with benign mandibular tumors was 25.0% (18/72), which was significantly greater than that in the patients with malignant tumors 11.0% (9/82, P < 0.05). There was no significant difference in denture function score between the patients with condylar defect and those without condylar defect in denture repair rate and denture function score (P>0.05). The functional score of implant denture was significantly greater than that of removable denture (P < 0.05). According to Brown classification, the denture function score of the patients with the defect invo-lving the anterior mandibular region was significantly greater than that of the patients without the anterior mandibular region involved (P < 0.05). The poor oral conditions, such as less amount of remaining teeth, insufficient retention strength, large mobility of soft tissue in the surgical area, poor oral vestibular groove condition became the main reason of not receiving denture restoration (37.86%). CONCLUSION: The denture rehabilitation of mandibular defect reconstructed with vascularized free fibula flap is closely rela-ted to pathological properties and oral conditions. The clinical outcome of implant denture has been confirmed effectively and it is a better choice for future denture restoration after mandibular reconstruction.

Evaluation of photodynamic therapy efficacy vs. conventional antifungal therapy in patients with poor-fitting dentures suffering from denture stomatitis. A prospective clinical study.

BACKGROUND: The long-term use of antifungal therapy in denture stomatitis (DS) treatment could be accompanied by antifungal-resistant strain onset, leading to compromised therapeutic procedure and disease reappearance. Photodynamic therapy (PDT) has shown the ability to eradicate oral infections and resistance strains. This prospective clinical study aimed to assess the PDT's effectiveness compared to the conventional treatment on clinical and microbiological parameters in patients with DS without denture wear during the treatment and follow-ups. METHODS: Forty-two patients diagnosed with DS were randomly assigned to one-session single PDT application (test group) or conventional antifungal therapy (control group). Clinical and microbiological parameters were assessed and analyzed before and at 3rd, 15th, and 30th day following the treatments. Microbiological samples were analyzed by a Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The data was statistically analyzed. RESULTS: Prior to the treatment, Candida species, including C. albicans (100%), C. glabrata (33%), C. tropicalis (31%), C. krusei (31%) were isolated in all patients. Both treatment procedures demonstrated a statistically significant reduction in C. albicans at all follow-up time intervals (p < 0.05). However, PDT displayed a statistically significant reduction in C. krusei compared to the conventional treatment at all follow-up periods (p < 0.05). Clinical parameters improved considerably in the test group compared to the control group at the 3rd and 15th day of follow-up. CONCLUSION: One-session single PDT application demonstrated significant improvement in both clinical and microbiological outcomes in a short-term period, resulting in complete Candida spp. eradication compared to conventional antifungal therapy.

Influence of visual acuity, manual dexterity and handgrip strength on oral and denture hygiene ability of non-frail older people: Development of the Gerostomatological Assessment Battery.

BACKGROUND: Due to the heterogeneity of older people, it is difficult to identify reliable factors influencing oral health. OBJECTIVE: The aim was to illustrate the influence of visual acuity, manual dexterity, and handgrip strength on the oral and denture hygiene ability of older non-frail people. METHODS: In a cross-sectional study, conducted at a specialized dental clinic, at baseline, all participants received professional prophylaxis and instruction on daily oral and denture hygiene regimes for a 6-week intervention period. Data on the Quigley and Hein modified plaque index (QHI), respectively, the Denture Hygiene Index (DHI), visual acuity, manual dexterity and handgrip strength in non-frail participants (≥ 65 years) were collected. Recruitment was done within the clinic's patient clientele and within the staff (control cohort). RESULTS: Women showed significantly better manual dexterity than men (Mann-Whitney U, p = .01), while women's mean handgrip strength was significantly lower (Mann-Whitney U, p < .01). Manual dexterity (Mann-Whitney U, p = .003) and handgrip strength (Mann-Whitney U, p = .052) were associated with age. However, visual acuity, manual dexterity and handgrip strength had no influence on oral or denture hygiene. CONCLUSION: Visual acuity, manual dexterity and handgrip strength have no influence on oral and denture hygiene ability in older non-frail people. Further studies should investigate whether these factors also have no influence on oral and denture hygiene in vulnerable older patients. Therefore, an assessment tool for the evaluation of potential influencing factors of oral and denture hygiene is proposed in a dental context. This Gerostomatological Assessment Battery (G-AB) can be used as a helpful tool to check the individual cognitive function and comprehension, dental therapy approaches and their individual adaption.

Denture use and risk for cardiometabolic disease: observational and Mendelian randomization analyses.

AIMS: Denture use may potentially increase the risk of cardiometabolic diseases (CMDs), but the casual relevance and strength of the associations are currently unknown. METHODS AND RESULTS: A total of 495 938 participants from the UK Biobank were included in the observational analyses. Linkage disequilibrium score (LDSC) regression and Mendelian randomization analyses were employed to estimate genetic correlation and the associations between the genetic liability for denture use with coronary artery disease, myocardial infarction, heart failure (HF), any stroke (AS), ischaemic stroke, haemorrhagic stroke, type 2 diabetes (T2D), and related clinical risk factors. In observational analysis, denture use was associated with 14-25% higher risks of various CMDs. The LDSC analysis found that denture use showed a positive genetic correlation with CMDs (rg 0.21-0.38). Genetic liability for denture use was associated with an elevated risk of HF [odds ratio: 1.49 (1.20-1.83)] and T2D [1.11 (1.01-1.24)]. By integrating genetic summary data of denture use with the sum of decayed, missing, and filled tooth surfaces (DMFS), a clinical measure of dental caries obtained from an independent source, genetically determined denture use/DMFS was also associated with an elevated risk of AS [1.21 (1.04-1.40)]. Furthermore, genetically predicted denture use/DMFS was significantly associated with established cardiometabolic risk factors, including HDL cholesterol, triglycerides, waist circumference, waist-to-hip ratio, and height. CONCLUSION: Our study supported potential causal associations between the genetic liability for denture use and risks for HF, AS, T2D, and related clinical risk factors. These findings may inform prevention and intervention strategies targeting dental diseases and CMDs.

This study examined the association of denture use with cardiometabolic diseases (CMDs) and related clinical risk factors through Mendelian randomization analyses using data from UK Biobank and published consortia. Genetic liability for denture use was associated with an 11­49% higher risk of heart failure, stroke, and type 2 diabetes.The potential causal relationship between denture use and CMDs was further strengthened by the associations of denture use with HDL cholesterol, triglycerides, waist circumference, waist-to-hip ratio, and height, which are among the major risk factors of CMDs.

Assessment of usefulness and reliability of YouTube™ videos on denture care.

INTRODUCTION: The world's population is in a demographic transition with a rising ageing population. Tooth loss is frequent among older people resulting in the replacement of natural teeth using complete or partial dentures. YouTube™ is the second most popular website in the world and is being increasingly used to access health care information. The aim of this study is to evaluate the usefulness and reliability of the information in YouTube™ videos regarding denture care. METHODS: The YouTube™ website was used to systematically search for videos using the keyword 'denture care'. Videos meeting the eligibility criteria were assessed separately by two independent researchers. The usefulness of the videos was assessed using the Global Quality Assessment Scale and a customized usefulness scoring scheme. Based on these scores, the usefulness of the videos was categorized as low, medium and high. A modified DISCERN tool (mDISCERN) was used for assessing reliability with scores ranging from 0 to 5. Other video characteristics like source/ownership of the videos, duration, views, likes, dislikes, number of days posted, like ratio, view ratio, interaction index and Video Power Index were also obtained. Statistical analysis was carried out using the Kruskal-Wallis test, Spearman correlation test and multiple linear regression analysis. RESULTS: A total of 120 videos were included. Based on the usefulness score, the usefulness of 65.8% of videos were classified as low, 32.5% were medium and 1.6% had high usefulness. The mDISCERN score for 74.2% of videos was 2 or below 2 indicating that the majority of videos had low reliability. Video characteristics did not differ significantly according to the usefulness of videos. Videos uploaded by dentists or dental hygienists had significantly higher usefulness scores (p < 0.001) in comparison to videos uploaded by other sources. However, reliability scores did not differ based on the sources of the videos. Video reliability was found to have a significant (B = 2.08, p < 0.001) positive association with video usefulness. CONCLUSION: YouTube™ cannot be recommended as the only source of information for denture care as most videos received low usefulness and reliability ratings in our study. Dentists and dental health professionals could take an active part in enhancing denture care-related content on YouTube™ and enable patients to have adequate and reliable knowledge of denture hygiene practices.

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.

In vitro comparison of antifungal activity of conventional alcohol sprays and antimicrobial photodynamic therapy on acrylic denture resin.

BACKGROUND: Traditionally, alcohol sprays are used for disinfection of acrylic-base denture surfaces. A limited number of studies have assessed the role of antimicrobial photodynamic therapy (aPDT) in this regard; however, it remains debatable whether conventional alcohol sprays are superior to aPDT in terms of antifungal activity or vis versa. OBJECTIVE: The aim of the present in vitro study is to compare the antifungal activity of conventional alcohol sprays and aPDT on acrylic denture resin. METHODS: Individuals wearing complete dentures at least on one arch were included. Dentures were randomly divided into three groups. Groups 1-3 were disinfected with an alcohol-based antiseptic spray and aPDT, respectively. Assessment of oral yeast growth was done using swab samples. The culture mediums were incubated at 37∘C for 72 hours and viewed through a microscope. The numbers of colony forming units (CFU/ml) were determined. P< 0.05 were considered statistically significant. RESULTS: At baseline, the mean CFU/ml in Groups 1-3 were comparable. After disinfection, a statistically significant reduction in microbial CFU/ml was observed in Groups 1 (P< 0.05) and 2 (P< 0.05) compared with baseline. In Group 3, there was no difference in CFU/ml throughout the study. After disinfection, there was no difference in microbial CFU/ml in dentures in Groups 1 and 2. CONCLUSION: Conventional alcohol sprays are as effective as aPDT towards reducing oral yeasts CFU/ml on acrylic denture resin.

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

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

Mapping the role of oral cavity physiological factors into the viscoelastic model of denture adhesives for numerical implementation.

Physiological parameters of the oral cavity have a profound impact on any restorative solutions designed for edentulous patients including denture adhesives. This study aims to mathematically quantify the influence of three such variables, namely: the temperature, pH, and the swelling of such adhesives under the influence of saliva on its mechanical behavior. The mathematical quantification is further aimed to implement a material model for such adhesives which considers the impact of such physiological factors. The denture adhesive is experimentally investigated by means of rheological steady state frequency sweep tests to obtain the relaxation spectrum of the material. The relaxation behavior is measured for a wide range of oral cavity temperatures and pH. Also, the adhesive is hydrated and upon swelling to different levels again tested to understand the impact of swelling on the mechanical behavior. The experimentally measured continuous relaxation spectrum is modeled as a viscoelastic material using a discrete set of points based on the Prony series discretization technique. The relaxation spectrums for various temperatures are compared and the possibility of a time-temperature superposition is explored for the model. Similarly, the measured values of Storage and loss modulus are investigated to understand the role of pH and swelling. The results in this study clearly indicated a horizontal shift in the relaxation behavior with increase in temperature. And hence, the time-temperature shift factor was calculated for the adhesive. The relaxation spectrum also showed a strong correlation with swelling of the adhesive and the pH. The influence of these two parameters were captured into the model based on the relaxation time parameter in the Prony series approach. Based on this study the impact of these parameters could be appreciated on the performance and mechanical behavior of denture adhesives and implemented into a Prony series based viscoelastic material model which can be used with numerical simulations.

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

BACKGROUND: The continuously increasing demand for removable denture appliances and the importance of adequate denture cleaning have led to the development of various denture cleansing products. The aim of this study was to evaluate the efficacy of two novel denture cleansing agents (GE and TM) and three commonly available cleansers (0.5% sodium hypochlorite; NaClO, 0.12% chlorhexidine gluconate; CHX, and Polident®; POL) on multispecies microbial biofilm formation, stain removal and physical properties of dentures. METHODS: The antimicrobial activities of denture cleansing agents were determined against major oral opportunistic pathogens including Streptococcus mutans, Staphylococcus aureus, Escherichia coli and Candida albicans, using time-kill assays. Multispecies microbial biofilms grown on acrylic resins for 72 h were generated to determine the antibiofilm effects of cleansing agents by confocal laser scanning microscopy (CLSM). Evaluations of the tea and coffee stain removal properties and the alterations in the physical properties of dentures were also performed. The toxicity of cleanser residues released from denture acrylics to fibroblast cells was investigated using MTT assay. RESULTS: All denture cleansing agents tested could effectively kill oral bacteria and Candida albicans. Furthermore, after immersion for more than 3 h, the cleansers Polident®, GE and TM could efficiently penetrate and inhibit multispecies denture biofilms with effects similar to 10 min of immersion in 0.5% NaClO. However, immersion in 0.12% CHX for 20 min showed less antibiofilm activity. The NaClO solution had the highest efficacy for removing stains from the artificial teeth. Conversely, the CHX solution enhanced tea and coffee staining, and the teeth immersed in this solution showed clinically unacceptable colour changes (ΔE > 5.5). However, the colour differences of teeth stained and immersed in POL, GE and TM cleansers were in the clinically acceptable range. There was no significant difference among the POL, GE and TM cleansers in terms of stain removal efficacy. The cleansers GE and TM did not alter the surface roughness and colour of the materials, moreover the residues of both cleansers did not exhibit cytotoxicity. CONCLUSION: Two novel denture cleansing agents containing natural products, GE and TM exhibited effective antimicrobial activity, antibiofilm and stain removal capabilities without toxicity or disturbance of the physical properties of acrylics.

Number of Teeth and Denture Use Are Associated with Frailty among Chinese Older Adults: A Cohort Study Based on the CLHLS from 2008 to 2018.

OBJECTIVES: The aim of this study was to determine the association between oral health and the development of frailty over a 10-year period in older Chinese adults. DESIGN: This was a cohort study. SETTING AND PARTICIPANTS: The data in this study were derived from the 2008, 2011, 2014 and 2018 waves of the Chinese Longitudinal Health Longevity Survey (CLHLS). The final analysis included 1155 older adults who had complete data for the Frailty Index (FI) and the other factors(oral health, sociodemographics, etc) that were analyzed in the study. MEASUREMENTS: Frailty was assessed by the FI, which consists of 40 deficits(self-health assessments, diseases, physical functions,etc). Multivariable logistic regression was carried out to calculate the odds ratios (ORs) of the independent variables,which were obtained from investigator surveys and self-reports, in association with the development of frailty. RESULTS: The prevalence of frailty at baseline was 22.94%, and the 10-year incidence of frailty was 24.16% (215/890). Age, number of natural teeth, use of dentures, toothache and sex were independent risk factors for frailty at baseline. After full adjustment, multivariate logistic regression analysis indicated that compared with having ≥21 teeth, edentulism (ORs 3.575; 95% CI 2.095,6.101) and partial tooth loss (ORs 2.448; 95% CI 1.592,3.766) were associated with progression to frailty. Compared with those with ≥21 teeth, those with <21 teeth and without dentures (ORs 2.617; 95% CI 1.713,3.999) were more likely to progress to frailty. CONCLUSION: The loss of natural teeth is associated with the progression of frailty in older Chinese adults and denture using can help lower the odds of being frailty. Further research on maintain natural teeth and the appropriate use of dentures may help to establish effective frailty prevention strategies for the older adults.