Evaluation of surface roughness, wettability and adhesion of multispecies biofilm on 3D-printed resins for the base and teeth of complete dentures

OBJECTIVE

This study evaluated the surface roughness, wettability and adhesion of multispecies biofilms (Candida albicans, Staphylococcus aureus and Streptococcus mutans) on 3D-printed resins for complete denture bases and teeth compared to conventional resins (heat-polymerized acrylic resin; artificial pre-fabricated teeth).

METHODOLOGY

Circular specimens (n=39; 6.0 mm Ø × 2.0 mm) of each group were subjected to roughness (n=30), wettability (n=30) and biofilm adhesion (n=9) tests. Three roughness measurements were taken by laser confocal microscopy and a mean value was calculated. Wettability was evaluated by the contact angle of sessile drop method, considering the mean of the three evaluations per specimen. In parallel, microorganism adhesion to resin surfaces was evaluated using a multispecies biofilm model. Microbial load was evaluated by determining the number of Colony Forming Units (CFU/mL) and by scanning electron microscopy (SEM). Data were subjected to the Wald test in a generalized linear model with multiple comparisons and Bonferroni adjustment, as well as two-way ANOVA (α=5%).

RESULTS

The roughness of the conventional base resin (0.01±0.04) was lower than that of the conventional tooth (0.14±0.04) (p=0.023) and 3D-printed base (0.18±0.08) (p<0.001). For wettability, conventional resin (84.20±5.57) showed a higher contact angle than the 3D-printed resin (60.58±6.18) (p<0.001). Higher microbial loads of S. mutans (p=0.023) and S. aureus (p=0.010) were observed on the surface of the conventional resin (S. mutans: 5.48±1.55; S. aureus: 7.01±0.57) compared to the 3D-printed resin (S. mutans: 4.11±1.96; S. aureus: 6.42±0.78). The adhesion of C. albicans was not affected by surface characteristics. The conventional base resin showed less roughness than the conventional dental resin and the printed base resin.

CONCLUSION

The 3D-printed resins for base and tooth showed less hydrophobicity and less adhesion of S. mutans and S. aureus than conventional resins.

Relation between the risk factors for the severity of denture stomatitis and quality of life of complete edentulous individuals: a cross-sectional study

OBJECTIVE

To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers.

METHODOLOGY

Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%.

RESULTS

184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL.

CONCLUSION

Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

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.

Analysis of microbial communities of ocular prostheses and anophthalmic sockets using 16S rRNA gene sequencing

Ocular prostheses are liable to host microbial adhesion, which can favor conjunctival inflammation. Knowing the microbiota of the ocular prosthesis and anophthalmic socket is important for predicting infection-related pathogens. This study evaluated the microbiota of the prostheses and anophthalmic sockets of six individuals by 16S rRNA sequencing. The microbial abundance and diversity were analyzed using the Operational Taxonomic Units at the genus level. Forty-seven phyla, capturing 1,258 named genera, were recorded in the sample set. In both sites, the most frequent genera were Fusobacterium, Staphylococcus, Prevotella, and Streptococcus. The microbial abundance was higher for the anophthalmic socket than for the prosthesis. Alpha diversity showed no significant differences in bacterial richness or diversity between sites. Although the microbial abundance in the anophthalmic socket was higher, both sites had similar microbiota with high diversity and low dominance among the genera.

Effect of a Hygiene Protocol on Denture-Related Stomatitis Remission, Local Inflammatory Factors, and Hemodynamic Responses by Arterial Pressure

Denture-related stomatitis (DRS) is frequent oral inflammation in complete denture wearers. This study evaluated the effect of a hygiene protocol on DRS remission, local inflammatory factors, and hemodynamic responses. Thirty-three individuals were enrolled in the study. The outcomes were measured before and after 10 days of a hygiene protocol treatment consisting of brushing the palate with a soft brush and water and denture brushing with a denture-specific brush and mild soap, as well as immersion of the denture for 20 min in a 0.25% sodium hypochlorite solution. Data were analyzed by paired Wilcoxon for biofilm removal and CFU count of microorganisms. The paired T test was used to assess salivary MUC 1, cytokines, and arterial pressure (p < 0.05). A significant difference was found in the DRS degree (p < 0.001), biofilm (p < 0.001), microbial load of Candida spp. (p < 0.001), Gram-negative (p < 0.004), Staphylococcus spp. (p < 0.001), and S. mutans (p < 0.001) of the denture, and S. mutans (p < 0.001) of the palate after use of the protocol. The salivary flow (p = 0.2) and pH (p = 0.97) did not change; there was an increase of MUC 1 (p = 0.049) and a decrease in IL-6 (p = 0.038), IL-2 (p = 0.04), IL-10 (p = 0.041), and IFNγ (p = 0.04). There was also a decrease in systolic (p = 0.012) and mean arterial pressure (p = 0.02). The current hygiene protocol reduced the inflammation degree of DRS and promoted an improvement of local inflammatory factors and a reduction in the systolic arterial pressure of the patients.

Effect of Denture Hygiene Protocols on Patient Satisfaction, Oral Health-Related Quality Of Life, and Salivary Parameters: A Randomized Clinical Trial

PURPOSE

This randomized controlled trial compared four denture hygiene protocols in terms of patient satisfaction, oral health-related quality of life (OHRQoL), and salivary parameters in complete denture wearers with denture stomatitis.

MATERIAL AND METHODS

For this randomized, double-blind controlled clinical trial, 108 participants were assigned to soak their dentures in one of the following solutions: (1) 0.25% sodium hypochlorite (positive control), (2) 0.15% Triclosan, (3) denture disinfecting tablets, or (4) denture disinfecting tablets plus palatine mucosa brushing solution. The outcomes of patient satisfaction, OHRQoL, and salivary parameters (salivary flow rate and pH) were measured at baseline and after 10 days. Results were compared by Kruskal-Wallis, between-group by the Dunn test, and Wilcoxon tests between times (α = 0.05).

RESULTS

After the hygiene protocols, and when compared with baseline, the overall patient satisfaction, maxillary denture satisfaction, maxillary denture comfort, and maxillary denture retention were ameliorated. A significant improvement was noted in OHRQoL in 3 of 4 domains evaluated (orofacial pain and discomfort, masticatory discomfort and disability, and psychological disability and discomfort). The salivary flow rate (unstimulated and stimulated); and pH were not significantly affected at the times evaluated.

CONCLUSIONS

Complete denture wearers may feel more satisfied with their complete dentures when treated for denture stomatitis. The tested treatments lead to similar improvement in terms of patient satisfaction and OHRQoL. This article is protected by copyright. All rights reserved.

Influence of glucose supplementation on biofilm formation of Candida albicans and Candida glabrata isolated from diabetic and non-diabetic individuals

OBJECTIVE

This study evaluated the effect of different glucose concentration on biofilm formation of Candida albicans and Candida glabrata strains isolated from diabetic and non-diabetic individuals.

METHODS

The study was divided into two stages: (I) selection and identification of 48 C. albicans and C. glabrata strains by polymerase chain reaction followed by restriction fragment length polymorphism analysis (PCR/RFLP); (II) evaluation of biofilm formation by means of viability rates (colony-forming units), biofilm dry matter (mg) and biofilm-covered areas (μm²). Statistical comparisons were performed through nonparametric analysis of longitudinal data in factorial experiments with pairwise comparisons using Friedman Conover's test (α = 0.05).

RESULTS

All the Candida spp. had their identifications confirmed by PCR/RFLP. C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed higher viability rates than strains from non-diabetic individuals. No difference was observed on viability of C. glabrata biofilm. Regarding biofilm dry matter, C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed lower amount in weight than strains from non-diabetic individuals. In C. glabrata strains, this result was only observed in biofilms cultivated with no glucose supplementation. With regard to biofilm-covered areas, only glucose supplementation and non-diabetic condition showed a positive effect on C. albicans biofilm development, and no condition affected C. glabrata biofilm formation.

CONCLUSION

The strain type (C. albicans and C. glabrata) isolated from diabetic and non-diabetic individuals influenced on biofilm formation, but glucose supplementation did not.

Action of disinfectant solutions on adaptive capacity and virulence factors of the Candida spp. biofilms formed on acrylic resin

BACKGROUND

Understanding the behavior of Candida spp. when exposed to denture disinfectants is essential to optimize their effectiveness. Changes in the virulence factors may cause increased resistance of Candida spp. to disinfectant agents.

OBJECTIVE

To evaluate the microbial load, cellular metabolism, hydrolytic enzyme production, hyphae formation, live cell and biofilm quantification of Candida albicans, Candida tropicalis and Candida glabrata after exposure to disinfectant solutions.

METHODOLOGY

Simple biofilms were grown on heat-polymerized acrylic resin specimens, and divided into groups according to solutions/strains: distilled water (control); 0.25% sodium hypochlorite (NaOCl 0.25% ); 10% Ricinus communis (RC 10%); and 0.5% Chloramine T (CT 0.5%). The virulence factors were evaluated using the CFU count (microbial load), XTT method (cell metabolism), epifluorescence microscopy (biofilm removal and live or dead cells adhered), protease and phospholipase production and hyphae formation. Data were analyzed (α=0.05) by one-way ANOVA/ Tukey post hoc test, Kruskal-Wallis test and Wilcoxon test.

RESULTS

NaOCl 0.25% was the most effective solution. CT 0.5% reduced the number of CFUs more than RC 10% and the control. RC 10% was effective only against C. glabrata. RC 10% and CT 0.5% decreased the cellular metabolism of C. albicans and C. glabrata. Enzyme production was not affected. Hyphal growth in the RC 10% and CT 0.5% groups was similar to that of the control. CT 0.5% was better than RC 10% against C. albicans and C. tropicalis when measuring the total amount of biofilm and number of living cells. For C. glabrata, CT 0.5% was equal to RC 10% in the maintenance of living cells; RC 10% was superior for biofilm removal.

CONCLUSIONS

The CT 0.5% achieved better results than those of Ricinus communis at 10%, favoring the creation of specific products for dentures. Adjustments in the formulations of RC 10% are necessary due to efficacy against C. glabrata. The NaOCl 0.25% is the most effective and could be suitable for use as a positive control.

Complete denture hygiene solutions: antibiofilm activity and effects on physical and mechanical properties of acrylic resin

BACKGROUND

Appropriated denture hygiene is a predictive factor for longevity of rehabilitation treatment and maintenance of the oral mucosal health. Although, disinfectant solutions are commonly used as denture cleansers, the impact of these solutions on acrylic resin-based dentures remain unclear.

OBJECTIVE

To evaluate, in vitro, the antibiofilm activity of complete denture hygiene solutions and their effects on physical and mechanical properties of acrylic resin.

METHODOLOGY

For antibiofilm activity measurement acrylic resin specimens were contaminated with Candida albicans, Candida glabrata and Streptococcus mutans. After biofilm growth, the specimens were assigned to the hygiene solutions: Distilled water (Control); 0.2% Sodium hypochlorite (SH); Efferdent Power Clean Crystals (EPC) and 6.25% Ricinus communis (RC). The viability of microorganisms was evaluated by agar plate counts. In parallel, physical, and mechanical properties of the acrylic resin were evaluated after simulating a 5-year period of daily immersion in the previously mentioned solutions. The changes in surface roughness, color, microhardness, flexural strength, impact strength, sorption and solubility were evaluated. Data were compared by ANOVA followed by the Tukey test or Kruskal-Wallis followed by the Dunn test depending on the distribution (α=0.05).

RESULTS

Regarding antibiofilm action, SH eliminated all microorganisms while EPC and RC exhibited moderate action against S. mutans (p=0.001) and C. glabrata (p<0.001), respectively. Relative to effects on the physical and mechanical properties of the acrylic resin, RC led to higher values of color change (p=0.030), hardness (p<0.001), surface roughness (p=0.006) and flexural strength (p<0.001). Moreover, RC induced the highest values of changes in solubility (p<0.001). EPC promoted greater changes in surface morphology, whereas immersion in SH retained the initial appearance of the acrylic resin surface. All hygiene solutions reduced the impact strength (p<0.05).

CONCLUSION

SH presented the most effective antibiofilm activity. In addition, changes on properties were observed after immersion in RC, which were considered within acceptable limits.

Effectiveness of Brushing Associated With Oral Irrigation in Maintenance of Peri-Implant Tissues and Overdentures: Clinical Parameters and Patient Satisfaction

Hygiene of implant-supported prostheses and the health of peri-implant tissues are considered to be predictive factors of successful prosthetic rehabilitation. Therefore, the purpose of this study was to evaluate the effectiveness of brushing associated with oral irrigation measured as biofilm-removing capacity, maintenance of healthy oral tissues, and patient satisfaction. A randomized, crossover clinical trial was conducted with 38 patients who wore conventional maxillary complete dentures and mandibular overdentures retained by the O-ring system. The patients were instructed to use the following hygiene methods for 14 days: mechanical brushing (MB; brush and dentifrice, control) and MB with oral irrigation (Waterpik [WP], experimental). Biofilm-removing capacity and maintenance of healthy oral tissues were evaluated by the modified plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing index (BP) recorded at baseline and after each method. In parallel, patients answered a specific questionnaire using a visual analog scale after each hygiene method. Data were analyzed by Friedman and Wilcoxon tests (α = .05). The results showed significantly lower PI, GI, PD, and BP after application of the hygiene methods (P < .001) than those observed at baseline. However, no significant difference was found between MB and WP. The responses to the satisfaction questionnaire for both methods showed high mean values for all questions, with no statistically significant difference found between the answers given after the use of MB and WP (P > .05). The findings suggest that WP was effective in reducing PI, GI, PD, and BP indices and provided a high level of patient satisfaction.

The Impact of an Ocular Prosthesis on the Quality of Life, Perceived Stress, and Clinical Adaptation of Anophthalmic Patients: A Clinical and Longitudinal Trial

PURPOSE

This prospective study evaluated and correlated the impact of ocular prostheses on quality of life and stress with socioeconomic level and clinical characteristics. The clinical difficulties and perceptions of patients after ocular rehabilitation were evaluated.

MATERIALS AND METHODS

Anophthalmic patients (at least 18 years of age) who were not users of ocular prostheses were recruited. The Medical Outcomes Short-Form Health Survey (SF-36) and Perceived Stress Scale (PSS-10) questionnaires were administered before and after 3 and 6 months of prosthesis installation. Clinical characteristics, difficulties, and perceptions were evaluated by quantitative and descriptive analysis (7 days, 3 months, 6 months). Data were analyzed by the Friedman test and Pearson Correlation test (α = 0.05).

RESULTS

The final sample consisted of 26 patients. Quality of life showed improvement in the "Bodily Pain" and "General Health" domains. Wearing the prosthesis did not influence perceived stress. The clinical evaluation showed clinical discharge over 6 months and presence of pain only at 7 days. A weak correlation occurred between sociodemographic characteristics and the categories "Role-Physical" (r = 0.423) and "General Health" (r = 0.494); cause of anophthalmia and "Role-Physical" (r = -0.471); and type of surgery and "General Health" (r = -0.432).

CONCLUSIONS

According to the results of this study, the provision of ocular prostheses showed positive influence in 2 domains of quality of life and weak correlations with socioeconomic level, type of surgery, and cause of loss. Ocular rehabilitation did not influence stress. The use and care of the prostheses did not affect tissue inflammation, but the discharge was continuous.

Expression of virulence factors by Pseudomonas aeruginosa biofilm after bacteriophage infection

The use of bacteriophages for the treatment of bacterial infections has been extensively studied. Nonetheless, the stress response regarding bacteriophage infection and the expression of virulence factors of Pseudomonas aeruginosa after phage infection is poorly discussed. In this study, we evaluated biofilm formation capacity and expression of virulence factors of P. aeruginosa after bacteriophage infection. Biofilm growth rates, biofilm morphology, pyocyanin production and elastase activity were evaluated after 2, 8, 24 and 48 h of co-cultivation with bacteriophages that was recently characterized and showed to be infective towards clinical isolates. In parallel, quantitative real-time polymerase chain reactions were carried out to verify the expression of virulence-related genes. Bacteriophages promoted substantial changes in P. aeruginosa biofilm growth at early co-culture time. In addition, at 8 h, we observed that some cultures developed filaments. Although bacteriophages did not alter both pyocyanin and protease activity, changes on the expression level of genes related to virulence factors were detected. Usually, lasI, pslA, lasB and phzH genes were upregulated after 2 and 48 h of co-culture. These results highlight the need for extensive investigation of pathways and molecules involved in phage infection, since the transcriptional changes would suggest a response activation by P. aeruginosa.

Brushing associated with oral irrigation in maintaining implants and overdentures hygiene - a randomized clinical trial

Evaluate, through a randomized clinical trial, the efficacy of brushing associated with oral irrigation in maintaining implant and overdenture hygiene. Thirty-eight participants, who had a clinically acceptable conventional maxillary complete denture and mandibular overdenture retained by either implants or mini-implants using an O-ring-retained system, were enrolled to participate in the study. They were instructed to use two different hygiene methods, in a random sequence for a period of 14 days, with a 7-day wash-out interposed period: (I) mechanical brushing (MB); (II) association of mechanical brushing with oral irrigation (WP). Biofilms from both subgingival sulci and overdentures were collected and processed by Checkerboard DNA-DNA hybridization method at baseline and after using the proposed hygiene protocols. Comparisons were performed using Wilcoxon test and Friedman test with Benjamini-Hochberg false discovery rate, followed by Conover post-hoc test (α = 0.05). In the subgingival sulci-related biofilm, a lower number of microbial cells were detected, after WP compared to the MB method (P < 0.001). The findings of overdenture-related biofilm suggest that both methods were similar (P = 0.607) being the identified microbiota qualitatively coincident after each method. Despite the number of microbial counts, it was concluded that the association of mechanical brushing with oral irrigation was more effective in reducing microorganisms in the subgingival sulci biofilm; however, the same outcome was not observed in the overdentures.

Antibiofilm Activity of an Experimental Ricinus Communis Dentifrice on Soft Denture Liners

The disadvantage of liners materials is the difficulty of biofilm control. It was compared an experimental dentifrice contained Ricinus communis, with commercials dentifrices as antibiofilm activity against microorganisms on denture liner. Six hundred specimens were distributed in 5 groups (n=18/ microorganism): water; experimental dentifrice; specific dentifrice for denture and two conventional dentifrices against C. albicans; C. glabrata; S. mutans; S. aureus; E. coli. Each group had a negative (n=5; without contamination) and positive control (n=15/ microorganism; without cleaning). The antibiofilm activity was evaluated by the method of biofilm formation in triplicate. The specimens were contaminated in a standard way and incubated. After that, manual brushing was performed (60 s), washed with PBS, immersed in liquid culture medium for resuspension and sowing in solid medium. The results (mean of triplicates) were expressed in CFU/mL. The data was submitted to Shapiro-Wilk, ANOVA and Tukey test (p<0.05). The specific dentifrice (1.27±1.20) was the most effective against S. mutans, followed by conventional (Trihydral, 3.13±0.88; Colgate, 2.16±2.02) and experimental (3.81±1.37) dentifrices, which were similar to each other (p=0.008). All of them were different from water (4.79±1.42). The specific (0.21±0.21) and experimental (0.36±0.25) dentifrices were similar against S. aureus, with a higher mean of CFU when compared to conventional (Colgate, 0.06±0.13), which was more efficient (p=0.000). For C. albicans, C. glabrata and E. coli, all dentifrices were similar to water (p=0.186). It was concluded, that the experimental dentifrice was effective against S. aureus and had not efficacy against Candida spp.; S. mutans; E. coli, as occurred with the commercials dentifrices.

Desenvolvimento de um Produto à Base de Óleo Essencial de Lippia Sidoides como Auxiliar para Prevenção e Tratamento da Estomatite Protética

O presente estudo tem como objetivo apresentar os resultados preliminares relacionados a atividade antimicrobiana de uma solução a base de óleos essenciais de Lippia sidoides (OELS) frente à microrganismos envolvidos na formação de biofilme sobre superfícies protéticas. Após obtenção da planta e identificação taxonômica, extração dos OELS e confirmação dos seus constituintes por meio de cromatografia, foram obtidas soluções iniciais em três diferentes solventes - Twin 80, Lauril sulfato de sódio (LSS) e álcool. A atividade antimicrobiana das mesmas foi testada por meio da determinação da concentração inibitória (CIM) e bactericida/fungicida mínimas (CBM/CFM) frente aos microrganismos Staphylococcus aureus (S. aureus, gram positivo), Pseudomonas aeruginosa (P. aeruginosa, gram negativo) e Candida albicans (C. albicans, levedura), separadamente. Após realização do teste de microdiluição em caldo, em duplicata, o solvente LSS demonstrou o melhor resultado com MIC de 1,25mg/ml para P. aeruginosa, 0,039mg/ml para S. aureus e 0,078mg/ml para C. albicans. Os resultados para CBM/CFM encontrados foram: 1,25mg/ml para P. aeruginosa, 0,039mg/ ml para S. aureus e 0,156mg/ml para C. albicans. A solução de OELS em LSS mostrou-se atividade antimicrobiana efetiva frente aos microrganismos testados. Sua efetividade será testada em biofilmes mistos, seguido da determinação do tempo regime de utilização mais adequado, toxicidade e efeito sobre os materiais utilizados em próteses dentárias, como resina acrílica.Palavras-chave: Prótese Dentária. Estomatite sob Prótese. Lippia

Efeito do Uso Contínuo de um Protocolo de Polimento Mecânico na Adesão de Biofilme Multiespécie em Dentes Artificiais de Resina Acrílica

Foi avaliado o efeito de um protocolo de polimento mecânico frequente na adesão de biofilme em dentes artificiais de resina acrílica. Incisivos centrais superiores (n60) foram divididos em dois grupos: imersão em água destilada (AD) e café (CF) e estes, subdivididos em (n10): apenas imersão, associação com polimento quinzenal (POL1) e mensal (POL2). O polimento foi realizado por meio de motor manual (3000 rpm) com roda de feltro e pasta de óxido de alumínio, em intervalos de tempo simulando 15 e 30 dias de consumo diário de café. Ao final da simulação de 2 anos, foram realizados testes de adesão de biofilme multiespécie de Candida albicans (Ca) e Streptococcus mutans (Sm), contagem de unidades formadoras de colônias (UFC) e microscopia de fluorescência. Os maiores valores de UFC foram observados nos grupos imersos em café tanto para Ca (CF5,966±0,035 AD5,175±0,141 p0,006) quanto para Sm (CF5,673±0,047 AD4,762±0,140 p0,002). Ambos os regimes de polimento, quando associados à imersão em AD, não alteraram a adesão de Ca (p0,783) e Sm (p0,058). Já para os grupos imersos em café, o POL1 (Ca5,326±0,037 Sm4,204±0,0268) e o POL2 (Ca5,442±0,036 Sm 4,895±0,132) apresentaram redução significativa de ambos os microrganismos (p<0,001), sendo que para o Sm essa redução foi maior no POL1. A microscopia de fluorescência evidenciou imagens em conformidade com os resultados quantitativos obtidos no teste de formação de biofilme. O polimento testado, quando realizado de forma frequente, reduz a adesão de biofilme, sendo a frequência quinzenal mais efetiva.Palavras-chave: Dente Artificial. Polimento Dentário. Biofilmes.

Genomic identification of microbial species adhering to maxillofacial prostheses and susceptibility to different hygiene protocols

This study investigated the microbial colonization of maxillofacial prostheses and support tissues using the Checkerboard DNA-DNA hybridization method, and the efficacy of 0.12% chlorhexidine gluconate, 10% Ricinus communis solutions, or brushing, on colony forming unit (CFU) reduction in monospecies biofilms (Candida glabrata, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa) formed on two silicones (MDX 4-4210 and Bio-Skin). Biofilm was harvested from 43 maxillofacial prosthesis wearers for detection of 38 species of microorganisms. The CFU counts of the six above mentioned species were recorded after using the hygiene protocols. All 38 investigated species were identified in prostheses and tissues, with a higher prevalence in the prostheses. 0.12% chlorhexidine gluconate immersion showed the greatest antimicrobial effectiveness, followed by mechanical brushing protocols. MDX 4-4210 silicone produced lower CFU counts than Bio-Skin.

In Vitro Evaluation of Resilient Liner after Brushing with Conventional and Experimental Ricinus communis-Based Dentifrices

PURPOSE

To evaluate the effect of experimental (Ricinus communis) and commercial dentifrices used for denture cleaning on abrasiveness (gravimetric method; roughness), hardness, and color stability of a resilient relining material.

MATERIALS AND METHODS

Sixty circular (15 × 3 mm) specimens were distributed into four groups: C (control; brushing with water); CO (brushing with Colgate - for natural teeth); CB (brushing with Corega Brite - for complete dentures); RC (brushing with experimental dentifrice). Brushing was performed in a toothbrushing machine with a soft brush and a dentifrice suspension for 50 minutes, calculated to correspond to 1 year of regular brushing. Variables were measured initially and after the trial period. For the gravimetric method, the difference in mass was considered. The surface roughness was measured by a rugosimeter, and the hardness test was performed by a Shore A durometer. Color changes (ΔE; CIE L*a*b* and NBS systems) were measured by a portable spectrophotometer. Results were analyzed by ANOVA/Tukey's test (α = 0.05).

RESULTS

The largest mass variation (μg; p < 0.0001) occurred in C (-6.21 ± 3.18). Concerning roughness, CB (0.26 ± 0.04) showed the lowest value, followed by RC (0.29 ± 0.08) and CO (0.34 ± 0.24) (p < 0.0001). Group C produced the greatest surface roughness (0.72 ± 0.25). Hardness values decreased after brushing with water (p = 0.014). No significant differences were found among RC (50.31 ± 1.03), CO (49.11 ± 1.31), CB (49.17 ± 1.23), and C (48.02 ± 1.26). Color stability was similar in all groups (p = 0.135; C: 2.3 ± 0.77; CO: 2.6 ± 0.54; CB: 2.2 ± 0.44; RC: 2.9 ± 1.56).

CONCLUSIONS

The use of experimental dentifrice could be indicated, as it showed similar results to the specific dentifrice, keeping the resilient material properties within acceptable values.

Clinical trial for evaluation of Ricinus communis and sodium hypochlorite as denture cleanser

Objective

This study evaluated Ricinus communis and sodium hypochlorite solutions in terms of biofilm removal ability, remission of candidiasis, antimicrobial activity, and participant satisfaction.

Material and Methods

It was conducted a controlled clinical trial, randomized, double-blind, and crossover. Sixty-four denture wearers with (n=24) and without candidiasis (n=40) were instructed to brush (3 times/day) and immerse their dentures (20 min/day) in different storage solutions (S1 / S2: 0.25% / 0.5% sodium hypochlorite; S3: 10% R. communis; S4: Saline).The trial period for each solution was seven days and a washout period of seven days was used before starting the use of another solution. The variables were analyzed at baseline and after each trial period. The biofilm of inner surfaces of maxillary dentures was disclosed, photographed, and total and dyed areas were measured (Image Tool software). The percentage of biofilm was calculated. Remission of candidiasis was assessed by visual scale and score were attributed. Antimicrobial activity was assessed by the DNA-Checkerboard hybridization method. Patient satisfaction was measured using a questionnaire.

Results

S1 (4.41±7.98%) and S2 (2.93±5.23%) were more effective then S3 (6.95±10.93%) in biofilm remotion(P<0.0001). All solutions were different from the control (11.07±11.99%). S3 was the most effective solution in remission of candidiasis (50%), followed by S1 (46%). Concerning antimicrobial action, S1/S2 were similar and resulted in the lowest microorganism mean count (P=0.04), followed by S3. No significant differences were found with patient's satisfaction.

Conclusions

10% R. communis and 0.25% sodium hypochlorite were effective in biofilm removal, causing remission of candidiasis and reducing the formation of microbial colonies in denture surfaces. All solutions were approved by patients.

Trial of an experimental castor oil solution for cleaning dentures

Denture hygiene is essential because denture biofilm is involved in oral infections and systemic diseases. Although there are chemical agents available on the market, none of them have ideal properties and research on such products is still necessary. The aim of this study was to evaluate the efficacy of a castor bean (Ricinus communis)-based solution for removing denture biofilm, compared to two traditional products (sodium hypochlorite and alkaline peroxide). Fifty maxillary complete denture wearers were instructed to brush their dentures after meals and to immerse their dentures once a day in the following solutions: Saline (20 min; control), Polident alkaline peroxide (3 min), NaOCl (20 min) and 2% castor oil solution (20 min). Participants used each solution for a period of 7 consecutive days, according to a random sequence. After each period, the internal surfaces of maxillary complete dentures were stained with a disclosing solution (1% neutral red), photographed and the disclosed biofilm was quantified with the aid of specific software. The influence of treatments on results was verified by the Friedman test (α=0.05). Tested solutions presented significant difference (Fr=51.67; p<0.001). Saline and NaOCl were significantly different (median: 2.0% and 0.0%) whereas Polident and castor oil presented intermediate results (median: 1.0% and 1.5%, respectively). It can be concluded that the castor oil solution tested in this study was comparable to alkaline peroxide in terms of efficiency in denture biofilm removal.

In Vitro Analysis of Surface Roughness of Acrylic Resin Exposed to the Combined Hygiene Method of Brushing and Immersion in Ricinus communis and Sodium Hypochlorite

PURPOSE

To evaluate a solution based on Ricinus communis (Castor oil) for denture cleansing, comparing it to sodium hypochlorite (NaOCl) for the surface roughness of heat-polymerized acrylic resin.

MATERIALS AND METHODS

Forty polished and unpolished resin specimens (90 × 30 × 4 mm) were evaluated before and after their exposure to protocol hygiene: brushing the specimens with a specific denture brush and mild soap for 3 minutes, three times a day, and immersing them in hygiene solutions (0.25% NaOCl-S1 and 0.5% NaOCl-S2; 10% R. communis-S3; saline-S4: control) for 20 minutes. Surface roughness was evaluated by rugosimeter and scanning electron microscopy (SEM) before and after the protocol. For evaluation of surface roughness, polished and unpolished surfaces were used.

RESULTS

The roughness of the polished surface was not affected by time (p = 0.062), but was affected by solutions (p < 0.0001) and the interaction between factors (p = 0.005). For S1 and S4, the period did not influence the roughness. For S2, there was a change after 7 days, remaining stable after 14 days. For S3, there were changes, and stabilization occurred after 14 days. After 7 and 14 days, S2 and S3 promoted major changes, but after 21 days, there were no differences among solutions, except saline. The unpolished surface was not influenced by factors: period (p = 0.115), solution (p = 0.120), and their interaction (p = 0.382). SEM analysis showed similar results on the evaluation of surface roughness.

CONCLUSIONS

The polished surface of the prosthesis was more susceptible to changes when exposed to hygiene solutions, and although the 0.5% NaOCl solution promoted an increase in the surface roughness compared with the same solution at 0.25% and R. communis at 10%, the values are clinically acceptable.

A randomised trial of a simplified method for complete denture fabrication: patient perception and quality

Complete denture fabrication involves a series of complex technical procedures. Nevertheless, simplified methods may be as effective as conventional ones albeit the lesser use of time and resources, without disadvantage for the patient. This study compared a simplified method for complete denture fabrication to a conventional protocol in terms of oral health-related quality of life (OHRQoL), patient satisfaction and denture quality. Forty-two edentulous patients requesting treatment with complete dentures were randomly allocated into two study groups. Group S received dentures fabricated by a simplified method and Group C received conventionally fabricated dentures. Before interventions and after three and 6 months following insertion, OHRQoL and patient satisfaction were analysed by specific instruments. A prosthodontist assessed denture quality 3 months after delivery. Groups presented no difference for OHRQoL, denture quality and general satisfaction. Differences regarding patient satisfaction with some aspects of the dentures were found after 3 months (S > C), but were insignificant at 6 months. It was concluded that the simplified method is able to produce dentures of a quality comparable to those produced by the conventional method, influencing OHRQoL and patient satisfaction similarly.

Color Stability, Surface Roughness and Flexural Strength of an Acrylic Resin Submitted to Simulated Overnight Immersion in Denture Cleansers

This study evaluated color stability, surface roughness and flexural strength of acrylic resin specimens after immersion in alkaline peroxide and alkaline hypochlorite, simulating a period of one and a half year of use of overnight immersion. Sixty disc-shaped (16X4 mm) and 80 rectangular specimens (65X10X3.3 mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and distributed into 4 groups (n=20): C1: without immersion, C2: 8 h immersion in distilled water; AP: 8 h immersion in alkaline peroxide effervescent tablet; SH: 8 h immersion in 0.5% NaOCl solution. Properties were evaluated at baseline and after the immersion. Color data were also calculated according the National Bureau of Standards (NBS). Results were analyzed statistically by ANOVA and Tukey's HSD test (α=0.05). AP (2.34 ± 0.41) caused color alteration significantly higher than C2 (0.39 ± 0.30) and SH (1.73 ± 0.52). The mean ΔE values were classified as indicial for C2 (0.36 ± 0.29) and noticeable for AP (2.12 ± 0.39) and SH (1.59 ± 0.48). SH (0.0195 ± 0.0150) caused significantly higher ΔRa (p=0.000) than the C2 (0.0005 ± 0.0115) and PA (0.0005 ± 0.0157) groups. There was no statistically significant difference (p=0.063) among the solutions for flexural strength (C1: 105.43 ± 14.93, C2: 100.30 ± 12.43, PA: 97.61 ± 11.09, SH: 95.23 ± 10.18). In conclusion, overnight immersion in denture cleansing solutions simulating a year and a half of use did not alter the flexural strength of acrylic resin but caused noticeable color alterations, higher for alkaline peroxide. The 0.5% NaOCl solution caused increase in surface roughness.

The effectiveness of chemical denture cleansers and ultrasonic device in biofilm removal from complete dentures

Adequate denture hygiene can prevent and treat infection in edentulous patients. They are usually elderly and have difficulty for brushing their teeth.

Clinical and antimicrobial efficacy of NitrAdine ™-based disinfecting cleaning tablets in complete denture wearers

Objective

This study evaluated the efficacy of NitrAdine^TM-based disinfecting cleaning tablets for complete denture, in terms of denture biofilm removal and antimicrobial action.

Material and methods

Forty complete denture wearers (14 men and 26 women) with a mean age of 62.3±9.0 years were randomly assigned to two groups and were instructed to clean their dentures according to two methods: brushing (control) - 3 times a day with denture brush and tap water following meals; brushing and immersion (experimental) - brushing the denture 3 times a day with denture brush and tap water following meals and immersion of the denture in NitrAdine^TM-based denture tablets (Medical Interporous^TM). Each method was used for 21 days. Denture biofilm was disclosed by a 1% neutral red solution and quantified by means of digital photos taken from the internal surface before and after the use of the product. Microbiological assessment was conducted to quantify Candida sp.

Results

An independent t-test revealed a significant lower biofilm percentage for the experimental group (4.7, 95% CI 2.4 to 7.9) in comparison with the control group (mean 37.5, 95% CI 28.2 to 48.1) (t38=7.996, p<0.001). A significant reduction of yeast colony forming units could be found after treatment with Medical Interporous^TM denture tablets as compared to the control group (Mann-Whitney test, Z=1.90; p<0.05).

Conclusion

The present findings suggest that NitrAdine^TM-based disinfecting cleaning tablets are efficient in removal of denture biofilm. In addition, a clear antimicrobial action was demonstrated. Therefore, they should be recommended as a routine denture maintenance method for the prevention of the development of microbial biofilm-induced denture stomatitis.

Prevalence of mutans streptococci isolated from complete dentures and their susceptibility to mouthrinses

The aims of this study were to evaluate the incidence of mutans streptococci (MS - sessile form) on complete maxillary dentures after use of a specific denture paste, and to determine the minimum inhibitory concentration (MIC) and maximum inhibitory dilution (MID) of 3 oral mouthrinses: Cepacol, Plax and Periogard. Seventy-seven complete denture wearers were randomly assigned into 2 groups, according to the product used for denture cleaning: Control group - conventional dentifrice (Kolynos-Super White); and Test group: experimental denture cleaning paste. Denture biofilm was collected at baseline and after 90 and 180 days after treatment by brushing the dentures with saline solution. After decimal serial dilution, samples were seeded onto agar sucrose bacitracin to count colonies with morphological characteristics of MS. MS identification was performed by the sugar fermentation tests. After this procedure, brain heart infusion broth (BHI) was added to oral mouthrinses (Plax, Cepacol e Periogard) and seeded on Petri dishes. The colonies were seeded using the Steers multiplier and, after the incubation, the MIC and MID of the mouthrinses were calculated. The results showed an incidence of 74.0% (n=57) of MS in the 77 complete dentures examined in the study, being 76.3% (n=29) of the Control group (conventional dentifrice) and 71.8% (28) of the Test group (experimental denture cleaning paste). In both groups, the number of positive cases for MS decreased from day 0 to day 180. In the Test group there was a slight decrease in the incidence of Streptococcus mutans 90 days after use of the experimental denture cleaning paste, which was not observed in the Control group. As regards to mouthrinses, for both groups, Periogard showed antimicrobial action with the highest dilution, followed by Cepacol and Plax. In conclusion, the incidence of MS in complete dentures was high and Periogard was the mouthrinse with the strongest antimicrobial action against MS. The experimental denture cleaning paste showed a slight action against S. mutans after 90 days of treatment.

Effects of the domestic use of a disclosing solution on the denture biofilm: a preliminary study

To investigate the effect of the home use of a disclosing agent on the microbial composition of denture biofilm, by means of a cross-over randomized clinical trial. Two interventions were tested during 7 days each: (I) oral and denture hygiene instructions and (II) instructions associated with the home use of a disclosing agent (1% neutral red). Eleven participants with visible biofilm deposits over their maxillary complete dentures were randomly assigned to one of the two sequences of interventions: (i) I followed by II, and (ii) II followed by I. A washout period of 7 days was established. After each intervention, samples of denture biofilm were evaluated by DNA checkerboard hybridization for the detection of Candida spp. and 17 bacterial species. Counts were low for all the tested species, and no significant difference was found between the tested interventions (Wilcoxon test, P > 0.05). The home use of a disclosing agent does not remarkably change the composition of denture biofilm.

Effects of mechanical and chemical methods on denture biofilm accumulation

The aim of this study was to quantify biofilm on the internal surface of upper complete dentures following six possible cleansing methods. Thirty-six edentulous subjects were submitted to a time-series trial and dentures were cleansed according to six methods: (i) rinsing with water; (ii) soaking in an alkaline peroxide solution (Bonyplus); (iii) brushing with dentifrice (Dentu-Creme) and soft Johnson and Johnson's toothbrush; (iv) combination between soaking and brushing according to methods 2 and 3; (v) brushing with dentifrice (Dentu-Creme) and soft Oral B toothbrush; (vi) combination between soaking and brushing according to methods 2 and 5. Each method was randomly used throughout 21 days. Denture biofilm was disclosed by 1% neutral red solution and quantified by means of digital photos taken from the internal surface. The six methods presented significant differences in percentage of biofilm coverage (repeated measures anova, P < 0.0001). Method 1 showed the highest values, 2 was intermediate and other results were the lowest. The most efficacious approach was 6. Biofilm tended to accumulate predominantly over specific zones of the denture base, but this pattern did not change regardless of the method employed. It can be concluded that brushing alone was more effective than the chemical method employed. The best results were obtained by a combination of methods.