Effect of Ozonated Water on the Color Stability of Denture Teeth and Heat Polymerized Acrylic Base Resin

Abstract Objective: To determine the effect of ozonated water on the color stability of denture tooth and denture bases. Material and Methods: Thirty denture base discs consisting of 15 Acropars and 15 ProBase Hot specimens with the dimensions of 40 × 5 mm were prepared. Fifteen denture teeth in shade A1 (Ivoclar Vivadent, Schaan, Liechtenstein) were mounted in a specific acrylic jig. All specimens were immersed in three solutions (1% sodium hypochlorite, ozonated water, and distilled water) for four months (one year of clinical use). Color measurements were done with a spectrophotometer and assessed using the CIE L*a*b* colorimetric system (0, 4, 8, 12, and 16 weeks). Data were analyzed using the three-way ANOVA and Tukey test (α=0.05). Results: Tukey's post hoc test revealed a significant change in color in the Acropars denture base for the distilled water group compared to the ozonated water and 1% hypochlorite (p<0.05). Regarding the ProBase Hot denture base, significantly less color change was observed in the 1% hypochlorite group compared to the ozonated water and distilled water (p≤0.001). For the denture teeth, significantly less color change was seen in the distilled water group than in the ozonated water (p=0.015) and 1% hypochlorite (p<0.05) groups. Conclusion: The color change of denture bases and denture tooth in ozonated water are acceptable. Ozonated water can be considered a good disinfectant for cleaning dentures.

In Vitro effect of denture cleansers on the color stability of polyetheretherketone and other denture base polymers / Efecto in vitro de los limpiadores de prótesis en la estabilidad del color de la polieteretercetona y otros polímeros base de prótesis

Abstract The aim of this in vitro study was to compare the long-term effect of overnight use of denture cleansers with different chemical compositions on the color stability of denture base polymers (DBPs). The four DBPs evaluated were PEEK (PK group), thermoinjection-molded polyamide (PA group), auto-polymerized polymethylmethacrylate (PMMA) (AP group), and heat-polymerized resin PMMA (HP group). The cleaning agents used were Corega tablet (CT), Protefix tablet (PT), and 0.5% sodium hypochlorite (NaOCl) solution (SH). Distilled water (DW) served as a control. Forty-eight disc-shaped specimens (10mm × 2mm) were prepared from each DBP and randomly immersed in the different storage media (n=12 in each group). Color measurements of the specimens before and after immersion in the denture cleansers were made using a spectrophotometer (VITA Easyshade V). The color changes were measured and recorded in L* a* b*. After 120 d, the CIEDE2000 formula was used to calculate color changes (ΔE00). For analysis of the data, a multivariate analysis of variance was used (p<0.05). The results of the statistical analysis revealed significant color change differences in the DBPs immersed in the various denture cleansers (p<0.05). Groups PA and PK showed the highest values for all solutions. AP-SH showed the highest ΔE00 value in group AP, no significant difference was found between other solutions. In group HP, there was no statistically significant difference between the average ΔE00 values of all solutions. Long-term daily use of the denture cleansers affected the color stability of all the DBPs, although the level of color change was acceptable. Laboratory and clinical studies on the color stability of PEEK are needed to confirm the results of this study.

Resumen El objetivo de este estudio in vitro fue comparar el efecto a largo plazo del uso nocturno de limpiadores de prótesis con diferentes composiciones químicas sobre la estabilidad del color de los polímeros base de prótesis (DBP). Los cuatro DBP evaluados fueron PEEK (grupo PK), poliamida moldeada por termoinyección (grupo PA), polimetilmetacrilato (PMMA) autopolimerizado (grupo AP) y resina PMMA termopolimerizada (grupo HP). Los agentes de limpieza utilizados fueron Corega (CT), Protefix (PT) y la solución de hipoclorito de sodio (NaOCl) al 0,5% (SH). El agua destilada (DW) sirvió de control. Se prepararon 48 especímenes en forma de disco (10mm × 2mm) de cada DBP y se sumergieron al azar en los diferentes medios de almacenamiento (n=12 en cada grupo). Las mediciones del color de las muestras antes y después de la inmersión en los limpiadores de dentaduras se realizaron con un espectrofotómetro (VITA Easyshade V). Los cambios de color se midieron y registraron en L* a* b*. Después de 120 d, se utilizó la fórmula CIEDE2000 para calcular los cambios de color (ΔE00). Para el análisis de los datos, se utilizó un análisis multivariante de la varianza (p<0,05). Los resultados del análisis estadístico revelaron diferencias significativas en el cambio de color de los DBP sumergidos en los distintos limpiadores de dentaduras (p<0,05). Los grupos PA y PK mostraron los valores más altos para todas las soluciones. AP-SH mostró el valor ΔE00 más alto en el grupo AP, no se encontraron diferencias significativas entre las demás soluciones. En el grupo HP, no hubo diferencias estadísticamente significativas entre los valores medios de ΔE00 de todas las soluciones. El uso diario a largo plazo de los limpiadores de dentaduras afectó a la estabilidad del color de todos los DBP, aunque el nivel de cambio de color fue aceptable. Se necesitan estudios de laboratorio y clínicos sobre la estabilidad del color del PEEK para confirmar los resultados de este estudio.

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

Abstract 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.

Effects of denture cleansers on denture material properties ­an observational case­control study / Efectos de los limpiadores de prótesis dentales sobre las propiedades del material: un estudio observacional de casos y controles

Everyday use of denture cleansers to prevent microbial colonization on dentures can affect the properties of the denture base material. Limited literature is available on the effects of denture cleanser on reinforced resins. This study aimed to evaluate and compare the effect of denture cleanser on the flexural and impact strength of conventional and reinforced heat cure acrylic resins. Materials and Methods: Rectangular shaped specimens were prepared for flexural and impact strength as per ISO 1567. The denture base resins used included conventional, high impact, nylon fiber reinforced and glass fiber reinforced heat cure acrylic resins. They were further categorized into subgroups A and B depending on immersion in distilled water or denture cleanser (3.8% sodium perborate based). The flexural strength and impact strength of specimens were measured. The study design is a observational case-control study. SPSS version 25 statistical analysis software was used, and the STROBE statement checklist was followed. Results: The mean flexural strength was highest for glass fiber reinforced heat cure resin followed by conventional heat cure resin, high impact heat cure resin and nylon reinforced heat cure resin, respectively. The mean impact strength was highest for high impact heat cure resin followed by glass fiber reinforced heat cure resin, conventional heat cure resin, and nylon fiber-reinforced resin respectively.Conclusion: All the denture base resins tested exhibited a decrease in flexural and impact strength following use of a denture cleanser.

El uso diario de limpiadores para prótesis dentales para prevenir la colonización microbiana en las prótesis puede afectar las propiedades del material base de estas. Existe literatura limitada sobre los efectos de los limpiadores de prótesis sobre resinas reforzadas. Este estudio tuvo como objetivo evaluar y comparar el efecto de un limpiador de prótesis sobre la resistencia a la flexión y al impacto de las resinas acrílicas de curado con calor convencionales y reforzadas. Material y Métodos: Muestras de forma rectangular se prepararon para testear la resistencia a la flexión y al impacto según ISO 1567. Las resinas de base de prótesis utilizadas fueron resinas acrílicas convencionales, de alto impacto, y de curado térmico reforzadas con fibra de vidrio o nylon. Posteriormente se clasificaron en los subgrupos A y B según la inmersión en agua destilada o limpiador de prótesis (3,8% de perborato de sodio). Se midieron la resistencia a la flexión y la resistencia al impacto de las muestras. El diseño del estudio fue de un estudio observacional de casos y controles. Se utilizó el software de análisis estadístico SPSS versión 25, y se siguió la guía de la declaración STROBE. Resultado: La resistencia a la flexión fue más alta para la resina de curado por calor reforzada con fibra de vidrio seguida de la resina de curado por calor convencional, la resina de curado por calor de alto impacto y la resina de curado por calor reforzada con nylon, respectivamente. La resistencia al impacto fue más alta para la resina de curado por calor de alto impacto seguida de la resina de curado por calor reforzada con fibra de vidrio, la resina de curado por calor convencional y la resina reforzada con fibra de nylon, respectivamente. Conclusión: Todas las resinas de base de prótesis probadas exhibieron una disminución en la resistencia a la flexión y al impacto después del uso de un limpiador de prótesis.

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

Abstract Objective Although the effectiveness of chemical cleansing against Candida albicans biofilm has been shown, the effective concentration of denture cleanser tablets has not been studied. The aim of this study was to assess the effect of three denture materials against Candida albicans biofilm and to determine effective concentrations of denture cleanser tablets. Material and methods The surface-roughness of Acron-hi™, QC-20™ and Deflex™ (n=45 per resin) resins was standardized by using a profilometer and their contact angle or surface free energy was calculated. C. albicans biofilm was formed on all three resins and were treated with Polident 3 min™, Corega™ and Fittydent™ cleanser solutions at various concentrations and both resin-biofilm and cleanser-biofilm interest were determined by using a MTT protocol according to the European Committee on Antimicrobial Susceptibility Testing's antifungal susceptibility testing (AFST-EUCAST). Scanning electron microscopy was used to compare the efficacy of different resin materials against C. albicans biofilm. Anticandidal activity and surface free energy statistical parameters were calculated by using 3-way and 1-way ANOVA, respectively (p<0.05). Results Polident 3 min™ and Corega™ tablets significantly inhibited (p<0.05) the proliferation of C. albicans against all denture resins at 27-37 mg/mL. Scanning electron microscopy results indicated that there was no significant difference among resin specimens regarding biofilm formation on dentures. We failed to find a significant relationship between surface free energy and the anticandidal effect of resin types. However, the polarity value of the resins was statistically associated with their anticandidal activity. Conclusions The polarity of the resins, the concentrations of tablets and the chemical content of the cleanser may directly affect C. albicans biofilm formations. Polident 3 min™ and Corega™ tablets should be suggested for patients who use any denture resin types, whereas the Fittydent™ tablet should only be proposed for those who use Deflex™, when two tablets are dropped into 150 mL water.

Denture disinfection using Salvia officinalis L: microbial load and selected properties of PMMA

Denture use may aggravate the occurrence of oral infections, considering it enhances microbial adherence. Aim: This study assessed the reduction of microbial loads of Candida albicans, Staphylococcus aureus, and Klebsiella oxytoca by disinfecting the polymethylmethacrylate (PMMA) of complete dentures with hydroalcoholic extract of Salvia officinalis. Additionally, the effect of such extract on the properties of PMMA was examined. Methods: Microorganisms were isolated from saliva samples collected from complete denture wearers. The hydroalcoholic extract of S. officinalis was produced according to the Brazilian Pharmacopoeia 5. The PMMA specimens (n=188) were immersed in microbial inoculum and incubated at 37°C for 16 hours per day. Then, they were subjected to a disinfection protocol for 30 days. The specimens were divided into five treatment groups: sterile saline solution (0.85%; control), 0.2% chlorhexidine digluconate, and hydroalcoholic extract of S. officinalis (0.2%, 0.8%, and 1.16%). Microorganism adherence to the PMMA surface was also assessed, as well as surface roughness (Ra in µm) and color stability of the PMMA (mean ΔE). Changes in microbial load and surface roughness after the disinfection protocol were verified with paired t-test. Substances at day 10, adherence, and color stability were compared by the Kruskall-Wallis and Mann-Whitney tests, and one-way ANOVA was used to compare substances at the beginning and end of the experiment (α=0.05). Results: The 1.16% S. officinalis extract significantly reduced the microbial load of all the microorganisms after 30 days of disinfection (p<0.05). The microbial load of K. oxytoca was also reduced at lower concentrations of the S. officinalis extract (0.2% and 0.8%) (p<0.02). Antimicrobial and anti-adherent effects against microorganisms isolated from the oral cavity were observed. There was no significant change in surface roughness (p>0.05) and color stability was significantly higher in the control group (p<0.0001). Conclusions: The hydroalcoholic extract of S. officinalis may be used as a disinfectant solution for dentures

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

Abstract The development of opportunistic infections due to poor denture hygiene conditions justified the search for effective hygiene protocols for controlling denture biofilm. 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.

Surface change assessment of Co-Cr alloy subjected to immersion in denture cleansers

Choosing the right chemical cleanser for removable partial dentures is a challenge, because they present an acrylic and a metallic portion, which should be cleaned and not damaged. Aim: The aim of this study was to assess surface changes of cobalt chromium alloys immersed in diferente cleaners solutions: 0.05% sodium hypochlorite, 4.2% acetic acid, 0.05% sodium salicylate, sodium perborate (Corega Tabs®) and 0.2% peracetic acid. Material and Methods: One hundred and twenty circular specimens (10 mm in diameter) of two commercial available Co-Cr alloys were tested: GM 800 ® (Dentaurum) and Co-Cr® (DeguDent). The samples were randomly divided into tem experimental groups (n=10), according to the trend mark of alloy and cleaners solutions in which they were immersed, and two control groups, in which the samples of the two alloys were immersed in distilled water. Evaluations were performed through roughness measurement (rugosimeter Surftest 211, Mitutoyo), visual evaluation with stereomicroscope (Stereo Discovery 20, Carl Zeiss) and scanning electron microscope surface (JSM, 6360 SEM, JEOL), at experimental times T0 ­ before immersions, T1 - after one immersion, and T2 - after 90 immersions. Intergroup comparison for the effect of immersion in the different cleanser agents was evaluated through ANOVA/Tukey tests (p≤0.05). The effect of the time in the immersion of each alloy was evaluated by t-pared test (p≤0.05). The two alloys were compared using the t-Student test. Results: The analysis of roughness and microscopy showed that surface changes were significantly greater in groups submitted to 0.05% sodium hypochlorite after 90 immersions (T2). When comparing the two alloys, a similar behavior of roughness was observed for the cleaning agents. However, alloy GM 800® showed significant statistical difference for roughness variations in experimental times (Δ1 and Δ2), when immersed in sodium 0.05% hypochlorite. The number of exposures of the alloys to the cleaning agents showed a negative influence when using sodium hypochlorite solution. Conclusions: It is possible to conclude that 0.05% sodium hypochlorite has caused the greatest apparent damage to alloy surface. (AU)

Effect of different denture cleansers on surface roughness and microhardness of artificial denture teeth

PURPOSE: The aim of this study was to compare the effects of different denture cleansers on the surface roughness and microhardness of various types of posterior denture teeth. MATERIALS AND METHODS: 168 artificial tooth specimens were divided into the following four subgroups (n=42): SR Orthotyp PE (polymethylmethacrylate); SR Orthosit PE (Isosit); SR Postaris DCL (double cross-linked); and SR Phonares II (nanohybrid composite). The specimens were further divided according to the type of the denture cleanser (Corega Tabs (sodium perborate), sodium hypochlorite (NaOCl), and distilled water (control) (n=14)) and immersed in the cleanser to simulate a 180-day immersion period, after which the surface roughness and microhardness were tested. The data were analyzed using the Kruskal–Wallis test, Conover's nonparametric multiple comparison test, and Spearman's rank correlation analysis (P<.05). RESULTS: A comparison among the denture cleanser groups showed that NaOCl caused significantly higher roughness values on SR Orthotyp PE specimens when compared with the other artificial teeth (P<.001). Furthermore, Corega Tabs resulted in higher microhardness values in SR Orthotyp PE specimens than distilled water and NaOCl (P<.005). The microhardness values decreased significantly from distilled water, NaOCl, to Corega Tabs for SR Orthosit PE specimens (P<.001). SR Postaris DLC specimens showed increased microhardness when immersed in distilled water or NaOCl when compared with immersion in Corega Tabs (P<.003). No correlation was found between surface roughness and microhardness (r=0.104, P=.178). CONCLUSION: NaOCl and Corega Tabs affected the surface roughness and microhardness of all artificial denture teeth except for the new generation nanohybrid composite teeth.

Bactericidal Effect of the Aos Denti Germ for Denture Cleansing Effervescent Tablet against Oral Microorganisms

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at 36℃. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.

Antimicrobial, Antioxidant and Cytotoxic Activities of Dendropanax morbifera Léveille extract for mouthwash and denture cleaning solution

PURPOSE: The purpose of this study was to analyze the antimicrobial, antioxidant activity and cytotoxicity of Dendropanax morbifera Léveille extract for assessing whether Dendropanax morbifera Léveille can be used for the development of natural mouthwash and denture cleaning solution. MATERIALS AND METHODS: The extract was obtained from branches of Dendropanax morbifera Léveille. The solvent fractions were acquired by fractionating Dendropanax morbifera Léveille extract using n-hexane, ethyl acetate, chloroform and butanol solvent. Paper disc test was used to evaluate the antimicrobial and antifungal activity of Dendropanax morbifera Léveille extract and solvent fractions against Streptococcus mutans and Candida albicans. The analysis of antioxidant activity was carried out through DPPH radical scavenging assay. The cytotoxicity of Dendropanax morbifera Léveille extract was analyzed through MTT assay using normal human oral keratinocytes. RESULTS: Dendropanax morbifera Léveille extract showed antimicrobial activity against Streptococcus mutans and especially Candida albicans. The solvent fractions of Dendropanax morbifera Léveille showed strong antimicrobial activity against Streptococcus mutans and Candida albicans in n-hexane and butanol solvent fraction, respectively. Dendropanax morbifera Léveille extract also showed outstanding antioxidant activity. Butanol, ethyl acetate, and chloroform solvent fraction of Dendropanax morbifera Léveille tended to have increased antioxidant activity as the concentration increased. Dendropanax morbifera Léveille extract showed high cell survival rate in cytotoxicity test. CONCLUSION: Dendropanax morbifera Léveille extract turned out to have antimicrobial, antioxidant activity and cytophilicity. Based on these results, it is expected that Dendropanax morbifera Léveille is applicable as an ingredient for natural mouthwash and denture cleanser.

Color stability and surface roughness of artificial teeth brushed with an experimental Ricinus communis toothpaste

To evaluate, in vitro, the effect of brushing with a Ricinus communis-based experimental toothpaste on color stability and surface roughness of artificial teeth. Methods: Ninety artificial teeth (maxillary central incisors) in different shades, light and dark (NatusDent Triple Pressing, Dentbras) were used. Initial color (Spectrophotometer Easyshade, VITA) and surface roughness (Rugosimeter Surfcorder SE 1700, Kosakalab) readouts were performed. After baseline measurements, samples were assigned to 10 groups (n=9) according to the artificial tooth shade and type of toothpaste used during the mechanical brushing test (Pepsodent, MAVTEC): Sorriso Dentes Brancos - SDB, Colgate Luminous White - CLW (Colgate-Palmolive), Close up White Now - CWN (Unilever), Trihydral - THL (Perland Pharmacos) and Ricinus communis - RCE (Experimental). After 29,200 cycles of brushing, corresponding to 2 years of brushing by a healthy individual, new color and roughness readouts of the specimens were performed. Data (before and after the tests) were statistically analyzed (2-way repeated measures ANOVA, Tukey, p<0.05). Results: RCE toothpaste produced the greatest color stability for dark tooth shade and the second best color stability for light tooth shade. For surface roughness alteration, there was no difference (p>0.05) for any tested toothpaste regardless of tooth shade. Conclusions: The experimental Ricinus communis toothpaste did not cause color and surface roughness alteration in the artificial teeth, and it may be considered a suitable option for denture cleaning...

Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis: a randomized clinical study

ABSTRACT To preserve oral health and to maintain the prosthetic devices, it is important not only to improve the properties of commonly known hygiene products, but also to investigate new materials with antimicrobial action. Objectives This study evaluated the antimicrobial activity of sodium hypochlorite (0.25% and 0.50%) and 10% Ricinus communis’ solutions against specific microorganisms. Material and Methods Sixty four maxillary complete denture wearers were instructed to brush their dentures three times a day and to soak them (20 min/day) in the solutions: SH1: 0.25% sodium hypochlorite; SH2: 0.5% sodium hypochlorite; RC: 10% R. communis oil; and C: 0.85% saline (control). The solutions were used for 7 days in a randomized sequence. Following each period of use, there was a 1-week washout period. Antimicrobial activity was determined by Colony Forming Units (CFU) counts of Streptococcus mutans, Candida spp., and gram-negative microorganisms. For collecting biofilm, the internal surface of maxillary dentures was brushed with saline solution, and biofilm suspension obtained. After dilutions (100 - 10-3), aliquots were seeded in Mitis salivarius, CHROMagar Candida®, and MacConkey agar for detecting S. mutans, Candida spp., or gram-negative microorganisms, respectively. After incubation, colonies were counted, and CFU/mL values were calculated. Then, transformation - log10 (CFU+1) - data were analyzed using the Friedman test (α=0.05). Results showed significant differences between the solutions (p<0.001). Results All three solutions showed antimicrobial activity against S. mutans. Against Candida spp., RC and SH1 solutions showed similar effect while SH2 showed superior activity. SH1 and SH2 solutions showed antimicrobial action against gram-negative microorganisms. The Candida species most frequently isolated was C. albicans, followed by C. tropicalis and C. glabrata. Conclusions The 0.5% sodium hypochlorite solution was the most effective and might be used to control denture biofilm. C. albicans was the most frequently isolated Candida sp.

Effect of polishing and brushing on removal of cigarette smoke stains from artificial teeth / Efecto del pulido y cepillado en la eliminación de manchas de humo de cigarrillo en dientes artificiales

Color alteration is still a disadvantage of acrylic resin teeth and this problem seems to be greater in smokers. The objective of this study was to evaluate the efficiency of polishing and brushing on removal of stains from artificial teeth submitted to cigarette smoke. Forty denture teeth of distinct shades (62 and 69) were selected. The teeth were divided into 4 groups (n= 10), according to the tooth shade and method of stain removal performed: Groups 1 and 2 were submitted to the smoke of 20 cigarettes, and after new color readouts, were submitted to polishing with pumice stone and Spanish white paste. Groups 3 and 4 were submitted to 4 cycles of 5 cigarettes interspersed with standardized manual brushing. The values of color stability (DE) were compared using 2-way ANOVA, Bonferroni test (p<0.05). For all the groups, color change occurred at clinically unacceptable levels (E>3.3). After exposure to 20 cigarettes, the greatest degree of color change occurred for teeth in shade 62. Polishing significantly reduced the color change for groups 1 and 2, however, without significant difference between them. For Groups 3 and 4 there was no difference between the teeth of shade 62 and 69. When the treatments for each tooth shade were compared alone, there was similarity between polishing and brushing irrespective of the shade of samples. Routine manual brushing and common clinical polishing methods were capable of removing a large portion of staining caused by cigarettes, and there was no difference between the methods.

La alteración del color sigue siendo una desventaja de los dientes de resina acrílica y este problema parece ser mayor en los fumadores. El objetivo de este estudio fue evaluar la eficacia de pulido y cepillado en la eliminación de manchas de los dientes artificiales presentados al humo del cigarrillo. Se seleccionaron cuarenta dientes de la dentadura de tonos diferentes (62 y 69). Los dientes fueron agrupados en 4 grupos (n= 10), de acuerdo con el color del diente y el método de eliminación de manchas realizado: Los grupos 1 y 2 fueron sometidos al humo de 20 cigarrillos, y después de nuevas lecturas de color, se pulieron con piedra pómez piedra y pasta blanca española. Los grupos 3 y 4 se sometieron a 4 ciclos de 5 cigarrillos intercalados con cepillado manual estandarizado. Los valores de estabilidad del color (Delta E) se compararon mediante las pruebas de ANOVA de dos vías y Bonferroni (p<0,05). Para todos los grupos, el cambio de color se produjo a niveles no aceptables clínicamente (DE>3,3). Después de la exposición a 20 cigarrillos, el mayor grado de cambio de color se produjo para los dientes de tono 62. El pulido redujo significativamente el cambio de color para los Grupos 1 y 2, sin diferencia significativa entre ellos. Para los Grupos 3 y 4 no hubo diferencia entre los dientes de tono 62 y 69. Cuando los tratamientos para cada color de diente se compararon individualmente, hubo similitud entre el pulido y el cepillado, independientemente del tono. El cepillado manual rutinario y los métodos comunes de pulido clínicos fueron capaces de eliminar una gran parte de manchas causadas por los cigarrillos, sin diferencia entre los métodos.

Effects of Denture Cleansers on Heat-Polymerized Acrylic Resin: A Five-Year-Simulated Period of Use

This study evaluated color stability, surface roughness and flexural strength of acrylic resin after immersion in alkaline peroxide and alkaline hypochlorite solutions, simulating a five-year-period of use. Sixty disc-shaped (16x4 mm) and 60 rectangular specimens (65x10x3.3 mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and assigned to 3 groups (n=20) of immersion (20 min): C1: distilled water; AP: warm water and one alkaline peroxide tablet; SH: 0.5% NaOCl solution. Color data (∆E) were determined by a colorimeter and also quantified according to the National Bureau of Standards units. A rugosimeter was used to measure roughness (μm) and the flexural strength (MPa) was measured using a universal testing machine. Data were evaluated by Kruskal-Wallis followed by Dunn tests (color stability and surface roughness) and by one-way ANOVA and Bonferroni test (flexural strength). For all tests was considered α=0.05. AP {0.79 (0.66;1.42)} caused color alteration significantly higher than C1 {0.45 (0.37;0.57)} and SH {0.34 (0.25;0.42)}. The mean ∆Ε values quantified by NBS were classified as "trace" for C1 (0.43) and SH (0.31) and "slight" for AP (0.96). SH {-0.015 (-0.023;0.003)} caused significantly higher ΔRa than the C1 {0.000 (-0.004;0.010)} and AP {0.000 (-0.009;0.008)} groups. There was no statistically significant difference among the solutions for flexural strength (C1: 84.62±16.00, AP: 85.63±12.99, SH: 84.22±14.72). It was concluded that immersion in alkaline peroxide and NaOCl solutions simulating a five-year of 20 min daily soaking did not cause clinically significant adverse effects on the heat-polymerized acrylic resin.

Este estudo avaliou as alterações de cor, rugosidade de superfície e resistência à flexão de resinas acrílicas após imersão em soluções de peróxido alcalino e hipoclorito alcalino, simulando um período de cinco anos de uso. Sessenta corpos de prova circulares (16 mm x 4 mm) e 60 retangulares (65 mm x 10 mm x 3,3 mm) de resina acrílica termicamente ativada (Lucitone 550) foram distribuídos (n=20) em três grupos de imersão (20 min): C1: água destilada; PA: solução com água morna e uma pastilha de peróxido alcalino; HS: solução de hipoclorito de sódio a 0,5%. A alteração de cor (∆E) foi determinada por meio de colorímetro e também calculada de acordo com unidades da National Bureau of Standards (NBS). Um rugosímetro foi utilizado para mensuração da rugosidade de superfície (μm) e a resistência à flexão (MPa) foi medida utilizando uma máquina universal de ensaios. Os dados foram avaliados pelo teste de Kruskal-Wallis seguido pelo teste de Dunn (estabilidade de cor e rugosidade de superfície) e análise de variância (ANOVA) a um fator seguida pelo teste de Bonferroni (resistência à flexão). Para todos os testes foi considerado α=0,05. PA {0,79 (0,66;1,42)} causou alterações de cor significativamente maiores que C1 {0,45 (0,37;0,57)} e HS {0,34 (0,25;0,42)}. Os valores médios de ∆E quantificados pela NBS foram classificados como "indiciais" para C1 (0,43) e SH (0,31), e "leves" para PA (0,96). O HS {-0,015 (-0,023;0,003)} acarretou maiores valores de ∆Ra que C1 {0,000 (-0,004;0,010)} e PA {0.000 (-0,009;0,008)} Não houve diferença estatística significante entre as soluções para a resistência à flexão (C1: 84,62±16,00, PA: 85,63±12,99, HS: 84,22±14,72). Concluiu-se que imersões em soluções de peróxido alcalino e hipoclorito de sódio simulando imersões diárias de 20 min por um período de cinco anos não causaram efeitos adversos clinicamente significantes sobre a resina acrílica termicamente ativada.

Adverse Effects on PMMA Caused by Mechanical and Combined Methods of Denture Cleansing

This study evaluated the abrasiveness of mechanical and combined methods of denture hygiene, by the analysis of mass loss and surface roughness. Acrylic resin specimens (Plexiglass) were brushed by a tooth brushing machine (Mavtec) with a soft brush (Tek) and water (control) or four dentifrices (Sorriso, Colgate, Polident and Corega) (Experimental groups) for 50 min, representing one year of brushing (mechanical method). After brushing, the specimens were immersed in 0.5% sodium hypochlorite simulating a daily cleaning of 20 min for one year (combined method). Distilled water (23 ºC) was employed as control. The mass loss (g) was analyzed by an analytical balance and the surface roughness (μm) by a rugosimeter. Data were subjected to ANOVA and Bonferroni test (α=0.05). Polident dentifrice showed lowest values of mass loss for both methods (mechanical: -0.0072±0.0017, combined:-0.011±0.002) and the combined method resulted in greater mass loss than the mechanical, except for Corega. For the surface roughness, after the mechanical method, the lowest values were registered for water (-0.007±0.016) and Polident (0.402±0.378); for the combined method, water (-0.063±0.013) showed the lowest values; there was no statistically significant difference between methods. It was concluded that Polident was the less abrasive dentifrice and the association between chemical and mechanical methods increased the mass loss but did not change the surface roughness of specimens.

Este estudo avaliou a abrasividade causada pelos métodos mecânico e combinado de higiene de próteses totais, por meio da análise da perda de massa e rugosidade de superfície. Corpos de prova de resina acrílica (Plexiglass) foram escovados em máquina de escovação (Mavtec) com escova macia (Tek) e água ou dentifrícios (Sorriso, Colgate, Polident e Corega) (Grupos Experimentais) por 50 min, simulando 1 ano de escovação (método mecânico). Após a escovação, os corpos de prova foram imersos em hipoclorito de sódio a 0,5%, simulando imersões diárias de 20 min por 1 ano (método combinado). Água destilada (23 °C) foi empregada como controle. A perda de massa foi analisada por meio de balança analítica de precisão (g) e a rugosidade de superfície por rugosímetro (μm). Os dados foram submetidos à ANOVA e teste de Bonferroni (α=0,05). Em relação à perda de massa, os menores valores foram obtidos para o Polident em ambos os métodos (mecânico: -0,0072±0,0017; combinado: -0,011±0,002) e o método combinado resultou em maior perda de massa que o método mecânico, exceto para o Corega. Para a rugosidade de superfície, após aplicação do método mecânico, os valores mais baixos foram registrados para água (-0,007±0,016) e Polident (0,402±0,378); para o método combinado, os valores mais baixos foram obtidos para água (-0,063±0,013); não houve diferença estatística entre os métodos. Conclui-se que o Polident foi o dentifrício menos abrasivo e que a associação do método químico ao método mecânico aumentou a perda de massa, porém não alterou a rugosidade de superfície dos corpos de prova.

Antimicrobial action of sodium hypochlorite and castor oil solutions for denture cleaning – in vitro evaluation

The objective of this in vitro study was to evaluate the antimicrobial action of sodium hypochlorite (0.25% and 0.50%) and 10% castor oil solutions against specific microorganisms, by counting Colony Forming Units (CFU) of clinically important bacteria and Candida species. Acrylic resin specimens (n = 320; Lucitone 550) were obtained from square metal matrices (10 x 10 x 2 mm), sterilized by microwave (650W, for 6 minutes) and contaminated by Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Escherichia coli, Streptococcus mutans, Enterococcus faecalisand Candida glabrata. The specimens were immersed for 20 minutes in one of the following hygiene solutions (n = 10/each): A – 0.25% Sodium hypochlorite; B – 0.5% Sodium hypochlorite; C – 10% Castor oil solution; and D (Control) – saline. Adhered cells were suspended and inoculated into a selective solid medium (37ºC for 24 h). The Student’s t-test (α = 0.05) was performed to compare log10(CFU+1)/mL between Groups C and D. The results showed that sodium hypochlorite (0.25% and 0.5%) completely eliminated all detectable microorganisms. The castor oil solution eliminatedB. subtilisand reduced counts for other strains. Differences between C and D were significant (p < 0.05) for all species except for E. faecalis. Both sodium hypochlorite solutions (0.25% and 0.5%) were effective in eliminating all microorganisms evaluated, and may be useful as cleaning solutions for complete dentures. The castor oil solution provided moderate efficacy and performed differently on the tested species, with the strongest effect on B. subtilis and with non-significant action on E. faecalis.

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.

A higiene de próteses totais é essencial, uma vez que o biofilme da prótese está envolvido com infecções orais e doenças sistêmicas. Apesar de existirem agentes químicos disponíveis no mercado, nenhum deles apresenta propriedades ideais e pesquisas com esses produtos ainda são necessárias. O objetivo neste estudo foi avaliar a eficácia de uma solução de mamona (Ricinus communis) para a remoção do biofilme de prótese total, comparada com dois produtos comerciais (NaOCl e peróxido alcalino). Cinqüenta usuários de próteses totais maxilares foram instruídos a escovar as próteses após as refeições e imergi-las uma vez por dia nas seguintes soluções: soro fisiológico (20 min), Peróxido alcalino Polident (3 min), NaOCl a 1% (20 min) e solução de mamona (20 min). Os participantes utilizaram cada solução por um período de sete dias consecutivos, de acordo com uma sequência aleatória. Após cada período, as superfícies internas das próteses totais superiores foram coradas com solução evidenciadora (vermelho neutro a 1%), fotografadas e o biofilme evidenciado foi quantificado com software. A influência dos tratamentos sobre os resultados foi verificada pelo teste de Friedman (α=0,05). Houve diferença significativa entre as soluções (Fr=51,67;p<0,001). O soro fisiológico e o NaOCl foram significativamente diferentes (mediana: 2,0% e 0,0%), enquanto o Polident e a solução de mamona apresentaram resultados intermediários (mediana: 1,0% e 1,5%, respectivamente). Concluiu-se que a solução de mamona avaliada é comparável ao peróxido alcalino, em termos de remoção do biofilme de prótese total.

Effect of denture cleansers on Candida albicans biofilm formation over resilient liners

PURPOSE: The purpose of this study was to analyze the effect of denture cleansers on Candida albicans biofilm formation over resilient liners and to evaluate compatibility between resilient liners and denture cleansers. MATERIALS AND METHODS: Acrylic resin (Lucitone 199(R)) and 3 resilient liners (COE-SOFT(TM), GC RELINE(TM) and SOFRELINER TOUGH TOUGH(R)) were incubated in denture cleansers (Polident(R) and Cleadent(R)) for 8 hours a day and in unstimulated saliva for 16 hours a day (n=25/gp) for 60 days. Two-way and three-way repeated measures ANOVA were performed to compare the surface roughness (Ra), pH and C. albicans binding level by radioisotope (alpha=0.05). The statistical significance of the relation between Ra and adhesion was evaluated by correlation analysis. RESULTS: The degree of Ra was significantly decreased in the following order: COE-SOFT(TM), acrylic resin, GC RELINE(TM) and SOFRELINER TOUGH(R). The immersion in denture cleansers significantly increased Ra of resilient liners, except for SOFRELINER TOUGH(R) in Cleadent(R). No significant differences in pH curves were observed among groups immersed in distilled water and denture cleansers. The binding levels of C. albicans were significantly decreased in the following order: COE-SOFT(TM), GC RELINE(TM), SOFRELINER TOUGH(R), and acrylic resin. The immersion in Cleadent(R) seemed to decrease C. albicans binding level on GC RELINE(TM) and SOFRELINER TOUGH(R). CONCLUSION: Based on the C. albicans binding levels results, it is not recommended to immerse COE-SOFT(TM) in denture cleansers, and GC RELINE(TM) and SOFRELINER TOUGH(R) should be immersed in Cleadent(R).