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

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

BACKGROUND

The continuously increasing demand for removable denture appliances and the importance of adequate denture cleaning have led to the development of various denture cleansing products. The aim of this study was to evaluate the efficacy of two novel denture cleansing agents (GE and TM) and three commonly available cleansers (0.5% sodium hypochlorite; NaClO, 0.12% chlorhexidine gluconate; CHX, and Polident®; POL) on multispecies microbial biofilm formation, stain removal and physical properties of dentures.

METHODS

The antimicrobial activities of denture cleansing agents were determined against major oral opportunistic pathogens including Streptococcus mutans, Staphylococcus aureus, Escherichia coli and Candida albicans, using time-kill assays. Multispecies microbial biofilms grown on acrylic resins for 72 h were generated to determine the antibiofilm effects of cleansing agents by confocal laser scanning microscopy (CLSM). Evaluations of the tea and coffee stain removal properties and the alterations in the physical properties of dentures were also performed. The toxicity of cleanser residues released from denture acrylics to fibroblast cells was investigated using MTT assay.

RESULTS

All denture cleansing agents tested could effectively kill oral bacteria and Candida albicans. Furthermore, after immersion for more than 3 h, the cleansers Polident®, GE and TM could efficiently penetrate and inhibit multispecies denture biofilms with effects similar to 10 min of immersion in 0.5% NaClO. However, immersion in 0.12% CHX for 20 min showed less antibiofilm activity. The NaClO solution had the highest efficacy for removing stains from the artificial teeth. Conversely, the CHX solution enhanced tea and coffee staining, and the teeth immersed in this solution showed clinically unacceptable colour changes (ΔE > 5.5). However, the colour differences of teeth stained and immersed in POL, GE and TM cleansers were in the clinically acceptable range. There was no significant difference among the POL, GE and TM cleansers in terms of stain removal efficacy. The cleansers GE and TM did not alter the surface roughness and colour of the materials, moreover the residues of both cleansers did not exhibit cytotoxicity.

CONCLUSION

Two novel denture cleansing agents containing natural products, GE and TM exhibited effective antimicrobial activity, antibiofilm and stain removal capabilities without toxicity or disturbance of the physical properties of acrylics.

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

BACKGROUND

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

OBJECTIVE

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

Efficacy of Denture Cleansers on Microbial Adherence and Surface Topography of Conventional and CAD/CAM-Processed Denture Base Resins

This study assessed the efficacy of five denture cleansers on the microbial adherence and surface topography of conventional and CAD/CAM denture base resins. Acrylic resin discs were fabricated using conventional, milling, and 3D printing methods (N = 180). The discs were contaminated with dual species of Candida albicans and Streptococcus mutans biofilm for 72 h and then disinfected with either of the denture cleansers (Fittydent cleansing tablets, 2% Chlorhexidine gluconate, 0.2% Chlorhexidine gluconate, 0.5% sodium hypochlorite, and 1% sodium hypochlorite (n = 10). Distilled water served as the control group. The colony-forming units of the microorganisms were calculated, followed by post-treatment surface roughness. Data were statistically analyzed using one-way ANOVA, paired t-test, and post hoc Tukey HSD test (α = 0.05). Among the denture cleansers, 2% Chlorhexidine gluconate, 0.5% sodium hypochlorite, and 1% sodium hypochlorite had the best cleansing effect on the resin discs and demonstrated zero growth of colonies for both the species. Comparing the material groups, the 3D-processed discs showed higher colony-forming units followed by the conventional and CAD/CAM milled group. The highest surface roughness was demonstrated by the 3D-printed discs (0.690 ± 0.08 μm), followed by the conventional (0.493 ± 0.11 μm) and the milled groups (0.301 ± 0.08 μm). The tested chemical denture cleansers affected the Candida albicans and Streptococcus mutans adhesion compared to control discs immersed in distilled water. The clinician may recommend to their patient to use 2% chlorhexidine gluconate for the disinfection of CAD/CAM PMMA denture base materials.

Effect of sodium hypochlorite on biofilm of Klebsiella pneumoniae with different drug resistance

BACKGROUND

Biofilm formation is a major factor in the resistance mechanism of Klebsiella pneumoniae. This study aimed to evaluate the effects of sodium hypochlorite on the biofilm of K. pneumoniae with different drug resistance.

METHODS

We collected 3 different types of K. pneumoniae respectively. The growth trend of biofilms of different drug-resistant K. pneumoniae was quantified by measuring the OD₅₉₀ for 7 consecutive days using crystal violet staining. Scanning confocal fluorescence microscopy was used to observe biofilm morphology.

RESULTS

After adding sodium hypochlorite, there were significant differences between the OD₅₉₀ value of the 200, 500, and 1,000 µg/mL groups and the positive control group (all P < .05) on the fifth day. Concentrations of 2,000 and 5,000 µg/mL sodium hypochlorite were added after the biofilm had matured. In the 5,000 µg/mL sodium hypochlorite group, the OD₅₉₀ of K. pneumoniae biofilm in the 3 groups decreased significantly compared with the blank control group (all P < .05).

CONCLUSIONS

Sodium hypochlorite inhibited and cleared the biofilm of K. pneumoniae with different drug resistance, and the effect was enhanced with the increase of concentration in the range of bacteriostatic and bactericidal concentration.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Sodium bicarbonate gels: a new promising strategy for the treatment of vulvovaginal candidosis

Vulvovaginal candidosis (VVC), caused mainly by the yeast Candida albicans, is the second most prevalent vaginal infection. It has been found to have a large impact on women's quality of life, self-esteem and routines. The prevalence of recurrent vulvovaginal candidosis (RVVC) remains high so the development of alternative treatments is needed. The main objective of this study was to develop and characterize sodium bicarbonate gels to treat VVC. We described key formulation characteristics and analyzed their influence on in vitro performance evaluations. The potential to inhibit Candida albicans's growth, the pH, osmolality, viscosity and rheological performance in contact with vaginal fluid simulant and the bioadhesion's profile (using a vaginal ex vivo porcine model) were studied for all formulations. Among the formulations, formulation C (5% sodium bicarbonate, 1% carbomer and 94% water) was the most effective in inhibiting the C. albicans' growth. This gel presented the same potential (the same MIC 2.5%) to inhibit other etiological agents of VVC (C. glabrata, C. krusei, C. tropicalis and C. parapsilosis) for all species tested. Additionally, sensorial characteristics of gel C were in accord with users' preferences. This gel exhibited physicochemical characteristics acceptable for short term treatments, suggesting good overall performance for the treatment of VVC. Furthermore, Gel C was biocompatible with the HeLa cell line (MTT assay) and was classified as a non-severe irritant in the HET-CAM assay (irritation score 4 ± 1). Overall, gel C was deemed the best performing of the set tested, and suitable for further development.

Microbial Contamination and Disinfection of Sport Mouthguard: In Vitro Study

Mouthguards in Ethylene Vinyl Acetate (EVA) should be sanitized to prevent alteration of oral microbiota. The present study determined, in vitro and by SEM observation, the decontaminating effect of different substances on EVA mouthguards previously contaminated with saliva and broth culture of Enterococcus faecalis ATCC 29212 and Candida albicans CH 34 (clinically isolated). Subsequently, the mouthguards were subjected to the following treatments: (A) Untreated; (B) 5 min with sterilized distilled water (H₂O d); (C) 5 min with H₂O₂; (D) 5 min with a physiological solution; (E) toothbrush and fluoride toothpaste; (F) 5 min with 0.5% NaOCl; (G) 5 min with Oral Care Foam™; (H) 5 min with Bite Sept™. The highest efficacy against E. faecalis was demonstrated by H₂O₂ (84.19% bacterial load reduction). H₂O₂ and Oral Care Foam™ showed a greater reduction of salivary cell load. The highest efficacy against C. albicans was demonstrated by 0.5% NaOCl which caused a 92.95% reduction of cell load. In conclusion, hydrogen peroxide, 0.5% sodium hypochlorite and the solution Oral Care Foam™ allowed to obtain an optimum disinfection of the mouthguard. SEM observation showed that different substances demonstrated a decontaminating effect decreasing the microbial communities on the EVA surface.

Antidiarrheal activity of methanol extract of Sophora tonkinensis in mice and spasmolytic effect on smooth muscle contraction of isolated jejunum in rabbits

Context: In China, the herb Sophora tonkinensis Gagnep. (Fabaceae, ST) (Committee of National Pharmacopeia. 2015) exhibits anti-inflammatory, antitumor, and antiviral effects. However, to date, there have been few studies on its gastrointestinal effect. Objective: The gastrointestinal effect of the methanol extract of ST rhizome (STR) was evaluated. Materials and methods: Study was conducted from February to December 2018. In vivo, antidiarrheal activity of STR (125, 250 and 500 mg/kg; orally) in castor oil-induced diarrheal mice was studied. In vitro, the effects of STR (0.01-10 mg/mL) on the isolated tissue preparations of rabbit jejunum were also investigated, the rabbit jejunum stripes were pre-contracted with Ach (10^-5M), K⁺ (60 mM) and tested in the presence of STR, the possible spasmolytic effect was analyzed in the pretreatment of the jejunum preparations with STR or verapamil in Ca²⁺-free high-K⁺ (60 mM) solution containing EDTA. Results: STR (125, 250 and 500 mg/kg) exhibited antidiarrheal activity. STR (0.01-10 mg/mL) completely relaxed spontaneously contracting, Ach (10^-5M) and high K⁺ (60 mM) induced contracted jejunum with an EC₅₀ value of 0.66 (0.49-0.96), 0.39 (0.28-0.44) and 0.17 (0.10-0.21), similar to verapamil. Concentration-response curves of CaCl₂ could be significantly moved to the right and down in the presence of STR (0.3, 1 mg/mL). Discussion and conclusions: Results suggest the presence of antidiarrheal activity and spasmolytic effects of STR, possibly mediated through Ca²⁺ channel blocking activity, providing the pharmacological basis for its traditional uses in gastrointestinal disorders.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Chemical hygiene protocols for complete dentures: A crossover randomized clinical trial

STATEMENT OF PROBLEM

Clinical evidence on the best chemical protocol for the disinfection and removal of biofilm from complete dentures is lacking.

PURPOSE

The purpose of this crossover randomized clinical trial was to assess the effectiveness of various chemical hygiene clinical protocols in reducing the microbial viability of biofilm formed on complete dentures.

MATERIAL AND METHODS

In this triple-blind (participants, dentist, and outcome evaluator) study, complete denture wearers without candidiasis were randomly divided into 4 groups (n=40) according to the chemical hygiene protocol: water (placebo), 0.5% sodium hypochlorite solution, 0.12% chlorhexidine gluconate solution, and 5% sodium bicarbonate solution. The biofilm formed on the palate intaglio and denture teeth was collected and assessed in each experimental phase for quantitative microbial viability at the seventh and 14th day after using the chemical protocol.

RESULTS

Two participants were lost. Data were analyzed by MANOVA and Tukey HSD tests. Soaking dentures was not effective in decreasing Candida albicans, C. non-albicans, and lactobacillus counts. The use of sodium hypochlorite and chlorhexidine decreased total microorganisms and Streptococcus mutans counts for both palate and teeth compared with water and sodium bicarbonate. The intaglio of the dentures always presented higher microbial counts than did the denture teeth.

CONCLUSIONS

The use of sodium hypochlorite and chlorhexidine and mechanical cleansing with a toothbrush decreased microbial viability in healthy complete denture wearers.

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.

Efficacy of denture cleaners on the surface roughness and Candida albicans adherence of sealant agent coupled denture base materials

This study investigated the effect of denture cleansers on the surface roughness and Candida albicans adherence of surface sealant agent coupled denture base resins. One hundred and twenty specimens were fabricated from 2 polymethyl methacrylate (PMMA) (Meliodent; Acron MC) and 1 polyamide (Deflex) denture base materials, coated with a sealant agent (Palaseal) and divided into 4 groups (n=10) according to overnight cleaning procedures: distilled water (control), 5% sodium hypochlorite (NaOCl) and two different sodium perborate (Corega; Rapident). The surface roughness values were measured with a profilometer before (R_a0) and after 90 days immersion in denture cleaners (R_a1). Specimens were incubated with Candida albicans suspension and Candida colony- forming units (CFU) (Cfu/mm) were counted. Significant differences were found, between the R_a0 and R_a1 values of 5% NaOCl applied Acron MC, Deflex and also Rapident applied Deflex groups (p<0.05). Denture cleaning procedures had no significant effects on the quantitiy of Candida albicans.

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

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.

Self-cleaning and antibiofouling enamel surface by slippery liquid-infused technique

We aimed to create a slippery liquid-infused enamel surface with antibiofouling property to prevent dental biofilm/plaque formation. First, a micro/nanoporous enamel surface was obtained by 37% phosphoric acid etching. The surface was then functionalized by hydrophobic low-surface energy heptadecafluoro-1,1,2,2-tetra- hydrodecyltrichlorosilane. Subsequent infusion of fluorocarbon lubricants (Fluorinert FC-70) into the polyfluoroalkyl-silanized rough surface resulted in an enamel surface with slippery liquid-infused porous surface (SLIPS). The results of water contact angle measurement, diffuse-reflectance Fourier transform infrared spectroscopy, and atomic force microscope confirmed that the SLIPS was successfully constructed on the enamel surface. The antibiofouling property of the SLIPS was evaluated by the adsorption of salivary protein of mucin and Streptococcus mutans in vitro, as well as dental biofilm formation using a rabbit model in vivo. The results showed that the SLIPS on the enamel surface significantly inhibited mucin adhesion and S. mutans biofilm formation in vitro, and inhibited dental plaque formation in vivo.

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.