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.

Anti-biofilm effectiveness of protocols for cleaning complete dentures in hospitalized patients: a randomized controlled trial

BACKGROUND

Denture biofilm acts as a potential reservoir for respiratory pathogens, considerably increasing the risk of lung infections, specifically aspiration pneumonia, mainly 48h after hospital admission. The establishment of a straightforward, affordable, and applicable hygiene protocol in a hospital environment for the effective control of denture biofilm can be particularly useful to prevent respiratory infections or reduce the course of established lung disease.

OBJECTIVES

To evaluate the anti-biofilm effectiveness of denture cleaning protocols in hospitalized patients.

METHODOLOGY

The maxillary complete dentures (MCDs) of 340 hospitalized participants were randomly cleaned once using one of the following 17 protocols (n=20): brushing with distilled water, toothpaste, or neutral liquid soap (controls); immersion in chemical solutions (1% sodium hypochlorite, alkaline peroxide, 0.12% or 2% chlorhexidine digluconate), or microwave irradiation (650 W for 3 min) combined or not with brushing. Before and after the application of the protocols, the biofilm of the intaglio surface of the MCDs was evaluated using two methods: denture biofilm coverage area (%) and microbiological quantitative cultures on blood agar and Sabouraud Dextrose Agar (CFU/mL). Data were subjected to the Wilcoxon and Kruskal-Wallis tests (α=0.05).

RESULTS

All 17 protocols significantly reduced the percentage area of denture biofilm and microbial and fungal load (P<0.05). The highest percentage reductions in the area of denture biofilm were observed for 1% hypochlorite solution with or without brushing and for 2% chlorhexidine solution and microwave irradiation only in association with brushing (P<0.05). The greatest reductions in microbial and fungal load were found for the groups that used solutions of 2% chlorhexidine and 1% hypochlorite and microwave irradiation, regardless of the association with brushing (P<0.05).

CONCLUSIONS

A single immersion for 10 min in 1% sodium hypochlorite, even in the absence of brushing, proved to be a straightforward, rapid, low-cost, and effective protocol for cleaning the dentures of hospitalized patients.

Isolation of Candida species from the oral cavity and fingertips of complete denture wearers

BACKGROUND

Wearing a dental prosthesis is known to increase oral candidal colonization and predispose the wearer to oral candidosis. Denture wearers frequently use fingers to take the prosthesis out of their mouth. Oral Candida, if present may contaminate wearer's finger. The objective of this study was to investigate the simultaneous candidal colonization of oral cavity and fingertips of complete denture wearers.

MATERIALS AND METHODS

A total of 25 apparently healthy male subjects who had worn complete dentures for at least 1 year were selected. Information about each patient's denture age, denture hygiene, handling, and wearing habits, and hand washing habits after denture handling were be obtained. Intraoral examination of all the patients was done. For microbiological examination samples were collected from the fingertip and oral rinse of each patient. Candida species were identified with use of germ tube test and commercially available yeast identification system. Data was statistically analyzed. Significance was set at p < 0.05.

RESULTS

It was found that frequency of hand washing, denture handling and denture stomatitis with respect to fingertip candidal isolation was not statistically significant. But poor denture hygiene and denture stomatitis with respect to oral candidal colonization was statistically significant.

CONCLUSION

Denture wearers with oral Candida had a higher prevalence of Candida contamination on their fingers. Patients with removable prostheses should be informed about the importance of proper prosthesis and personal hygiene and the possibility of microbial contamination of the hands and other parts of the body.

Can new dentures decrease Candida levels?

PURPOSE

The aim of this study was to evaluate the influence of time-course changes and various types of removable dentures on the oral levels of Candida species.

MATERIALS AND METHODS

In this prospective clinical trial, 72 subjects were divided into three groups according to the type of denture replaced: Kennedy Class I or II removable partial dentures (RPDs), Kennedy Class III or IV RPDs, and complete dentures. Whole saliva and biofilm samples from the palate, tongue, dentures, and inner surface of the cheek were obtained and evaluated for Candida diversity before the delivery of the new prostheses (baseline) and at 1, 6, and 12 months postdelivery. The results were analyzed using a three-way analysis of variance, followed by a post hoc Student-Newman-Keuls test.

RESULTS

Candida levels decreased after the insertion of the new dentures; however, after 6 months, Candida levels were similar to baseline, and complete denture wearers presented higher Candida counts than RPD wearers.

CONCLUSION

The type of denture does not seem to be a decisive factor in Candida levels. After 6 months, Candida colonization was well established in all types of removable prostheses. Denture replacement alone did not guarantee a decrease in Candida levels for more than 6 months.

Comparison of denture microwave disinfection and conventional antifungal therapy in the treatment of denture stomatitis: a randomized clinical study

OBJECTIVE

The aim of this study was to compare the effectiveness of denture microwave disinfection and antifungal therapy on treatment of denture stomatitis.

STUDY DESIGN

Sixty denture wearers with denture stomatitis (3 groups; n = 20 each), were treated with nystatin or denture microwave disinfection (1 or 3 times/wk) for 14 days. Mycologic samples from palates and dentures were quantified and identified with the use of Chromagar, and clinical photographs of palates were taken. Microbiologic and clinical data were analyzed with the use of a series of statistical tests (α = .05).

RESULTS

Both treatments similarly reduced clinical signs of denture stomatitis and growth on palates and dentures at days 14 and 30 (P > .05). At sequential appointments, the predominant species (P < .01) isolated was C. albicans (range 98%-53%), followed by C. glabrata (range 22%-12%) and C. tropicalis (range 25%-7%).

CONCLUSIONS

Microwave disinfection, at once per week for 2 treatments, was as effective as topical antifungal therapy for treating denture stomatitis.

Quantification and identification of bacteria in acrylic resin dentures and dento-maxillary obturator-prostheses

PURPOSE

To quantify and identify bacteria detected in acrylic resin dentures and dento-maxillary obturator-prostheses after long-term use.

METHODS

The internal layer of denture bases from 13 daily-use removable acrylic resin dentures was sampled, while the inner fluid samples/no-fluid samples of obturators were collected from 11 in-use acrylic resin dento-maxillary obturator-prostheses. Samples were cultured, and isolated bacteria were counted and identified by molecular biological methods.

RESULTS

Bacteria were detected in five (38.5%) acrylic resin dentures and six (54.5%) acrylic resin obturators. Four Lactobacillus species and one Propionibacterium species were isolated from three repaired denture bases, and from two non-repaired dentures, two Actinomyces species and Streptococcus mutans were isolated. On the other hand, 17 bacterial species, belonging to the family and genera of Olsenella, Bacillus, Citrobacter, Enterobacteriaceae, Lactobacillus, Pantoea, Peptoniphilus, Klebsiella and Pseudomonas, were isolated from obturators. Several species of viable bacteria were detected in acrylic resin denture bases and obturators.

Microwave denture disinfection versus nystatin in treating patients with well-controlled type 2 diabetes and denture stomatitis: a randomized clinical trial

PURPOSE

The aim of this randomized clinical trial was to compare the effectiveness of microwave denture disinfection and nystatin in the treatment of well-controlled type 2 diabetic patients with denture stomatitis in terms of microbiologic and clinical outcomes.

MATERIALS AND METHOD

Diabetic patients wearing maxillary complete dentures with denture stomatitis (n = 40) were divided into two groups: NYS (patients treated with topical nystatin 4 times/day for 14 days) and MW (patients who had their dentures microwaved [650 W for 3 minutes] 3 times/week for 14 days). Mycologic samples were taken from the palates and dentures of the patients for quantification and identification of Candida, and standardized photographs of the palates were taken for clinical analysis. Evaluations were repeated at baseline, the end of treatment (day 14), and throughout follow-up (days 30, 60, and 90). Microbiologic data were evaluated by analysis of variance using a random effects statistical model, Tukey post hoc test, and chi-square test (α = .05). Clinical results were analyzed using Mann-Whitney and Fisher exact tests (α = .05).

RESULTS

Both treatments were considered successful in reducing the clinical signs of denture stomatitis and significantly reduced the values of colony-forming units/mL from the palates and dentures at days 14 and 30. In addition, 40% of treated patients were cured by the end of treatment. No significant differences in the microbiologic and clinical outcomes were revealed between the two groups (P > .05). C albicans was the most predominant species isolated (P < .01), followed by C tropicalis and C glabrata.

CONCLUSION

Denture microwave disinfection was as effective as nystatin for the treatment of diabetic patients with denture stomatitis.

Candida albicans isolation from buccal mucosa of patients with HIV wearing removable dental prostheses

PURPOSE

The aim of this study was to evaluate the influence of complete or partial removable dental prostheses (RDPs) on the frequency of Candida albicans isolated from the mouth and the presence of oral candidiasis in human immunodeficiency virus-positive (HIV+) patients correlated with CD4 levels.

MATERIALS AND METHODS

One hundred ninety-three HIV+ patients were evaluated; 68 had RDPs and 125 did not. CD4 cell count was obtained after blood sampling and performed on the day of clinical examination. The material was collected from the buccal mucosa for isolation of yeasts with a sterile swab and seeded onto Sabouraud dextrose agar with chloramphenicol. C albicans strains were identified by testing germ tubes and chlamydospore formation and biochemical (zymogram, auxanogram) characteristics. The results were subjected to the Fischer exact test and chi-square tests.

RESULTS

C albicans were isolated from 45 (66.17%) patients who had RDPs and 48 (38.4%) who did not (P = .0003). The presence of oral candidiasis was observed in 14 patients (7.25%), and 10 of the 14 (71.43%) were RDP users. The absence of candidiasis occurred in 121 (67.59%) nonusers and 58 (32.40%) users of RDPs (P = .0065). The mean CD4 cell count was lower in patients with oral candidiasis regardless of the use of RDPs.

CONCLUSION

The use of RDPs was an important factor in the isolation of C albicans among HIV+ patients, and CD4 level seems to play a role in the presence of oral candidiasis.

Evaluation of cleansing methods for previously worn prostheses

STATEMENT OF PROBLEM

Although there are many product claims that address the issue of denture sanitization, controlled scientific studies on previously worn dentures have not been performed.

PURPOSE

The purpose of this study was to evaluate procedures directed at sanitizing previously worn contaminated dentures from two regions of the United States.

MATERIALS AND METHODS

This study examined 51 previously worn dentures from two regions. An established method of denture retrieval, sectioning, and culturing was used, including isolation of anaerobes. Evaluation of microbial contamination posttreatment was used to determine the effects of soaking dentures in Polident (US and European formulations) for varying periods of times/temperatures, microwaving dentures with varying temperatures, sonicating dentures, and immersing the dentures while using a vacuum. A combination of analysis of variance (ANOVA) and general linear model (GLM) of the SPSS was used to analyze the data with P < .05 being considered statistically significant when using a two-tailed test.

RESULTS

While all Polident treatments were found to significantly reduce microorganism loads in dentures, extended soaking (8 hours) and 65 degrees C (5 minutes) were the most effective. Microwaving was slightly more effective than either sonication or vacuum. Regardless the treatment, dentures underwent sanitization rather than sterilization.

CONCLUSIONS

Denture-borne microorganisms can be significantly reduced by using a Polident solution for 8 hours at room temperature or for 5 minutes at 65 degrees C. Microwaving, sonication, and use of a vacuum were less effective. ClLINICAL IMPLICATIONS The importance of daily use of Polident solution for 8 hours or for 5 minutes at 65 degrees C to sanitize worn prostheses must be stressed.

[Preferred zones of accumulation of prosthetic microbial plaque on removable complete dentures]

INTRODUCTION

Denture plaque (DP) is not visible with naked eye when it is not mineralized or not fully fixed. Describing and studying its qualitative and quantitative aspects in Complete Dentures (CD) require precisely-located sampling but selection criteria have not yet been well defined. In order to improve our treatment and preventive strategies for patients with CD, it is necessary to explore the various DP accumulation zones on CD fitting surfaces.

PURPOSE

The aim of this study is to assess the DP accumulation on fitting surfaces of CD.

MATERIAL AND METHODS

Distribution of DP accumulation zones was assessed by naked eye observation of the fitting surfaces on 31 maxillary and 31 mandibular CD. The prostheses were to be carried regularly since at least one year. The data were collected at the Prosthodontics department of the Annaba University Medical Center in Algeria. Prostheses were immersed for 24 hours in a plaque disclosing solution containing erythrosin 2% (Dento-Plaque Inava). The maxillary fitting surface was divided into five sectors: the post damming zone (1MaxFS), the top of the palate zone (2MaxFS), the incisor zone (3MaxFS), the maxillary tuberosity zone (4MaxFS), and the end of the canine and 1st premolar zone (5MaxFS). For mandibular fitting surfaces: trigonal and retromolar zone (1ManFS), canine and 1st premolar zone (2ManFS), and incisor zone (3ManFS).

RESULTS

DP distribution was found to be homogeneous on the fitting surface of mandibular CD, however it was distributed in unequal way on the maxillary fitting surfaces. We noted a highly significant difference (p < 0.001) in the staining frequencies of the targeted zones. The most colored zone was the post damming one (1MaxFS), with a rate of 96.7%, whereas the least colored zone was the top of palate one (2MaxFS), with 35.5%. On the mandibular fitting surfaces, the rate of staining was 93.5% for the trigonal and retromolar zone (1ManFS) versus 83.8% on canine, 1st premolar (2ManFS) and incisor (3ManFS) zones. There was no significant difference (p = 0.422).

CONCLUSION

The accumulation of DP was found to be homogeneous on mandibular fitting surfaces and no homogeneous on maxillary fitting surfaces. These results require further investigations in order to understand the causes of this difference. This will allow us to improve our treatment and preventive strategies for edentulous patients.

[Preferred sites of accumulation of microbial plaque as shown by the color of the exterior surface of complete dentures]

PURPOSE

The observation of the denture plaque for complete dentures caused many clinical works and researches, since 30 years. Most of the studies were interested, by the prosthetic under-surface. New data show that the polished (exterior) surface on the denture palate is colonized more than hard palate. The aim of our study is to locate the favorite zones of the accumulation of the denture plaque on the level of the suction polished faces of the acrylic resin.

MATERIAL AND METHODS

We proceeded by immersion during 24 hours of 62 used full dentures belongs to 33 patients, with mucous membranes of various clinical aspects in a plaque disclosing solution of erythrosine type. The suction faces were divided into several zones of marking.

RESULTS

We record 100% of coloring of the interdental zones on the maxillary and mandibular prosthesis. On maxillary prosthesis: 100% of the former and posterior vestibular zones are colored. The bottom of the palate is colored to 67.74%, a rate equivalent to the zones of fractures. On mandibular prosthesis: retromolar and sublingual zones, are colored to 96.77%. The former hall is colored with a rate of 90.32%. The posterior vestibular zone seems the least colored with a rate of 80.64%.

CONCLUSIONS

The former area of the hall carved in an aesthetic objective is generally colored as well on the maxillary and mandibular prosthesis. We point out that this zone should not be much carved on the level of the area simulating the attached gum. Patients should be always incited to practice a mechanical hygiene, which takes part largely in the evacuation of the denture plaque on prosthetic surfaces. This revealing plaque use should integrate a clinical attitude of good practice, to motivate a patient with prosthetic hygiene or to detect zones of cracks objectifying a mechanical weakness of a prosthesis to be taken again, as well as the checking of the quality of repair joint during a routine control.

Application of a diagnostic-therapeutic procedure using implant-supported dental prosthesis as a preventive therapy for candidiasis of upper gastrointestinal tract in complete denture users

Our previous studies demonstrated that the use of acrylic based prosthesis in edentulous patients had a direct impact on the increased incidence of oral mycosis and further episodes of mycosis in the digestive tract. This dependency is associated with formation of a space between the surface of the prostheses and adhering mucosal membrane, where a specific micro environment is being formed, which - as stated - creates a superior breeding ground mainly for microorganisms of the genus Candida.

Impact of routine oral care on opportunistic pathogens in the institutionalized elderly

Routine oral hygiene is important for the control of opportunistic pathogens in the oral cavity of institutionalized elderly individuals. We evaluated the effects of routine oral care on opportunistic pathogens at various time points after admission to a nursing home. Twenty-five elderly subjects living in the nursing home (mean age: 86.0 +/- 10.4 years) participated in the study. Caregivers and dental hygienists cleaned the teeth, dentures, tongue, and mucosa after each meal using both routine and professional oral care techniques. Opportunistic pathogens were collected from the teeth, tongue, and mucosal surfaces using a cotton swab; and the species of microbes were determined and the numbers were counted following cultivation on selective agar. Regular oral care including professional oral care was found to be effective for reducing infections by many kinds of opportunistic pathogens on the teeth surfaces and the oral environment without food residue during a long-term study (6 months). Further, this care after 1 month significantly reduced infections by opportunistic pathogens on mucosal surfaces in subjects without dentures; however, this was not observed in those with dentures. Our data shows the importance of regular oral care in cleaning hard and soft surfaces of the oral cavity improves the oral health of the institutionalized elderly.

Assessment of oral status and oro-pharyngeal candidosis in elderly in short-term hospital care

OBJECTIVES

To evaluate prevalence of oral candidosis and predisposing conditions in hospitalized elderly patients.

DESIGN

We examined 104 elder patients recently hospitalized in two geriatric hospitals for shortterm hospital care.

METHODS

Information was collected on patients' sex, age, mental and physical disabilities, smoking habits, medical prescriptions, oral pathologies, denture wearing, oral hygiene habits and oral hygiene level. Quality of existing dentures was evaluated. Oral mucosae were examined for clinical signs suggesting oral candidosis. Semiquantitative cultures of Candida were carried out to confirm the clinical diagnosis.

RESULTS

The diagnosis of oral candidosis was confirmed in 18/54 patients showing clinical signs of oral candidosis. Confirmed oral candidosis was associated with the presence of other infections, proteo-caloric denutrition, ongoing antibiotic therapy, and denture wearing. Dentures in patients with confirmed oral candidosis at poorer technical quality of the acrylic surface in contact with the underlying mucosa.

CONCLUSION

The wearing of removable dentures is a major predisposing factor for oro-pharyngeal candidosis of elderly patients in short-term hospital care. Appropriate oral and denture hygiene measures as well as denture wearing habits should be introduced or maintained to prevent this infection.

Erythematous candidosis in patients with complete dentures and HIV+/AIDS

This investigation was designed to evaluate the frequency of erythematous candidosis (EC) and Candida species, proteinase and phospholipase exoenzyme production, and to compare clinical features in patients with complete dentures and HIV+/Acquired Immunodeficiency Disease Syndrome (AIDS). Fifty-one patients were selected from a total of 285 with EC: denture wearers (n = 30) and HIV+/AIDS (n = 21). The yeast prevalence and the production of exoenzymes, such as proteinase and phospholipase by Candida species were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis. The frequency of Candida albicans was significantly higher (P < 0.05) in both groups although other yeast species (Candida glabrata, Candida krusei, Candida parapsilosis, Candida guilliermondi and Candida tropicalis) were also found. Candida albicans showed greater levels of proteinase production in the denture wearers, when compared with the HIV+/AIDS group. There was no difference between groups with regard to phospholipase production. The protein bands presented similar molecular weights, showing the presence of proteinases in both groups. It could be concluded that the clinical manifestation of EC may be related to its proteinase production capacity. Combination therapies using proteinase inhibitors play an important role in inhibiting exoenzyme production by Candida species, mainly C. albicans.

Relationship between Candida and nocturnal denture wear: quantitative study

The purpose of this study was to evaluate the relationship between Candida and denture wear during the night. Twenty-four edentulous volunteers were randomly divided into two groups. Group I (GI, n = 11) was composed of volunteers who wore their complete dentures day and night and Group II (GII, n = 13) was composed of volunteers who wore their complete dentures only during the day. Three examination periods were performed for both groups. In GI, the first examination (A) was carried out after overnight denture wearing. Subsequent examinations were conducted after one (B) and seven nights (C) without denture use during sleep. In GII, the first (A) was done without previous use during sleep, and the following were carried out after one (B) and seven nights (C) of overnight denture wearing. Total unstimulated saliva was collected in a sterile container and cultured in duplicate inside Petri dishes. The values of colony forming units (CFU mL(-1) +/- s.d.) were obtained: GI A - 10.1 x 10(3) +/- 1.2 x 10(4), B - 2.0 x 10(3) +/- 2.6 x 10(3), and C - 2.6 x 10(3) +/- 5.9 x 10(3) and GII: A - 0.4 x 10(3) +/- 0.6 x 10(3), B - 9.4 x 10(3) +/- 17.7 x 10(3) and C - 6.3 x 10(3) +/- 15.3 x 10(3). The mean counts for Candida sp. were expressed as log (CFU + 1) mL(-1) and statistical significance of differences among groups was tested by anova (alpha = 0.05). Multiple comparisons were performed according to Bonferroni test and indicated significant differences between A-B and A-C, but not between B and C for both groups. It was concluded that there is a significant relationship between continuous denture wear and Candida sp.

Distribution and phospholipase activity of Candida species in different denture stomatitis types

The aim of this study was to evaluate the correlation between frequency and phospholipase activity of Candida species and denture stomatitis according to Newton's classification. Seventy-five complete denture wearers were evaluated for the presence of yeasts on the palatal mucosa by culture method. In addition, the number of yeast isolates producing phospholipase and amount of this enzyme were determined using egg yolk agar plate method. According to Newton's classification, 25 denture wearers were with healthy palatal mucosa while 50 were with any types of denture stomatitis. The frequency of yeasts was linked to whether subjects had Type II or Type III, but not Type I denture stomatitis. Candida albicans was the most frequently isolated species in denture wearers with and without clinical signs of denture stomatitis and it was the only species produced phospholipase. Although the amount of phospholipase produced by the C. albicans isolates from denture wearers in control and Type II and III DS groups was not significantly different, there was statistically significant difference in the number of C. albicans isolates producing phospholipase between patients with and without clinical signs of DS.

Bacteria adhesion to the surface of various prosthetics materials

Increased life span of humans and dynamic development of prosthetic treatment has caused that increased number of people are using removable dentures for longer periods of time. The materials used to make those prosthesis are becoming a potential pathogen factor for oral mucosa being in contact with this material. Prosthetic stomatopathy occurs in 20% to 70% of the patients who are using removable dentures. The present paper evaluates and compares adhesion of bacterial plague to the most common materials used for removable dentures i.e. acrylic material Vertex R.S., metal alloy used for frame prosthesis and a material which is an alternate to acrylic resin and acetal metal-resin Acetal Pressing D. Samples were made from the above mentioned materials and placed in mediums with four basic bacteria cultures and fungus Candida albicans (fungus) as the adhesion of bacterial plague to individual materials was evaluated. Such an evaluation facilitates choice of appropriate prosthetic material, allowing to make prosthetic restoration that is functional and aesthetic at the same time taking into account prosthetic stomatopathy prevention.

Correlation between adhesion, enzyme production, and susceptibility to fluconazole in Candida albicans obtained from denture wearers

OBJECTIVE

The aim of this study was to assess the contribution and the correlation between the virulence factors of Candida albicans in denture stomatitis.

STUDY DESIGN

Thirty C. albicans strains obtained from the oral cavity of patients with denture stomatitis and 30 C. albicans obtained from the oral cavity of denture wearers with normal palatal mucosa were compared for adhesion ability to buccal epithelial cells (BEC), reduction in adhesion after exposure to fluconazole, and enzyme production. The correlation between these virulence factors was assessed by Pearson's correlation coefficient.

RESULTS

C. albicans obtained from denture stomatitis patients were more adherent to BEC and higher enzyme producers than those obtained from healthy patients. Our results demonstrated that exposure to fluconazole reduces C. albicans adherence to BEC. This study could also provide evidence of correlation between virulence factors.

CONCLUSION

Our results suggest that adhesion and enzyme production could be factors that, along with predisposing conditions related to the host, determine if an individual will develop disease or remain as a healthy carrier and confirm that fluconazole has an impact on the adherence ability and enzyme production in C. albicans.

Effectiveness of microwave irradiation on the disinfection of complete dentures

PURPOSE

The purpose of this study was to evaluate the effectiveness of microwave irradiation on the disinfection of simulated complete dentures.

MATERIALS AND METHODS

Eighty dentures were fabricated in a standardized procedure and subjected to ethylene oxide sterilization. The dentures were individually inoculated (10(7) cfu/mL) with tryptic soy broth (TSB) media containing one of the tested microorganisms (Candida albicans, Streptoccus aureus, Bacillus subtilis, and Pseudomonas aeruginosa). After 48 hours of incubation at 37 degrees C, 40 dentures were individually immersed in 200 mL of water and submitted to microwave irradiation at 650 W for 6 minutes. Forty nonirradiated dentures were used as positive controls. Replicate aliquots (25 microL) of suspensions were plated at dilutions of 10(-3) to 10(-6) on plates of selective media appropriate for each organism. All plates were incubated at 37 degrees C for 48 hours. TSB beakers with the microwaved dentures were incubated at 37 degrees C for 7 more days. After incubation, the number of colony-forming units was counted and the data were statistically analyzed by Kruskal-Wallis test (alpha = .05).

RESULTS

No evidence of growth was observed at 48 hours for S. aureus, B. subtilis, and C. albicans. Dentures contaminated with P. aeruginosa showed small growth on 2 plates. After 7 days incubation at 37 degrees C, no growth was visible in the TSB beakers of S. aureus and C. albicans. Turbidity was observed in 3 broth beakers, 2 from P. aeruginosa and 1 from B. subtilis.

CONCLUSION

Microwave irradiation for 6 minutes at 650 W produced sterilization of complete dentures contaminated with S. aureus and C. albicans and disinfection of those contaminated with P. aeruginosa and B. subtilis.

Antimicrobial activity of monocaprin: a monoglyceride with potential use as a denture disinfectant

Monocaprin is a 1-monoglyceride of capric acid that has antimicrobial activity against enveloped viruses, certain bacteria, and the yeast Candida albicans. Solutions containing monocaprin were formulated and tested in vitro against a number of micro-organisms, including species found in the oral cavity and common pathogenic species. The antimicrobial activity of monocaprin was tested with strains growing on a surface as well as in the planktonic phase. Micro-organisms tested were: Streptococcus mutans, Candida albicans, Lactobacillus sp., Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Two sets of dilutions were prepared for each test strain; one to be inoculated with the micro-organism growing in the planktonic phase and the other with the same strain growing on a filter paper disk. Control solutions were also prepared to find out if any of the excipients were affecting the microbicidal effect of monocaprin. Test strains growing on the filter paper surface were less sensitive to monocaprin than the same strain growing in its planktonic phase. C. albicans was the micro-organism that was most sensitive to monocaprin, but S. mutans also showed appreciable sensitivity. The indication that monocaprin may have potential as a topical agent against Candida was tested in an open study of denture disinfection in 32 patients attending a geriatric daycare centre. A significant, but short-term, reduction in counts of Candida on the fitting surface of full dentures was observed.

Colonization of Candida species in denture wearers with emphasis on HIV infection: a literature review

Candida colonization in denture wearers, especially immunocompromised patients, can be disruptive to dental treatment and may be a barrier to patient health. The surface irregularities of acrylic resin are a factor in the entrapment of microorganisms. Consequently, controlling the spread of fungal infection in HIV-infected patients who wear removable prostheses and who are more susceptible to fungal infections because of their immunosuppression is of critical importance. This article reviews the literature on the colonization of Candida species in HIV-infected denture wearers using keywords such as complete dentures, candidiasis, and HIV-infection . The source for this review was representative English-language, peer-reviewed articles between the period of 1885 to 2003 obtained using Medline, as well as a hand search.

Comparison of two cleansing pastes for the removal of biofilm from dentures and palatal lesions in patients with atrophic chronic candidiasis

The efficacy of 2 oral hygiene products, an experimental toothpaste specific for complete denture cleansing and a regular standard toothpaste, was compared in terms of denture biofilm removal and cure of palatal lesions in patients with atrophic chronic candidiasis. The degree of correlation between presence of biofilm and mucosa erythema was also evaluated. Twenty-four complete denture wearers (45-80 years old) were divided into 2 groups: experimental paste and standard toothpaste (Sorriso-Kolynos, Brazil). Both groups received soft toothbrushes. The internal surfaces of upper dentures were stained using 1% sodium fluorescein and photographed at a 45 masculine angle at 0, 15, 30 and 60 days. The slides were scanned and the areas of interest (denture total area and biofilm area) were measured (Image Tool software). The degree of erythema was evaluated on slides according to the Prosthesis Tissue Index. There was a significant reduction (1%) in the degree of biofilm (ANOVA/Tukey) between the two initial visits (0 and 15 days) and the two final visits (30 and 60 days), and in the average erythema scores (Kruskal-Wallis) between 0 and 60 days, in both groups. The Mann-Whitney test showed a significant difference (1%) between pastes in terms of biofilm degree, but no difference was found for the erythema score. Correlation values between biofilm and erythema degree were 0.3801 (experimental paste) and (0.3678 (standard toothpaste). We may therefore conclude that the experimental product was efficient for the removal of denture plaque biofilm.

Malodour in denture wearers: an ill-defined problem

Denture plaque has not been studied to the same extent as dental plaque, and although there are many similarities in microbial composition, there are some significant differences. Denture-induced stomatitis is associated with poor denture hygiene, a more acidogenic plaque and the presence of Candida albicans. Obligate Gram-negative anaerobic micro-organisms, although present in denture plaque, have rarely been specifically investigated. Opportunist pathogens including coliforms and staphylococci have been isolated from dentures. Teeth adjacent to partial dentures are more susceptible to caries and periodontal diseases, perhaps due to an increased plaque buildup at the prosthesis/tooth interface. Little work has been published on malodour associated with dentures. The inert material provides a substratum for the plaque biofilm, which encompasses a range of odour-producing species. The microbiology of the tongue in denture wearers has not been specifically studied. Thus the nature, origin and extent of malodour in denture wearers is ill-defined, but many species capable of producing malodorous compounds are present. The wide age and health range presented by denture wearers further confounds investigation. There is a need for further work in the area, both for cosmetic- and health-associated reasons in the increasing elderly population.

Comparative study of methods for the quantification of biofilm on complete dentures

This study compared the application and reliability of 4 methods for biofilm quantification (computerized, paper-weighing, point-counting, and planimetric) in complete dentures, verifying the correlation between them. The internal surfaces of 62 complete dentures were stained (5% erythrosine) and photographed. The slides were projected on paper, and the areas (total and biofilm-covered) were outlined with a pencil. These areas were measured with an equidistant point grid (point-counting method), a digital planimeter (planimetric method), and for the paper weighing method they were cut and weighed with a precision scale. For the computerized method, ImageTool software was used. In order to perform a validation test of the methods, all of them were applied to slide projections of geometric figures with known dimensions. The correlation tests showed high correlation values (r = 0.82 to 0.99) among the methods. The validation test (ANOVA) showed no statistically significant differences among the values obtained from the measurement of figures using all four quantitative methods and the real dimensions of these geometric figures. Quantitative methods were efficient and reliable for measuring quantity of biofilm in complete dentures, and may be useful in experimental studies on the efficacy of hygiene products. The computerized method was fast and easy to perform.

Candida pararugosa isolation from the oral cavity of an Italian denture wearer

Candida pararugosa was first isolated from human feces, but after the initial description no further recovery from humans has been reported. During a study on oral Candida colonization in denture wearers living in Palermo (Italy), we isolated C. pararugosa from a 61-year-old woman without signs of oral candidosis. This constitutes, to the authors' knowledge, the first isolation of C. pararugosa from the oral cavity. After six months, colonization by C. pararugosa persisted, suggesting that this species could be a component of the normal oral microbiota. The identification procedure we used could be useful in elucidating the epidemiology of C. pararugosa and for establishing its clinical significance.

Clinical and microbiological efficacy of chlorine dioxide in the management of chronic atrophic candidiasis: an open study

OBJECTIVE

To assess the clinical and microbiological efficacy of chlorine dioxide (ClO2) as a topical antiseptic for the treatment of chronic atrophic candidiasis in geriatric patients.

PARTICIPANTS

Thirty patients with chronic atrophic candidiasis.

METHODS

Patients were instructed to rinse the mouth with 0.8% ClO2 mouth rinse (DioxiDent) twice daily for one minute and to soak their dentures overnight in the ClO2 for 10 days. Patients were evaluated both clinically and microbiologically at baseline and after 10 days, and any significant side effects were recorded. The clinical appearance of the oral soft tissues was scored on a scale of 0-3 (0 indicating no clinical signs, 1 indicating involvement of < 25% of the palatal mucosa, 2 indicating involvement of 25-50% of the palatal mucosa, and 3 indicating marked erythema involving > 50% of the palatal mucosa). Microbiological testing was undertaken to determine the number of colony forming units (CFUs) of Candida albicans.

RESULTS

ClO2 significantly improved the clinical appearance and microbial count (p < 0.001) after treatment, without significant side effects. Results showed marked improvement in the clinical appearance of the tissues after 10 days, with total resolution in the majority of cases. The total CFU/ml ranged from 15,000-53,000 at baseline and was reduced to < or = 500 after 10 days of treatment (p < 0.001). The mean clinical score was 2.50 at baseline, and was reduced to 0.17 after 10 days of treatment (p < 0.001).

CONCLUSIONS

Within the limitations of this pilot study, the effectiveness of topical chlorine dioxide (0.8%) in the management of chronic atrophic candidiasis was demonstrated. ClO2 provided a safe and clinically effective option in the management of chronic atrophic candidiasis.

Evaluation of the sanitization effectiveness of a denture-cleaning product on dentures contaminated with known microbial flora. An in vitro study

OBJECTIVES

To see if dentures contaminated with Staphylococcus aureus, Pseudomas aeruginosa, Bacillus cereus, Candida albicans, and herpes simplex virus 1 could be effectively decontaminated by using Medical Tabs for Dentures.

METHOD AND MATERIALS

Ten methylmethacrylate dentures with processed soft liners (soft-liner dentures) and 10 methylmethacrylate dentures without processed soft liners (hard dentures) were aseptically fragmented and individually incubated with a target microorganism. Test denture fragments were immersed in Medical for 5 minutes, vortexed for 5 minutes, and serially diluted onto media. The control denture fragments were similarly treated in sterile water. For virus contamination, denture fragments were contaminated with 1.2 x 10(9) tissue culture infective dose (TCID)50/mL. They were treated with either Medical for 5 minutes (test fragments) or water (controls) for 5 minutes. Serial dilutions were performed and viral (TCID)50/mL titers were calculated using the Reed-Muench method.

RESULTS

Medical treatments effectively eliminated C. albicans, S. aureus, and P. aeruginosa from soft-liner dentures. Treatment of hard dentures eradicated C. albicans and reduced the numbers of S. aureus and P. aeruginosa to < 10. B. cereus showed a reduction of 10 microorganisms in hard dentures while the soft-liner dentures did not show an appreciable reduction. Viral analyses found that both types of dentures retained large amounts of virus when washed with water, but no virus was recovered from any of the 40 samples treated with Medical.

CONCLUSION

A single use of Medical Tabs for Dentures is effective in eliminating certain species of microorganisms, including selected viruses, in vitro.

[NO TITLE AVAILABLE]

Polishing of dental prostheses can cause a dangerous cycle of cross-contamination involving dentists, laboratory technicians, patients and auxiliary personnel. The aim of this study was to show the microbial contamination in the dental laboratory during the polishing procedure of complete dentures. For this purpose, 4 experiments were conducted. Experiment I - Determination of the total colony-forming units (CFU) counts contaminating complete maxillary dentures. During the polishing procedure, determination of the CFU counts transferred to the operator (Experiment II) and of the total CFU counts transferred to previously sterilized complete dentures (Experiment III). Experiment IV - The total counts of remaining CFU in the lathe spindle after Experiments II and III. Complete dentures were highly contaminated (mean = 1.4 x 10(7) CFU/mL). There was a elevated level of contamination by splatter and aerosols. There was high microbial transfer from the contaminated lathe spindle to the sterile prostheses (mean = 1.7 x 10(7) CFU/mL). The spindles were highly contaminated after polishing procedures (mean = 3.5 x 10(8) CFU/mL). The polishing of dental prostheses is a possible source of transmission of communicable diseases in the laboratory and requires improved techniques for infection control.

High correlation between the bacterial species in denture plaque and pharyngeal microflora

OBJECTIVES

The morbidity and mortality of the dependent elderly that result from aspiration pneumonia are recognized as a major geriatric health problem. Most cases of bacterial pneumonia are initiated following colonization or superinfection of the pharynx by pathogenic bacteria, followed by aspiration of pharyngeal contents. A recent study revealed that bacteria, that commonly cause respiratory infection, colonized the dentures of dependent elderly. This suggests that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the pharynx. The purpose of this study was to determine the possible correlation between denture and pharyngeal microflora.

STUDY DESIGN

The denture and pharyngeal bacterial flora of 50 dependent elderly were examined, and the microorganisms identified by culturing. The agreement between the bacterial species in denture plaque and pharyngeal microflora was investigated using the Kappa method.

RESULTS

The microorganism species on the dentures and pharyngeal mucosa of the subjects had an agreement rate of 68.5%. The agreement rate for each of the bacterial species of the dentures and pharynx was also demonstrated to be high.

CONCLUSIONS

Dentures should be considered an important reservoir of organisations which could colonise the pharynx, and the importance of controlling denture plaque for the prevention of aspiration pneumonia cannot be overemphasized.

Control of denture plaque and mucosal inflammation in denture wearers

The aims of this study were to collect data about the popular methods and materials used for cleaning dentures among complete and partial denture wearers in Jordan and to discuss the relationship between denture base plaque and mucosal inflammation under dentures. A questionnaire consisting of six questions regarding denture hygiene practices and cleaning products was completed by 321 patients who attended two prosthodontic clinics for replacement or adjustment of their dentures. Following careful oral examination and examination of dentures, the relationship between denture hygiene and inflammation under the denture base was investigated. In this study there were 615 dentures and 321 patients. The mean age of patients was 65 years and it ranged from 18 to 100 years (s.d. = 10.1). The mean age of their dentures was 7.3 years (s.d. = 5.6) ranging from one to 27 years. The most popular method of cleaning dentures was brushing. Ninety-four (29 per cent) of the denture wearers had denture stomatitis. There was a statistically significant relationship between poor denture hygiene and denture stomatitis (P = 0.0001). There was also a significant relationship between continuous wearing of the dentures, day and night, and denture stomatitis (P < 0.0001). The presence of bacterial and yeast plaque on the fitting surface of the denture base appeared to be of critical importance for development and maintenance of denture stomatitis. It is necessary, therefore, that dentists should give instructions to denture wearers on how to clean their denture surfaces properly so as to maintain good hygiene and prevent denture stomatitis.

A statistical comparison of denture sanitation using a commercially available denture cleaner with and without microwaving

Polymethyl-methacrylate dentures, worn by patients for periods ranging from 12 days to 48 years, were cultured and found to be heavily contaminated with a variety of microorganisms both externally and internally. A commercially available denture sanitizer, used as prescribed by the manufacturer, was ineffective at decontaminating the dentures. This study examined the effectiveness of this denture sanitizer when used in combination with a microwaving procedure. Statistical methods were used to compare the decontamination results of the denture sanitizer applied with and without microwaving. The statistical results indicated that the dentures were decontaminated most effectively when the denture sanitizer was used in conjunction with a two-minute microwave procedure.

Salivary cytokine profiles in the immunocompetent individual with Candida-associated denture stomatitis

Cell-mediated immunity conferred by CD4+ T helper cells is considered the predominant host defense against mucosal Candida infections, with Thelper (Th1)-type responses associated with resistance to infection and Th2-type responses associated with susceptibility to infection. Oropharyngeal candidiasis, the most common oral opportunistic infection in HIV-infected persons, is associated with a Th2-type cytokine profile in saliva. To obtain more direct evidence for a role of salivary cytokines in susceptibility to oropharyngeal candidiasis during immunosuppression, we evaluated Th1/Th2-type cytokines in the saliva of those with denture stomatitis, a form of oropharyngeal candidiasis not related to immunosuppression. Results showed that HIV-negative denture wearers with and without denture stomatitis demonstrated a mixed Th1/Th2 cytokine profile with no significant differences found between the groups. These results suggest that a local Th cytokine dichotomy in saliva is not associated with susceptibility to denture stomatitis in immunocompetent persons.

[Biofilm disclosing agents in complete denture: clinical and antimicrobial evaluation]

This study evaluated the disclosing ability, removal facility and antimicrobial effect of biofilm disclosing agents applied on complete dentures. Disclosing ability was evaluated by means of the visual method. The solutions were applied on the internal surface of dentures. After being photographed, the dentures were brushed with denture-specific brush and dentifrice and photographed again. The obtained slides were projected on paper (10 X amplification) and the total and stained surfaces were outlined with graphite, cut off and weighed, in order to assess removal facility. The evaluation of antimicrobial effects was carried out by means of the method of diffusion in agar, and the results were obtained by measuring the length of the halos and rings. In terms of disclosing ability, the best solutions were 0.05% methylene blue, 5% erythrosin, 1% sodic fluorescein, Replak and 1% neutral red. One percent eosin, 1% sodic fluorescein and 5% erythrosin were the most easily removed solutions. One percent eosin, 5% erythrosin, 1% sodic fluorescein, 0.3% proflavine, Replak and 1% neutral red presented no antimicrobial effect. The solutions which presented the greatest disclosing ability and removal facility as well as absence of antimicrobial effect - which are essential requirements in the assessment of hygiene methods and guidance on oral health - were 1% eosin, 1% neutral red and 5% erythrosin.

Oral hygiene habits, denture cleanliness, presence of yeasts and stomatitis in elderly people

The purpose of this study was to determine oral hygiene habits, denture cleanliness, presence of yeasts and denture stomatitis in elderly people. Seventy complete denture wearers were investigated clinically and mycologically. Subjects were evaluated according to, presence of denture stomatitis, presence of yeasts, denture cleanliness, frequency of denture brushing and denture cleaning methods. Swabs were taken from the palate investigated mycologically in order to identify the yeast colonies. No statistical relationship was found between denture stomatitis and frequency of denture brushing and denture cleaning methods. However, there was a statistically significant relationship between denture stomatitis, yeasts' presence and denture cleanliness.

A clinical and microbiological evaluation of denture cleansers for geriatric patients in long-term care institutions

BACKGROUND

Many elderly patients in long-term care hospitals cannot adequately brush their dentures because of disease, dementia and poor dexterity. Such inadequate cleaning may allow for the multiplication of Candida spp. and bacteria, which could serve as reservoirs for disseminating infections.

OBJECTIVE

To assess the efficacy of 3 denture cleansers in reducing the number of microorganisms on dentures in a hospitalized geriatric population.

METHODS

Three brands of cleanser (Denture Brite, Polident and Efferdent) were compared; water was used as the control. Microbiological samples were obtained before and after 3 one-week periods of cleanser use; these samples were taken by a microbiologist blinded to the assigned treatment. In the statistical analysis, the ranks of the differences between the before-treatment and after-treatment scores of each regimen were compared by means of the general linear model. In addition, the efficacy of each cleanser in reducing accumulation of plaque, stain and food was assessed.

RESULTS

The rank of the differences in the number of colony-forming units (CFUs) of Candida spp. before and after one week of use of Denture Brite (p = 0.04) and Polident (p = 0.01), was significantly greater than that of the control group, but there was no difference between Efferdent use and control (p = 0.10). No significant differences in reduction of Streptococcus mutans were observed between Denture Brite (p = 0.13) or Polident (p = 0.12) and the control group, whereas dentures cleaned with Efferdent exhibited significantly greater reduction in Streptococcus mutans (p = 0.02) than dentures cleaned with water. Over all study periods, there were no significant differences among the cleansers in reduction of Candida spp. or Streptococcus mutans. Dentures cleaned with Denture Brite, Polident or Efferdent appeared to have similar reductions in the level of plaque, stain and food, and all had substantially greater reductions than dentures cleaned with water only. The significant difference in the rank of the reduction in Candida spp. CFUs (p = 0.005) was related to the variance between study periods (p = 0.01) and the variance between subjects (p = 0.008).

CLINICAL SIGNIFICANCE

The use of denture cleansers significantly reduced the number of microorganisms on dentures in a hospitalized geriatric population.

Comparison of the effectiveness of several denture sanitizing systems: a clinical study

The purpose of this clinical study was to test the effectiveness of three methods of decontamination on complete dentures. Dentures worn by patients for varying lengths of time were handled aseptically and treated with three different treatment modalities. The dentures were touched and sectioned and then retouched to a variety of microbiological media. The quantity of microbial growth was recorded and predominating microorganisms were identified using standard microbiological techniques. System A was found to consistently decontaminate and sanitize dentures worn by patients. System B and System C showed variable reduction of microorganisms. An unexpected spectrum of both pathogenic and opportunistic microorganisms was found in the dentures examined, including a wide range of gram-negative bacteria, gram-positive bacteria, and yeasts. A wide range of microorganisms must be considered when treating either oral or systemic diseases in denture wearers. Denture hygiene and decontamination are critical to the prevention of oral and systemic disease transmission. The dentures of ill patients must be considered as possible sources of pathogenic microorganisms.

Isolation of Candida species from the oral cavity and fingertips of complete denture wearers

STATEMENT OF PROBLEM

Candida species usually colonize in the oral cavity of denture wearers and may also colonize on their fingers because of frequent manual manipulation of the dentures.

PURPOSE

This study investigated the association between oral and fingertip candidal isolation in a group of denture wearers.

MATERIAL AND METHODS

Oral rinse and fingerprints obtained from 25 healthy male complete denture wearers were microbiologically investigated for candidal growth, and isolated Candida species were identified with a germ tube test and a commercially available yeast identification system. Denture cleanliness, hand washing, and denture wearing and handling habits were recorded for each subject.

RESULTS

Candida species were isolated from the oral cavity of 15 (60%) and fingertips of 11 (44%) subjects. Ten (66.7%) subjects had concomitant oral and fingertip candidal isolation, whereas 5 (33.3%) subjects had only oral Candida (P=.005).

CONCLUSION

The hands of denture wearers who had oral Candida were significantly more colonized with Candida species than oral Candida-free subjects. Further studies identifying Candida species to the strain level and the significance of hand Candida as a source for mouth reinfection are needed.

Respiratory pathogen colonization of the dental plaque of institutionalized elders

Although it has been established that aspiration of pharyngeal bacteria is the major route of infection in the development of nosocomial pneumonia, colonization of the pharyngeal mucosa by respiratory pathogens has been shown to be a transient phenomenon. It has been suggested that the dental plaque may constitute an additional, possibly more stable, reservoir of respiratory pathogens. The purpose of this study was to assess the prevalence of oral colonization by potential respiratory pathogens in a group of elderly (mean age = 75.9 yrs) chronic-care-facility residents (n = 28) and a group of age-, gender-, and race-matched outpatient control subjects (n = 30), with specific attention to plaque present on tooth, denture, and oral mucosal surfaces. Plaque scores on teeth and dentures were significantly higher in the chronic-care-facility (CCF) subjects than in the dental outpatient control (DOC) subjects (PII 2.3 vs. 1.2 and denture plaque 1.4 vs. 0.3). While no subjects in the DOC group were found to be colonized with respiratory pathogens (> 1.0% of the cultivable aerobic flora), 14.3% (4/28) of the CCF subjects were found to be colonized. Oral colonization with respiratory pathogens in CCF subjects was associated with the presence of chronic obstructive pulmonary disease (COPD) and higher plaque scores. These results suggest that deficient dental plaque control and the presence of COPD may be related to respiratory pathogen colonization of dental plaque in chronic-care-facility residents.

A review of in vitro and in vivo methods to evaluate the efficacy of denture cleansers

PURPOSE

This review summarizes the methods employed to evaluate denture cleansers and makes some suggestions on the methodology of evaluation.

MATERIALS AND METHODS

More than 20 articles evaluating the efficacy of denture cleansers were compared, and the advantages and disadvantages of each method were evaluated.

RESULTS

The results obtained vary depending on the methods used to evaluate the efficacy of denture cleansers, particularly among in vitro and in vivo assays. In addition, it is pointed out that chemical denture cleansers are not as efficacious in clinical use as in the in vitro assay. The uncertainty over efficacy may be caused by nonstandardized methodology and reports of conflicting results.

CONCLUSION

A standardization of the methodology is needed. This should include evaluation of the efficacy of cleansers through both in vivo and in vitro assay methods; standardization of the materials and methods used in studying the efficacy of denture-cleansing regimens; and the examination of not only selected microorganisms from limited surface areas of a denture, but the microorganisms in denture plaque from the whole surface of a denture. It would also be preferable to use methods and/or media that make it possible to not only qualify but also quantify the microbial plaque.

Disinfection of denture base acrylic resin

STATEMENT OF PROBLEM

During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected.

PURPOSE

This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins.

MATERIAL AND METHODS

Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses.

RESULTS

Viable microorganisms still remain on the internal and external surfaces of treated resins.

CONCLUSION

Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

The effect of bioburden on in-depth disinfection of denture base acrylic resin

This study evaluated the effectiveness of three different disinfectant solutions against denture bioburden absorbed within the depth of acrylic resin. Specimens were taken from dentures that had been worn by the patients for 15 to 20 years and were scheduled for replacement.

The effect of prosthesis disinfection on salivary microbial levels

The aim of this study was to evaluate how the soaking of dentures in a disinfection solution affects salivary microbe counts and stomatitis of partially dentate patients. Patients soaked their dentures for 4 weeks randomly both in a disinfection solution and in a placebo solution. Mutans streptococci, lactobacilli and yeast counts were measured before and after each test period and also the flow rate, buffer capacity and pH of saliva were registered. Disinfection decreased all microbe levels investigated, but only lactobacilli counts decreased significantly. Placebo treatment had either no effect on salivary microbe counts or they increased slightly. Disinfection caused some reduction of the mucosal inflammation under the denture base, but could not completely remove stomatitis during the 4-week test period.

The prevalence of Candida albicans populations in the mouths of complete denture wearers

Using imprint cultures, the prevalence of oral candidosis and the frequency of isolation of Candida albicans and its density in oral mucosal sites and denture surfaces was determined in 190 healthy dentate subjects and 230 complete denture wearers. Candida colonization was 36.8% and 78.3% in healthy dentate and complete denture wearers patients, respectively. In the healthy dentate subjects the tongue, palate and cheeks, and in complete denture wearers additionally the upper and lower dentures, were the most frequently and densely colonized oral sites. Oral carrier rate and density of C. albicans were both higher in the denture wearers diabetic group than in the control non-diabetic group. Smoking was associated with an increase in the frequency and density of the yeast in denture wearers. Attention to these predisposing factors could reduce the incidence of oral candidosis particularly in immunocompromised patients.

Isolation of Enterobacteriaceae from the mouth and potential association with malodor

Bad breath is a common phenomenon, usually the result of bacterial metabolism in the oral cavity. It is generally accepted that Gram-negative bacteria are responsible for this problem, largely through degradation of proteinaceous substances. In initial experiments, screening of malodorous isolates following outgrowth of samples obtained from saliva, periodontal pockets, and the tongue dorsum yielded enterobacterial isolates. Clinical studies were conducted to examine the prevalence of such bacteria in four different populations: orthodontic patients, malodor clinic patients, complete-denture wearers, and a healthy young population. The prevalence of Enterobacteriaceae in the oral cavities of the denture-wearing population was very high (48.0%) as compared with the other groups: 27.1% in the malodor clinic patients, 16.4% in the normal population, and 13% among orthodontic patients. Isolates of Klebsiella and Enterobacter emitted foul odors in vitro which resembled bad breath, with concomitant production of volatile sulfides and cadaverine, both compounds related to bad breath. When incubated on a sterile denture, enterobacterial isolates produced typical denture foul odor. Isolates exhibited cell-surface hydrophobic properties when tested for adhesion to acryl and aggregation with ammonium sulphate. The results, taken together, suggest that Klebsiella and related Enterobacteriaceae may play a role in denture malodor.

Existence of Candida albicans and microorganisms in denture stomatitis patients

The aetiology of denture stomatitis is not clear from the literature. Some studies show its aetiology as Candida albicans, while other reports point out the significance of microorganisms. In this study the existence of C. albicans and microorganisms was investigated in subjects with and without denture stomatitis. The results showed that a combination of C. albicans and microorganisms is more likely to be responsible for denture stomatitis.

Aetiology of denture stomatitis

The purpose of this study was to determine the etiologic factors of denture stomatitis. Fifteen subjects with clinical evidence of localized simple denture stomatitis, fifteen subjects without clinical signs of denture stomatitis, and forty-five subjects with clinical evidence of generalized simple denture stomatitis were investigated clinically and mycologically. Subjects were evaluated according to age, sex, duration of denture usage, smoking habits, frequency of denture brushing, overnight denture wearing, pH level of saliva and degree of candidal colonization and candidal formation. Salivary samples and swabs were taken from the palate and the mucosal surfaces of the dentures investigated mycologically in order to identify the yeast colonies. Smears were taken from the palate and investigated in order to identify candidal formation. No statistically significant relationship was found between denture stomatitis and age, sex, duration of denture usage, frequency of denture brushing, overnight denture wearing or pH level of saliva. There was however, a statistically significant relationship between denture stomatitis and denture hygiene, smoking habits, candidal colonization and candidal formation.

Early microbial colonization of permucosal implants in edentulous patients

In edentulous patients, the microbial colonization of permucosal implants of sintered hydroxyapatite was studied. Samples were taken from mucosa and dentures before insertion of implants and from supra- and subgingival sites two to 10 weeks after insertion. In total, five patients and 10 implants with clinically healthy peri-implant tissues were studied. The samples were investigated by dark-field microscopy and anaerobic culture. The supragingival plaque of the implants was dominated by Gram-positive cocci and rods, the subgingival plaque by Haemophilus spp. and Veillonella parvula. A group of bacteria was found specifically related to the implants: Actinomyces odontolyticus, Peptostreptococcus micros, Haemophilus actinomycetemcomitans, Eikenella corrodens, Capnocytophaga sputigena, and Leptotrichia buccalis. Black-pigmented Bacteroides was not found in any of the examined samples. Spirochetes were observed in denture plaque samples and in supragingival plaque of the implants. It is concluded that bacteria known as potential periodontal pathogens colonize the permucosal implants in the first weeks after insertion. The presence of these species seems to be dependent on the ecological factors provided by the artificial gingival crevice of the permucosal implants in the edentulous mouth.