Biomedical subjects

H Nikawa

Publications and source records attributed to H Nikawa.

61 records · Page 4Linked to original sources

PubMedDate not supplied

Exposure to subtherapeutic concentrations of polyene antifungals suppresses the adherence of Candida species to denture acrylic.

BACKGROUND: The adherence of Candida species to denture acrylic is the initial event leading to Candida-associated denture stomatitis, with Candida albicans being the main aetiological agent. However, the increased incidence of immunocompromised patients in the community has resulted in the emergence of a number of non-albicans Candida species as causative agents of this disease, which is commonly managed by topically delivered polyene antifungals. Hence, we investigated the effect of the exposure of denture acrylic surfaces to nystatin and amphotericin B on the subsequent adhesion of six different Candida species. METHODS: Acrylic strips were exposed to subtherapeutic concentrations of the two polyenes for 30 min, and the adhesion of 4 isolates each of C. albicans, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis was assessed using a previously described in vitro method with slight modifications. RESULTS: Overall, the results indicated a 35.9% (p < 0.01) and 63.1% (p < 0. 01) reduction, respectively, in yeast adhesion to denture acrylic following exposure to nystatin and amphotericin B, although this effect was not uniform for all the tested isolates. Thus, all C. glabrata, 3 C. guilliermondii and a single isolate each of C. krusei, C. parapsilosis and C. tropicalis were not significantly affected by nystatin exposure, and a single isolate each of C. glabrata and C. guilliermondii were not significantly affected by amphotericin B. CONCLUSIONS: The present data, the first on the effect of polyenes on a wide range of Candida species, indicate that the in vitro exposure of denture acrylic to subtherapeutic concentrations of nystatin and amphotericin B suppresses the adherence of pathogenic Candida species in general.

Acrylic Resins↗

PubMedDate not supplied

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.

Dental Plaque↗

PubMedDate not supplied

Growth of Candida species on commercial denture adhesives in vitro.

PURPOSE: Although denture adhesives are widely used by the elderly, it is unknown whether denture adhesives support microbial growth. Therefore, we investigated the growth of Candida species on six commercial denture adhesives. MATERIALS AND METHODS: The growth of a single isolate of C albicans and C tropicalis on six commercial denture adhesives was investigated by monitoring pH changes in growth media. RESULTS: In the preliminary study, the effect of each product on the pH value of the medium was examined; a single product itself significantly reduced the pH of medium below 5.0. When the yeast was grown on the materials, the pH changes in the media varied depending on the adhesive materials and, to a greater or lesser extent, on whether they showed antifungal activity. Two products (Cushion Collect and Collect Soft A) significantly suppressed C albicans growth (P < 0.01), and one product (Collect Soft A) effectively reduced C tropicalis growth (P < 0.01). CONCLUSION: Our results suggest that denture adhesives possess antifungal activity to a greater or lesser degree. However, one product caused the reduction of pH below 5.0. Thus, in the daily use of denture adhesives, attention should be paid to both the materials and their microbiologic properties.

Acrylic Resins↗

PubMedDate not supplied

Perforation and proteinaceous contamination of dental gloves during prosthodontic treatments.

The effect of the type of prosthodontic treatment on glove perforation and proteinaceous contamination of gloves was investigated for 364 prosthodontic treatments using poly(vinyl chloride) plastic (218 occasions) and latex gloves (146 occasions). The amount of protein contamination on plastic or latex gloves varied depending on the prosthodontic treatment performed and the patient treated. As determined directly, it averaged from approximately 800 to 1,500 micrograms per treatment, and the maximum value of protein contamination was more than 4,000 micrograms, corresponding to the amount of protein in 1.5 mL of saliva or 0.1 mL of serum. The perforation of plastic gloves was observed in 83.0% of the total occasions, and the perforation went unrecognized 96.1% of the time. In contrast, the proportion of glove perforation for latex gloves was 12.3% and the proportion of unrecognized perforation of latex gloves was 5.4%. The results suggest that latex gloves are effective in reducing the risk of cross-infection. Nevertheless, prosthodontists still have a potential risk of being exposed to bodily fluids, without being aware of glove perforation, at least once in every 20 treatments, even if latex gloves are worn.

Blood Proteins↗

PubMedDate not supplied

Commercial denture cleansers--cleansing efficacy against Candida albicans biofilm and compatibility wit soft denture-lining materials.

Chemical cleansing has been suggested as one of the most effective methods for plaque control, particularly for resilient denture-lining materials. These materials are known to be easily colonized and infected by Candida albicans. Maintaining the cleanliness of such materials is difficult because of porosity and incompatibility with some types of denture cleansers. Therefore, denture cleansers used for soft liners must address both microbiologic and physical requirements. This study evaluated the antifungal efficacy of 11 commercial denture cleansers on C albicans biofilm, studied the compatibility of tissue conditioners with denture cleansers, and makes suggestions for the chemical cleansing of dentures lined with tissue conditioners.

Acrylic Resins↗

PubMedDate not supplied

Cleansing efficacy of commercial denture cleansers: ability to reduce Candida albicans biofilm activity.

A simple method to measure Candidal biofilm activity using pH change of Stomastat was developed and used to evaluate the efficacy of 11 commercial denture cleansers on Candida albicans biofilm. The initial number of yeasts inoculated correlated with the pH value of Stomastat after both 24- and 30-hour incubation periods (r=0.992; r=0.988, respectively; P<.01), which supported the method's validity. The ability of the cleansing agents to decrease fungal biofilm activity varied depending upon the components of the agents. In general, peroxide denture cleansers, a disinfectant, and one enzyme cleanser were more efficacious than the other types tested in this study.

Acrylic Resins↗

PubMedDate not supplied

Perforation of dental gloves during prosthodontic treatments as assessed by the conductivity and water inflation tests.

The incidence of latex glove perforation during prosthodontic treatment was investigated on 122 occasions using two methods, a conductivity test and a water inflation test. Latex glove perforation was detected in 38.5% of the treatments by the conductivity test and in 27.9% by the water inflation test. The perforation went unrecognized in 74.7% of the occurrences (35/47 incidents) using the conductivity test and in 64.7% (22/34) when the water inflation test was used. Of the total 55 glove perforations, 21 perforations were detected only by conductivity test, 3 were detected only by the water inflation test, and 31 perforations were detected by both methods, which suggested that the conductivity test is more sensitive than the water inflation test for the detection of glove perforation. The results of this research suggested that even when latex gloves are worn, the risk to prosthodontists of exposure to body fluids remains in four of every six treatments, often without the awareness of the prosthodontist.

Chi-Square Distribution↗