Mustafa Ates

Long-Term Antibacterial Effects and Physical Properties of a Chlorhexidine- Containing Glass Ionomer Cement

STATEMENT OF THE PROBLEM Many regions in the world do not have electricity, water, or access to dental facilities that allows the treatment of caries with dental handpieces and rotary burs. For restorative techniques used in these regions, an antibacterial self-adherent glass ionomer material would contribute considerably. PURPOSE This study aimed to test if chlorhexidine diacetate (Fluka BioChemika, Buchs, Switzerland)- or chlorhexidine digluconate (Sigma-Aldrich, Steinheim, Germany)-added ChemFil Superior glass ionomer cement (Dentsply DeTrey, Konstanz, Germany) had any long-term antibacterial effect against certain oral bacteria and to test the new formulations physical properties. MATERIALS AND METHODS ChemFil Superior was used as a control. Chlorhexidine diacetate (powder) was added to the powder and chlorhexidine digluconate (liquid) was mixed with the powder in order to obtain 0.5, 1.25, and 2.5% concentrations of the respective groups. Setting time, compressive strength, and acid erosion were tested according to ISO 9917-1. Working time, hardness, diametral tensile strength, and biaxial flexural strength were also determined. Long-term antimicrobial activity against S. mutans, L. acidophilus, and C. albicans were tested with the agar diffusion method. Analysis of variance (ANOVA) was used for comparison (p < 0.05). RESULTS Regarding the immediate antibacterial effect for S. mutans, all the tested groups showed inhibitions of the strain compared with the control group (p < 0.05), with larger zones for the higher concentration groups and all the diacetates. For L. acidophilus, all the groups were effective compared with the control, but the greatest antibacterial effect was observed with the 2.5% diacetate group. The 2.5% group of chlorhexidine diacetate showed antibacterial activity up to 90 days against S. mutans and up to 60 days against L. acidophilus. The working and setting time, acid erosion test, diametral tensile strength, and biaxial flexural strength of the tested groups were not different from the control ChemFil group. However, the 1.25 and 2.5% groups of chlorhexidine diacetate had significantly lower compressive strengths than the control group. Lower hardness values were obtained with the 0.5 and 2.5% chlorhexidine digluconate groups in comparison with the control group. CLINICAL SIGNIFICANCE The results of this in vitro investigation demonstrated that chlorhexidine diacetate or digluconate added to the ChemFil Superior glass ionomer material can exhibit long-term antibacterial effects against S. mutans and L. acidophilus without compromising the physical properties of the material.

Characterization of the phenolic composition and antimicrobial activities of Turkish medicinal plants

In this paper, antibacterial and antimycobacterial activity of five Labiatae plant methanol extracts, commonly used for treating cold, stomachache, and sore throat, Salvia fruticosa Mill., Salvia tomentosa Mill., Sideritis albiflora Hub.-Mor. (endemic), Sideritis leptoclada O. Schwarz & P.H. Davis, (endemic), and Origanum onites L., were investigated, and their phenolic compounds were determined by HPLC. Antibacterial activity was analyzed against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Enterobacter aerogenes, and Klebsiella pneumoniae. Antimycobacterial activity was assayed against Mycobacterium tuberculosis. The best antibacterial activity (MIC 640 μg/mL) was shown against S. typhimurium and E. aerogenes by S. fruticosa; E. coli, and S. typhimurium, E. aerogenes by S. tomentosa; S. typhimurium, and E. aerogenes by S. leptoclada and S. typhimurium, E. aerogenes and S. epidermidis by O. onites, respectively. The best antimycobacterial activity (MIC 196 μg/mL) was shown by S. tomentosa. S. fruticosa (MIC 392 μg/mL) and O. onites (MIC 784 μg/mL) showed moderate activity against M. tuberculosis. S. albiflora, with low level rosmarinic acid and carvacrol content, showed inhibition against bacteria except K. pneumoniae, B. cereus and M. tuberculosis. The correlation between in vitro activity and ethnobotanical usage was evaluated.

In vitro antimicrobial effects of commercially available mouth-wetting agents.

Products have been developed to provide palliation for persons with dry mouth. In addition to mouth-wetting agents, some products incorporate antimicrobial constituents with the goal of improving oral microbial defenses. The aim of this in vitro study was to investigate the potential antimicrobial and antifungal effects of two commercially available saliva substitutes on Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans by using the agar-well diffusion method. Antimicrobial activity as measured by the size of the inhibition zone growth for S. mutans and L. acidophilus was observed only with Biotene Dry Mouth Oral Rinse® and BioXtra® gel. The zone of inhibition of Biotene Dry Mouth Oral Rinse was larger than that of BioXtra gel (p= 0.00, p < 0.01). No anticandidal effect was seen with any of the test products. The pH of the preparations, the variations between the amount of active ingredients within the products, and the potential antimicrobial effects of inactive ingredients should be investigated to determine the factors that impacted microbial inhibition.

The effect of treatment of radicular dentin on colonization patterns of C. albicans

OBJECTIVE The aim of this study was to observe the colonization pattern of C. albicans on treated and untreated radicular dentin. STUDY DESIGN Root sections of 10 human mandibular premolar teeth were longitudinally separated into halves. The 20 halves were separated into 2 groups and each half served as its own control. In Group 1, only gross pulpal remnants were removed with pliers. Root canal walls in the corresponding 102 halves (Group 2) were instrumented with Gates-Glidden burs and treated with sequential use of 15% EDTA solution for 3 minutes and 2.5% NaOCl solution for 3 minutes. Finally, all teeth were washed with distilled water. Each specimen was placed individually in each well of a 24-well cell culture plate. After the assembly was sterilized with ethylene-oxide, the root canal of each specimen was inoculated with 20 microL of C. albicans (1-1.5 x 10(6) cfu/mL) that was kept in place for 24 hours for initial attachment. Then, 2 mL of SDB was added to each well and the assembly was placed in an incubator at 37 degrees C for 10 days. Following the incubation period, the specimens were washed, fixed, dehydrated, and processed for scanning electron microscopy. RESULTS C. albicans was present on the root canal surfaces of all specimens; however, the colonization pattern was different. In the untreated group, the main growth pattern was a dense mass of yeast cells forming biofilm layers while hyphal structures were not common. On the other hand, pseudohyphae invaded all root canal surfaces in Group 2 and yeast cells were occasionally observed. CONCLUSION The treatment procedures of root canal dentin have a strong influence on the colonization pattern of C. albicans. This fact should be considered when planning and evaluating in vitro Candida adhesion and/or penetration studies.

Effects of different antibacterial agents on enamel in a biofilm caries model

Using a mature biofilm model, the aim of this study was to evaluate the effectiveness of different antibacterial agents in comparison with silver diamine fluoride (SDF). Forty-eight saliva-coated enamel slabs were inoculated with Streptococcus mutans monospecies biofilm. The biofilms were then exposed to 10% sucrose in tryptone yeast-extract culture medium, 8 times per day for 7 days. After the biofilm growth period, the enamel slabs were treated with one of the following substances: 1) distilled water; 2) SDF; 3) acidulated phosphate fluoride (APF); 4) ammonium hexafluorosilicate (AHF); 5) ammonium hexafluorosilicate + cetylpyridinium chloride (AHF+CPC); or 6) 0.2% chlorhexidine (CHX). After these treatment procedures, the samples were incubated at 37ºC for 2 days, and the numbers of viable microorganisms in the biofilms were counted. The number of viable bacteria was significantly reduced by all of the antibacterial agents (P < 0.05). However, SDF showed the highest antibacterial activity (P < 0.05), and the effectiveness of the other agents was lower (P < 0.05). SDF has a highly effective antibacterial action against cariogenic Streptococcus mutans biofilm; none of the other fluoride agents used in this study, or 0.2 CHX agent, showed an antibacterial effect comparable to that of SDF.

Specific identification ofCandida albicans andCandida dubliniensis by PCR using species-specific primers

The aim of our study was to evaluate the effectiveness of phenotyping and genotyping methods for the identification ofCandida albicans andCandida dubliniensis. Phenotyping methods used are colony colour on CHROMagar Candida medium, growth at 45°C, TTC (2,3,5-triphenyl-tetrazolium chloride) reduction, germ tube and chlamydospores formation, and API 20C AUX. We also usedC. albicans andC. dubliniensis specific primers for identification performed with genotyping methods. DNAs ofC. albicans reference strains, differentCandida species,Cryptococcus neoformans, mycelial fungi, bacterial strains and human DNA were used as a template in order to evaluate the specificity of the primers. These primers yielded a 175-base-pair product only whenC. albicans DNA exists; however when other DNAs (except two isolates that are phenotypically identified asC. dubliniensis andC. tropicalis) exist no product appeared. In another PCR assay conducted by usingC. albicans DNA andC. dubliniensis specific primers, no product was observed.Candida albicans andC. dubliniensis specific primers were designed by Mannarelli and Kurtzman. Detection limit ofC. albicans primers was found to be 19 pg chromosomal DNA. In order to verify phenotypical definition with PCR amplification,C. albicans andC. dubliniensis specific primers were exposed to PCR by using DNAs that belong to 25 phenotypically defined oralCandida isolates.

Microbiological analysis of stuffed mussels sold in the streets.

Stuffed mussel is a traditional food that sold by street venders in various countries. In the present study, samples of stuffed mussels were collected from various places in Ankara. The mussels were analyzed to show the microbiological risks for human health. Thirty samples (600 stuffed mussels in total) were collected periodically and microbiological analyses were performed by standard procedures for Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella sp., Clostridium sp. In terms of Salmonella sp., approximately 50% of samples were not suitable for consumption. Besides, in accordance with Turkish Food Codex Microbiological Criteria Announcement in terms of E. coli 30%, in terms of B. cereus 80%, in terms of S. aureus 76.6%, in terms of Clostridium perfringens 13.3% of these samples were not suitable for consumption. The aim of this study is to discuss the microbiological quality of stuffed mussels as a ready-to-eat food according to Turkish Food Codex (TFC). The result of this investigation indicates that stuffed mussels as a street food may constitute a potential health hazard, depending on contamination level and lack of sanitary practices, and therefore, handling practices should require more attention and improvement.

Are antibacterial component additions in etchants and adhesives effective against Streptococcus Mutans

Abstract The aim was to investigate the antibacterial activity of various acids and adhesives with and without antibacterial components against Streptococcus mutans. The antibacterial activities of 35% phosphoric acid (Ultra-Etch), 37% phosphoric acid with benzalkonium chloride (Etch-37), adhesive with chlorhexidine (Peak Universal Bond) and without any agent (PQ1) were investigated by agar-diffusion test. The inhibition-zones were measured after 48 h of incubation. For the tooth-cavity model test; cylindrical cavities were prepared on occlusal dentin surfaces of human molars and divided into four groups (n = 10 cavity/group). Group 1: Ultra-Etch + Peak Universal Bond, Group 2: Ultra-Etch + PQ1, Group 3: Etch-37 + PQ1 were applied. The fourth group without any agent application served as control. The teeth were immersed in 5.8 × 106 cfu/ml of S. mutans solution to infect the cavities for 72 h before the application of the groups. After 72 h, dentin chips were collected from the cavity walls with burs for bacterial counting. Statistical analysis was performed by ANOVA, Bonferroni and Dunnett C tests (p < 0.05). Ultra-Etch and Etch-37 performed similar antibacterial activities in agar-diffusion test. Both acids showed better antibacterial activity compared to adhesives (p < 0.05). The antibacterial activity of PQ1 and Peak Universal Bond was observed to be inactivated by light-polymerization. According to the tooth-cavity model; Group I, II, and III demonstrated reduction in bacterial number and there was no significant difference between them. Antibacterial component additions in etchant and adhesive did not show superior antibacterial activity against S. mutans in both in vitro tests.

Comparison of real-time PCR and conventional cultural methods to detect Escherichia coli O157:H7 in spices in Turkey

In this study, 66 different spice samples were analyzed in order to compare Real-Time PCR and conventional cultural methods for the detection of E. coli O157:H7 in spices. Thus, 66 different spice samples (raw materials) were collected from various places in Izmir, Turkey. Conventional cultural methods included pre-enrichment step, selection step and confirmation step. The molecular method included two steps: pre-enrichment and Real-Time PCR step. Beside these methods, total aerobic mesophilic bacteria, coliform, fecal coliform in samples, were also counted and the presence of Salmonella sp. was investigated in order to determine total microbial load in samples. The results showed that aerobic mesophilic bacteria counts were 5.1x103 -2.0x108 CFU/g, coliform counts were 8.0 x 102 CFU/g for the average values of all samples. Salmonella sp. was not found in any of the samples.In four samples E. coli O157:H7 positive by Real-Time PCR were found while all of the samples were negative by cultural methods. We observed that the results of Real-Time PCR were more reliable than conventional methods. Furthermore, the results were obtained in only 20 hours by Real-Time PCR method whereas conventional cultural method was completed in 4 days. Keywords: Cultural method, E. coli O157:H7, real-time PCR, spice