Gülçin Akca

Antibacterial Activity of Propolis versus Conventional Endodontic Disinfectants against Enterococcus faecalis in Infected Dentinal Tubules

INTRODUCTION The antibacterial activity against Enterococcus faecalis of 2 propolis samples was investigated in a dentin block model, and their effectiveness was compared with that of established endodontic disinfectants, chlorhexidine (CHX) and calcium hydroxide [Ca(OH)(2)]. METHODS Standardized dentin blocks were infected with E. faecalis ATCC 29212. The root canal space was filled with one of the ethanolic extracts of propolis (Artvin or Tekirdağ mix [TM]), CHX 2%, Ca(OH)(2), or ethanol or phosphate-buffered saline for control. Canal dentin was sampled after 1 or 7 days by using a standard-size bur. The dentinal shavings were vortexed vigorously in phosphate-buffered saline, and aliquots were cultured on tryptone soy agar plates. Colonies were counted after 2 days of incubation. Statistical significance was set to 5%. RESULTS All experimental agents significantly reduced the number of the cultivable bacteria. CHX was the most potent disinfectant at both times. Compared with the ethanol control, no significant reduction in the number of colonies was found for the propolis extracts at day 1; however, significant reduction was found at day 7. The 2 propolis samples were statistically similar to each other and to Ca(OH)(2), but the TM sample was also similar to CHX at day 7. This has been linked to the greater concentration of flavonoids, a group of antibacterially active compounds, in the TM sample as determined by gas chromatography-mass spectrometry analysis. CONCLUSIONS The antimicrobial activity of the propolis samples tested in this study was between Ca(OH)(2) and CHX. Both propolis samples were antimicrobially effective; however, their activity did not exceed CHX.

The role of hemagglutination and effect of exopolysaccharide production on bifidobacteria adhesion to Caco-2 cells in vitro.

It is believed that an important criterion for a potential probiotic strain is that it is capable of adhering to mucosal surfaces in the human gastrointestinal tract. The purpose of this study was to investigate a possible relationship between exopolysaccharide production and adhesion to Caco‐2 cells by Bifidobacterium breve A28 and Bifidobacterium bifidum A10. In a preselection process, the hemagglutination abilities of these bacteria were determined prior to undertaking adhesion studies. B. breve A28, which produces large amounts of EPS (97.00 ± 2.00 mg/l) and has good hemagglutination abilities (+3) was found to adhere strongly to Caco‐2 cells. Under gastrointestinal conditions, the high EPS producing‐ B. breve A28 was found to have better viability and adhesion to Caco‐2 cells than the low EPS producing‐ B. bifidum A10. Also, B. breve A28 was found to be more effective at inhibiting Escherichia coli ATCC 11229 than B. bifidum A10. This investigation showed that high EPS production and adhesion ability may be important in the selection of bifidobacteria as probiotic strains.

Short-term antimicrobial properties of mineral trioxide aggregate with incorporated silver-zeolite

The purpose of this in vitro study was to determine whether adding silver-zeolite (SZ) to mineral trioxide aggregate (MTA) would enhance the antimicrobial activity of MTA against Staphylococcus aureus (ATCC #25923), Enterococcus faecalis (ATCC #29212), Escherichia coli (ATCC#25922), Pseudomonas aeruginosa (ATCC #27853), Candida albicans (ATCC #90028), Porphyromonas gingivalis (ATCC #33277), Actinomyces israelii (ATCC #12102), and Prevotella intermedia (ATCC# 15032). SZ was added at 0.2% and 2% mass fraction concentration to MTA powder. The control group was MTA powder with no SZ. The antimicrobial effect test was accomplished by placing freshly mixed MTA specimens on agar plates inoculated with microorganisms and comparing the zones of inhibition at 24, 48, and 72 h. The amounts of silver ion release from MTA specimens were measured with atomic absorption spectrophotometry at 10-min, 24-, 48-, and 72-h periods. The pH of MTA specimens was measured with a pH meter at 10-min, 24-, 48-, and 72-h periods. MTA with 2% and 0.2% SZ specimens showed inhibitory effects on some microorganisms at all time periods, whereas no antimicrobial activity showed for P. intermedia and A. israelii. MTA without SZ inhibited C. albicans, E. Coli, and P. intermedia. The highest silver release was detected in 2% SZ MTA at 24 h. The incorporation of SZ may enhance the antimicrobial activity of MTA.

Effect of timing of glutamine-enriched enteral nutrition on intestinal damage caused by irradiation.

Intestinal mucosal damage and bacterial translocation are clinical problems that may be caused by the use of ionizing radiation. Glutamine (Gln) support reduces the mucosal barrier in several ways. This study was undertaken to investigate the effect of timing of Gln-enriched enteral nutrition (EN) on bacterial translocation and mucosal damage due to radiotherapy (RT). A rat model of whole body irradiation was designed in which a single dose of 485 cGy was given. A total of 50 rats were randomly assigned to the following 5 groups, each of which comprised 10 rats: (1) balanced rat chow given for 8 days without RT (group 1); (2) balanced rat chow given 4 days before and 4 days after RT (group 2); (3) Gln-enriched EN given 4 days before RT (group 3); (4) Gln-enriched EN given 4 days after RT (group 4); and (5) Gln-enriched EN given 4 days before and 4 days after RT (group 5). Mesenteric lymph node and ileum samples were removed for evaluation of bacterial translocation (BT) and histopathologic investigation, respectively. BT and intestinal mucosal injury scores in all rats that received RT were higher than in rats without RT. No difference was seen in parameters between groups 3 and 4 (P>.05, P>.016, respectively); BT and intestinal mucosal injury scores of group 5 were significantly lower than those of groups 3 and 4 (P<.05, P<.016, respectively). Meanwhile, the BT and mesenteric injury scores of group 5 were significantly lower than those of group 2 (P<.05, P<.016, respectively). As a result, intestinal injury due to RT was significantly decreased by Gln-enriched EN support given before and after whole body RT.

Antibacterial effect of a new haemostatic agent on oral microorganisms.

Objective: The purpose of this study was to determine the antibacterial effect of a newly developed haemostatic agent Ankaferd Blood Stopper® (ABS) and Ferric Sulphate (FS) on various oral microorganisms. Study design: Bacterial strains were freshly incubated in their specific broth media. For each of the strains, 3 wells per each agent, with a 5 mm diameter were made under aseptic conditions in the specific agar media. Then they were filled with a test agents or 0.2% chlorhexidine digluconate (CHX) (control group). After 24h and 48h incubation periods, inhibition zones were measured. Results: ABS showed antibacterial effect on all test microorganisms except Lactobacillus acidophilus and Lactobacillus salivarius. Ferric sulphate and CHX have antibacterial effect on all microorganisms. When the test agents compared, the inhibition zones of the ABS were found smaller than the ferric sulphate and CHX. Conclusions: Although ferric sulphate and ABS have antibacterial effect, ferric sulphate had better antibacterial activity than ABS on oral microorganisms under in vitro condition. FS and ABS not only exhibit the haemostatic activity but also antimicrobial activity. Key words:Ankaferd blood stopper, ferric sulphate, haemostatic agent, haemostasia, bleeding, bactericide.

Influence of thermoplastic retainers on Streptococcus mutans and Lactobacillus adhesion

INTRODUCTION This study was designed to test the hypothesis that thermoplastic retainers influence oral microbial flora during the retention period because they prevent the flushing effect of saliva on dental and mucous tissues. METHODS Twenty-four orthodontic patients finished the study. After debonding, the patients were given thermoplastic retainers (Essix ACE 0.040-in plastic, Dentsply International, York, Pa) for both jaws and instructed to wear them all day. Plaque samples from tooth surfaces and saliva samples were collected from each patient just after debonding (T0), and on day 15 (T1), day 30 (T2), and day 60 (T3) of retention. The jaws were divided into 6 regions, and the data for each region were evaluated separately. Total viable Lactobacillus and Streptococcus mutans colonies were counted, and the numbers of the viable microorganisms were calculated. RESULTS The numbers of Lactobacillus colonies at T3 were higher than at T0, T1, and T2, and the difference between T0 and T3 was statistically significant (P <0.05). The numbers of S mutans colonies at T3 were higher than at T0, T1, and T2, and the differences between T0 and T1, and T1 and T2 were statistically significant (P <0.05). CONCLUSIONS Retention with thermoplastic retainers might create oral conditions conducive to S mutans and Lactobacillus colonization on dental surfaces.

Influence of gastrointestinal system conditions on adhesion of exopolysaccharide-producing Lactobacillus delbrueckii subsp. bulgaricus strains to caco-2 cells

This study aimed to assess the transit tolerance of potential probiotic dairy Lactobacillus strains in human uppergastrointestinal tract in vitro, and to evaluate the effect of EPS production on the viability and adhesion of these strains. Survival and adhesion of two exopolysaccharide (EPS)-producing L. delbrueckii subsp. bulgaricus strains (B3 and B2) and E. coli ATCC11229 were assessed after the exposure of different pH (gastric juice) and gastric plus pancreatic juice challenges. In the artificial gastric juice (pH 2), both the viability of the strain B3 and B2 was decreased. Artificial juice treatments significantly reduced the adhesion to caco-2 cells (P< 0.05). High EPS-producing B3 survived better in the adverse gastrointestinal conditions and showed better ability of adhesion to Caco-2 cells when assessed for competition with E. coli ATCC 11229 compared to low EPS-producing B2. This investigation showed that EPS production could be affected or be involved in the viability, adherence and competition of L. delbrueckii subsp. bulgaricus strains and support the potential of B3 strain for development of new probiotic products.

The Effect of Platelet Activating Factor Antagonist BN 52021 on Bacterial Translocation and ICAM-I Expression in Experimental Obstructive Jaundice

Expression of intracellular adhesion molecule-1 (ICAM-1) in an obstructive jaundice model and the potential protective role of platelet activating factor antagonist over small intestine and liver together with its effects on bacterial translocation are examined in this study. Forty-eight male Wistar albino rats were assigned into four equal groups of 12. In groups I and II, animals were sham operated. In groups III and IV, common bile duct ligation and division were performed. In group I and group III, 0.5 ml/day normal saline was applied intraperitoneally daily from day 2 to 6 of the study; in group II and group IV, 1 mg/kg/day BN 52021 was applied intraperitoneally daily from day 2 to 6 of the study. All animals were sacrificed on postoperative day 7. ICAM-1 expression (CD54 positivity) was analyzed in the liver and ileum tissue by immunohistochemical method. Samples from blood, liver mesenteric lymph nodes, and spleen were cultured under aerobic conditions. It is revealed that ICAM-1 expression was statistically higher in group III, with highest bacterial translocation and liver and spleen injury when compared to other groups. Serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), gamma-glutamyltranspeptidase (GGT), bilirubin, tumor necrosis factor α (TNFα), and interleukin 1β(IL-1β) values were at the highest level in group III, and there was a statistical decrease in group IV compared to group III. The administration of BN52021 in experimental obstructive jaundice is a useful way to reduce liver and intestinal mucosal villi damage by inhibiting bacterial translocation and systemic inflammatory response.

Effectiveness of Alternative Methods for Toothbrush Disinfection: An In Vitro Study

Objective. This study aimed to evaluate the effectiveness of alternative methods for toothbrush disinfection. Methods. Two-hundred eighty toothbrushes were included in the study. The toothbrushes were divided into 7 groups and were contaminated by standardized suspensions of Lactobacillus rhamnosus (L. rhamnosus), Streptococcus mutans (S. mutans), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The following disinfectants were tested: 1% sodium hypochlorite (NaOCl), 100% and 50% white vinegar, microwave (MW) oven, ultraviolet (UV) sanitizer, and mouth rinse-containing propolis (MCP). Data were analyzed with Kruskal Wallis and Dunns tests. Results. Statistically significant differences were found between different methods and control group for all tested bacteria. There were statistically significant differences between all test groups for all microorganisms. MW was the most effective for L. rhamnosus and 100% white vinegar was the most effective method for S. mutans and S. aureus. NaOCl was the most effective for E. coli. Conclusion. This study showed that 100% white vinegar was considered to be effective for tested microorganisms. Similarly, 1% NaOCl is cost-effective, easily accessible, and comparatively effective for toothbrush disinfection. Because these agents are nontoxic, cost-effective and easily accessible, they may be appropriate for household use.

In Vitro Antifungal Evaluation of Seven Different Disinfectants on Acrylic Resins

Objective. The aim of this study was to evaluate alternative methods for the disinfection of denture-based materials. Material and Methods. Two different denture-based materials were included in the study. Before microbial test, the surface roughness of the acrylic resins was evaluated. Then, the specimens were divided into 8 experimental groups (n = 10), according to microorganism considered and disinfection methods used. The specimens were contaminated in vitro by standardized suspensions of Candida albicans ATCC#90028 and Candida albicans oral isolate. The following test agents were tested: sodium hypochlorite (NaOCl 1%), microwave (MW) energy, ultraviolet (UV) light, mouthwash containing propolis (MCP), Corega Tabs, 50% and 100% white vinegar. After the disinfection procedure, the number of remaining microbial cells was evaluated in CFU/mL. Kruskal-Wallis, ANOVA, and Dunns test were used for multiple comparisons. Mann Whitney U test was used to compare the surface roughness. Results. Statistically significant difference (P < 0.05) was found between autopolymerised and heat-cured acrylic resins. The autopolymerised acrylic resin surfaces were rougher than surfaces of heat-cured acrylic resin. The most effective disinfection method was 100% white vinegar for tested microorganisms and both acrylic resins. Conclusion. This study showed that white vinegar 100% was the most effective method for tested microorganisms. This agent is cost-effective and easy to access and thus may be appropriate for household use.