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ABSTRACT: To evaluate and observe the cellular reactions that occur during the interaction/integration between 2-hydroxyethyl methacrylate/host tissue/microbial environment, in a co-culture of human gingival fibroblasts (HGF) and Streptococcus mitis strains.
Streptococcus mitis were cultured with strains in the presence of 3 mmol L(-1) HEMA for 48 h and 72 h. Cytotoxicity was evaluated by the trypan blue dye exclusion test. Apoptosis was evaluated by TUNEL analysis. Adhesion was evaluated by immunofluorescence and western blot analyses. Quantitative analyses of the results were acquired by Qwin Plus 3.5 and QuantityOne I-D analysis software, respectively. The statistical significance of the results was evaluated using t-tests and linear regression tests.
The trypan blue dye test revealed 47.3% and 46.5% of dead fibroblasts after 48 and 72 h HEMA treatment, respectively, while bacterial viability was not influenced by the presence of HEMA and fibroblasts. The expression of pro-collagen I, involved in fibroblast adhesion, in untreated samples ranged from 12.49% to 6.91% of the positive area after 48 and 72 h, respectively, dropping to below 2% of the positive area in the other experimental conditions. Unlike the trypan blue test, co-cultured samples treated with HEMA showed 20% and 25% versus 17% and 21% (after 48 and 72 h, respectively) of apoptotic cells.
The evidence for HEMA toxicity and anti-adhesive effects against eukaryotic cells was reduced in the presence of bacteria, suggesting that dental resins should be well polymerized to avoid the spread of toxic monomers within the mouth.
International Endodontic Journal 09/2011; 44(12):1145-54. · 2.18 Impact Factor
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ABSTRACT: The aim of the present study was an in vivo evaluation of the wear of different sealing materials using the replication technique.
Four different sealing materials were randomly applied on 2 out of 4 caries-free permanent first molars of each patient. Impressions were taken at T0: before the sealing material was applied; T1: right after the application; T2: 6 months after the application, and T3: 1 year after the application. The impressions were then processed for scanning electron microscopy analysis of the wear of the examined materials. Statistical analysis was used to evaluate differences among and within the 4 groups.
At T2, the average ratio of residual material in all the groups was 62.37% ± 1.21%, while at T3 it was 49.63% ± 1.11%. At both T2 and T3 there were no statistically significant differences among the 4 groups examined (p=0.76 and p=0.50 respectively). Comparison within the same group at T2 and T3 showed that statistically significant differences were only detected in group D (p=0.015).
Sealing materials do not undergo a complete loss after 1 year of application, thus indicating that they are suitable for caries prevention.
European Journal of Paediatric Dentistry. Official Journal of the Italian Society of Paediatric Dentistry. 06/2011; 12(2):95-8. · 0.44 Impact Factor
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ABSTRACT: The effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) was evaluated on biofilm formation and preformed biofilm of Streptococcus mitis, Streptococcus mutans and Streptococcus oralis, alone or combined to each other.
Twofold serial dilution of HEMA ranged from 12 to 0·75 mmol l(-1) was added to Streptococcal broth cultures and mature biofilms in 96-well-microtitre plates to evaluate bacterial biomass and cell viability. HEMA affected the Streptococcal population in a strain-specific way producing few significant effects. A reduction on biofilm formation and a detachment of preformed biofilm was recorded in Strep. mitis ATCC 6249, whereas in mixed cultures, the monomer expressed a general aggregative effect on mature biofilms. A reduction in cell viability was also recorded in an HEMA-concentration-dependent way in each experimental condition studied.
These results suggest that the HEMA prevalent effects are both the reduction of bacterial adhesion to a polystyrene surface and the increase in dead cells also characterized by an aggregative status.
Understanding the potential effect of HEMA, released from resin-based materials, on oral bacteria may furnish information for surveillance of the risk reduction in secondary caries via hindering biofilm generation.
Letters in Applied Microbiology 03/2011; 52(3):193-200. · 1.62 Impact Factor
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ABSTRACT: The aim of the present study was to characterize clinical isolates of Staphylococcus epidermidis, one of the bacterial species most often implicated in foreign-body-associated infections, for their ability to form biofilms and for the presence of mecA and IS256 element. Sixty-seven Staphylococcus epidermidis clinical isolates, obtained from implantable medical devices, were investigated. Overall, 70% of the strains were positive for ica operon genes, 85% possessed atlE, and 46% contained aap. In 89% of the population, the Congo red agar test confirmed the correlation between the presence of ica genes and slime expression. Almost all of the strains could be classified as biofilm producers by both the crystal violet assay and microscopy. The bacterial population studied showed a very high frequency of strains positive for mecA as well as for the IS256 element. Although well-structured biofilms have been previously observed only in those strains possessing genes belonging to the ica operon, this study demonstrates that strains lacking specific biofilm-formation determinants can be isolated from catheters and can form a biofilm in vitro. Hence, different and yet-to-be identified factors may work together in the formation and organization of complex staphylococcal microbial communities and sustain infections associated with implanted medical devices.
European Journal of Clinical Microbiology 01/2007; 25(12):773-81. · 2.86 Impact Factor
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ABSTRACT: In total, 124 Streptococcus pyogenes isolates were obtained from throat cultures of different symptomatic patients. All isolates showed M-phenotype macrolide resistance and contained the macrolide efflux gene mef(A). The isolates were screened for the presence and insertion site of mef(A)-containing genetic elements. In 25.8% of the isolates, mef(A) was found to be carried by elements belonging to the Tn1207.3/Phi10394.4 family inserted in the comEC gene, while 74.2% contained chimeric elements with a different genetic structure and chromosomal location, probably associated with the recently described 60-kb tet(O)-mef(A) element.
Clinical Microbiology and Infection 12/2005; 11(11):927-30. · 4.54 Impact Factor
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ABSTRACT: Recent studies have suggested an association between periodontal disease and the presence of Herpesviruses, in particular: Epstein-Barr virus (EBV) and Human Cytomegalovirus (CMV) (Contreras et al., 1999--Contreras et al., 2000--Slots et al., 2000--Ting et al., 2000). In the work reported in this paper, we use a multiplex Polymerase Chain Reaction (PCR) to compare the presence of Herpesviruses and putative bacterial pathogens in patients with periodontal disease and in healthy individuals. Direct detection of microorganisms with PCR is shown to offer significant advantages in terms of time, effort and cost. The study detected no statistically significant differences between the prevalence of EBV and CMV in patients and controls. The failure to replicate previous findings may be due to differences in the age composition and the geographical and social origins of the study groups. The study detected a significant excess of HSV-1 in periodontal patients. This suggests that the role of Herpesviruses in the pathogenesis of periodontal disease deserves further investigation. The bacterial assay confirmed the results of previous studies showing a strong association between periodontitis and the presence of A. actinomycetemcomitans, P. gingivalis and P. intermedia.
The new microbiologica: official journal of the Italian Society for Medical, Odontoiatric, and Clinical Microbiology (SIMMOC) 05/2004; 27(2):133-7. · 1.00 Impact Factor
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ABSTRACT: The capability of Nd:YAG laser in sterilizing root canals and the alterations of dentinal walls induced by laser treatment were investigated. Thirty root canals were infected by P. aeruginosa ATCC 27853 and thirty canals by A. naeslundii CH-12. Within each infection, 4 groups were selected on the basis of the treatment. Among them, 2 test groups (TGs) were treated by Nd:YAG laser at 15 Hz for 15 s, using 2 different settings: 1 Watt/70 Joule and 1.5 Watt/100 Joule, respectively (n = 10 each). The other 2 groups, used as controls (CGs), were: untreated (positive control, n = 5) and sterilized by 5.25% NaClO group (negative control, n = 5). Observations under scanning electron microscope (SEM) and quantitative bacterial counts were performed. These analyses were performed once per group after infections and treatments. Laser treatments significantly reduced the number of both bacteria. SEM investigation showed melting and crystallization of canal dentin over 1.5 W/100 J. Laser irradiation has a bactericidal effect but it does not completely sterilize the root canal as NaClO 5.25% solution does if the goal of treatment is also to avoid alterations of dentinal walls.
The new microbiologica: official journal of the Italian Society for Medical, Odontoiatric, and Clinical Microbiology (SIMMOC) 02/2004; 27(1):55-63. · 1.00 Impact Factor
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ABSTRACT: Novel fluoroquinolones have been recently introduced in the management of neutropenic patients because of their increased activity against gram-positive and gram-negative micro-organisms.
The activities of levofloxacin and ciprofloxacin were determined by the E test against 223 bacterial isolates from patients with haematological malignancies.
In general, the activity of levofloxacin was comparable to that of ciprofloxacin. Levofloxacin was somewhat more active against methicillin-resistant Staphylococcus aureus isolates. All methicillin-susceptible S. aureus isolates were inhibited by ciprofloxacin and levofloxacin at a concentration of < or =0.5 and < or =0.25 microg/ml, respectively. Among gram-negative isolates tested, levofloxacin was significantly (p < 0.001) more active than ciprofloxacin against Stenotrophomonas maltophilia, inhibiting 68 and 53% of these isolates, respectively.
Levofloxacin was not superior to ciprofloxacin in its overall antibacterial activity, although small differences between these agents were seen depending on the species tested. In particular, our data suggested that levofloxacin may potentially be used for the management of S. maltophilia infections in neutropenic patients.
Chemotherapy 07/2002; 48(3):134-7. · 1.82 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the clinical and bacteriological effects of the intrasulcular application of a 1% metronidazole-gel (repeated administrations outdistanced of 7 days weeks long) currently employed in dermatological practice, to observe if a lower concentration of the chemotherapic agent could be equally effective as the 25% formulation in improving the periodontal condition of nine patients with adult periodontitis. The results showed that this regimen can modify, at a statistically significant level, the clinical (Pocket Probing Depth, Gingival Bleeding Index and Plaque Index) and bacteriological (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Veillonella parvula) parameters associated with adult periodontitis. The results are similar to those obtainable with a 25% Metronidazole-gel administered two times outdistanced by 7 days.
The new microbiologica: official journal of the Italian Society for Medical, Odontoiatric, and Clinical Microbiology (SIMMOC) 08/1999; 22(3):219-25. · 1.00 Impact Factor
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ABSTRACT: The aim of this study was to report the microbiological and clinical effects of repeated subgingival administration of a 1% Chlorhexidine-gel in periodontal pockets from 10 patients with adult periodontitis. Results showed that the experimental treatment significantly improved clinical parameters (Plaque Index, Gingival Bleeding Index, and Pocket Probing Depth). Direct subgingival administration of Chlorhexidine-gel also produced a remarkable modification in the proportions of putative periodontopathic microorganisms, such as Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Veillonella parvula, Fusobacterium nucleatum, and Peptostreptococcus micros, in subgingival bacterial plaque from periodontitis patients.
The new microbiologica: official journal of the Italian Society for Medical, Odontoiatric, and Clinical Microbiology (SIMMOC) 05/1999; 22(2):111-6. · 1.00 Impact Factor
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ABSTRACT: The demineralization of dentin obtained by treatment with a chelating agent ethylene diamminotetracetic acid (EDTA) or ethylene glycol-bis(beta-aminoethyl ether)-N-tetraacetic acid (EGTA), is a dynamic process involving chelation and solubilization. The actions of the EDTA and EGTA on dentin are influenced by the pH. Increasing mM concentrations of EDTA or EGTA the equivalent pH decreases in a similar slope to 80 mM chelator concentration. Increasing the chelator concentration different data were obtained: with EGTA the pH decreases slightly while with EDTA goes back up to the initial values. After 80 mM, EDTA reduces the activity on the dentin, and EGTA continues to work at higher concentrations. We demonstrated that EGTA solubilized more of 60 percent of dentin while EDTA gives about 20% at the maximal of the solubility.
International journal of immunopathology and pharmacology 20(1 Suppl 1):93-6. · 2.99 Impact Factor
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ABSTRACT: The correct use of antiseptics, disinfectants and sterilization processes to inactivate or remove micro-organisms is an essential component of an effective infection control program. To reach this result the use of phenolic detergent-disinfectants which work well as a presoak has always been suggested in lieu of sterilization involving submerging instruments in a properly prepared glutaraldehyde solution for about 6 to 10 hrs. This study investigated the in vitro effectiveness of disinfectant solution containing 2% glutaraldehyde and 1% o-phenylphenol.
The organisms used were purchased from the American Type Culture Collection (Escherichia coli ATCC 25922, Candida albicans ATCC 10231, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228), and from our clinical collection (Proteus mirabilis CH 14, Klebsiella oxytoca CH 22, Serratia liquefaciens CH 90). MIC and MBC were evaluated as testing solution for antimicrobial activity. The contact time studied between disinfectant and bacteria were 30 sec, 1, 2, 5, 10, 20 and 30 min.
The results showed that MIC values for most bacteria were 3.75 mg/ml. The MBC values were similar or higher than the MIC. The disinfectant solution killed E. coli and C. albicans already after 10 min, but for S. aureus 30 min was necessary.
This study proved that this solution attained the sterilization of surgical instruments in good timing and at low cost.
Minerva stomatologica 51(1-2):29-33.
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ABSTRACT: Microbial penetration inside the implants internal cavity produces a bacterial reservoir that is associated with an area of inflamed connective tissue facing the fixture-abutment junction. The aim of this clinical trial is to evaluate the effectiveness of a 1 percent chlorhexidine gel on the internal bacterial contamination of implants with screw-retained abutments and on the level of AST secreted in peri-implant crevicular fluid. Twenty-five patients (aged 29 to 58 years) each received one implant. Three months after the end of the restorative treatment, and immediately after a clinical and radiographic examination and the abutment removal, microbiological samples were obtained from the internal part of each fixture and biochemical samples were collected by peri-implant sulci. The patients were then divided into two groups: the control (CG; n=10) and test (TG; n=15) groups. The CG had the abutment screwed into place and the crown cemented without any further intervention. In contrast, before the abutment placement and screw tightening, the TG had the internal part of the fixture filled with a 1 percent chlorhexidine gel. Three months later, the same clinical, microbiological and biochemical procedures were repeated in both groups. Total bacterial count, specific pathogens and AST activity were detected. The clinical parameters remained stable throughout the study. From baseline to the 3-month examination, the total bacterial counts underwent a significant reduction only in the TG. In contrast, the AST activity showed a significant increase in the CG. The administration of a 1% chlorhexidine gel appears to be an effective method for the reduction of bacterial colonization of the implant cavity and for safeguarding the health status of peri-implant tissue over a 3-month administration period.
International journal of immunopathology and pharmacology 22(4):1019-26. · 2.99 Impact Factor
