Examination of gutta-percha cones for microbial contamination during chemical use

OBJECTIVE: The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions. MATERIAL AND METHODS: Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 µL of saline. The tubes were vortexed, serially diluted and samples of 250 µL were cultured on agar plates. The plates were incubated at 37ºC for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above. RESULTS: Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p >; 0.05). The numbers of microorganisms cultured at the first day (8 ± 9.9 CFU) and the third day (4.5 ± 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p >; 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman's rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917). CONCLUSIONS: Gutta-percha cones taken directly from manufacturer's sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals

Strength of selection pressure is an important parameter contributing to the complexity of antibiotic resistance evolution

Revealing the genetic changes responsible for antibiotic resistance can be critical for developing novel antibiotic therapies. However, systematic studies correlating genotype to phenotype in the context of antibiotic resistance have been missing. In order to fill in this gap, we evolved 88 isogenic Escherichia coli populations against 22 antibiotics for 3 weeks. For every drug, two populations were evolved under strong selection and two populations were evolved under mild selection. By quantifying evolved populations' resistances against all 22 drugs, we constructed two separate cross-resistance networks for strongly and mildly selected populations. Subsequently, we sequenced representative colonies isolated from evolved populations for revealing the genetic basis for novel phenotypes. Bacterial populations that evolved resistance against antibiotics under strong selection acquired high levels of cross-resistance against several antibiotics, whereas other bacterial populations evolved under milder selection acquired relatively weaker cross-resistance. In addition, we found that strongly selected strains against aminoglycosides became more susceptible to five other drug classes compared with their wild-type ancestor as a result of a point mutation on TrkH, an ion transporter protein. Our findings suggest that selection strength is an important parameter contributing to the complexity of antibiotic resistance problem and use of high doses of antibiotics to clear infections has the potential to promote increase of cross-resistance in clinics

Microbiological evaluation of three endodontic disinfection methods in the treatment of root canal failures.

Bu çalışma, başarısız kök kanal tedavisi olgularında, geleneksel kimyasal yıkayıcılarla, lazerin ve bunların kombine kullanımının kök kanalındaki mikroorganizmaları yok etmedeki etkinliklerinin karşılaştırılması amacıyla yapıldı. Genel sağlık durumu iyi, en az 4 yıllık kanal tedavisine sahip, apikal radyolüsensi bulunan, kanal dolgusu apikalden en fazla 4 mm kısa olan 46 olgu klinik çalışma için seçildi. Kanal içi dezenfeksiyon olarak sodyum hipoklorit + EDTA (Grup 1), Nd:YAG lazer (Grup 2) ve Nd:YAG lazer + sodyum hipoklorit + EDTA (Grup 3) uygulandı. Kanallar 50 numaraya kadar genişletildi. Kanal dolgusu çıkarıldıktan, kanal genişletmesi yapıldıktan, dezenfeksiyon yöntemlerinden biri uygulandıktan ve kanal içi ilaç pansumanı yapıldıktan sonra kanal içinden kağıt konlarla kültür örnekleri alındı (sırasıyla S1, S2, S3, S4). Kanal içinden alınan bu örnekler geleneksel kültür yöntemi ve biyokimyasal ve enzimatik yöntemlerle tiplendirildi ve sayıları belirlendi. Tekrarlayan kanal tedavisi sırasında olguların % 55,8&#8217;inde Corynebacterium spp, % 39,5&#8217;inde Bacillus spp, % 25,5&#8217;inde Enterococcus faecalis, % 25,5&#8217;inde Streptococcus mutans ve % 25.5&#8217;inde tanımlanamamış oral streptokoklar belirlendi. Üç dezenfeksiyon yönteminde de anlamlı derecede bakteri azalması görüldü (t-testi; p<0.05). sodyum hipoklorit + EDTA uygulamasının (Grup 1) ve Nd:YAG lazer + sodyum hipoklorit + EDTA kombinasyonunun (Grup 3) daha etkili dezenfeksiyon yöntemleri olduğu fakat aradaki farkın istatistiksel olarak anlam taşımadığı belirlendi (Kruskal-Wallis testi; p>0,05). Lazer uygulamasının olasılıkla dentin duvarındaki etkisinden dolayı, pansuman maddesi olarak yerleştirilen kalsiyum hidroksitin antibakteriyel etkinliğini azalttığı tespit edildi. Yalnızca sodyum hipokloritin uygulanıp ardından kalsiyum hidroksit pansumanın yapıldığı Grup 1&#8217;de en yüksek mikroorganizma azalması olduğu fakat diğer gruplarla aradaki farkın istatistiksel açıdan bir farklılık göstermediği belirlendi. (Kruskal-Wallis testi; p>0.05)In this study traditional EDTA + sodium hypochlorite endodontic irrigation was compared with Nd:YAG laser irradiation either alone or in combination with EDTA + sodium hypochlorite irrigation, in vivo, for the eradication of infecting microorganisms. Forty six human subjects with good general health and with failed root canal treatment were selected. The criteria included root canals filled within 4 mm from the apex, presence of a periapical radiolucency and a minimum obturation history of 4 years. After removal of the filling material, root canal enlargement (#50), disinfection and medication, root canal samples were taken with sterile paper points (Samples S1, S2, S3 and S4, respectively). Colonies were counted and isolated colonies were identified using traditional microbiological and biochemical and enzymatic methods. Corynebacterium spp; 55,8, Bacillus spp; 39,5, Enterococcus faecalis; 25,5, Streptococcus mutans 25,5 and unidentified oral Streptococcus spp 25,5 % were amongst the most frequently recovered microorganisms in the retreated cases. All disinfection methods significantly reduced the number of cultivable microorganisms (t-test; p<0.05). Sodium hypochlorite + EDTA (Group 1) and laser combined with sodium hypochlorite + EDTA irrigation (Group 3) among the three groups yielded decreased colony counts, however difference were not statically significant (Kruskal-Wallis; p>0,05). Laser treatment, probably due to its physical effect on the root canal dentinal wall, reduced the antibacterial effectiveness of the calcium hydroxide medication. Best colony counts results were taken in group 1 where calcium hydroxide was applied after irrigation with sodium hypochlorite, however differences between the groups were not statistically significant (Kruskal-Wallis; p>0,05)

Bilateral parotitis in a patient under continuous positive airway pressure treatment

Background and objectives: Many conditions such as bacterial and viral infectious diseases, mechanical obstruction due to air and calculi and drugs can cause parotitis. We present a case of unusual bilateral parotitis in a patient under non-invasive continuous positive airway pressure (CPAP) therapy for chronic obstructive pulmonary disease exacerbation in intensive care unit

Bilateral parotitis in a patient under continuous positive airway pressure treatment

Abstract Background and objectives: Many conditions such as bacterial and viral infectious diseases, mechanical obstruction due to air and calculi and drugs can cause parotitis. We present a case of unusual bilateral parotitis in a patient under non-invasive continuous positive airway pressure (CPAP) therapy for chronic obstructive pulmonary disease exacerbation in intensive care unit. Case report: A 36-year-old patient was admitted to intensive care unit with the diagnosis of chronic obstructive pulmonary disease exacerbation. Antibiotherapy, bronchodilator therapy and non-invasive positive pressure ventilation were applied as treatment regimen. Painless swellings developed on the 3rd day of admission on the right and a day after this on the left parotid glands. Amylase levels were increased and ultrasonographic evaluation revealed bilateral parotitis. No intervention was made and the therapy was continued. The patient was discharged on the 6th day with clinical improvement and regression of parotid swellings without any complications. Conclusions: Parotitis may have occurred after retrograde air flow in the Stensen duct during CPAP application. After the exclusion of possible viral and bacteriological etiologies and possible drug reactions we can focus on this diagnosis

Bilateral parotitis in a patient under continuous positive airway pressure treatment

Abstract Background and objectives: Many conditions such as bacterial and viral infectious diseases, mechanical obstruction due to air and calculi and drugs can cause parotitis. We present a case of unusual bilateral parotitis in a patient under non-invasive continuous positive airway pressure (CPAP) therapy for chronic obstructive pulmonary disease exacerbation in intensive care unit. Case report: A 36-year-old patient was admitted to intensive care unit with the diagnosis of chronic obstructive pulmonary disease exacerbation. Antibiotherapy, bronchodilator therapy and non-invasive positive pressure ventilation were applied as treatment regimen. Painless swellings developed on the 3rd day of admission on the right and a day after this on the left parotid glands. Amylase levels were increased and ultrasonographic evaluation revealed bilateral parotitis. No intervention was made and the therapy was continued. The patient was discharged on the 6th day with clinical improvement and regression of parotid swellings without any complications. Conclusions: Parotitis may have occurred after retrograde air flow in the Stensen duct during CPAP application. After the exclusion of possible viral and bacteriological etiologies and possible drug reactions we can focus on this diagnosis