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The aim of this study was to determine the percentage of voids, gutta-percha and root canal sealer using 4 different filling techniques. Fifty-two extracted maxillary lateral incisors were prepared using the crown-down pressureless technique. The teeth were randomly divided in 4 groups (n=13): Lateral compaction (LC), Tagger's hybrid (TH), MicroSeal (MS) and GuttaFlow (GF) techniques. Horizontal cross-sections were made at the 2, 10 and 15 mm levels from the apex. Digital images of the root canal areas were acquired using a stereomicroscope and examined using the Image Tool 3.0 software. Statistical analysis was performed using the Kruskal-Wallis test (α=0.05). In general, a significant decrease in the gutta-percha filled area and increase of sealer area were observed at the apical level for all the evaluated techniques (p<0.05). With regard to the presence of voids, no significant difference was found. MS and TH techniques showed a larger gutta-percha filled area than LC and GF techniques at the coronal and middle third level (p<0.05). From the results of the present study, it may be concluded that the gutta-percha filled area of fillings decrease at the apical level, regardless of the filling technique used.

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans.

Storage in liquid nitrogen of a collection of C. albicans, C. tropicalis and related species checked by numerical and classical taxonomy is described. Strains stored for 3 years in liquid nitrogen were thawed and their survival was tested. After adaptation and regeneration, their fermentation and assimilation spectra, production of chlamydospores and pseudomycelia, appearance and radial growth rate of giant colonies were investigated and compared with the properties of cultures stored under paraffin oil. It follows from the results obtained that two different media--with an increased content of a nitrogen source and with an increased carbon source content--should be used for the post-heating adaptation and regeneration of yeast cells. In some strains it is useful to store them at 4 degrees C for additional time intervals in order to increase survival of the cells. The above strains can be successfully stored in liquid nitrogen.

This study aimed to examine programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) expression on leukocytes from chronic apical periodontitis, and to determine the levels of cytokines in the apical periodontitis lesions. Methods: Leukocytes from healthy gingival tissue (n=16) and chronic apical periodontitis (n=10) were evaluated using flow cytometry. The PD-1 and PDL-1 expressions were evaluated using flow cytometry. The cytokine levels were evaluated by enzyme-linked immunosorbent assay. Data were analyzed using one-way ANOVA. The statistical significance level was set at P<0.05. Results: Results showed that the apical periodontitis lesions are more infiltrated by PD-1 + and PDL1 + lymphocytes than the control samples. In addition, the PDL-1 expression was detected on macrophages in the apical periodontitis lesions, and was significantly higher compared to leukocytes from healthy gingival tissue. The IFN-γ, TGF-β, IL-10, and TNF-α levels were significantly higher in the apical periodontitis lesions compared to control samples. Conclusion: The PD-1, PD-L1, and CTLA-4 molecules are evident in apical periodontitis, and can be an important immune checkpoint in chronic periapical periodontitis.