This study aimed to assess the adaptability and penetration depth capacity of recent bioceramic systems, including regular EndoSequence (BC) versus HiFlow (BCH) sealers in the presence of BC points. A total of 54 single-rooted teeth were instrumented and obturated with either the cold or warm compaction technique (n = 9), using either BC, BCH, or AH Plus (AHP) combined with BC points. The adaptation, film thickness, and gaps/voids were evaluated by scanning electron microscopy. The sealer/dentin interface was evaluated by Raman spectroscopy, and depth penetration was evaluated by a confocal laser scanning microscope. According to the normality test, the data were statistically analyzed by ANOVA or Kruskal-Wallis and Mann-Whitney U tests at p < 0.05. BCH sealer showed the significantly thinnest film with the greatest flow (p > 0.001), with further improvement when subjected to the warm compaction technique. Moreover, it exhibited close adaptation with deep penetration into radicular dentin, forming a tag-like structure. The Raman spectra also indicated close contact with the dentin surface. The use of BC sealer with BC points exhibited homogenous, single-unit obturation, either with a cold or warm technique. Furthermore, the use of the warm compaction technique with BCH sealer achieved a gap-free interface associated with tag-like structures, which exhibit the monoblock phenomenon.

The use of hexachlorocyclohexanes (HCHs) in pesticides has been prohibited for decades in China. Since then, there have been urbanization and transformation of the functional areas of many sites, which were formerly involved in the HCH industry. However, it is possible that, unless properly managed, these sites may still contain HCH residues in the soil and thus pose a threat to the surrounding environment and the quality of groundwater. This study aimed to characterize soil residues in a typical site that was historically involved in HCH production in southern China, by analyzing the α-HCH, β-HCH, and γ-HCH contents of the soil. The results suggested that HCHs persist in the environment and can have long-term effects. It was found that α-HCH and β-HCH were present in many samples in concentrations that were comparable or higher than those specified by China\'s Class 1 screening values. The distribution of residues was significantly correlated with the historical HCH production activities in the areas. The characteristic ratios of α-HCH/γ-HCH and β-HCH/(α + γ)-HCH at different soil depths were 1.4-3.7 and 0.21-1.04, respectively, which indicated the presence of significant localized residues of HCHs. The presence of HCHs in the soil suggested a downward migration, with concentrations rapidly decreasing in the upper layer soil (0-5 m), but a gradual increase in the deeper soil (5-14 m). HCHs were detected at depths exceeding 24 m, indicating heavy penetration. The proportions of γ-HCH and β-HCH changed with increasing soil depth, which was related to their relatively volatile and stable molecular structures, respectively. The results strongly suggested that there is widespread contamination of both soil and groundwater by HCHs even after decades. The likelihood of residual HCHs in the soil should therefore be taken into full consideration during urban planning to limit risks to human and environmental health.

UNASSIGNED: Sealer penetration into dentinal tubules eliminates the pathways for bacterial leakage and entombs intratubular bacteria.
UNASSIGNED: The aim of this study was to evaluate and compare the depth of radicular dentinal tubule penetration of five root canal sealers using confocal laser scanning microscopy.
UNASSIGNED: Fifty freshly extracted single-rooted maxillary anterior teeth were used. After decoronation at the cementoenamel junction, they were prepared to ProTaper size F3. After irrigation with 5 mL smear clear, 5 mL 5% sodium hypochlorite and 5 mL distilled water alternatively, the samples were randomly divided into five groups (n = 10) and obturated by lateral compaction technique using the test sealers labeled by fluorescent rhodamine B dye (Mayor Diagnostics, Mumbai, India). Zinc oxide eugenol (ZOE) (Prime Dental Products), EndoREZ (Ultradent), Sealapex (SybronEndo), AH Plus (Dentsply Maillefer), and MTA-Fillapex (Angelus) formed the test groups. Teeth were then positioned in blocks of orthodontic resin. Three horizontal sections of 1-mm representing coronal middle and apical thirds were made and examined with Zeiss (laser scanning microscope [LSM] 780) confocal LSM. Images were analyzed using ZEN 2.1 software.
UNASSIGNED: Data were recorded and subjected to statistical analysis using one-way ANOVA test.
UNASSIGNED: Maximum penetration depth was demonstrated by AH Plus in the coronal and apical thirds, MTA-Fillapex in the middle thirds, while minimum penetration depth was seen in ZOE in the coronal and middle thirds and Sealapex in the apical thirds. None of the root canal sealers were able to penetrate the complete depth of radicular dentinal tubules.
UNASSIGNED: While AH Plus and MTA-Fillapex showed the highest penetration into radicular dentinal tubules, ZOE and Sealapex demonstrated the least penetration.