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UBC Theses and Dissertations

Leakage of bacteria into dentin-cement interface and dentin canals in human teeth after retro-filling with a calcium silicate cement : an SEM study Bhatt, Meeta


Aim To evaluate bacterial leakage in the apical part of the root canals of teeth after root end resection and filling by simulating the clinical scenario of coronal leakage. Methodology Twenty-five extracted teeth were instrumented and irrigated with 5% NaOCl. The final irrigation was done using 17% EDTA for 4 mins. The 3 mm of the root ends was resected, prepared and retro filled with RRM putty. The putty was set for at least 72 h at 37 °C in 100% humidity. Groups: Experimental group (N=12), positive control (no cement, N=5), and negative control (no bacteria, N=5). The canals in the experimental group and positive control were contaminated with Enterococcus faecalis (Ef) VP3-18. The bacterial suspension was replaced with a fresh culture every 3-4 days for 21 days. The samples were then scanned for electron microscopy (SEM) analysis. The leakage of bacteria was graded at four levels (1, 2, 3, 4). “1”-no bacterial cells, “2”-one to few bacterial cells, “3”-thin layers of bacterial cells, “4”-abundant bacterial cells. The three areas visualized were 1) the canal wall area coronally to the cement, 2) the interface between the cement and the dentin, and 3) the dentin canals next to the cement. Results No bacteria (level 1) were seen in negative controls, whereas in positive controls abundant bacteria (level 4) were seen. Leakage of abundant bacteria (level 4) and thin layer of bacteria (level 3) to the dentin-cement interface were detected in 42.86% and 28.57% of the samples in experimental group in area C respectively, when no gap was present. Leakage of one to few bacteria (level 2) and no bacteria (level 1) to the dentin-cement interface were detected in 57.14% and 42.86 % of the samples in the experimental group in area D respectively, when no gap was present. Significantly more bacteria (higher levels) were detected on the dentin surface and in dentinal tubules in samples with a gap than in samples with no gap present (p < 0.035). Conclusion RRM putty significantly reduces the penetration of bacteria especially when there was no gap present between the cement and dentin.

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