Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstr. 74, D-01307 Dresden, Germany.
Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstr. 74, D-01307 Dresden, Germany.
Arch Oral Biol. 2017 Nov;83:289-296. doi: 10.1016/j.archoralbio.2017.08.012. Epub 2017 Aug 25.
The aim of the present study was to evaluate the penetration characteristics of devitalized and vital E. faecalis cells into root dentinal tubules.
Thirteen root canals were incubated with devitalized (4days, 7days, 14days, 28days) and vital (28days) E. faecalis strains (streptomycin-resistant strains) after root canal enlargement (size 80, taper 0.02) with 3 % NaOCl solution. The smear layer was intentionally removed with 20 % EDTA before inoculation. Samples were processed for analysis by scanning electron microscopy (SEM) and DAPI (4',6-diamidino-2-phenylindole) staining. DAPI was conducted for fluorescence microscopic visualization of the bacterial penetration into dentinal tubules. The penetration depth was calculated with the measurement tool of the Axio Vision program (Zeiss, Jena, Germany).
Devitalized E. faecalis strains were able to penetrate into dentinal tubules of the root canal. Apikal penetration depths of the devitalized cells were 100.67μm±26.54μm after 7days, 230.67μm±111.5μm after 14days and 266.5μm±92.63μm after 28days of incubation. The total number and penetration depth of E. faecalis cells was lower compared to a vital suspension of E. faecalis (1002.45μm) after 28days. It was noted that bacterial penetration was not common to all of the dentinal tubules in the vital E. faecalis control and especially in the devitalized control.
Increased exposure times of devitalized bacteria into root canals lead to an increased number of penetrated dentinal tubules as well as to a deeper penetration.
本研究旨在评估失活和活菌 E. faecalis 细胞穿透根管牙本质小管的特性。
在根管扩大（80 号、0.02 锥度）后，用 3%次氯酸钠溶液处理 13 个根管，分别孵育失活（4 天、7 天、14 天、28 天）和活菌（28 天）E. faecalis 菌株（链霉素抗性菌株）。在接种前，用 20%EDTA 故意去除玷污层。用扫描电子显微镜（SEM）和 DAPI（4'，6-二脒基-2-苯基吲哚）染色对样品进行处理，用于荧光显微镜观察细菌穿透牙本质小管。用 Axio Vision 程序（蔡司，耶拿，德国）的测量工具计算穿透深度。
失活的 E. faecalis 菌株能够穿透根管牙本质小管。失活细胞培养 7 天后的根尖穿透深度为 100.67μm±26.54μm，培养 14 天后为 230.67μm±111.5μm，培养 28 天后为 266.5μm±92.63μm。与 28 天活菌悬浮液相比，失活细胞的总数和穿透深度较低。值得注意的是，在活菌对照和失活对照中，细菌穿透并不常见于所有牙本质小管。
失活细菌在根管内的暴露时间增加会导致穿透牙本质小管的数量增加和穿透深度加深。
