Abstract：
OBJECTIVE: To evaluate the influence of different preparation tapers on the reduction in planktonic bacteria and biofilms of Enterococcus faecalis and Candida albicans in the apical third (4 mm) of the mesial roots of mandibular molars, correlating decontamination with canal shape.
METHODS: After microtomography analysis for morphological standardization of the canals, 48 mandibular molar roots, each containing two canals (96 canals), were contaminated with E. faecalis and C. albicans and divided into four groups (n = 11) for canal instrumentation using ProDesign Logic 2 files with different tapers G (.03): # 25.03; G (.04): # 25.04; G (.05): # 25.05; and G (.06): # 25.06 and irrigation with 2.5% sodium hypochlorite. Four roots were examined under a scanning electron microscope (SEM) to qualitatively assess biofilm formation. Eight roots were used as the negative control group (samples were not contaminated). Bacteriological samples were taken exclusively from the apical third of the roots before and after chemical-mechanical preparation and bacterial counts were determined (CFU/mL). The final micro-CT scan was used to quantify the volume variation and unprepared canal area in the apical third. Statistical analysis was performed using the Kruskal-Wallis, Student-Newman-Keuls and Wilcoxon tests for analysis of microbiological data. anova and the Tukey or Games-Howell test were used for analysis of micro-CT data and Spearman\'s test for correlations (α = 5%).
RESULTS: All groups showed a significant reduction in bacteria (p < .05), with no statistically significant difference between groups. There was no significant difference in per cent volume increase between groups. The unprepared area (Δ%) was affected by the file used (p = .026) and was significantly lower for G (.06) compared to G (.03). There was no statistically significant correlation among bacterial reduction, volume and unprepared area (p > .05).
CONCLUSIONS: The different preparation tapers influenced root canal shaping in the apical third but did not improve decontamination in this region.
METHODS: After microtomography analysis for morphological standardization of the canals, 48 mandibular molar roots, each containing two canals (96 canals), were contaminated with E. faecalis and C. albicans and divided into four groups (n = 11) for canal instrumentation using ProDesign Logic 2 files with different tapers G (.03): # 25.03; G (.04): # 25.04; G (.05): # 25.05; and G (.06): # 25.06 and irrigation with 2.5% sodium hypochlorite. Four roots were examined under a scanning electron microscope (SEM) to qualitatively assess biofilm formation. Eight roots were used as the negative control group (samples were not contaminated). Bacteriological samples were taken exclusively from the apical third of the roots before and after chemical-mechanical preparation and bacterial counts were determined (CFU/mL). The final micro-CT scan was used to quantify the volume variation and unprepared canal area in the apical third. Statistical analysis was performed using the Kruskal-Wallis, Student-Newman-Keuls and Wilcoxon tests for analysis of microbiological data. anova and the Tukey or Games-Howell test were used for analysis of micro-CT data and Spearman\'s test for correlations (α = 5%).
RESULTS: All groups showed a significant reduction in bacteria (p < .05), with no statistically significant difference between groups. There was no significant difference in per cent volume increase between groups. The unprepared area (Δ%) was affected by the file used (p = .026) and was significantly lower for G (.06) compared to G (.03). There was no statistically significant correlation among bacterial reduction, volume and unprepared area (p > .05).
CONCLUSIONS: The different preparation tapers influenced root canal shaping in the apical third but did not improve decontamination in this region.
摘要：
目的:评价不同制剂锥度对下颌磨牙近中根尖第三(4mm)粪肠球菌和白色念珠菌浮游细菌和生物膜减少的影响,与运河形状相关的去污。
方法：在显微断层摄影分析后，对运河进行形态学标准化，下颌磨牙48根，每个包含两条运河（96条运河），被粪肠球菌和白色念珠菌污染，并分为四组（n=11），用于使用ProDesignLogic2文件进行运河仪器，这些文件具有不同的锥度G（.03）：＃25.03；G（.04）：＃25.04；G（.05）：＃25.05；和G（.06）：＃25.06，并用2.5％的次氯酸钠进行灌溉。在扫描电子显微镜（SEM）下检查四个根以定性评估生物膜的形成。八个根用作阴性对照组(样品未被污染)。在化学机械制备之前和之后，仅从根的顶端三分之一处获取细菌学样品，并确定细菌计数（CFU/mL）。最终的微CT扫描用于量化心尖三分之一的体积变化和未准备好的管面积。使用Kruskal-Wallis进行统计分析，用于分析微生物数据的Student-Newman-Keuls和Wilcoxon检验。使用anova和Tukey或Games-Howell检验分析显微CT数据和Spearman检验的相关性(α=5%)。
结果：所有组均显示细菌显着减少（p<0.05），组间差异无统计学意义。两组之间的体积增加百分比没有显着差异。未准备的区域(Δ%)受到所用文件(p=.026)的影响,并且与G(.03)相比,G(.06)显著更低。细菌减少之间没有统计学上的显着相关性，体积和未准备面积（p>0.05）。
结论：不同的预备锥度影响根尖三分之一的根管形状，但并未改善该区域的去污。
方法：在显微断层摄影分析后，对运河进行形态学标准化，下颌磨牙48根，每个包含两条运河（96条运河），被粪肠球菌和白色念珠菌污染，并分为四组（n=11），用于使用ProDesignLogic2文件进行运河仪器，这些文件具有不同的锥度G（.03）：＃25.03；G（.04）：＃25.04；G（.05）：＃25.05；和G（.06）：＃25.06，并用2.5％的次氯酸钠进行灌溉。在扫描电子显微镜（SEM）下检查四个根以定性评估生物膜的形成。八个根用作阴性对照组(样品未被污染)。在化学机械制备之前和之后，仅从根的顶端三分之一处获取细菌学样品，并确定细菌计数（CFU/mL）。最终的微CT扫描用于量化心尖三分之一的体积变化和未准备好的管面积。使用Kruskal-Wallis进行统计分析，用于分析微生物数据的Student-Newman-Keuls和Wilcoxon检验。使用anova和Tukey或Games-Howell检验分析显微CT数据和Spearman检验的相关性(α=5%)。
结果：所有组均显示细菌显着减少（p<0.05），组间差异无统计学意义。两组之间的体积增加百分比没有显着差异。未准备的区域(Δ%)受到所用文件(p=.026)的影响,并且与G(.03)相比,G(.06)显著更低。细菌减少之间没有统计学上的显着相关性，体积和未准备面积（p>0.05）。
结论：不同的预备锥度影响根尖三分之一的根管形状，但并未改善该区域的去污。
