Division of Endodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
Division of Basic Sciences, Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
Int Endod J. 2024 Jul;57(7):895-906. doi: 10.1111/iej.13996. Epub 2023 Nov 20.
To analyse the effect of ultrasonic irrigant activation (UIA) and the GentleWave (GW) multisonic irrigation (GW) with minimal instrumentation on the root canal microbial diversity in an ex vivo model that used extracted molars with a history of pulp necrosis.
Twenty-three mandibular molars were prepared ex vivo for collection of superficial (surface control), pre-treatment and post-treatment samples 24 h after extraction. Samples were divided into two groups: UIA using 6% NaOCl (n = 11) and GW group (n = 12). All samples were processed using quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA next-generation sequencing to measure microbial diversity before and after the antimicrobial treatment. For qPCR, a t-test (α = .05) was used to compare the log10 reduction. The Chao1 and Shannon indices evaluated alpha diversity. Differences in community composition (beta diversity) were evaluated by analysis of similarity (ANOSIM). Kruskal-Wallis test with Bonferroni corrections was performed to evaluate the differences in abundances genera in the samples.
Quantitative real-time polymerase chain reaction revealed an estimated 1.6 and 2.6 log10 reduction for UIA and GW groups respectively (p = .048). An average of 5 ± 4 and 3 ± 5 operational taxonomic units (OTUs) were found in surface's samples in the UIA and GW group respectively. These values were significantly lower (p < .001) compared to the number of preoperative OTUs in those groups (155 ± 79 and 187 ± 121). In assessing beta diversity, there were no significant differences found in pre-treatment samples (R = .090, p = .070 ANOSIM with Bonferroni corrections). Also, no significant differences in community composition were observed in post-treatment samples (R = -.05, p = .829). After treatment, there was a significant reduction of Eubacterium using conventional treatment with UIA and a significant reduction of Prevotella using minimal instrumentation with GW irrigation (p = .007 and p = .002 respectively).
Quantitative PCR analysis revealed a significant reduction in microbial load for GW group. Overall, diversity changes were similar between UIA and GW irrigation in this ex vivo model that used extracted teeth with a history of pulp necrosis. OTUs obtained from the surface sample were negligible and did not affect the statistical outcome of the study.
分析超声冲洗激活（UIA）和 GentleWave（GW）多频超声冲洗（GW）联合最小化器械预备对伴有牙髓坏死史的离体磨牙根管微生物多样性的影响。
对 23 颗下颌磨牙进行离体预备，以收集表面（表面对照）、预处理和根管冲洗后 24 小时的样本。样本分为两组：使用 6%次氯酸钠（n=11）的 UIA 组和 GW 组（n=12）。所有样本均使用定量实时聚合酶链反应（qPCR）和 16S rRNA 下一代测序进行处理，以测量抗菌处理前后的微生物多样性。对于 qPCR，使用 t 检验（α=0.05）比较 log10 减少量。Chao1 和 Shannon 指数评估 alpha 多样性。通过相似性分析（ANOSIM）评估群落组成（beta 多样性）的差异。采用 Kruskal-Wallis 检验和 Bonferroni 校正评估样本中属的丰度差异。
qPCR 显示 UIA 和 GW 组的估计 log10 减少量分别为 1.6 和 2.6（p=0.048）。UIA 和 GW 组表面样本的平均 OTU 数分别为 5±4 和 3±5。与这些组的术前 OTU 数量（155±79 和 187±121）相比，这些值显著降低（p<0.001）。在评估 beta 多样性时，预处理样本之间没有发现显著差异（R=0.090，p=0.070，ANOSIM 与 Bonferroni 校正）。同样，在根管冲洗后样本中，群落组成也没有观察到显著差异（R=-0.05，p=0.829）。治疗后，UIA 常规治疗使 Eubacterium 显著减少，GW 冲洗最小化器械预备使 Prevotella 显著减少（p=0.007 和 p=0.002）。
qPCR 分析显示 GW 组的微生物负荷显著减少。总的来说，在这个使用伴有牙髓坏死史的离体磨牙的体外模型中，UIA 和 GW 冲洗的多样性变化相似。从表面样本中获得的 OTU 微不足道，不会影响研究的统计结果。
