Pontifical Catholic University of Rio Grande do Sul - Porto Alegre, Porto Alegre, Brazil.
Int Endod J. 2018 Nov;51(11):1261-1270. doi: 10.1111/iej.12949. Epub 2018 Jun 11.
To evaluate the influence of different apical enlargement protocols on the radiographic and histological healing of apical periodontitis in rats.
Apical periodontitis was induced bilaterally in the mandibular right and left first molars of 24 Wistar rats by pulp exposure to the oral cavity for 3 weeks. A standard serial root canal preparation technique was performed in the molar of one side, whilst the opposite side was the control group. Rats were randomly divided into three experimental groups (n = 8), according to the diameter of apical enlargement during root canal preparation: K-files size 20 (EG1), size 25 (EG2) and size 30 (EG3). Each animal was its own positive control, because the opposite arch remained untreated. Root canals were filled with a standard technique. After 3 weeks, the animals were euthanized. The main outcome of apical periodontitis healing was evaluated radiographically (mm ) and histologically (ordinal scores of inflammation) using a HE staining technique. The measurement of effect was obtained between the three experimental groups by carrying out generalized estimating equations, with Poisson regression with robust variance, pairing each experimental group with its respective control group within animals, adjusted for the mean within animal differences, with α = 5%.
The mean and standard deviations of radiographic apical periodontitis size (mm ) and intensity of histological inflammatory scores were, respectively: EG1 (0.44 ± 0.27; 2.25 ± 0.46), EG2 (0.33 ± 0.10; 2.50 ± 0.53) and EG3 (0.22 ± 0.08; 2.63 ± 0.74). After 3 weeks, a significantly more favourable radiographic repair was observed when larger apical enlargement was performed (EG3), compared to EG1 and EG2 (P = 0.001). All experimental groups were associated with a significant difference on the radiographic and histological healing of apical periodontitis compared with its respective control group.
Under the experimental conditions of this study, a larger apical enlargement protocol favoured a more rapid radiographic repair of apical periodontitis in rats after a 3-week follow-up.
评估不同根尖扩大方案对大鼠根尖周炎放射学和组织学愈合的影响。
将 24 只 Wistar 大鼠双侧下颌右、左第一磨牙牙髓暴露于口腔内 3 周，诱导根尖周炎。一侧磨牙采用标准连续根管预备技术，对侧为对照组。根据根管预备时根尖扩大的直径，将大鼠随机分为 3 个实验组（n=8）：K 锉 20 号（EG1）、25 号（EG2）和 30 号（EG3）。每只动物都是自己的阳性对照，因为对侧牙弓未作处理。用标准技术根管充填。3 周后处死动物。采用 HE 染色技术，通过放射学（mm）和组织学（炎症ordinal 评分）评估根尖周病愈合的主要结局。通过广义估计方程，用具有稳健方差的泊松回归，在动物内将每个实验组与其各自的对照组配对，根据动物内的平均差异进行调整，α=5%，对 3 个实验组的测量效果进行比较。
放射学根尖周病大小（mm）和组织学炎症评分强度的平均值和标准差分别为：EG1（0.44±0.27；2.25±0.46）、EG2（0.33±0.10；2.50±0.53）和 EG3（0.22±0.08；2.63±0.74）。3 周后，较大的根尖扩大（EG3）与 EG1 和 EG2 相比，放射学修复明显更有利（P=0.001）。与各自的对照组相比，所有实验组在根尖周炎的放射学和组织学愈合方面均有显著差异。
在本研究的实验条件下，较大的根尖扩大方案有利于大鼠根尖周炎在 3 周随访后更快的放射学修复。
