Faculty of Dentistry, Federal University of Goiás, Goiânia, GO, Brazil.
School of Dentistry, UniEvangélica, Anápolis, GO, Brazil.
Braz Dent J. 2022 May-Jun;33(3):8-17. doi: 10.1590/0103-6440202204999.
This study evaluated the effect of photodynamic therapy (PDT) on infected root canals. Twenty-one human teeth were selected, and 18 were infected by E. faecalis for 60 days. The antimicrobial strategies tested were: G1. Root canal preparation (RCP) using Niquel-Titanium (NiTi) rotary instruments, 2.5% NaOCl, and final irrigation with 17% EDTA, followed by PDT with methylene blue photosensitizer and laser diode low power; G2. RCP using stainless steel files and the same irrigation and PDT protocols as G1; G3. Same RCP protocol as G1 without PDT; G4. Only irrigation with 2.5% NaOCl; G5. Same PDT protocol as G1 without RCP; G6. Negative control; G7. Positive control. Samples for microbiological tests were collected initially (S1), after RCP (S2), and after PDT (S3). Subsequently, the roots were sectioned and prepared for Scanning Electron Microscopy (SEM) analysis. Bacterial growth was analyzed according to the turbidity of the culture medium, followed by spectrophotometric optical density (nm). The effect of PDT on the dentinal structure was evaluated at magnifications 1,600X and 5,000X and described qualitatively. The Wilcoxon test was used for the comparisons from the same specimens, and the Mann-Whitney test was used to compare groups ((=5%). Bacteria were found in all experimental groups' microbiological samples (S1, S2 and S3). The optical density of culture media was lower in S2 than in S1 of G1, 2, 3, and 4 (p> 0.05). After PDT (S3) in G1 and 2, there was an additional reduction in optical density of the culture medium, respectively (p>0.05). In Group 5, the analysis of culture media at S2 revealed an increase in optical density compared to S1(p>0.05). In SEM images of G1, 2, and 5, dentin with melting and recrystallization areas were evidenced. After preparation of the root canal with the rotary system or manually associated with 2.5% NaOCl, PDT was not able to completely eliminate E. faecalis present in the root canal.
本研究评估了光动力疗法（PDT）对感染根管的作用。选择了 21 个人类牙齿，其中 18 颗牙齿被粪肠球菌感染了 60 天。测试的抗菌策略如下：G1. 使用镍钛（NiTi）旋转器械、2.5%次氯酸钠进行根管预备（RCP），并用 17% EDTA 进行最终冲洗，然后用亚甲蓝光敏剂和低功率激光二极管进行 PDT；G2. 使用不锈钢锉进行 RCP，并采用与 G1 相同的冲洗和 PDT 方案；G3. 与 G1 相同的 RCP 方案但不进行 PDT；G4. 仅用 2.5%次氯酸钠冲洗；G5. 与 G1 相同的 PDT 方案但不进行 RCP；G6. 阴性对照；G7. 阳性对照。最初（S1）、根管预备后（S2）和 PDT 后（S3）收集微生物学测试样本。随后，将根部分段并准备进行扫描电子显微镜（SEM）分析。根据培养基的浊度分析细菌生长情况，然后用光密度（nm）进行分光光度分析。在 1,600X 和 5,000X 放大倍数下评估 PDT 对牙本质结构的影响，并定性描述。对来自同一标本的比较采用 Wilcoxon 检验，对组间比较采用 Mann-Whitney 检验（=5%）。所有实验组的微生物样本（S1、S2 和 S3）均检出细菌。与 G1、2、3 和 4 的 S1 相比，G1、2、3 和 4 的 S2 培养基的光密度更低（p>0.05）。在 G1 和 2 进行 PDT（S3）后，培养基的光密度进一步降低（p>0.05）。在 G5 组中，与 S1 相比，S2 培养基的分析显示光密度增加（p>0.05）。在 G1、2 和 5 的 SEM 图像中，发现牙本质有熔融和再结晶区域。使用旋转系统或手动与 2.5%次氯酸钠联合制备根管后，PDT 未能完全消除根管内的粪肠球菌。
