del Carpio-Perochena Aldo, Bramante Clovis Monteiro, de Andrade Flaviana Bombarda, Maliza Amanda G Alves, Cavenago Bruno Cavalini, Marciano Marina A, Amoroso-Silva Pablo, Duarte Marco Hungaro
Department of Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Faculdade de Odontologia de Bauru, USP. Al. Octavio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil.
Clin Oral Investig. 2015 Nov;19(8):2067-73. doi: 10.1007/s00784-015-1431-6. Epub 2015 Feb 26.
The aim of this study was to investigate whether variation in pH of sodium hypochlorite (NaOCl) increased its antibacterial and dissolution ability on polymicrobial biofilms formed in situ.
Fifty-six dentin blocks (eight/group) were intraorally infected for 48 h and incubated in BHI for 48 h to standardize the biofilm growth. The specimens were irrigated with 1 and 2.5% NaOCl with pH levels of 5, 7, and 12 for 20 min. The control group was irrigated with distilled water. The cell viability and the bacterial volume were measured at the pre- and post-irrigation procedures. Five random areas of each sample were chosen and analyzed with confocal laser scanning microscopy (CLSM). Statistical analysis was performed using the non-parametric Kruskal-Wallis and Dunn's tests (p < 0.05).
All the experimental solutions were able to decrease the biomass (p < 0.05) except for the 1% NaOCl-pH 5 group. The antibacterial ability of the NaOCl was dependent on the concentration and acidification of the solution.
The acidification of NaOCl improves its antibacterial ability, but the dissolution effect of the irrigant is decreased.
Bacteria and their products are the main factors in development of apical periodontitis. The pH reduction in the NaOCl could enhance the reduction or elimination of the root canal bacterial colonies in comparison with the unaltered solution.
本研究旨在调查次氯酸钠（NaOCl）pH值的变化是否会增强其对原位形成的多微生物生物膜的抗菌和溶解能力。
56个牙本质块（每组8个）在口腔内感染48小时，然后在脑心浸液培养基（BHI）中孵育48小时以使生物膜生长标准化。用pH值分别为5、7和12的1%和2.5%的NaOCl冲洗标本20分钟。对照组用蒸馏水冲洗。在冲洗前后测量细胞活力和细菌体积。从每个样本中随机选择五个区域，并用共聚焦激光扫描显微镜（CLSM）进行分析。使用非参数Kruskal-Wallis检验和Dunn检验进行统计分析（p < 0.05）。
除1% NaOCl-pH 5组外，所有实验溶液均能降低生物量（p < 0.05）。NaOCl的抗菌能力取决于溶液的浓度和酸化程度。
NaOCl的酸化提高了其抗菌能力，但冲洗液的溶解效果降低。
细菌及其产物是根尖周炎发展的主要因素。与未改变的溶液相比，NaOCl的pH值降低可增强根管细菌菌落的减少或消除。
