Tabata Tomoko, Nakagawa Hisaichi, Matin Khairul, Otsuki Masayuki, Aoki Akira, Sumi Yasunori, Shimada Yasushi
Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Department of Oral Biomedical Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan.
Arch Oral Biol. 2024 Sep;165:106009. doi: 10.1016/j.archoralbio.2024.106009. Epub 2024 May 25.
The objective was to measure the thickness of Streptococcus mutans (S. mutans) biofilms forming in an oral biofilm reactor (OBR) by using a noninvasive swept-source optical coherence tomography (SS-OCT) system at every 4 h time interval until 20 h and analyze the correlations with the amounts of biofilms.
S. mutans biofilms were formed on square-shaped bovine enamel blocks inside an OBR. Biofilms were analyzed at every 4 h stage (4 h, 8 h, 12 h, 16 h and 20 h) using a SS-OCT system and a laser scanning confocal microscope (LSCM). The amounts of biofilms were measured at each stage by separating the water insoluble glucan (WIG) and bacterial cells. Co-relationships between the SS-OCT measured biofilm thickness and the amounts of adhered biofilms were analyzed.
The thickness of biofilms detected on SS-OCT images at 4 h stage was 0.059 ± 0.029 (Av ± SD) mm which increased time-dependently in a linear fashion after 8 h stage and reached to 0.435 ± 0.159 mm at 20 h stage and the correlation coefficient was about 0.89. The amounts of biofilms; bacterial optical density (OD) and WIG concentration increased time-dependently were 0.035 ± 0.008 / mm and 10.328 ± 2.492 µg/ mm respectively at 20 h stage. Correlation coefficients of 0.66 between 'the amounts of bacteria' and 'biofilm thickness on OCT' and 0.67 between 'the amounts of WIG' and 'biofilm thickness on OCT' were obtained, suggesting that there was a relatively positive correlation between them.
The SS-OCT can be a useful tool to measure time-dependent growth of biofilms. Further studies are needed in order to assess biofilms using SS-OCT more accurately.
本研究旨在通过使用非侵入性扫频光学相干断层扫描（SS-OCT）系统，每隔4小时测量一次口腔生物膜反应器（OBR）中变形链球菌（S. mutans）生物膜的厚度，直至20小时，并分析其与生物膜量的相关性。
在OBR内的方形牛牙釉质块上形成变形链球菌生物膜。使用SS-OCT系统和激光扫描共聚焦显微镜（LSCM）在每个4小时阶段（4小时、8小时、12小时、16小时和20小时）对生物膜进行分析。通过分离水不溶性葡聚糖（WIG）和细菌细胞，在每个阶段测量生物膜的量。分析了SS-OCT测量的生物膜厚度与附着生物膜量之间的相互关系。
在4小时阶段，SS-OCT图像上检测到的生物膜厚度为0.059±0.029（平均值±标准差）mm，在8小时阶段后呈线性时间依赖性增加，在20小时阶段达到0.435±0.159mm，相关系数约为0.89。生物膜量；细菌光密度（OD）和WIG浓度在20小时阶段分别为0.035±0.008/mm和10.328±2.492μg/mm，呈时间依赖性增加。“细菌量”与“OCT上的生物膜厚度”之间的相关系数为0.66，“WIG量”与“OCT上的生物膜厚度”之间的相关系数为0.67，表明它们之间存在相对正相关。
SS-OCT可作为测量生物膜时间依赖性生长的有用工具。为了更准确地使用SS-OCT评估生物膜，还需要进一步的研究。
