Vyas N, Dehghani H, Sammons R L, Wang Q X, Leppinen D M, Walmsley A D
Physical Sciences of Imaging for Biomedical Sciences (PSIBS) Doctoral Training Centre, College of Engineering & Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK; School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Mill Pool Way, Birmingham B5 7EG, UK.
School of Computer Science, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Ultrasonics. 2017 Nov;81:66-72. doi: 10.1016/j.ultras.2017.05.015. Epub 2017 May 24.
Cavitation is a potentially effective and less damaging method of removing biofilm from biomaterial surfaces. The aim of this study is to characterise individual microbubbles around ultrasonic scaler tips using high speed imaging and image processing. This information will provide improved understanding on the disruption of dental biofilm and give insights into how the instruments can be optimised for ultrasonic cleaning. Individual cavitation microbubbles around ultrasonic scalers were analysed using high speed recordings up to a million frames per second with image processing of the bubble movement. The radius and rate of bubble growth together with the collapse was calculated by tracking multiple points on bubbles over time. The tracking method to determine bubble speed demonstrated good inter-rater reliability (intra class correlation coefficient: 0.993) and can therefore be a useful method to apply in future studies. The bubble speed increased over its oscillation cycle and a maximum of 27ms was recorded during the collapse phase. The maximum bubble radii ranged from 40 to 80μm. Bubble growth was observed when the ultrasonic scaler tip receded from an area and similarly bubble collapse was observed when the tip moved towards an area, corresponding to locations of low pressure around the scaler tip. Previous work shows that this cavitation is involved in biofilm removal. Future experimental work can be based on these findings by using the protocols developed to experimentally analyse cavitation around various clinical instruments and comparing with theoretical calculations. This will help to determine the main cleaning mechanisms of cavitation and how clinical instruments such as ultrasonic scalers can be optimised.
空化是一种从生物材料表面去除生物膜的潜在有效且损伤较小的方法。本研究的目的是使用高速成像和图像处理来表征超声洁牙器尖端周围的单个微泡。这些信息将有助于更好地理解牙菌斑的破坏情况，并深入了解如何优化器械以进行超声清洁。通过每秒高达一百万帧的高速记录以及对气泡运动的图像处理，分析了超声洁牙器周围的单个空化微泡。通过跟踪气泡上多个点随时间的变化，计算出气泡的半径、生长速率以及崩溃速率。用于确定气泡速度的跟踪方法显示出良好的评分者间可靠性（组内相关系数：0.993），因此可以成为未来研究中一种有用的方法。气泡速度在其振荡周期内增加，在崩溃阶段记录到的最大值为27m/s。最大气泡半径范围为40至80μm。当超声洁牙器尖端从一个区域后退时观察到气泡生长，同样，当尖端向一个区域移动时观察到气泡崩溃，这与洁牙器尖端周围的低压位置相对应。先前的研究表明，这种空化作用与生物膜的去除有关。未来的实验工作可以基于这些发现，通过使用开发的方案来实验分析各种临床器械周围的空化作用，并与理论计算进行比较。这将有助于确定空化的主要清洁机制以及如何优化超声洁牙器等临床器械。
