Fig 1.
The three Satelec ultrasonic scaler tip designs imaged in this study.
Tip 10P is the most pointed, tip 1 is pointed but tapers out towards the bend and tip 2 is flat with a wide cross-section.
Fig 2.
Schematic of the experimental setup for high speed imaging, showing the petri dish used for imaging and a view of the setup from above.
Table 1.
Settings used during high speed imaging of cavitation around various parts of the ultrasonic scaler tips.
Fig 3.
Segmentation and quantification process (illustrated with a frame from a video of tip 2 at power 20).
(a) Raw image showing the region of interest selected for image analysis. (b) left to right: Thresholded segmented image of bubble cloud; image after removing any objects smaller than 20 pixels; binary outline of the segmented image; overlay of the segmented outline on top of the original bubble cloud to show the bubble cloud has been segmented accurately; sequential images showing the smaller bubble cloud lifting away from the main cloud. (Overlay of the original images and the thresholded images in blue) (c) graph illustrating how the width and the height of the bubble cloud was calculated from the minimum and maximum x and y coordinates.
Fig 4.
Still images from a high speed video of the bend of tip 1 at power 10 (refer to Fig 2 to see the part of the tip imaged).
Two smaller bubble clusters have been tracked and labelled as they migrate towards a larger bubble cluster in the centre. Also see S1 Video.
Fig 5.
Still images from a high speed video of the inner part of the free end of tip 1 at power 10.
Individual microbubbles are seen to grow and collapse on the scaler tip.
Fig 6.
Still images from a high speed video of the inner part of the free end of tip 10P at power 10.
A single microbubble can be seen to grow, split in two and collapse onto the scaler tip. Also see S2 Video.
Fig 7.
Box and whisker plots of (a) the area of the bubble clouds at the tip of three different ultrasonic scaler tips operating at medium and high (b) the height and width of the bubble cloud.
Fig 8.
Displacement amplitudes of each of the three tips measured at medium power (power 10) and high power (power 20) using scanning laser vibrometry (SLV).
The images overlaid on each graph are stills from high speed images of the corresponding tip taken at power 20 and are scaled in the x direction.
Fig 9.
Contrast enhanced image stills from a high speed video of tip 1 (a), tip 2 (b) and tip 10P (c) at power 20, showing cavitation occurring around the free end and at the bend of the tips. Green arrows indicate points of largest tip vibration and white arrows indicate the point of least displacement. Also see videos 3, 4 & 5.