Acoustic microstreaming: Detection and measurement around ultrasonic scalers

Background: Acoustic microstreaming (AMS) may be useful to the clinician wh en using the ultrasonic scaler to remove particulate matter from the teeth. The aim of this study was to detect and measure the effects of AMS produce d by ultrasonic scalers. Methods: For the study, an ultrasonic generator was selected with 4 differe ntly shaped scaling tip inserts (TFI-3, TFI-9, TFI-1, and P-12). A plaque s ubstitute (0.2 mm thick soft cream cheese) was coated onto a microscope sli de and immersed in water. The ultrasonic scaler tip was placed in the water and orientated either perpendicular or parallel to the slide. The instrume nt was operated both contacting the slide under a load of 0.3 N and non-con tacting at various distances from the slide surface. This was repeated with the tip parallel to the slide. The area of medium removed was quantified b y digital image analysis. Results: It was found that AMS removed the plaque substitute from around th e tip. The TFI-9 insert significantly removed more material with increasing displacement amplitude (P < 0.05). Significantly larger areas of plaque su bstitute were removed when the tips of the TFI-3, TFI-9, and P-12 inserts w ere orientated perpendicularly to the slide compared to the parallel orient ation (P < 0.05). Of the 4 inserts used, the TFI-9 insert removed the most material while the straight tip produced no apparent removal. Removal by AM S required the presence of a water medium and such forces were found to dec rease with distance from the scaling tip. No plaque substitute removal was seen at a distance of 7 mm for the TFI-9 insert at 37.5 pm displacement wit h the tip orientation parallel to the slide. Conclusions: It is concluded that AMS occurs around ultrasonic scalers and this depends on the displacement amplitude, tip orientation, and presence o f a water medium. AMS may play a role in disruption of subgingival biofilms associated with periodontal disease.