The Effect of Standoff Distance and Surface Roughness on Biofilm Disruption Using Cavitation
Dental implants are increasingly becoming a regular mode for tooth replacement with a low failure rate, they are the best option dentistry has to offer patients. Biofilm is associated with dental implant failure, therefore control of biofilm is imperative to retaining dental implants and preventing dental implant failure. Effective biofilm removal is challenging, currently, there is no overall effective method to remove plaque biofilm from dental implants. A study published in July 2020 in the journal PLOS One aimed to evaluate the biofilm removal process from an ultrasonic scaler tip at different standoff distances.1
The authors postulate that cavitation produced by ultrasonic scaler tips have the potential to clean implants in a non-touch model. They used multiple biomaterials with differing levels of roughness to represent different surfaces of dental implants. They also evaluated efficacy from multiple standoff distances including 0.5 mm, 1 mm, or 2mm. Using scanning electron microscopy to determine the level of biofilm disruption.
The majority of biofilm was removed within the first 0.5s, biofilm was removed in a radial pattern perpendicular to the tip. Not surprisingly, most biofilm removal was observed at a distance of 0.5 mm. The amount of biofilm removal on rough surfaces that did not exceed 2 μm was similar when compared to smooth surfaces at all distances. However, surface roughness of 3.5 μm or higher shows a significant reduction in biofilm removal when the standoff distance was 1 mm or 2 mm. Previous studies have shown the optimal roughness for osseointegration is 1-2 μm, this is the most commonly used surface roughness for dental implants.
The results of the study state, “biofilm removal can occur with cavitation from an ultrasonic scaler tip operating for only 2s.” Additionally, the authors suggest that cavitation from an ultrasonic scaler tip may be a clinically viable method if used at the proper standoff distance. There was no damage to the implant surfaces observed in this study. One limitation to note is the biofilm used may have “slightly different structural properties to a vital biofilm.”
In conclusion, the authors state, “high-speed imaging has shown biofilm removal via cavitation generated by an ultrasonic scaler in real-time on rough and smooth implant surfaces and at different standoff distances up to 2 mm. We observed significant biofilm removal after operating an ultrasonic scaler tip for only 2s. Cavitation from an ultrasonic scaler is more effective when the tip is closer to the surface, and equally effective on smooth and rough titanium surfaces, demonstrating its potential as a novel method of dental implant debridement.”
Do the results of this study make you feel comfortable using an ultrasonic scaler for dental implant debridement when used at the proper standoff distance? What method do you currently use for biofilm debridement for dental implants? Do you feel confident in the current method you use? Would you consider changing that method with further studies that confirm these findings in vivo?
Vyas N, Sammons RL, Kuehne SA, Johansson C, Stenport V, Wang QX, Walmsley AD. The effect of standoff distance and surface roughness on biofilm disruption using cavitation. PLoS One. 2020 Jul 30;15(7):e0236428. doi: 10.1371/journal.pone.0236428. PMID: 32730291; PMCID: PMC7392287.