Effect of polymer viscosity and viscoelasticity on tooth cooling and aerosolization during dental procedures

Abstract

Cooling liquids used in ultrasonic scalers are aerosolized into droplets. Larger droplets splatter over dental practitioners and patients, and small aerosols become airborne, posing a health threat to people in the surrounding area if a patient is infected by viral or bacterial infections. Polyacrylic acid (PAA), polyethylene glycol (PEG), and polyvinylpyrrolidone (PVP) can efficiently cool teeth and suppress aerosolization owing to their rheological properties, with PAA being the superior viscoelastic suppressant. Although the solutions of PEG and PVP studied here are also efficient in suppressing aerosol formation, their high viscosity may hinder their supply to the dental tools because of high viscous dissipation. The rheological behavior of PAA, PEG, and PVP is studied in the uniaxial elongational flow in self-thinning capillary threads. Then, the behavior of these solutions in an ultrasonic scaler in dental practice is explored. In particular, the aerosolization phenomena and the corresponding aerosol size distributions and droplet trajectories are studied and compared. The tooth temperature is found to be similar to that of water when these polymer solutions are used. The dispersion of the aerosolized droplets is qualitatively demonstrated by performing scaling using model teeth on a phantom mannequin face.