<p>The medical community has realized the importance of control of cross-transmission in dental healthcare settings. The risk of contamination is very high in procedures involving high-speed instruments like dental airotors. The airotors employ water sprays, which generate a significant amount of aerosols. Therefore, controlling such sprays is a challenge in dental healthcare settings, and dental care facilities are still not prepared for such challenges. This study characterizes a spray system of multiport high-speed dental airotors. Experimental investigations provide quantitative data on droplet size and velocity at multiple positions within the spray field. Distinct breakup modes are identified, and detailed physical insights are provided into the spray behaviour. Furthermore, the spray was impinged on the biofilm of <i>Streptococcus mutans</i> grown over cold-cure acrylic resin mimicking tooth material, which replicates the dental plaque. Impact of the spray on the biofilm leads to the disintegration of uniform biofilm and generates rebounding daughter droplets, which mainly contribute to aerosol formation and can be potential carriers of microbes from biofilm. For these rebounding droplets, the particle tracking techniques based on the initial ejection speed, angle, and size of the droplets are employed, which assist in predicting their trajectories. The current findings evaluate the risk of cross-contamination associated with these rebounding droplets and provide insights for future optimization of the spray nozzle design to mitigate such risks.</p>