Mitigation of aerosol particles during composite attachment removal

This study aimed to determine which strategies most effectively reduce aerosolized particles when removing orthodontic composite attachments.

A network of AeroSpec portable particle monitors was employed to record particulate data in real-time. Sixteen sensors were placed in a 3-dimensional grid system around an operatory at the University of Washington Orthodontics Department. Composite attachments (Transbond LR; 3M, St Paul, Minn) were removed from the anterior 6 teeth of maxillary and mandibular resin models. Particulate matter of optical diameter ≤2.5 μm (PM_2.5) was measured. Three different high-speed handpieces were tested: conventional air-driven (StarDental; DentalEZ, Malvern, Pa), electric (BienAir, Bienne, Switzerland), and air-free (Medidenta, Las Vegas, Nev). Four different suction conditions were tested with each handpiece: none, high-speed intraoral suction (IOS), extraoral suction (EOS), and both together. Four repetitions with each variant were performed. Linear regression was used to compare average and maximum particle concentration by suction and handpiece.

The highest concentration of particles was observed around the operator and decreased farther from the source of composite removal. Linear regression for the main effect of handpiece type indicated lower PM_2.5 when electric or air-free handpieces were used compared with the conventional handpieces. Linear regression for the main effect of suction showed significant reductions when any suction was used compared with none. The simultaneous use of both IOS and EOS resulted in the greatest reduction in PM_2.5.

Using an air-free or electric handpiece, along with simultaneous use of IOS and EOS, reduced the mean particle concentrations by 87% and 86% and the maximum particle concentrations by 92% and 94% near the operator, compared with a conventional handpiece and no suction.