Title: 2948 - The Effect of Water Spray on the Release of Composite Nano Dust


Stevan Cokic (Presenter)
KU Leuven (University of Leuven)

Christof Asbach, Institute of Energy and Environmental Technology (IUTA)
Jan De Munck, KU Leuven (University of Leuven)
Bart Van Meerbeek, KU Leuven (University of Leuven)
Peter Hoet, KU Leuven (University of Leuven)
Jin Won Seo, KU Leuven (University of Leuven)
Kirsten Van Landuyt, KU Leuven (University of Leuven)


Objectives: To evaluate the collection efficiency of water spray on the release of airborne composite particles during grinding of composite materials.

Methods: Composite sticks (34.8 mm x 5.4 mm x 1.6 mm) of seven commercial dental composites were ground with a rough diamond bur (grain size 100µm, speed 200,000rpm). All experiments were performed in an enclosed 1m3 chamber with low particulate background (<1,000 #/cm3) and airborne particles were evaluated based on their electrical mobility. The number size distribution was determined by scanning mobility particle sizer (SMPS; with long differential mobility analyzer (DMA) and either water UCPC or a butanol UCPC (TSI, Shoreview, MN, USA). Particles were collected by electrostatic precipitator (ESP) and ultramorphologically and chemically analyzed by transmission electron microscope equipped with energy dispersive spectroscopy (TEM-EDX).

Results: SMPS measurements confirmed that both dry and wet grinding generated high concentrations of nano-sized particles with the highest concentration recorded during the last minute of grinding (1.80×106 - 3.29×106 #/cm3), after which a gradual decline in particle concentration took place. Nevertheless, grinding with water spray resulted in a significant reduction of the number of released particles (5.6 x 105 - 1.37 x 106 #/cm3). The smallest particle diameter was recorded during the last minute of grinding followed by a continuous growth for every next measurement, suggesting particle agglomeration. TEM of composite dust revealed a high concentration of particles varying in both, size and shape.

Conclusions: Overall, regardless of whether the water-cooling spray system was used during bur manipulation of composite materials, predominately nano-particles were released. Even though the particle concentrations were still high, they significantly decreased with water spray. This suggests that applying water spray during abrasive manipulation of composites may be a strategy to reduce dentist and patient exposure to airborne particles.

Student Presenter

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE