Stevan M Cokic1, Christof Asbach2, Jan De Munck1, Bart Van Meerbeek1, Peter Hoet3, Jin Won Seo4, Kirsten L Van Landuyt5. 1. KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Kapucijnenvoer 7, 3000, Leuven, Belgium. 2. Institute of Energy and Environmental Technology (IUTA) e.V., Bliersheimer Straße 60, 47229, Duisburg, Germany. 3. Department of Public Health and Primary Care, Centre for Environment and Health, KU Leuven (University of Leuven), Kapucijnenvoer 35/5, 3000, Leuven, Belgium. 4. Surface and Interface Engineered Materials, Department of Materials Engineering, KU Leuven (University of Leuven), Kasteelpark Arenberg 44, 3001, Heverlee, Belgium. 5. KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Kapucijnenvoer 7, 3000, Leuven, Belgium. kirsten.vanlanduyt@uzleuven.be.
Abstract
OBJECTIVE: To evaluate the collection efficiency of water spray on the release of airborne composite particles during grinding of composite materials. MATERIALS AND METHODS: Composite sticks (L:35 mm × W:5.4 mm × H:1.6 mm) of seven commercial dental composites were ground with a rough diamond bur (grain size 100 μm, speed 200,000 rpm). All experiments were performed in an enclosed 1-m3 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). Particles were collected by an electrostatic precipitator (ESP), and were ultramorphologically and chemically analyzed by a transmission electron microscope equipped with energy-dispersive X-ray spectroscopy (TEM-EDS). RESULTS: SMPS measurements confirmed that both dry and wet grinding generated high concentrations of nanoparticles 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 × 105 - 1.37 × 106#/cm3). The smallest particle diameter was recorded during the last minute of grinding followed by a continuous growth for every next measurement. TEM of composite dust revealed a high concentration of particles varying in both size and shape. CONCLUSIONS: Regardless of whether the water cooling spray system was used during bur manipulation of composite materials, predominately nanoparticles were released. However, the particle concentrations were significantly decreased with water spray. CLINICAL RELEVANCE: Since water spray might not be sufficient in nanoparticle collection, special care should be taken to prevent inhalation of composite dust.
OBJECTIVE: To evaluate the collection efficiency of water spray on the release of airborne composite particles during grinding of composite materials. MATERIALS AND METHODS: Composite sticks (L:35 mm × W:5.4 mm × H:1.6 mm) of seven commercial dental composites were ground with a rough diamond bur (grain size 100 μm, speed 200,000 rpm). All experiments were performed in an enclosed 1-m3 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). Particles were collected by an electrostatic precipitator (ESP), and were ultramorphologically and chemically analyzed by a transmission electron microscope equipped with energy-dispersive X-ray spectroscopy (TEM-EDS). RESULTS: SMPS measurements confirmed that both dry and wet grinding generated high concentrations of nanoparticles 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 × 105 - 1.37 × 106#/cm3). The smallest particle diameter was recorded during the last minute of grinding followed by a continuous growth for every next measurement. TEM of composite dust revealed a high concentration of particles varying in both size and shape. CONCLUSIONS: Regardless of whether the water cooling spray system was used during bur manipulation of composite materials, predominately nanoparticles were released. However, the particle concentrations were significantly decreased with water spray. CLINICAL RELEVANCE: Since water spray might not be sufficient in nanoparticle collection, special care should be taken to prevent inhalation of composite dust.
Authors: Steve Marshall; Michael Duryea; Greg Huang; Onur Kadioglu; James Mah; Juan Martin Palomo; Emile Rossouw; Dina Stappert; Kelton Stewart; Eser Tufekci Journal: Am J Orthod Dentofacial Orthop Date: 2020-09-21 Impact factor: 2.650