Characterization and toxicity evaluation of air-borne particles released by grinding from two dental resin composites in vitro

• Published in: Dental materials Vol. 37; no. 7; pp. 1121 - 1133
• Main Authors: Camassa, L.M.A., Ervik, T.K., Zegeye, F.D., Mdala, I., Valen, H., Ansteinsson, V., Zienolddiny, S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.07.2021; Elsevier BV
• Subjects: Airborne sensing; Characterization; Composite materials; Cytoplasm; Cytotoxicity; Dental cement; Dental composites; Dental materials; Dental restorative materials; Dentistry; Dentists; Diameters; Diamond burs; Dust; Epithelial cells; Epithelium; Evaluation; Exposure; Grinding; Health hazards; Inhalation; L-Lactate dehydrogenase; Lactate dehydrogenase; Lactic acid; Light scattering; Particle size distribution; Particulate composites; Photon correlation spectroscopy; Polymer matrix composites; Polymers; Respiration; Scanning electron microscopy; Size distribution; Toxicity; Transmission electron microscopy; Ultrafines; Characterization; Diamond burs; Toxicity; Dental composites
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2021.03.011

[Display omitted] The project aims to evaluate whether inhalation of particles released upon grinding of dental composites may pose a health hazard to dentists. The main objective of the study was to characterize the dust from polymer-based dental composites ground with different grain sized burs and investigate particle uptake and the potential cytotoxic effects in human bronchial cells. Polymerized blocks of two dental composites, Filtek™ Z250 and Filtek™ Z500 from 3M™ ESPE, were ground with super coarse (black) and fine (red) burs inside a glass chamber. Ultrafine airborne dust concentration and particle size distribution was measured real-time during grinding with a scanning mobility particle sizer (SMPS). Filter-collected airborne particles were characterized with dynamic light scattering (DLS) and scanning electron microscopy (SEM). Human bronchial epithelial cells (HBEC-3KT) were exposed to the dusts in dose-effect experiments. Toxicity was measured with lactate dehydrogenase (LDH) assay and cell counting kit-8 (CCK8). Cellular uptake was observed with transmission electron microscopy (TEM). Airborne ultrafine particles showed that most particles were in the size range 15−35 nm (SMPS). SEM analysis proved that more than 80% of the particles have a minimum Feret diameter less than 1 μm. In solution (DLS), the particles have larger diameters and tend to agglomerate. Cell toxicity (LDH, CCK8) is shown after 48 h and 72 h exposure times and at the highest doses. TEM showed presence of the particles within the cell cytoplasm. Prolonged and frequent exposure through inhalation may have negative health implications for dentists.