Abstract
BackgroundExposure to crystalline silica in dental laboratories can occur during procedures that generate suspended mineral dusts, e.g. dispersion of mixing powders, removal of castings from moulds grinding and polishing castings and porcelain, and use of silica sand for blasting. Case presentationWe report a 55-year-old male dental technician who, after about 15 years of work, began to suffer from a dry cough and dyspnoea on exertion. The operations included in his job resulted in the generation of crystalline silica, aluminium, chromium, titanium dust. The worker did not regularly wear personal protective equipment and some of the above operations were not carried out in closed circuit systems.The Chest X-ray showed diffuse micronodulation in the lung interstitium in the upper-middle lobes bilaterally and a modest left basal pleural effusion, simple spirometry showed initial small airway obstruction, High Resolution Computerized Tomography of the chest showed bilateral micronodulation of a miliariform type, with greater profusion in the upper lobes, also present in the visceral pleura, bilaterally. Histological examination showed aggregates of pigment-laden macrophages forming perivascular macules or arranged in a radial pattern around a core of sclerohyalinosis. Scanning Electron Microscopy and Energy Dispersive Spectrometry revealed several mineral particles, whose composition is characterised by the presence of aggregates of crystalline silica and metals. The ambient concentrations of total dust and its respirable fraction were all lower than the relative TLV-TWA - ACGIH, but did not negligible. ConclusionsThe above findings and a multidisciplinary assessment led to the diagnosis of mixed dust pneumoconiosis s/q with 2/2 profusion of occupational origin. This diagnosis in a dental technician was supported by environmental exposure analysis for the first time in the literature.
