World at work: Dental laboratory technicians

Artists at risk The dental health of the population has improved worldwide due to fluoridation of drinking water and improved preventive dental care. In recent years, full dentures are less commonly used, with a wider application of bridges or crowns. During the last few years, demand for cosmetic prostheses has risen, especially among the aging population. Dentures are made by laboratory dental technicians. This is a job with relatively stable tasks and the process is used worldwide, but the occupational exposure can vary, according to working conditions and materials used. Rough data indicate that there are around 3800 dental technicians in Serbia, of which 30% are men and 70% women. Dentists send to the technicians a specification of the item (that is, crown, bridge, prosthesis, etc) to be made, along with an impression (mould) of the patient’s mouth or teeth. Dental technicians then create a model of the patient’s mouth by pouring plaster into the impression and allowing it to set (fig 1). Figure 1  Impression (mould) and a plaster model. The next step is to place the model on an apparatus that mimics the bite and movement of the patient’s jaw. The model serves as the basis of the prosthetic device. Technicians examine the model, and on these observations and the dentist’s specifications, build and shape a wax model, using small hand instruments called wax carvers. They use this wax model to cast the metal framework for the missing tooth or teeth. Dental technicians then prepare the metal surface to allow the alloy and porcelain to bond, by using small hand-held tools and sandblasting (fig 2). They then apply porcelain in layers, to achieve the desired shape and colour of a tooth (fig 3). Figure 2  Sandblasting of a metal framework. Figure 3  Application of porcelain layers. Technicians place the tooth in a porcelain furnace …