Comparative study of three different types of dental diamond burs

Wear mechanisms of three different types of dental burs were studied by means of cutting experiments performed on machinable glass ceramic using a laboratory system designed for this purpose. The dental handpiece used for this research was subjected to a constant feed rate in order to better simulate the actual working conditions of a dental bur. The new and the worn-out burs were studied by optical and scanning electron microscopy. Diamond particle wear-out was found to be the dominant wear mechanism in all cases; a quantitative analysis was performed on the optical micrographs of the new and worn burs. In situ force measurements showed that the forces exerted by the bur increase with the blunting process in order to keep the required feed rates; each bur type seems to have a different characteristic curve of force versus the number of cuts.