Development of ultrasonic diamond tips for prosthetic preparations : intra-sulcular penetration and finishing touches

There are two stages in the preparation of teeth aimed at receiving ceramo-ceramic crowns. During the first one, the finishing line is in a supra-gingival position, during the second one, the limit is gradually brought in an intrasulcular position. The aim of this work is to replace the diamond drill set on a turbine by diamond tips held on an ultrasonic manual tool during the second stage of preparation. As a consequence, we are going to give a survey on the preparation techniques as well as on the ultrasounds and their field of use in odontology. Then, we will describe the appliance and mainly the two types of ultrasonic inserts that have been worked out (first generation and second generation) as well as the experimental proceedings which will guide us during all our research. At this stage, we will assess the machining efficiency of these inserts on various materials such as dentine and according to two configurations : manually with several operators or on a machine. We will then study the surface layer generated by such a tooling not only from a qualitative point of view (scanning electron microscopy) but also from a quantitative point of view (mechanic and optical profilometries). We will then propose a new programme of preparation in which diamond ultrasonic inserts will be integrated