the use of multiple implants in the same jaw requires a detailed knowledge of abutment angulation. the position and angulation of the abutments play an important role in treatment planning and fabrication of the custom tray. therefore diagnostic casts that contain cover screws may cause problems during implant therapy. the current article describes a technique for making a preliminary cast with...

If one goes backward in time, the number of ancestors of an individual doubles at each generation. This exponential growth very quickly exceeds the population size, when this size is finite. As a consequence, the ancestors of a given individual cannot be all different and most remote ancestors are repeated many times in any genealogical tree. The statistical properties of these repetitions in g...