The late consultation in odontology often leads to tooth extraction. This negligence, in a long term, will cause complete toothlessness. This state of invalidity will be compensated by prosthesis. The removable prosthesis is often indicated because of the cost price. It is the result of a successful therapeutics, only if it fits aesthetically and functionally, within a chewing efficiency. In a first part, we will define masticatory efficiency, as different from masticatory capacity and capability. Then, in a second part, through some experimentation, we will show how fundamental research can guide the practitioner in his prosthetics choices and assessments.