When we are called upon to restore a fully edentulous patient with immobile restoration then we need to ensure a sufficient number of implants ranging from 6-8 in order to support such an extensive rehabilitation. What must be preceded in order to achieve absolute aesthetic restoration is the prosthetically directed placement of the implants by placing them in the most appropriate aesthetic position, which is not necessary in the hybrid rehabilitations.
Ideally, every missing tooth would be replaced by an implant. But this would be difficult, except for an excessive one, because no patient has a perfect bone volume, and the cost of the incident would be ejected. A good ratio is an implant for every two missing teeth, which involves 6-8 teeth for each jaw. An important role is played by the dispersion of the implants, by placement in places that will respond to their role as bridge abutments. So we see that in such incidents we do not want to place only a sufficient number of implants, but we have to place them having as a guide the final restoration, so we are talking about prosthetically directed implantation.
