A sterile transosteal (transosseous) device [transmandibular implant (TMI)] intended to be surgically implanted through mandibular bone to provide support and a means of retention for a dental prosthesis, especially in a patient with an extremely atrophied/deformed mandible. It is composed of a metal plate and transosteal pins or posts. The plate is held with retentive pins or screws fixed to the inferior border of the mandible, and supports the transosteal pins/posts that penetrate the full thickness of the mandible and project into the mouth in the inter-foraminal area.