Dowel post for dental and medical prosthetic devices

DETAILED DESCRIPTION The present invention relates to a new and improved dowel post for dental and medical prosthetic devices.
In accordance with the invention, we have developed a new post configuration, which improves the distribution of cement between the post and the hole, reduces pressure build-up ahead of the post during insertion, and generally obtains retention strengths substantially higher than that obtained with conventional parallel-sided or tapered posts, whether with the longitudinal venting groove or without.
In accordance with this invention, this is achieved by forming the shaft of the dowel post, i.
e.
the part which is to be received into the blind hole, with at least one concave flute formed in the surface thereof and helically wound thereabout at a pitch angle of 70.
degree.
or less to the axis of the post.
Optimum retention is obtained at pitch angles in the range 20.
degree.
-60.
degree.
, with the preferred angle being about 45.
degree.
.
Preferably four or five flutes are provided helically wound about the shaft along the length thereof and giving the shaft a polygonal cross-section, and an oblique section having a scalloped outline.
The flutes may extend only partway along the shaft portion of the dowel post, but preferably extend along substantially the whole length thereof.
An object of this invention is to provide a new and improved dowel post for dental and medical prosthetic devices.
Another object of this invention is to provide a new and improved dowel post for dental and medical prosthetic devices wherein the shaft of the post includes at least one concave flute formed in the surface thereof.
A more specific object of this invention is to provide a new and improved medical or dental dowel post to reduce pressure build-up during insertion into a blind hole and improve retention strength wherein the shaft of the post includes a plurality of concave flutes wound helically thereabout at a predetermined pitch angle.