Dental Blade Implant

This is a blade type dental implant.  It is used when the mandible is too thin or weak for a screw implant.  The blade is made of titanium.  The jaw bone is split down the middle and the blade is inserted into the bone.  As the bone grows back it will grow through the slots in the blade and permanently anchor in the jaw.  The two small bosses stick up just above the gum line.  An abutment is screwed into the bosses of the implant and on the abutments is where the tooth or other dental work would be anchored.

    The part is fairly straightforward.  We cut the blade section of the part on our CNC mills.  We built a holding fixture that allowed us to use rectangular bar stock.  This made it possible for us to do both sides using our "A" axis on the mill, and keep both sides registered correctly.  Where the bosses are we left excess stock to machine next.  We cut the part off using a small end mill.

    On a CNC chucker we held the blade part of the implant with a two jaw chuck.  We had to make some special tools to be able to get into some of the reliefs and blend the OD with the milled blade.  The section of the blade that required significant thought was what would seem to be pretty common, the threaded ID.   One of the requirements for an implant is that it not get infected.   Antibiotics do not work when the infection involves a prosthesis.  If the abutment that goes on top of the implant is eccentric then foreign material (food) could get caught in the mismatch.  If not removed this could start an infection.  This requires that the concentricity be very good.  When we first started making the blade we had a tolerance of .002 tir.  Even though we bored the ID, when the hole was tapped concentricity was not consistent enough to produce satisfactory results.  The obvious solution was to single point the thread.  The thread was a 2 x .75mm, and the minor was .081/.083.  The routines that come with the CNC control required too much tool movement.  So we wrote a macro that would use the minimum amount of movement and would allow us to make our threading tool the strongest possible.  It was very successful and concentricity was no longer a problem.