AN IMPROVEMENT IN ARTIFICIAL TEETH
Year: 1872

page_text: COMPLETE SPECIFICATION filed by Charles Henry Mack at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 17th January 1872, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
HENRY MACK, of Portland, Multnomah County, State of Oregon,
United States of America, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVEMENT
IN ARTIFICIAL TEETH," and have petitioned Her Majesty to grant unto
me, my executors, administrators, and assigns, Her Royal Letters
Patent for the same, and have made solemn Declaration that I am the
first and true Inventor thereof.
NOW KNOW YE, that I, the said Charles Henry Mack, do hereby
declare that the following Complete Specification under my hand and
seal fully describes and ascertains the nature of the said Invention, and

page_text: The nature of my Invention consists in providing an artificial crown
with an undercut or dovetailed mortise by means of which it is secured
to the natural root, substantially as herein-after set forth.
To enable others skilled in the art to which my Invention relates to
make and use the same I will now proceed to describe its construction
and mode of operation.
Figure 1 is a section of the crown showing the undercut or dovetailed
mortise; Figure 2 is a bottom view of the same; Figure 3 is a side view 1
of the root; Figure 4 is a front view of the root showing the screws.
Figure 5 is a modification of the crown, and Figure 6 is a cross
section of the same. A represents the undercut or dovetail in the
artificial crown, and b, b, the pins in the root.
I first fill the nerve cavity in the root with gold or other appropriato 1
filling, and then at the anterior and posterior side of the filling I drill
into the solid dentine a hole for the admission of the pins b, b, upon
which are cut small screw threads, the pins are then firmly secured in
the holes. I now fill the undercut with a fusible metal one that will
fuse at a low degree of temperature (such as the compound known as 2
Wood's fusible metal), and while yet soft I press the crown firmly over
the pins b, b. It will be particularly observed that the top of the root
is slightly excavated and the bottom of the crown so rounded or shaped
as to fit snugly therein. Thus the two parts when joined together as
described will form a strong and durable tooth.
2
I am aware that artificial crowns have been provided with round holes
for the insertion of single pins, but it is observed that it will be
impossible to so firmly secure the crown to the fang as in my method of
constructing the mortise, for two reasons; first, because the round holes
will not retain the fusible alloy so well; and secondly, because the crown a
is only secured at the centre instead of both the anterior and posterior
portions thereof.

page_text: shown in my Invention, as my object is to use the natural fang in
connection with an artificial crown, and so securing the two that a tooth
may be inserted as good and as strong as if grown in the mouth without
the pain of extracting the root.
I am also aware that a recess has been formed on the outer surface of
the crown, but this differs from my Invention, as the mortise thus
constructed will not retain or hold the fusible alloy.
Having thus fully described my Invention, what I claim as new and
desire to secure by Letters Patent is,―
1st. An artificial tooth crown for pivot teeth with an clongated
mortise extending toward the labial and back towards the lingual
surfaces sufficiently far to receive two pins or screws located in the
anterior and posterior portions of the fangs, said mortise or undercut
being dovetailed or otherwise shaped to retain firmly its fill of fusible
alloy, substantially as set forth.
2nd. An artificial tooth crown provided with an undercut or dovetail
mortise in combination with two continuous screw pins, said pins being
firmly secured in the solid dentine of the natural fang or root, and the
two parts held together by means of a fusible alloy in said undercut,
substantially as herein described.
In testimony that I claim the foregoing, I have hereunto set my
hand and seal, this Thirtieth day of December, in the year of
our Lord One thousand eight hundred and seventy-one, at
• Washington, District of Columbia, United States of America.
Witnesses,
THOMSON H. ALEXANDER.
JOHN ALFRED ELLIS.
CHARLES HENRY MACK. (L.S.)