Improvements in Dentistry.
Year: 1896

page_text: Date of Application, 1st May, 1896-Accepted, 20th June, 1896
COMPLETE SPECIFICATION.
Improvements in Dentistry.
We WALTER LEVY MASON, Dentist, and HENRY AVERY CURTIS, Merchant,
both of Riverside Avenue, Broad Street, Red Bank, in the County of Monmouth
and State of New Jersey, U.S.A. do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
Our invention relates to an improvement in dentistry, and especially to an
improvement in detachable porcelains for crown and bridge work, the object of the
invention being to provide a porcelain which may be employed as a finish for a
tooth, or as a single tooth, or may be used as a portion of bridge work, and which
may be conveniently and expeditiously removed from its support and replaced in as
convenient and ready a manner, the operation of removing, returning or replacing
the porcelain being accomplished without the necessity of interfering in the
slightest degree with the support therefor.
The invention consists in the novel construction and combination of the several
parts, as will be hereinafter fully set forth and pointed out in the claims.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar characters of reference indicate corresponding parts
in all the figures.
Figure 1 is a side elevation of a tooth having the improved detachable porcelain
applied;
Figure 2 is a vertical section through the root of a tooth upon which the porcelain
and its support are mounted, together with a vertical section through the support
and the porcelain :
Figure 3 is a perspective view of the porcelain and anchor plate for the pivot
pin therefor;
Figure 4 is a perspective view of the complete support for the porcelain, viewed
from its upper side;
Figure 5 is a perspective view of a portion of the backing for the porcelain,
and a cap or band to surround the root of the tooth;
Figure 6 is a perspective view of the porcelain and support, adapted either for
bridge work or for kindred uses, the support differing slightly from that shown in
Figures 4 and 5 ;
Figure 7 is
perspective view of the improved porcelain viewed from the
inside, and also a perspective view of the tongue adapted for attachment to the
said porcelain;
Figure 8 is a perspective view of the porcelain viewed from the inside,
illustrating the tongue as applied thereto.
Figure 9 is a perspective view of a backing for the porcelain shown in Figures 7
and 8, and viewed from the back;
Figure 10 is a perspective view of a porcelain fitted to a backing which is
adapted for attachment to a natural root; and
Figure 11 is a vertical section taken substantially on the line 5-5 of
Figure 10.
In the practice of our invention, the porcelain A is provided with a chamber 10
in the back portion thereof, and a transverse recess 10 at the bottom portion of
tlis chamber; and in the recessed portion of the porcelain preferably two metal
pins 10 are laterally projected in a rearwardly direction, and the bottom of the

page_text: chamber 10 is formed through the medium of an anchor plate B, which is preferably
of metal and is adapted to fill the recess 10° in the back of the porcelain. The
anchor plate is provided with apertures 11, corresponding in number and location
to the horizontal pins 10°, since when the anchor plate is in position on the back of
the porcelain the said pins extend through the apertures 11, and are soldered,
riveted or otherwise mauipulated to render the anchor plate and porcelain virtually
integral.
The open or chamber portion 10 of the porcelain is as heretofore stated at the
back and likewise at that portion of the porcelain which is placed next to the
gums. The anchor plate A has secured thereto or formed integral therewith a vertical
pivot pin 11 which is centrally located within the aforesaid chamber 10 of the
porcelain, and is usually of sufficient length to extend from the base of the chamber
substantially flush with the edge of the porcelain that is to contact with the gum,
or beyond this edge as occasion may demand.
When the porcelain is to be applied to a root C, as shown in Figures 1 and 2, a
band 12 is provided adapted to encircle the root and to be cemented or otherwise
secured thereto, the band being shown particularly in Figures 4 and 5; and
preferably the said band is provided at the back with a plate 13 having one of its
sides more or less curved and beveled and its other side practically straight, the
curved or beveled side being that which is to be presented to the tongue, and
constituting the lingual face of the tooth, or of the bridge-work.
A backing D is provided for the porcelain, being secured to the back plate 13; and
in order that this backing may perfectly fit the porcelain, a tube 14 of a very thin
metal is placed around the pivot pin 11 of the porcelain. The porcelain is then
placed against the straight face of the back plate 13, or against any other flat
surface, and the material from which the backing is to be made is poured into the
chamber 10 of the porcelain around the tube 14, adhering to this tube. In this
manner the porcelain is used as a mold for its backing, and the tube is made an
integral portion of the backing, it then being adapted to receive the pivot pin of
the porcelain at any time.
The backing after it has been cast or molded is removed from the porcelain and
secured in any suitable or approved manner to the straight surface of the back
plate 13, and is carried upward within the band 12 to rest against the upper or
lower face of the root according to whether the said root is in the upper or the
lower jaw. It is evident that the backing, back plate and band having been
secured to the root, the porcelain may be quickly placed in position by sliding it
over the backing, its pivot pin 11 entering the opening 15 in the backing formed
by the inserted tube 14, and the pin may be cemented or otherwise secured in the
said opening or socket 15.
It is further evident, that should anything happen to the porcelain, that is,
should it become broken or otherwise damaged, it may be readily removed and
replaced by another without disturbing the backing or the attaching devices to the
root or to the bridge work if used in that connection. It is also evident that the
porcelain will not be injured by contact with the fire, since under this new and
improved process, the porcelain is not soldered, as under the old process, nor is
it held in any metal binding which must be soldered while the porcelain is in
place.
In Figure 6, I have illustrated a slight modification in the formation of the
backing, being especially adapted for use in connection with bridge work, and
therefore the back plate 13" is straight on both of its faces and is provided with
a cap or flange 13b at the top, the band 12ª being shown in dotted lines.
In carrying out the invention as illustrated in Figures 7 to 11, the porcelain A is
provided with a metallic strip 10%, which is embedded and secured in any suitable
or approved manner in the body of the porcelain, extending from its upper or gum
section 11 to a point at or near the bottom, and the back or outer face of the
strip 10 is made flush with the back surface of the porcelain, or in other words as
the back of the porcelain is ground down to a proper surface the metallic surface

page_text: is ground proportionately or evenly with the aforesaid porcelain. In the drawings
the metallic strip 10° is shown as of wedge-shape, and is embedded in the porcelain
when in a plastic state and is then baked therein, although it may be otherwise
secured to place.
The metallic strip 10° forming virtually an integral portion of the porcelain, is
adapted as an anchorage for a bar 12b, which is preferably made dove tailed shape
in cross section, the said bar being brazed, soldered or otherwise secured to the
aforesaid metallic or anchorage strip 10° throughout the length of the latter; and
also preferably the lower end of the dove tail bar 12b is provided with an inclined
surface 13, the inclination being downward and forward, meeting the lower edge
of the porcelain as shown in Figure 8, and in attaching the dove tail strip 12° to
the porcelain the narrower longitudinal surface is that which is secured to the
anchorage strip 10°.
Such a strip applied to a porcelain enables a backing B₁ to be attached in a
convenient and expeditious manner, the said backing, no matter of what material
it may be made, being provided with a dove-tail slot 14 in that face which is
adapted for engagement with the inner face of the porcelain; and the aforesaid
dove-tail slot 14 of the backing will nearly receive the dove-tail bar 12 of the
porcelain, the inclined lower end of the bar serving to facilitate the introduction
of the bar into the aforesaid slot; and the lower end of the dove-tail slot 14" is
carried through the inner face of the backing, as illustrated at 15% in Figure 10,
in order that the backing and the bar may be soldered or brazed, if in practice it
is found desirable, or the backing and the porcelain may be otherwise held firmly
together.
The cross section shown in Figure 11, illustrates a backing and a porcelain,
the former being provided with an upper band 16 adapted for engagement with a
natural root.
The aforesaid strip 10° forms the connection between the dove-tail rib and the
porcelain and the importance and necessity of making the strip 10° separate from
the dove-tail rib 12 results from the necessity of making the surface of the
porcelain a true and unbroken plane which is accomplished by grinding off the said
surface and if such grinding be attempted with the dove-tail rib applied, it will in
nearly, if not every instance result in a marring of the said rib by the grinding
tool which marring of the dove-tail rib would not only detract from its efficiency,
but would tend to permit a jarring of the porcelain and a rapid loosening thereof
Apart from such objection it would be practically impossible to grind the surface
of the porcelain true subsequent to the application of the dove-tail rib.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A detachable porcelain for crown and bridge work, provided with a pivot pin,
a backing shaped to fit the inner face of the porcelain, and having a socket to
receive the pivot pin, and means for securing the said backing to a root or to the
structure or bridge work, whereby the said porcelain may be removed or replaced
without disturbing the backing or the support therefor, as and for the purpose
specified.
2. A detachable porcelain for crown and bridge work provided with a chamber,
and a pin in the said chamber, extending from the base wall thereof in direction
of the edge to be presented to the gum, a support adapted to be secured to a root
or to a portion of the structure of bridge work, and a backing secured to said
support and having a socket to receive the pin, on the detachable porcelain as and
for the purpose set forth.
3. As an improved article of manufacture an artificial tooth, consisting of a
back plate having a backing secured thereto, a vertical tube secured in the said
backing, a band for securing the said back plate to a root or to the structure of

page_text: bridge work, and a porcelain shell provided with a chamber at its back adapted to
enter the tube in the said backing, substantially as shown and described.
4. The herein described method of applying detachable porcelains for crown
and bridge work, which consists in forming a chamber in the back of the
porcelain, placing a pin in said chamber, molding the backing for the porcelain
in the chamber of the latter, whereby the tube will adhere to the backing and
will be withdrawn from the porcelain with the backing, and finally securing the
backing to a back plate or support adapted for attachment to a root, or to a portion
of the structure of bridge work, as and for the purpose set forth.
5. An artificial tooth comprising a backing having a dove-tail groove, the
porcelain, an anchorage strip secured in said porcelain and true and flush with the
inner face thereof and a separate dove-tail rib secured to said anchorage strip and
fitted to the groove of the backing, substantially as set forth.
6. In an artificial tooth, the porcelain having at its inner face an anchorage
strip secured in the porcelain and a separate dove-tail rib secured to said anchorage
strip, substantially as set forth.
Dated this 1st day of May 1896.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.