Improvements in Artificial Teeth.
Year: 1890

page_text: Date of Application, 1st May, 1890
Complete Specification Left, 2nd Feb., 1891-Accepted, 11th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in Artificial Teeth.
I, ROBERT BREWSTER, of Clynedale, Victoria Road, New Barnet, in the
County of Herts, Manufacturer, do hereby declare the nature of this invention to
be as follows:—
The invention has for its object Improvements in Artificial Teeth whereby
cheapness of production and security of hold to the backing and base plate are
obtained.
According to my present invention I fix a single platinum pin in the body of
the tooth in the process of moulding and firing the same in lien of employing two
of such pins as heretofore and I form in the back of the neck of the tooth an
undercut recess and in some cases a shoulder or lip near the cutting edge such as
that employed in connection with a vulcanite base.
The platinum pin is bent down in a line with the axis of the tooth so as to
obtain a firm hold of the vulcanite base which latter by entering the undercut
recess in the back of the tooth obtains a firm hold of the latter and prevents its
liability to rotation on the platinum pin.
When employing a metal base plate the undercut recess may receive a pin to
enable the tooth to be fixed to a stump in the mouth in which case the base plate and
the pin would be firmly soldered together or the said undercut recess may simply
be filled with solder which is attached to the backing for ordinary plate work.
ROBERT BREWSTER.
By Harris & Mills,
23, Southampton Buildings, London, Agents.
COMPLETE SPECIFICATION.
Improvements in Artificial Teeth.
I, ROBERT BREWSTER, of Clynedale, Victoria Road, New Barnet, in the
County of Herts, Manufacturer, 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 stateinent:-
The invention has for its object Improvements in Artificial Teeth whereby
cheapness of production and security of hold to the backing and base plate are
obtained.
According to my present invention I fix a single projecting platinum pin in the
body of the tooth in the process of moulding and firing the same in lieu of
employing two of such pins as heretofore generally adopted and in combination
therewith I form in the back of the neck of the tooth an undercut recess.
And in order that my said invention may be more clearly understood and readily
carried into effect I will proceed aided by the accompanying drawings more fully

page_text: teeth are constructed nerording to my invention with a single projecting platinum
pin fixed in the body thereof in combination with an undercut recess a formed
in the back of the neck of the tooth in which is a narrow longitudinal groove or
opening communicating with such underent recess.
When employing such a tooth in combination with a vulcanite or plastic base as
represented at Figure 5 bend down the pin 6 preferably in a line with the axis
of the 'onth or thereabouts so as to obtain a firm hold of the vulcanite or plastic
base which latter by entering and filling the undercut recess a' in the back of
the neck of the tooth obtains a firm holl of the latter and prevents its liability
to rotation on the platinum pin b.
may
When employing a tooth such as that hereinbefore described in combination
with a metal base plate e as shown at Figure 6, the undercut recess receiro
a pin to which the parking d, represented at Figure 7, is soldered thereby affording
a larger metal surface for attachment to the base plate e as the solder used will not
only connect the top edge of the backing d to the base plate e but will also connect
the top end of the pin in the recess al to such base plater whilst the backing d will
also be very securely connected to the tooth as the opening in the back of the
neck of the tooth will enable the solder to connect such backing with the length
of the pin occupying the recess a' in addition to its connection with the projecting
pin b. To facilitate the connection of the backing d to the pin in the recess a', the
backing d is as will be readily understood sawn up a short distance to allow the
solder to run through to the said pin.
When using these improved teeth for crowning roots, the pin which occupies the
recess will be securely soldered as before described along the opening in the back
of the neck of the tooth to the barking d and such pin will project froin such tooth
or crown so as to enter the hole formed in the root.
It will be seen on examining Figures 2 to 6 that the tooth there represented
has the neck spread out towards the base of the tooth thus forming what I have
herein called a buttress tooth.
By the employment of "buttress" teeth, such as that shown at Figures 2 to 6, I
obtain a firmer connection of the tooth with the metal or plastic base and a greater
similarity to natural teeth when in the mouth, than when employing tecth
having flat backs extending from the cutting edge to the base of the tooth.
I would here remark that I am aware that artificial teeth have heretofore been
provided with a single projecting platinun pin, but in such case there was no
undercut recess in the neck of the tooth, which latter was consequently liable
to rotation on the said pin and was consequently not sufficiently solidly
connected with the buse; I am also aware that artificial teeth have hereto-
fore been made with undercut recesses in the necks thereof, but in such cases no
projecting platinum pin was employed. According to my present invention I
combine these two features and thereby obtain an economy in the amount of
platinum employed, whilst the tooth is as securely connected with the base as when
two projecting platinum pins are used, in addition to which 1 obtain the herein-
before described advantages over those of teeth having either of those features
separately.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In artificial teeth, or in artificial crowns for natural roots, the employment of
a single projecting metal pin at the back, and an undercut recess in the neck
thereof, having a longitudinal opening in the back of the tooth, substantially as
herein shown and described and for the purpose stated.
2. In artificial teeth, or in artificial crowns for natural roots, the employment of
a single projecting metal pin for connection with a metal backing or with a
vulcanite or plastic base and an undercut recess to receive a pin or to be filled with

page_text: plastic material substantially as herein shown and described and for the purpose
stated.
D
1001
ROBERT BREWSTER.
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.