System of Removable Dental Bridges.
Year: 1895

page_text: Date of Application, 25th Sept., 1395-Accepted, 9th Nov.,
1895
COMPLETE SPECIFICATION.
System of Removable Dental Bridges.
I, FRANK COMER, of 9 Hereford Square, South Kensington, in the County of
London, Surgeon Dentist, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer
ained in and by the following statement:-
Heretofore the system generally adopted in dental bridge work has been first
to fit the roots by which the bridge is to be supported in position, with caps or
rings of gold or other metal, and then, with these caps or rings in position, to take
a plaster of Paris impression of the mouth.
These rings are sufficiently loose fitting that they come away with the impression,
so that upon taking a plaster cast from the latter the caps or rings will be left in
position on the cast when the impression is broken away from the latter after this
has been allowed sufficient time to harden.
The cast so obtained is then fitted with the necessary artificial teeth, these being
backed with gold or other metal and soldered together and to the caps or rings,
and the case when finished secured in position by first drying the roots to which
the bridge so formed is to be attached, filling the caps or rings with cement, and
pressing the case firmly into position. The case is thus firmly and permanently
fixed in position and so long as removal is not required generally answers its
purpose, but when removal is found necessary for repairing, cleansing, or the like,
it is usually experienced that this is impossible without injury, if not entirely
destroying the cases.
Now the object of my invention is to overcome this difficulty by a system in
which bridges are rendered easily removable, which I will now describe by the aid
of the accompanying drawings.
My system carry into practical effect by first grinding the stumps to which
the bridge is to be attached by the aid of corrundum coning cups, to a conical form
as shown in Figure 1. The nerve canals are then enlarged and tapped with
a screw thread, and annealed, platinum or other screws a Fig. 2, screwed into
these tapped holes in the roots, and the projecting portion of said screws bent into
the required position.
Gold or platinum caps b are now fitted and cemented over the roots, passing well
up under the gums as shown in Fig. 3, in order to protect the roots from decay,
and the whole prepared for taking the necessary impression by placing small split
metal tubes c Fig. 34, over the projecting screws.
With the impression these split tubes come away, and in these tubes other screws
are placed, when taking a cast from the impression, the result being that said
screws when the impression is broken away from the cast, occupy exactly the same
position as those in the mouth of the patient, as shown in Fig. 4, which is a repre-
sentation of a model so obtained.
Beads & Fig. 6, of gold or platinum are then slipped on the screws on the model,
and to these are soldered the required number of artificial teeth.
Thus when the bridge so prepared is placed in position the beads, which may
also form grinding surfaces, will fit over the screws on the stumps in the patients
mouth, and the bridge may be firmly secured in position by screwing nuts e Fig. 5,
5 onto the ends of these screws as shown in Fig. 7, the beads being preferably
countersunk and the nuts tapered so that said nuts may occupy a position level
with or slightly below the masticating surface, loosening being prevented when
necessary by nacking with gold foil.

page_text: With such an arrangement it will be seen that the bridge may be easily and
quickly removed by the simple operation of unscrewing a few nuts, and a duplicate
bridge as easily secured in position.
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 :-
The system of removable dental bridges substantially as described and illustrated
in the accompanying drawings.
Dated this Twenty-fourth day of September 1895.
FRANK COMER.