US2203089A - Dental device - Google Patents

Description

June 1940- G. M. HOLLENBACK g V 9 DENTAL DEVICE IN VENTOR Geo/ye 1y, fizzle/Mack ATTORNEY Patented June 4, 1940 UNITED STATES PATENT- OFFICE 3 Claims.

This invention broadly relates to a dental device, and particularly to means adapted to triturate amalgams. I

It is common practice by dentists to use in the 5 cavities of teeth amalgams of various metals,

particularly where the tooth is not readily observable and an inexpensive filling is desired by the patient. However, amalgams have not proved entirely satisfactory due to'various causes, among which may be specifically mentioned, that of contraction. The average amalgam, so-called, consists of mercury and alloy. The alloy varies with different manufacturers, based upon their experience, but generally contains copper, silver and possibly zinc. It has been found that particle size of the filings of the metal alloy may control contraction of the amalgam when the amalgam is triturated. In fact, the subject of expansion and contraction of amalgams has been studied -8: over a period of time. It is possiblev to cause considerablecontraction of the amalgam when the amalgam is not properly triturated.

Trituration of an alloy with mercury is usually accomplished in what is termed a mortar through ,5 the medium of a pestle. This pestleis revolved within the mortar to effect trituration but unless a given pressure is maintained by the pestle upon the amalgam, varying degrees of contraction may result in the amalgam, irrespective of the given rate of speed at which the pestle is moved over the amalgam. It is ordinary practice for a dentist to place a drop or more of triple distilled mercury over the alloy and to work the mercury and alloy together, to wit, triturate it. After the dentist has reached what to him or experience teaches is proper trituration, the amalgam. is.

removed from the mortar, usually by rollingthe same into a compact form by the fingers whereupon, in the palm of the hand, the amalgam. is mulled. This is done in order to remove excess mercury and to assure a proper coating of all of the alloy grains with mercury. Usually, the mulled. amalgamis rolled into a cylindrical form and out intosmall pieces so that a short cylinder may be placed in the tooth. cavity and thereafter condensed by a-suitable condenser.

Over a period of time, the inventor has made tests for dimensional changes, flow and crushing strength of various amalgams, and has found that the factors just mentioned can be controlled to a high degree by the invention to be described. In fact, it is possible for the tyre dentist to obtain results comparable to those obtained by the most expert dental technician.

Under-trituration will tend to increase expansion and to reduce crushing strength of an amalgain and to increase flow. Over-trituration will tend to produce shrinkage in the amalgam in direct proportion to the amount of over-trituration, to increase the crushing strength and flow. Correct trituration will prevent shrinkage and tend to hold expansion within desirable limits. It will-decrease flow and increase crushing strength.

While I have mentioned mulling of the amalgam in the hand, still I do not recommend this procedure, but prefer to place the amalgam after its removal from the mortar in. a small piece of rubber dam and work the amalgam in said dam into a compact mass. The reason for this is that any method of manipulation which tends to contaminate the amalgam in anyway may result in an inferior amalgam.

An object of the present invention is the provision of means whereby correct trituration of an amalgam may be obtained.

Another object is the provision of means whereby an amalgam may be formed in such a manner that the result to be obtained from said amalgam in use or service may be accurately predetermined.

Another object is the provision of a device for" use in triturating amalgams which may be used as readily by an amateur as a professional, the same results being obtained in the amalgam.

Another object is the provision of a device of the character stated, wherein accurate pressure engagement may be maintained on an amalgam during trituration thereof.

Another object is the provision of a pestle and mortar wherein the pestle may be maintained at a selected pressure engagement with the said mortar at all times during rotation of the said pestle.

Another object is the provision of suitable means for use in conjunction with a pestle and a mortar adapted to receive said pestle whereby a technician is eifectively prevented from increasing pressure of said pestle against said mortar during movement thereof.

Other objects of the invention consist of a device which is inexpensive in cost of manufacture, efiicient in operation, capable of performing superior results for the purpose intended, is compact and ornamental in appearance, capable of being readily cleaned, easily assembled, and of great utility. I

With the above mentioned and other objects in view, the invention'consists in the novel and useful provision, formation, construction, association, and relative arrangement of parts, members and features, all as depicted in a certain embodiment in the accompanying drawing, described generally, and more particularly pointed out in the claims.

In the drawing:

Figure l is a perspective view of my dental device as an entirety, and,

Figure 2 is a vertical sectional view on the line 22 of Figure 1.

Referring now with particularity to the drawing, I provide a base i which may be substan' tially circular in form and provided with an cecentric concavity 2 in the upper surface of said base. This concavity is adapted to have received therein and to hold in position a mortar 3. What is termed a mortar usually comprises a bowl-like receptacle and, in the present instance, the bowl portion is provided on the inner surface of the base with a raised center l. This construction results in the provision of an annular concavity 5. Adapted for reception within the bowl portion of the mortar and particularly in the concavity 5, is a pestle 6. A tubular shank, l, provided with a cap '8, has the cap thereof secured to the pestle at its upper end in any ordinary manner. The end opposite the capB carries a socket member 9, the socket portion being at iii. Adapted for reception in the socket is ball head H on one end of a shank i2.

The base i has secured thereto a pedestal i3, such as by having a reduced threaded diameter portion threaded into an opening of the base, as indicated at it and an arm i5 secured at the opposite end of the pedestal 3. The arm is provided with a transverse bore adapted to receive a bushing 56. Through the bushing is passed the shank i2.

Adapted to be carried by the shank i2 is an annular disc I], provided with an annular cnlargement i8 upon the under stuface thereof,

. which annular enlargement is pinned at 45, or

otherwise secured to the shank E2. The disc ii is adapted to sustain and act as a platform for one or more annular weights, such as shown at 2d, 2! and 22. Thus, a constant pressure is exerted by said weights in a downward dlrection to impose a given pressure between the head of the pestle and the concavity 5 of the mortar. Surrounding the shank l is a double conical spring 23. One end of said spring may be Socured to the cap 8, the other end being free. This spring acts as the handle or finger-hold for actuating the pestle. By separating the coils of the spring as designated in the drawing, any attempted downward pressure is immediately absorbed by the spring without in any manner increasing the pressure of the pestle against the mortar.

General directions for actuating mortars and as accepted by dentists everywhere, is to hold the pestle with a pin grip, and this practice should be followed so far as actuation of the pestle is concerned. In other words, the fingerhold or handle portion 23 should be held with a pen grip between the thumb and the first finger.

The operation, uses and advantages of the invention are as follows:

Having a good alloy with known characteristics as furnished by the manufacturer thereof, and assuming the use of triple distilled mercury and combining the same in the proper proportions as indicated by the manufacturer of the alloy,-

by way of example, this proportion being as 5 to 8, the same is placed within the mortar. The

pressure to be exerted by the pestle upon this material may be three pounds and, accordingly, a proper weight is supported upon the platform ll. It is known that the number of revolutions of the pestle within the mortar greatly affects the characteristics of the amalgam so far as in-- crease or decrease of flow, and expansion or pestle is easily revolved due to the ball and socket arrangement and the weight or weights on the platform exert a constant downward pressure under gravity influence. It will be observed that the ball 8 i is adapted to be directly centered over the raised center of the mortar.

The device Works exceedingly easily and produces efficient results, as it readily may be seen that lateral and vertical pressures other than that exerted downwardly by the weights is effectively overcome by the construction described and shown.

It is obvious that various changes and modifications and variations may be made in practicing the invention in departure from the particular showing of the drawing and description as given without, however, departing from the true spirit of the invention.

I claim:

1. In a dental device of the character disclosed; a mortar formed with a raised center defining an annular pathway; a pestle disposed in said pathway and guided thereby when moved 2. In a dental device of the character disclosed; a mortar formed with a raised center defining an annularpathway, a pestle disposed in said pathway and guided thereby when moved therein, weight means, and means slidably guiding the weight means along a vertical axis passing through the axis of the raised center of the mortar, and means between the second named means and the pestle'whereby the said weight means exerts a constant downward pressure on said pestle, and a spring finger hold on said pestle through which the pestle may be moved in said pathway.

3. In a dental device of the character disclosed; a mortar formed with a raised center defining an annular pathway, a pestle disposed in said pathway and guided thereby when moved therein, weight means, and means slidably guiding the weight means along a vertical axis passing through the axis of the raised center of the mortar, means transmitting the weight against the pestle shank while permitting gyratory motion of said shank, and a conical. spring on said pestle shank adapted to be held by the fingers

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