US2017955A - Device for forming amalgam fillings - Google Patents

Description

INVENTOR ATTORN IV Patented Oct. 22, 1935 DEVICE FOR FORMING AMALGAM FILLINGS Anders Ejde, Poulsbo, Wash.

Application November 21, 1934, Serial No. 754,139

3 Claims.

This invention relates to a matrix retainer especially adapted for use by dentists to give proper form to amal am fillings and has for the primary object the provision of a device of the above stated character which may be quickly and conveniently positioned with respect to a tooth to be filled and only requires space for the mold element on one side of the tooth and provides clear vision to the work and causes the mold element to readily conform to the tooth and thereby prevent lapover of the filling and further prevents the danger of injury to the gums.

With these and other objects in view this invention consists in certain novel features of construction, combination and arrangement of parts to be hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawing, in which Figure l is a top plan view illustrating a matrix retainer applied to a tooth and constructed in accordance with my invention.

Figure 2 is an end elevation illustrating the retainer.

Figure 3 is a sectional view taken on the line 33 of Figure 2.

Figure 4 is a side elevation illustrating the device.

Figure 5 is a transverse sectional view taken on the line 55 of Figure 4.

Figure 6 is a plan view illustrating the mold element.

Referring in detail to the drawing, the numeral I indicates a channeled bar provided at its offset end with apertured ears 2 arranged at right angles to the bar to form journals for the ends of a feed shaft 3. A feed nut 4 in the form of a block is threaded on the feed shaft 3 and has an offset portion 5 engaging in the channeled bar to retain the block against rotation with the shaft so that on rotation of the shaft through the manipulation of a finger piece 6 the block will be caused to slide from one end of the bar to the other end. Opposite walls or faces of the block have formed thereon lugs I either one of which is adapted to fit an opening 8 of a mold element 9. The mold element is of elongated formation having an opening 8 adjacent each end and is preferably constructed of a flexible metallic material.

A frame member it) is fixed to the bar I intermediate the latters ends and extends transversely of the bar and consists of relatively spaced teeth I I cooperating with each other in defining substantially U-shaped spaces to accommodate a tooth, as shown in Figure 1.- The end teeth of the frame member l6 have formed thereon lugs I2 either of which is adapted to enter one of the openings 8 of the mold member.

The device is positioned as shown in Figure 1 relative to a tooth to be filled and with one end of the mold member fastened to one of the lugs of the block and the other end fastened to one of the lugs I2, said mold member will be caused to adjust itself to the tooth overlying the amalgam filling. A device of this character obviates the use of the customary band now employed and which encircles the tooth having the cavity requiring the necessity of forcing the band between the tooth and the tooth adjacent thereto, which practice frequently injures the gum between the teeth. It is to be noted that this device avoids the necessity of forcing the teeth apart and only requires space for the mold element on one side of the tooth having the cavity and further that the device can be quickly and conveniently placed in position and adjusted and when adjusted causes the mold element to conform to the shape of the tooth and thereby prevent lapover of the filling.

The device herein described will work successfully on upper and lower right and left bicuspids and molars in connection with mesial occlusal and distal occlusal cavities.

Having described the invention, I claim:

1. A matrix retainer comprising a bar, a frame element fixed to said bar and arranged transversely thereof and provided with a tooth receiving notch, a flexible mold element removably secured to either end of said frame element, and means adjustably mounted to the bar and having the mold element adjustably connected thereto.

2. A matrix retainer comprising a bar, a frame element carried by said bar and arranged transversely thereof, a flexible mold element removably secured to either end of said frame element, means adjustably mounted to the bar and having the mold element adjustably connected thereto, said frame element having relatively spaced teeth defining therefrom substantially U-shaped spaces.

3. A matrix retainer comprising a channeled bar, a feed shaft journaled to said bar, a finger piece for said shaft, a feed nut mounted to the shaft and having an offset fitting in the channeled bar, a frame element carried by and arranged transversely of said bar and positioned intermediate the ends of the latter, lugs formed on opposite faces of the nut and at opposite ends of the frame member, a flexible mold element having openings to permit application of said mold element to lugs of the nut and frame member, said frame element having relatively spaced teeth to define substantially U-shaped spaces for accommodating a tooth to be filled.

ANDERS EJDE.

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