US2386103A - Checking device - Google Patents

Description

C. E. GALLEY -GHEGKING` DEVICE Oct. z, 1945.

Filed Marchl, 11945 Patented Oct. 2, 1945 This invention relates to the checking of the dimensions of molded objects, particularly dentures, and to apparatus for that purpose.

In the customary denture processing a waxvcast or pattern is made ofthe gums, the articial teeth are inserted for the proper occlusion or bite, and the cast is cased or lled out with wax. The wax case is then invested with plaster in the lower half of a ask, the upper part or ring of the flask is mounted on the lower part, and filled with plaster, and the lid placed on the flask. When the plaster has set, the ask parts are separated, and the wax is boiled out, the teeth being held in place by the plaster in the upper half of the flask. 'Ihe cavity left by removing the wax is packed with the denture material, the flask is closed and locked, and the material is hardened or set by immersing the flask in boiling water. In these various steps customarily followed, the teeth are apt to be displaced, or there may be separation of the mold parts through overpacking or other cause with the formation of fins of the denture material and a consequent change in dimensions and disturbance of the occlusion.

The invention, in its application to dentures, provides for checking the occlusion and dimensions against the original Wax pattern invested in the usual manner in the lower half of the flask. A plaque of plaster of the right consistency is poured on a piece of paper; and before the plaster sets, the wax denture, invested in the lower half of the ask, is inverted upon the plaque so that the tips of the teeth are embedded therein. When the plaster has set, the flask with the wax denture and the plaque on the teeth are turned right side up. Another wad 0r bfall of soft plaster is then mixed and placed on the plaque. While the plaster is soft, a gauge, consisting of a perforated plate mounted on legs spaced to contact the metal rim of the ask, is pressed down on the soft ball until the legs rest firmly on the rim. When the plaster ball has set, an accurate recording is obtained of the position of the teeth, the slope and the dimensions of the wax denture with relation to the flask in which it is invested.4 The gauge with its attached plaster impression is then removed.

The usual practice of placing the top half of the flask and filling with plaster, removing the wax pattern and molding the denture is then followed. When the denture is made, the plaster mold is forced out of the upper part of the flask and cut away from the denture, leaving the molded den- 'CharlesEf (Jralleyiy Chicago, Ill., assignerV to Luxene t Inc. `,ac'orporation`of 1*)elaware` I f Applicata Marchal, 1an;senainpgiisnzscf Y.

crains. (01:33 174)@l f ture mounted on the lower half of the flask just faslthe, wanfjease or Apattern was originally.` .i11-

vested. The check is then applied to the denture. If there Ahas been no distortion or shifting of the teeth or in the height or slope of the denture, the gauge rests firmly on the rim of the flask with the impression plaque in accurate contact with the teeth; on the other hand, any tooth displacement, spreading or change in height or slope is clearly made evident.

In the accompanying drawing there is illustrated a check, in which Fig. 1 illustrates an impression sheet and a nished denture (or wax pattern) resting upon it;

Fig. 2 is a side view in partial cross section of the impressed sheet;

Fig. 3 is a top view of a gauge assembly; and

Fig. 4 is a side View of the assembly in position on the lower half of the flask. A

The impression material I0 is any suitable hardening plaster which is soft enough in consistency when applied to readily take the impression I2 of the teeth of a denture pattern I I. Preferably the sheet is applied to the pattern after it has been invested in plaster I4 in the lower half I3 of a flask as shown in Fig. 4. A sufficient amount of a hardening plaster wad 2| is placed on the positioned impression sheet.l

A gauge consists of a plate I5 supported by legs I6 threaded into the plate; lock nuts Il hold the legs in adjusted position. The metal rim of the ask part I3 forms a reference surface for contact bythe legs I6. A rim I8 with a llet I9 joining it to the plate I5 extends about the outer edge of the plate, and there are openings 20 in the plate. q

When the gauge is pressed on the soft wad of plaster the plaster exudes through the openings 20 and overflows into the space conned by the rim I8 to form a layer of-plaster 22 connected by the plaster slugs 23 extending through the holes'20. y The plaster wad attaches itself to the impression sheet, and on hardening locks the sheet to the gauge in the exact position it occupies on the pattern. When the case is replaced by the molded denture, the latter occupies the position of the case with relation to the lower half of the flask. It is then only necessary to remove the upper part of the flask and the plaster carried by it from the denture to have the denture in position for testing by setting the gauge legs on the, rim

of the flask and resting the impression on the'f If there has been no change teeth of the denture. in the occlusion or dimensions the impression ts the teeth and the legs of the gauge contact the rim; any departure in dimension or occlusion,

face, and testing the molded object replacing the4 Y pattern by the impression secured to the gauge with the latter in position on the same reference surface.

2. Method of checking a molded object against a pattern from which it is molded which comprises mounting the pattern with reference to a surface, making an impression of the pattern on a substance sufi'iciently plastic to take the impressionwithout distortion of l the pattern, vsecuririg the impressed substance While in position on the pattern to a, gauge in contact with the reference surface, and testing the molded object replacing the pattern by the impression secured to the gauge With the latter in position on the same reference surface.

3. Method of checking a molded denture against a case from which it is molded which comprises investing thecase -in the lower half of a ask, impressing onthe case' a substance suiciently plastic to take the impression without distortion of the case, positioning a gauge on the rim of the flask half as a reference surface, securing the impressed substance in place on the case to the gauge, and testing the molded denture replacing the case before itsseparation from the lower half of the ask by the impression .secured to the gauge with the latter in position on the rim of the ask.

CHARLES E. GALLEY.

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