Pin centering and paralleling instrument

Feb. 23, 1954

A. W. MANN

PIN CENTERING AND PARALLELING INSTRUMENT

2,669,780

Filed Feb. 5, 1953

Sheets-Sheet 1

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Feb. 23, 1954

a. w. mann 2,669,780

PIN CENTERING AND PARALLELING INSTRUMENT

Filed Feb, 5, 1953

Sheets-Sheet 2

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<img file="US2669780A_D0003.tif" />

Fig. 6

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Fig.7

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78 9! 80

Arvin W. Mann

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78

Fig. 9

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INVENTOR.

BY ^σ V Attorneys

Patented Feb. 23, 1954

2,669,780

UNITED STATES PATENT OFFICE

2,669,780

PIN CENTERING AND PARALLELING INSTRUMENT

Arvin W. Mann, Fort Lauderdale, Fla.

Application February 5, 1953, Serial No. 335,285

Claims.

This invention relates to restorative dentistry and more particularly to a device especially adapted for use in obtaining a hard cast or model from an elastic impression in which the individual prepared teeth in the cast can be removed for convenience in using the reseated in their exact original position in the base of the cast again resulting in a solid cast. This, then is truly a “master” cast.

Elastic impression materials such as hydrocolloid, enable the detist to obtain a more accurate reproduction of the oral structures. The material is inserted into the mouth in a fluid state, held in an impression tray. It is then allowed to gel, or induced to gell by introducing cold water through a water jacket in the impression tray, and after complete gelation, is removed from the mouth. Its elastic nature allows the impression material to spring out of undercuts after gelation with a negligible distortion. A hard model or cast is obtained by pouring hydrocal into such an impression, allowing it to set hard and then separating it from the impression. This model or cast is then the most accurate reproduction of the mouth structures that is possible. Any prosthetic appliance restoring individual teeth or combinations of teeth if made to fit the model accurately, should then fit the mouth structures with the same accuracy.

_ It is therefore the primary object of this invention to provide means for simplifying the pouring of the hydrocal into the elastic impression material to obtain a hard model or cast so as to provide dowel pins centered in each prepared tooth, and parallel to each other which will allow said prepared teeth to be removed and then reseated accurately in their original positions in the “master” cast.

The construction of this invention features the use of a clamp which has a plurality of tapered apertures therein for reception of the dowel pins. These dowel pins are adapted to be centered in the impression of a tooth a small distance above the elastic impression material. Then the pins may be removed from the vicinity of the impression, the impression tray removed from its indexed position in the instrument, hydrocal poured into it, and both pins and impression returned to their exact original positions. The dowel pins can then be positioned exactly as they were when previously centered due to the action of this device.

Still further objects and features of the invention reside in the provision of a pin centering and paralleling of the nature described that is strong (Cl. 32—67) '

and durable, simple in construction and manufacture, capable of being readily produced for wide distribution in the dental fields at a relatively low cost, while being highly effective in achiev_ύ ing highly accurate reproductions while using the new techniques necessary for proper handling of elastic impression material.

These, together with the various ancillary objects and features of tlie invention which will become apparent as the following description proceeds, are attained by this pin centering and paralleling instrument, preferred embodiments of which have been illustrated in the accompanying drawings, by way of example only, wherein: ₁₅ Figure 1 is a perspective view of the entire instrument;

Figure 2 is a vertical sectional view as taken along the plane of line 2—2 in Figure 1;

Figure 3 is an enlarged sectional detail view of 20 the clamp member and the bracket pivotally attached to the clamp member;

Figure 4 is a perspective view illustrating one of the clamps used for centering and paralleling the dowel pins comprising important elements of ₂₅ this invention;

Figure 5 is a sectional detail view illustrating in particular the tapered apertures in the clamp member and the tapered dowel pin;

Figure 6 is a bottom plan view of one of the clamp members;

Figure 7 is a top plan view of a clamp member showing the device as provided with a set screw having a slotted head;

Figure 8 is a view of the modified form of the ₃ invention similar to that of Figure 7 but showing the set screw being provided with an Allen head; and

Figure 9 is a top plan view of a further modification of the invention employing a Phillips head ₄₀ screw.

With continuing reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, reference numeral 10 generally designates _4S a base to which a fitting i2 is secured by screws, bolts or fasteners 14. The fitting 12 is provided with a tubular flange 16 having a set screw 18 threadedly secured therein for locking engagement so as to support and hold a vertically ex60 tending stand 29. There is also secured to the base 10 a cylindrical member 22 having a recess 24 therein for reception of the socket elements 26 and 28 forming one portion of the ball and socket joint including the spherical member 30 which is 6a attached to an upwardly extending standard 32.,

2,669,780

A threaded rod 34 is provided for tightening the socket elements 26 and 28 into clamping engagement with the spherical ball 30. The upper end of the standard 32 terminates in an annular flange 36 to which a tray 38 preferably formed from a transparent synthetic plastic material is secured by means of bolts 48. Obviously, the tray 38 may be formed from any other material as may be· desired^; but the use of- the: aforesaid material has- its advantages in enabling' the op- 1° erator to more easily remove the plaster index holding the impression tray after using.

Slidably embracing the stand, 20 is- a. clampmember 42. A knurled headed’ thumb screw,· 44? is used to lockingly adjust the clamp member 42 ^{! 5}at any desired height and position on the* stand 20. The clamp member 42 is, provided· with bifurcations 46 and 47 between which there is received a bracket 48 which is mounted for pivotal; movement by means of pin 50. The bracket 48 ²⁰is provided with, an, extension, or. limit, ston? 52 haying., a: flattened· upper surface, 5.4· adapted· to abut, against the. lowermost, surface of :the? clamp member 42.. to limit rotation', of the-bracket 48; The-bracket; 48 ,includes;a.mounting; plate· 5: i· within which, a vertically extending; knurled, head thumb screw 53 is threadedly engaged.. The, thumb,-screw: 53,-extends? through a, slot 55. .in a support plate, 5.6,- and. the-flange, 58. of the thumb screw, 53; plus , a washer- is adapted to.· lockingly hold the, support,plate, 56. in an,adjusted position relative, to? the .mounting plate ,5-1-/ The support. plate,5.6is..prov-ided;with_;an arcuate configuration as.-.at, 69, in order that,.the-dowel pin clamps as. indicated, at; 62, may be, arranged in. such manner as to permit the dowel pin 64 to having, their, anchors. 68, arranged to. conform, with: the· contours of a ja,w.-and_: center, of: the .prepared teeth of our impression..

Referring now- particularly t.o Eigures - 4 through 9 wherein the· dowel. pin, clamp. 62-, and the, dowel. pin: S4. forming, the-most important elements.- of - the invention · are· illustrated.;' it will be. seen, that. each.· of; the.· dowel. pin.· clamps · 82; are formed with a fixed lower jaw 66·..and: movable upper. jaw.· 7,0.-, The, upper, jaw· 7-0.- is· provided, with a: recess 12. within which an. inner- rib 74 is embraced- The. inner, rib· 7.4: is. formed on the connection, 7 6; interconnecting the lower jaw 70 with a fixed portion 78 used in_:;s.uppor.t.ing?the ₅₀upper, movable jaw 70. Attached, to the, upper ’ jaw--7,0.-.is. a, guide .rod, 80-, which, extends- through: an aperture in the upper portion 73.·. Another aperture. 82 is, formed in ·. the. upper- portion? 78 for. reception, of, a? headed· internally, threaded -,. collar 84, which-extends through-the upper: por- **’’ tion and which is crimped as at 88 so. as to form... a. flange, preventing, the disengagement· of the, sleeve,.84 fromrihe. upper, portion? 70.. The. sleeve 84 has its internal threads threadedly,en- .,. gaged. with a threaded.rod S3, rigidly attached.,to the upper jaw. member. 70.. In.this manner, upon, rotation of.: the. headed..-sleeve. 63.;the. upper... jaw will; be. drawn upwardly toward. the. .fixed, portion. 78 or urged·.downwardly, toward the. lower, jaw ₍₁₅68... A slot 90 for. reception, of a screw driver. is ..provided in the. headed sleeve' 84 and' alternatively as is.shown in.Figures 8 and 9'. an. Allen, head 91 may be provided' for' reception of an Allen wrench or a Phillips head:9.3 may alterna- -,, tively be used;. An outer-reinforcing rib: 92is. ‘ provided for. the clamp 82: and . extends about the, fixed portion.78; the. connecting.portion. 76.' and: the lower j aw. 68: The: portion of. the, rib. 92..on. the lower.ja.w,.68’perf0rms the..additionai: it,.

function of providing the lower surface of the jaw 68 with portions of varying depth. This is advantageous since a plurality of tapered apertures 94 are drilled into the lower jaw 68 for reception of beveled dowel pins 64. Hence, when the dowel pins 64 are positioned in the portion of the rib 92 they will extend somewhat below the dowel pins placed in the jaw 68 proper thus permitting: greater flexibility’ ih the; use·· of this device. Sometimes clamps· with' a smooth, flat lower jaw 68 without rib 92 are used to permit all pins to be evenly positioned in lower jaw 68. These, are. desirable in addition to clamps with rib, 92’on lower jaw 68. It is to be noted that the anchors 66 are provided with ridges and recesses.ih order that the plastic material being used in the cast may, become bonded thereto thus assuring against the pins being accidentally disengaged.

In operation, after the impression has been taken,,- it is . placed, in. a plaster of Baris matrix on.traySS; Then, the. clamps. 62 and the.pins-.64 ar.e. attached- to the support, plate 56.- with- the anchors 3S of, the pins· 64- positioned, a· small 25 distance, above the prepared- teeth, oi an. elastic impression, material, impression. The support plate. S6. is preferably formed· from-ai transparent plastic, material.in.order that the. impression-may continuously be observed' thus preventing, any 30 accidental distortion, or. destruction-of tire, impression. Then, the clamps,, dowel,· pins-64, and the. entire, bracket. ¢8. may, be. rotated: upwardly, as, is shown in, the. dotted, lines.in. Figure 3: and this, impression, can be, removed-from its piaster 35 of Baris matrix, on tray 58,. filled’, with,, hydrocal mixture for. molding, the cast,, and, returned: to its original,position.on tray, 58. . Prior to-the setting of the hydrocal mixture^ the.-bracket . 48? will be depressed, so. as.to. immerse.the.anchors -85dn 40 the hydrocal, mixture. This mixture, may be heaped up. about the.anchors df.such. is necessary, so as to. insure, a. proper, bond. In, this manner, each of the desired: teeth- may, be, provided with a centrally located dowel·’.- pin. even- though - the· impressions, of the. teeth, are. not-, in view, after, the hydrocal. mixture.has been,poured.'.

Since from.the foregoing, .the-construction- and. advantages of this - pin . centering and-paralleling instrument are readily, apparent,, further, description is believed to be unnecessary;.

However,, since numerous modifications? will, readily: occur; to those, skilled ‘ in. the. art ..after, aconsideration of the for egoing, specification, and accompanying, drawings,, it is. not. intended-, to limit the. invention, to. the. precise, embodiment, shown and,: described,, but all, suitable modifications, and, equivalents may- be-readily- resorted - to as desired.