US2722745A - Dental matrix appliance - Google Patents

Description

Nov. 8, 1955 l E. BRENNER 2,722,745

DENTAL MATRIX APPLIANCE Filed March 24, 1954 j f. HMHIIIIMMMHI free/Vey.

Sits

The present invention relates generally to the field of clamping devices, and more particularly to an improved dental matrix appliance or clamp, together with a band particularly adapted to be used therewith.

The general concept of a dentists matrix appliance is not new, nor is that of a flexible band which by the use of the appliance may be disposed in an encircling position on a portion of the exterior surface of a tooth to denne its configuration, and when so disposed permitting dental fillings to be made by the use of mercury amalgam or other quick setting compounds adapted for this purpose.

However, all of the appliances of this nature previous to applicants invention suffered from the major disadvantages that they were difficult to use, had an unduly complicated mechanical structure, were not positive in operation, frequently broke the iiexible bands when sufliciently tightening them into a tooth engaging position, and due to their mechanical complexity were difhcult to disassemble for the purposes of cleaning, sterilizing and maintaining in a clean and sanitary condition.

A major object of my present invention is to provide a matrix clamp and band that eliminates substantially all of the disadvantages of previously available devices used for this purpose.

Another object of my invention is to supply a matrix clamp that is of an extremely simple mechanical structure, may be fabricated from standard commercially available materials without the use of specialized machinery and extensive plant facilities, and may hence be retailed to the dental profession at a relatively modest price.

A further object of my invention is to furnish a matrix clamp that is easy to use, may be quickly taken apart and assembled with a minimum of inconvenience, is positive in operation, and one that minimizes the discomfort to which a patient is subjected, as the patients gums, cheeks and lips are at all times shielded from contact with the sharp edges of the tooth configuration defining flexible band or any threaded or movable members that may cut or pinch.

Yet, another object of my invention is to provide a matrix clamp of such design that the flexible band is merely snapped in place thereon, and the looped band when so mounted being restrained against movement relative to the engaging member both longitudinally and laterally.

A still further object of my invention is to provide a matrix clamp that is literally foolproof in operation, as the protective shield for the gums, cheeks and lips are automatically moved into position as tension is placed on the band.

Yet, another object of my invention is to provide a matrix clamp which due to its simplicity of structure is light weight and of an attractive appearance.

A further object of my invention is to provide a matrix band of simplified structure that is positively engaged by my clamp, and one that will be held by the clamp at subate tiff@ stantially the same tension during the filling operation irrespective of what length of time may be involved.

A still further object of my invention is to supply a matrix clamp and band that so cooperate that greater tension is placed on the lower longitudinal portion of the band than the balance thereof to assure that said band conforms to the normally inwardly tapering exterior surface of a tooth, but said clamp and band of such structure that the band is held in tight surface conforming contact with the tooth irrespective of whether said surface tapers inwardly or not.

These and other objects and advantages of my invention will become apparent from the following description of a preferred form thereof, and the drawing illustrating that form in which:

Figure l is a perspective view of my matrix clamp with a looped band engaging a tooth;

Figure 2 is a combined plan and horizontal cross sectional view of the device;

Figure 3 is a fragmentary combined side elevational and vertical cross sectional View of the forward portion of the clamp holding the band in a tooth encircling position;

Figure 4 is a vertical cross sectional View of the clamp taken on the line 4-4 of Figure 3 l Figure 5 is a fragmentary perspective view of the forward end portion of the actuating rod, and showing the manner in which a flexible looped band is removably maintained in position thereon; and

Figure 6 is a plan View of one of my bands, showing the openings formed in the end portions thereof that are positively but removably engaged by rigid teeth formed as a part of the actuating rod.

Referring now to vthe drawing for the general arrangement of my invention it will be seen that the matrix clamp is denoted generally by the letter C, and is adapted to hold the elongate flexible band B shown in Figure 6 in the looped tooth-engaging position shown in Figures 1, 2, 3 and 5.

The detailed mechanical structure of the clamp C may best be seen in Figure 2 wherein it will be noted that the clamp includes an elongate body 1t) formed of a rigid material such as steel, and preferably of annular cross section. A centrally disposed bore 11 extends longitudinally through body 10, which body terminates on its rearward end in flat face 12 normally disposed to bore 11. The forward end of body 10 terminates in two parallel, laterally separated guides 13 and 14 that slidably engage portions of the band B when it is in a tooth-encircling position. Guides 13 and 14 are preferably formed as an integral part of body 10, and are partially defined by two identical oppositely disposed, longitudinally extending slots 16 formed in the forward portion of the body. Slots 16 communicate with bore 11 to permit the contacting portions of the looped band B to be drawn Within the contines of body l@ as shown in Figure 2, as will hereinafter be explained in detail,

To avoid confusion, the guides identified as 13 and 14 in the drawings will be referred to hereinafter as the first guide and second guide respectively. The forward end portion of first guide 13 terminates in a flat face 17 that extends forwardly and outwardly to meet the exterior surface of the first guide to thus define a semi-elliptical, slightly rounded edge 18 at the junction therewith. The rearward edge of face 17 develops into one set of the interior surfaces of body lll resulting from the formation of bore 11 and slots 16. The angular configuration of face 17 is such that it may lie adjacent the side of a tooth, substantially tangent to a portion of band B when the band is looped in the tooth-encircling position shown .in Figure 2.

The second guide 14 is somewhat shorter than the firstA guide 131, and starting at a point 19, the exterior surface of the second guide tapers inwardly to meet the forwardly disposed interior surface thereof at a rounded forwardly and downwardly disposed edge 20, as may best be seen in Figures 2 and 3.

A rod R, of somewhat greater length than the body is provided, and is of such transverse cross section as to slidably engage bore 11. The rearward portion of rod R as may best be seen in Figure l is formed with threads Z1, and has a stop 22 of conventional design mounted on the rear extremity thereof. Rod R has two longitudinally extending, oppositely disposed teeth designated as first tooth 23 and second tooth 24 formed as an integral part of the forward portion thereof as may best be seen in Figures 2 and 5. Tooth 24 is preferably about one-third the length of tooth 23 and teeth 23 and 24 are defined rod R by a longitudinally extending slot 25 and transversely-l disposed opening 26. As may best be seen in Figure 5 the teeth are used to removably support the band B in a looped position whereby it may be placed in the tooth-encircling position shown in Figures l and 2.

Rodi R is moved relative to body 10 by a nut 26 that rotatably engages threads 21, and has a forwardly disposed fiat face 27 of larger diameter than the cross sectional diameter of body 10. The nut 26 when rotated with face 27 in Contact with body face 12 remains in fixed axial relationship with the body 10, and the rod R is moved forwardly or rearwardly with respect to the body dependent upon the direction of rotation of the nut.

In Figures l, 2 and 3 it will be noted that an elongate cylindrical shell 28 is slidably mounted on the exterior surface of body 10, with the shell of such length that when its rearward edge 29 is fiush with body face 12 i'tsV forward edge 3i) is in substantialy alignment with point 19 on second guide 14. The purpose of shell 2S is to serve as a shield to prevent the patients gums, cheeks and lips contacting the edge portions of band B that have been drawn into the confines of body 10. Nut 26 when it has been. rotated sufciently to place tension on the looped band B, has automatically advanced the shell 28 to the protective position shown in Figure 2.

Band B as shown in Figures 3, l, 2 and 6 is of an elongate substantially rectangular shape, and has identical centrally disposed openings 31 formed in the end portions thereof. Openings 31 are spaced inwardly from the extremities of band' B a distance sufficient to provide tab portions 31a of substantial length.

My matrix clamp C and band B are used by bending the band into the form of loop shown in Figure 5, with. the openings 31 in alignment whereby the tap portions 31a may 'rst be inserted in the rearwardly disposed portion of slot 25, and the band then moved forwardly to cause tooth 24. to engage the openings and hold the band i'n the looped form on rod R. The band is retained in the looped. form on rod R due to tabs 31a being of suicient length that a portion of them remain in the rearwardly disposed portion of slot 2S after tooth 24 has engaged the openings 31.

With the band B mounted on rod R in the looped form, the band may be loosely placed around the tooth on which dental work is to be performed, and the nut 26 rotated to move the rod relative to body 10 and draw the contacting portions of the band into the confines of the body. When the nut 26 has been. rotated sufficiently to place tension on the band B, the shell 28 has been advanced on body 1.0 to the gurns, cheeks and lips protecting position shown in Figure 2. Further rotationof nut 26 increases the tension on band B as it encircles tooth T, the tension on the band being at the maximum along the lower longitudinal edge portion thereof due to the forwardly and downwardly extending shape of edge 20 of second guide 14 as may best be seen in Figure 2.

Due to the tension on band B being a maximum along the lower edge. portion thereof, the band conforms smoothly to the configuration of the side wall of a tooth, such as shown in Figure 3 that tapers inwardly. From experience it has been found that the looped band B will also conform equally well to the side wall of a tooth that does not taper inwardly.

The physical characteristics of the sheet material from which the band B is formed are important, as the material must be sufficiently flexible to conform to the configuration of the engaged portion of a tooth, possess sufficient tensile strength to stand the force required to effect such tooth engagement, be sufficiently tough that it will not tear at openings 31 when force is applied to it by tooth 24, and sufficiently rigid that the tabs 31a may be easily inserted into slot 25 and so remain until it is desired to disengage the band from rod R. Furthermore, the metal from which band B is formed must possess sufcient resiliency that the contacting end portions thereof will separate easily when removed from contines of slot 2S. In Figures 3 and 4 it will be seen that the possibility of the looped band B moving laterally appreciably is eliminated due to the portions of the band inside body 10 being encased in the protective shell 28.

The shell 23 not only performs the previously mentioned functions, but prevents the guides 13 and 14 being deformed outwardly from one another to an increasing degree, as the band is subjected to greater tension. in the fabrication of the invention, it is highly desirable that the lengths of the slots 16 be such, that sufficient portionsy of the band B may be drawn therein as to permit the device to be used on any size tooth whether it be a molar or bicuspid. Furthermore, from the standpoint of convenience and sanitation it is most desirable that the invention be of such length that the manually operable parts thereof are disposed outside the confines of the patients mouth when band B is in a tooth-engaging position.

Although the matrix clamp and band herein shown and described are fully capable of providing the advantages hereinbefore mentioned, it is to be understood that they are merely the presently preferred embodiment of my invention and that I do not mean to be limited to the details of construction herein shown and described, other than as defined in the appended claims.

l claim:

l. A matrix clamp for use in forming an elongate band of bendable material having openings disposed in the end portions thereof into a loop that conforms substantially to the configuration of the outer surface of a tooth said band engages which includes: an elongate rigid body formed with a longitudinally extending bore, said body on its rearward end terminating in a flat face disposed normal to the longitudinal axis thereof, said body formed with two oppositely disposed slots that extend from substantially the center of said body to the end thereof opposite said flat face, said slots in communication with said bore, said slots and a portion of said bore dividing the4 part of said body adjacent thereto into a first elongate guide and a second elongate guide of less length than said first guide, said first guide formed with an outer flat face that extends outwardly and forwardly from the interiorly disposed surface thereof, with said face and the exterior surface of said first guide intersecting to define a first semi-ellipse shaped rounded edge, and the exterior surface of the end portion of said second guide tapering inwardly to define a rounded downwardly and rearwardly extending second edge at the junction with the interiorly disposed surface of said. second guide; a rod slidabl'y mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and first and second oppositely disposed longitudinally 'extending teeth formed asA a part of said rod and' defined by an elongate slot that is in communication with a laterally situated opening formed therein, said teeth serving to removably support. said bandl in a looped form when said first tooth engages said, openings formed therein and said second tooth portions of said band disposed rearwardly from said openings; an elongate cylindrical sleeve slidably mounted on said body and of such length that the forwardly disposed edge thereof is located in substantially vertical alignment with the rearwardly disposed edge of said tapered face of said second guide when the rearward edge of said sleeve is substantially flush with the rearward face of said body; and a nut threaded on said screws, said nut having a forwardly disposed flat face of sufiicient cross sectional area to rotatably engage the rearward edge of said sleeve, said nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said band outside said guides, said motion when said band encircles a tooth being continued until said band encircles a tooth being continued until said band conforms to substantially the engaged surface thereof, and said sleeve being advanced forwardly on said body by said rotation to increasingly envelop the portions of said band drawn into said body until further forward motion of said sleeve ceases due to said rearward edge of said sleeve and said rearward face of said body becoming flush.

2. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body on its rearward end terminating in a flat face disposed normal to the longitudinal axis thereof, said body formed with two oppositely disposed slots that extend from substantially the center of said body to the end thereof opposite said flat face, said slots in communication with said bore, said slots and a portion of said bore dividing the part of said body adjacent thereto into a first elongate guide and a second elongate guide of less length than said first guide, said first guide formed with an outer flat face that extends outwardly and forwardly from the interiorly disposed surface thereof, with said face and the exterior surface of said first guide intersecting to define a semi-ellipse shaped rounded edge, and the exterior surface of the end portion of said second guide tapering inwardly to define a rounded downwardly and rearwardly extending second edge at the junction with the interiorly disposed surface of said second guide; a rod slidably mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and rst and second oppositely disposed longitudinally extending teeth formed as a part of said rod and defined by an elongate slot that is in communication with a laterally situated opening formed in said rod, said teeth serving to removably support said band in a looped form when said first tooth engages said openings formed therein, and said second tooth portions of said band disposed rearwardly from said openings; an elongate cylindrical sleeve slidably mounted on said body and of such length that the forwardly disposed edge thereof is located in substantially vertical alignment with the rearwardly disposed edge of said tapered face when the rearward edge of said sleeve is substantially flush with rearward face of said body; and a nut that rotatably engages said threaded portion, said nut having a forwardly disposed flat face of sufficient cross sectional area to rotatably engage the rearward edge of said sleeve, said nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said loop outside the confines of said body, said rotation when said band encircles a tooth being continued until sufficient tension is on said band to cause it to conform to substantially the configuration of the engaged exterior surface of said tooth, and said sleeve advanced forwardly on said body by said rotation to increasingly envelop a greater portion of said band drawn into said body until further forward movement of said sleeve stops due to said nut moving said sleeve until said rearward edge thereof and said rearward face of said body are flush.

3. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate iiexible band formed with two openings inwardly from the ends thereof, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body terminating on the rearward end thereof in a flat face normally disposed to said bore, and on the forward end portion in first and second elongate guides that are laterally separated by two oppositely disposed longitudinally extending slots in communication with said bore, said first guide terminating in a flat forwardly and outwardly extending face, and said second guide that is shorter than said first guide terminating in a forwardly and downwardly extending rounded edge; a rod slidably mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and rst and second oppositely disposed longitudinally extending teeth formed as a part of said rod and defined by an elongate slot that is in communication with a laterally situated opening, said teeth serving to removably support said band in a looped form when said 'first tooth engages said openings formed therein, and said second tooth portions of said band disposed in said slot rearwardly from said openings; an elongate gums, cheeks and lips protecting cylindrical sleeve slidably mounted on said body and of such length that the forwardly disposed edge thereof is located in substantially vertical alignment with the rearwardly disposed edge of said tapered face when the rearward edge of said sleeve is substantially tiush with the rearward face of said body; and a nut rotatably mounted on said threaded portion, said nut having a forwardly disposed flat face of sufficient cross sectional area to rotatably engage the rearward edge of said sleeve, said nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said band outside said guides, said motion when said band encircles a tooth being continued until said band conforms to substantially the engaged surface thereof, and said sleeve being advanced forwardly on said body by said rotation to increasingly envelop the portions of said band drawn into said body until further forward motion of said sleeve ceases due to said rearward edge of said sleeve and said rearward face of said body becoming flush.

4. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from the ends thereof, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinaly extending bore, said 1oody terminating on the rearward end thereof in a flat face normally disposed to said bore, and on the forward end portion in first and second elongate guides that are laterally separated by two oppositely disposed longitudinally extending slots in communication with said bore, said first guide terminating in a fiat forwardly and outwardly extending face, and said second guide that is shorter than said first guide terminating in a forwardly and downwardly extending rounded edge; a rod slidably mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and first and second oppositely disposed longitudinally extending teeth formed as a part of said rod and defined by an elongate slot that is in communication with a laterally situated opening, said teeth serving to removably support said band in a looped forrn when said first tooth engages said openings formed therein, and said second too-th portions of said band disposed rearwardly from said openings in said slot; an elongate cylindrical gums, cheeks and lips protecting sleeve slidably mounted on said body and of such length that the forwardly disposed edge thereof is located in substantially vertical alignment with the rearwardly disposed edge of said tapered face when the rearward edge of said sleeve is substantially flush withL thek rearward face of said body; and a nut that rotatably engages said threaded portion, said nut. having a forwardly disposedy at face of sufficient cross sectional area to rotatably engage the rearward edge of said sleeve, saidk nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said loop outside the confines of said body, said rotation when saidy band encrcles a tooth being continued until suflieient tension isV on said band to cause it to conform to substantially the configuration of the engaged exterior surface of said tooth, and said sleeve advanced forwardly on said body by said rotation to increasingly envelop a greater portion of said band drawn into said body until further forward movement of said sleeve stops due tosaid nut moving said sleeve until said rearward edge thereof and. said rearward face of said body are flush.

5. A dental device for use in defining the exterior surface of a portion of a tooth` which includes: an elongate tlexible band formed with two openings spaced inwardly from the ends thereof, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body terminating on the rearward end thereof in a liat face normally disposed to said bore, and on the forward end portion in first and second elongate guides that are laterally separated by two oppositely disposed longitudinally extending slots in communication with said bore, said first guide terminating in a liat forwardly and outwardly extending face, and said second guide that is shorter than said first guide terminating in a forwardly and downwardly extending rounded edge; a rod slidably mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and first and second oppositely disposed teeth on the forward end portion thereof, with said first tooth engaging said openings in said band when it is in the form of a loop, and said second tooth engaging the portions of said band disposed rearwardly from said openings when in said slot to removably maintain said band in said looped position on said rod; an elonagte gums, cheeks, and lips protecting cylindrical sleeve slidably mounted on said body and of such length. that the forwardly disposed edge thereof is located in substantially vertical alignment with the rearwardly disposed edge of said tapered face when the rearward edge of said sleeve is substantially tlush with said rearward face of said body; and a nut that rotatably engages said threads, said nut having a forwardly disposed at face of sufiicient cross sectional area to rotatably engage the rearward edge of said sleeve, said nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said loop outside the confines of said body, said rotation when said band encircles a tooth being continued until sulhcient tension is on said band to cause it to conform to substantially the configuration of the engaged exterior surface of said tooth, and said sleeve advanced forwardly on said body by said rotation to increasingly envelop a greater portion of said band drawn into said body until further forward movement of said sleeve stops due to said nut having a forwardly disposed fiat face of sufthereof and said rearward face of said body are ush.

6. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate exible band formed with two openings spaced inwardly from one of the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body terminating on the rearward end thereof inV a fiat' face normally disposed to said bore, and on the forward end in first and second elongate guides that are defined by two oppositely disposed axially extending slots formed in said body that are in communication with said bore, .said second guide shorter than said first guideA and terminating in a downwardly and forwardly ex,` tending rounded edge; a rod slida'bly mounted in' saidbore,4 said rod foirned with a rearwardly' disposed threaded' portion, and tooth means on the forward end thereof that removably engage said openings when said band is in a looped position and somaintains same; an elongate cylindrical sleeve slidabl-y mounted on said body and of suchy length as to extend substantially the length of said body when the rearward edge of said sleeve is flush. with said rearward fate of said body to protect a patients gums, lips and cheeks from contact with. the edges of said band, and eliminate lateral movement of said band relative to said body; and a nut that rotatably engages said threaded portion, said nut having a forwardly disposed at face of sufficient cross sectional area to rotatably engage the rearward edge of said sleeve, said nut when rotated in one direction drawing said rod rearwardly to lessen the quantity of said loop outside the confines of said body, said rotation when said band encircles a tooth being continued until sufficient tension is on said band to cause it to conform to substantially the configuration ofi the en-` gaged exterior surface of said tooth., and said sleeve advancedforwardly on said body by said rotation to in creasingly envelop a greater portion of said band. drawn into saidbody until! further forward movement of said sleeve stops due tosaid nut moving said sleeve until saidl rearward edge thereof and said! rearward'V face of said body are flush.

7. A dental device foiuse. in defining, the exterior surface of a portion of a tooth which includes:` an elongate flexible band' formed with two open-ings spaced inwardlyy from the ends of saidband, and sai-d band capable of being formed intoI a loop that. may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said bod-y terminating on the rearward. end thereof in a flat face normally disposed to sa-id bore, and on the forward end` in lii'st and second elongate guides that are defined by two oppositely disposed axially extending slots formed insaid body that are in communication with said bore, said second g-uid'e shorter than said first guide and terminating inadownwardly and forwardly extending rounded edge; a rodl slidably mounted in saidl bore, said rod formed with a rearwardly disposed threaded' portion, and tooth means on the forward end thereof that removably engage saidl openings when said band is in a looped position and somaintains same; a-n elongate cylindrical sleeve slidabiy mounted on said; body and capable of being moved to a forwardly disposed position thereon to envelop substantially all of said band drawn into the portions of said slots in said body that are of uniform width, said sleeve when so disposed serving to protect a patients gums, lips and cheeks from contact with the edges of said bandl and eliminate lateral movement of said band relative to said body, and a nut formed with a flat forward face that may rotatably engage said rearward face of said body when said nut rotatably engages said threaded portion, said mit when so engaged and rotated in one direction drawing said rod rearwardly to lessen the amount of said band outside the confines of said body, said rearward movement when said looped band is engaging the exterior surface portion of a tooth placing sufficient tension on said band as to cause said band to conform to substantially the configuration thereof, with the maximum tension on said looped band' being in the lower portion thereof due to the shape of said forward edge of second guide.

8. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of va tooth with said' openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body on its rearward end terminating in a fiat face disposed normal to the longitudinal axis thereof, said body formed with two oppositely disposed slots that extend from substantially the center of said body to the end thereof opposite said fiat face, said slots in communication with said bore, said slots and a portion of said bore dividing the part of said body adjacent thereto into a first elongate guide and a second elongate guide of less length than said first guide, said first guide formed with an outer fiat face that extends outwardly and forwardly from the interiorly disposed surface thereof, with said face and the exterior surface of said first guide intersecting to dene a first semi-ellipse shaped rounded edge, and the exterior surface of the end portion of said second guide tapering inwardly to define a rounded downwardly and rearwardly extending second edge at the junction with the interiorly disposed surface of said second guide; a. rod slidably mounted in said bore, said rod formed with a rearwardly disposed threaded portion, and tooth means on the forward end thereof that removably engage said openings when said band is in a looped position and so maintains same; an elongate cylindrical sleeve slidably mounted on said body and capable of being moved to a forwardly disposed position thereon to envelop substantially all of said band drawn into the portions of said slots in said body that are of uniform width, said sleeve when so disposed serving to protect a patients gums, lips and cheeks from contact with the edges of said band and eliminate lateral movement of said band relative to said body, and a nut formed with a flat forward face that may rotatably engage said rearward face of said body when said nut rotatably engages said threaded portion, said nut when so engaged and rotated in one direction drawing said rod rearwardly to lessen. the amount of said band outside the confines of said body, said rearward movement when said looped band is engaging the exterior surface portion of a tooth placing sufiicient tension on said band as to cause said band to conform to substantially the configuration thereof, with the maximum tension on said looped band being in the gingival portion thereof due to the shape of said forward edge of said second guide.

9. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body on its rearward end terminating in a flat face disposed normal to the longitudinal axis thereof, said body formed with two oppositely disposed slots that extend from substantially the center of said body to the end thereof opposite said at face, said slots in communication with said bore, said siots and a portion of said bore dividing the part of said body adjacent thereto into a first elongate guide and a second elongate guide of less length than said first guide, said first guide formed with an outer fiat face that extends outwardly and forwardly from the interiorly disposed surface thereof, with said face and the exterior surface of said first guide intersecting to define a first semiellipse shaped rounded edge, and the exterior surface of the end portion of said second guide tapering inwardly to define a rounded downwardly and rearwardly extending second edge at the junction with the interiorly disposed surface of said second guide; a rod longer than said body, said rod having two oppositely disposed longitudinally extending teeth formed on the forwardly disposed portion thereof that engage said openings in said band when it is formed into a loop to so maintain same and removably retain said looped band on said rod; an elongate cylindrical sleeve slidably mounted on said body and of such length as to extend substantially the length of said body when rearward edge of said sieeve is Hush with said rearward face of said body to protect a patients gums, lips and cheeks from Contact with the edges of said band, and eliminate lateral movement of said band relative tosaid bodyyan'd manually operable means which when actuated move said rod rearwardly relative to said body to decrease the quantity of said band mounted on said rod outside the confines of said body, said rearward movement when said looped hand is engaging the exterior surface portion of a tooth placing sufficient tension on said band as to cause it to conform to the configuration of said engaged tooth portion.

10. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from one of the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body terminating on the rearward end thereof in a fiat' face normally disposed to said bore, and on the forward end in first and second elongate guides that are defined by two oppositely disposed axially extending slots formed in said body that are in communication with said bore, said second guide shorter than said rst guide and terminating in a downwardly and forwardly extending rounded edge; a rod slidably mounted in said bore and of greater length than said body, said rod having two oppositely disposed longitudinally extending teeth formed on the forwardly disposed portion thereof that engage said openings in said band when it is formed into a loop to so maintain same and removably retain said looped band on said rod; an elongate cylindrical sleeve slidably mounted on said body and capable of being moved to a forwardly disposed position thereon to envelop substantially all of said band drawn into the portions of said slots in said body that are of uniform width, said sleeve when so disposed serving to protect a patients gums, lips and cheeks from Contact with the edges of said band and eliminate lateral movement of said band relative to said body, and manually operable means which when actuated move said rod rearwardly relative to said body to decrease the quantity of said band mounted on said rod outside the confines of said body, said rearward movement when said looped band is engaging the exterior surface portion of a tooth placing sufficient tension on said band as to cause it to conform to the configuration of said engaged tooth portion.

11. A dental device for use in defining the exterior surface of a portion of a tooth which includes: an elongate flexible band formed with two openings spaced inwardly from the ends of said band, and said band capable of being formed into a loop that may engage the exterior surface of a tooth with said openings in alignment; an elongate rigid body formed with a longitudinally extending bore, said body terminating on the rearward end thereof in a fiat face normally disposed to said bore, and on the forward end in first and second elongate guides that are defined by two oppositely disposed axially extending slots formed in said body that are in communication with said bore, said second guide shorter than said first guide and terminating in a downwardly and forwardly extending rounded edge; a rod slidably mounted in said bore and of greater length than said body, said rod having two oppositely disposed longitudinally extended teeth formed on the forwardly disposed portion thereof that engage said openings in said band when it is formed into a loop to so maintain same and removably retain said looped band on said rod; means movably mounted on said body that may be disposed to protect a patients gums, lips and cheeks from contact with the edges of those portion of said band disposed in said body, and to eliminate lateral movement of said band relative to said body; and manually operable means which when actuated move said rod rearwardly relative to said body to decrease the quantity of said band mounted on said rod outside the confines of said body, said rearward movement when said looped band is engaging the exterior surface portion of a tooth plac- 1.1 ing suicient. tension on said band as to cause it` to conform to the configuration of said engaged tooth. portion.

12. An. actuating member for use with a dentists matrix clamp to removably engage and support an elongate flexible band formed with two openings spaced inwardly from the ends thereof, when said band is in the form of a loop with said openings in alignment which includes: an elongate rod that has threads formed on one end portion thereof that may be used to cause axial movement of said rod when said threads engage a tapped bore in a rigid member that is caused to rotate relative to said rod, and longitudinally extending, oppositely disposed first and second teeth of substantially the same length formed as a part of said rod on the end portion thereof opposite said threaded portion, said teeth being defined by a longitudinally extending slot formed in said rod that is in communication with a laterally positioned opening also formed in said rod, said rst tooth engaging said openings to hold said looped band on said rod, and said second tooth engaging the free end portions of said band to removably retain said looped band on said rod.

13. A dental device for use in defining the exterior surface of a portion of a tooth that includes: a matrix band formed with two openings spaced inwardly from the ends thereof so that when said band is looped about the exterior surface of a tooth the free end portions of said band are in contact with one another with said openings in alignment; an elongate cylindrical body having a forward end that is adapted to lie adjacent a side of said tooth and said end having a diametrical slot extending longitudinally of said body that slidably receives therein said contacting free end portions of said band; a rod slidably mounted through said body and having on the end thereof adjacent said forward end of said body means to engage said openings of said band; means mounted on said rod adjacent the rearward end of said body to slide said rod longitudinally through said body so that when said moving means are actuated to move said rod rearwardly through said body a portion of said matrix band is drawn rearwardlyl into the confines of said slot of said forward end of said body to reduce the peripheral extent of the looped portion of said band until sufficient tension is on said band to cause it to conform to the configuration of the engaged surface of said tooth; and a protective sleeve mounted on said body to cover the edges of the contacting end portions of said band disposed in said slot of said body to prevent lateral movement of said band and to protect a patients mouth from contact with said edges of said contacting end portions of said band.

l4. A matrix clamp for use in reducing the loop of a matrix band to define the. exterior surfacek of a portion of a tooth around which said band is looped whichA in cludes: an elongate rigid body having a longitudinally extending bore and having guide means formed on the forward end thereof in which the contacting1 free end portions of said matrix band may be longitudinally slidably received; an elongate actuating member in said bore of said body that engages said end portions of said band and that can be drawn rearwardly through said bore to move said end portions of said band rearwardly over said guide means to decrease the loop of said band; means operatively associated with said member to said body to move said member longitudinally relative to said body; and a protective sleeve mounted on said body that envelops substantially all of said contacting free end portions of said band to prevent lateral movement thereof out of said guide mea-ns of said body.

l5. A matrix clamp as defined in claim l4 in which said guide means on said body are formed by two oppositely disposed axially extending slots that extend radially outwardly from said bore to define first and second elongate guides with said second guide shorter than said first guide and terminating in a downwardly and forwardly extending rounded edge and said first guide terminating in a at face that extends outwardly and forwardly from the interiorly disposed surface thereof.

16. In a matrix clamp for use with a matrix band formed with two openings spaced inwardly from the ends of said band so that the end portions thereof define extended tabs, an actuating member that includes: an elongate rod that may be moved axially relative to an elongate body through which it passes, said rod having formed on the forward end thereof longitudinally extending, oppositely disposed teeth that are dened by a longitudinally extending slot formed in said rod that is in communication with a laterally positioned opening also formed in said rod, said first tooth being shorter than said second tooth and more forwardly situated on said rod, and said second tooth engaging said extended tabs of said band to removably maintain said looped band on said rod.

References Cited in the iile of this patent UNITED STATES PATENTS

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