US3577855A - Jaw hinge axis locator - Google Patents

Abstract

A jaw hinge axis locator having a stiff wire frame with two curving segments which extend around the sides of a dental patient''s face from the handle of a mouthpiece mounted on his lower jaw, and a pair of dead soft wires connected to the outer ends of the curving segments of the frame. The dead soft wires terminate near the ends of the patient''s jaw hinge axis, and have flat squares of clear plastic, with grid markings, attached to their outer extremities. Each plastic square has an easily observable center of rotation which pinpoints the patient''s jaw hinge axis when he moves his lower jaw.

Description

I United States Patent 1 1 3,577,855

[72] Inventor Lloyd Baum 3.078.584 2/1963 Cohn 33/l74(D) 7 pp NO gst g Loma Linda 92354 Primary Examiner-Samuel S. Matthews Filed Mar. 17, 1969 Attorney-John H. Crowe [4 Patented May 11, 1971 4 AW HINGE AXIS LOCAT R [5 1 Claims 4 Drawin 0 ABSTRACT: A aw hinge axis locator having a stiff wire trame g g t with two curving segments which extend around the sides of a U.S. dental aticnt's face from [he handlc of a mouthpigce 32/20 mounted on his lower jaw, and a pair of dead soft wires con- [5 1 III. i nected to the outer ends of the curving egments of the frame [50] Field of Smrch ..33/l74 (D); The dead ft wires terminate near the d f h i m' 32/20 jaw hinge axis, and have flat squares of clear plastic, with grid markings. attached to their outer extremities; Each plastic [56] Reiemnces (med square has an easily observable center of rotation which pin- UNITED STATES PATENTS points the patients jaw hinge axis when he moves his lower 3,056,210 10/1962 DePietro 33/174(D) jaw.

pma- May 11,1911 V 3,577,855

INVENTOR. LL 0 0 BAuM BY Mas-M Asa/7',

JAW runes AXIS LQCATOR BACKGROUND OF THE INVENTION This invention relates generally to dental apparatus, and more particularly to an improved device for use in locating the hinge axes of dental patients lower jaws.

In restorative dental work, it is sometimes necessary to accurately locate the temporomandibular joint, or jaw hinge, axis of a dental patient. Devices of various types have heretofore been proposed for use in locating this axis, and while many have served their purpose fairly effectively, none of which I am aware has been free of certain inherent shortcomings. Such devices have invariably been constructed along conventional face bow lines, characterized by the presence of a crossbar carrying a bite-supporting member and two side arms. Each side arm supports an indicator member at its rear end which moves in such a way as to indicate, in some fashion, the location of the patients jaw hinge axis under the stimulating influence of his jaw movements (generally following a series of positional adjustments coordinated with the jaw movements).

While some of the prior art jaw hinge axis locators have been lighter in weight, and less complex, than others, even the lightest and simplest of these devices have been somewhat bulky and cumbersome, leaving much to be desired from patient comfort and ease and facility of use standpoints. The heavier and more complex of the devices have generally been more difficult to use than their lighter counterparts, primarily because of their inclusion of a greater number of adjustable parts, and have, additionally, made things rather uncomfortable for a great many dental patients because of their weight and the relatively long periods of time they must be held by the patients while their parts are being adjusted for jaw hinge axis-locating purposes. Furthermore, such devices are, as a result of their complexity of parts and the precision with which those parts must be made, rather expensive to manufacture.

Regardless of its weight, bulk or complexity of parts, however, each of the prior art jaw hinge axis-locating devices of which l amaware requires coarse and fine adjustment of its functioning mechanism after being positioned for use on a dental patient. in certain of the more complex devices, such adjustment involves numerous steps, and is of a rather timeconsuming and tedious nature. In many cases, the adjustable parts are so interdependent that execution of certain of the necessary steps of adjustment requires a high degree of expertise to avoid the disturbance of settings obtained in previously executed steps of the procedure. While the lighter, less complex of the prior art jaw hinge axis locators have sometimes required less than their more complex counterparts in the way of adjustment, every such locator of which l am aware requires both coarse and fine adjustment of some sort, generally including such steps as screw-tightening, anntelescoping, pointer-bending, etc., steps, for satisfactory operation. The necessity for such adjustment is doubly disadvantageous in increasing the difficulty of use of the prior art locators and adding to the dental patients discomfort because of the time-consuming nature of the adjusting manipulations.

Besides their above-noted bulk and weight, difficulty of use, and patient discomfort shortcomings, present to a greater or lesser degree in each, the aforesaid jaw hinge axis locators are characterized by yet another shortcoming, namely, lack of any self-contained means for a quick doublecheck of the accuracy of their findings. While it is, of course, possible to back any such instrument away from a final position of adjustment, and repeat all or part of the just-completed jaw hinge axis-locating procedure, this is time consuming and, moreover, does not represent a doublecheck approach to the problem. Finally, most of the prior art jaw hinge axis locators employ a pointer, or pointed stylus, as the aforesaid indicator member, sometimes used in conjunction with a flag," or plate covered with graph paper, which is placed against the patient's skin in the area of his jaw hinge axis. The point of the stylus is adjusted until it spins in place as the patient moves his lower jaw,

whereat it is considered to be in line with the patients jaw hinge axis. Determination of the spinning position of the stylus point is made by eye, and therefore depends upon the observers perceptive ability and judgment for its accuracy.

The stylus-manipulating procedures for locating jaw hinge axes described above are often incapable of producing accurate results because of inherent shortcomings of the necessary procedural steps, and/or the inherent necessity for human judgment in areas where such judgmentis readily susceptible of error. Thus, where a flag is employed in conjunction with a stylus for determining the location of a dental patients jaw hinge axis, the position of the axis is actually spotted on the outer surface of the flag, where, because of the flags thickness, it is spaced outwardly from the patients skin surface. Strictly speaking, the finding is true only at this location, and it is a common practice to attempt minimization of the error introduced by the flag thickness to press the flag against the patients skin during the jaw hinge axis-locating procedure, and remove it after the spin point of the forward end of the stylus has been determined to permit the skin surface to resume its natural contours. Tattooing ink is then placed on the end of the stylus, after which the latter is pressed against the skin to form a spot. This technique generally fails to compensate for the above-noted error, however, because it is almost impossible to hold the flag completely flush against the skin. This is primarily true because of the influence of such physical abnormalities as asymmetrical facial contours, prominence of the malar processes, depressed areas at the condylar regions, markedly tapering faces, protruding ears, and the like, which result in the formation of spaces between the-flags and adjacent skin areas or otherwise prevent flush emplacement of the flag against such areas. Moreover, the accuracy of transfer of the jaw condyle axis point from the flag surface to the skin may be adversely affected by head posture, skin folds, undetected muscular contractions of the ear or other facial movements capable of causing a change of skin position over the condylar area.

Whether or not pointed styli are employed in conjunction with flags or plates of the above-described type, error often results in attempts to mark jaw hinge axis locations on patients faces because of misalignment between the styli and the patients jaw condyle axes. Thus, in conventional methods of jaw hinge axis location emplying styli, only the inner ends of the latter are-set for spinning movement, with the result that their outer ends almost always move in arcuate paths after their inner ends have been spin oriented. Assuming that the pointed end of such a stylus is accurately aligned with the patients jaw hinge axis, it will be apparent that any movement of the stylus toward the patients face to mark a spot on his skin throws the point of the stylus off of the jaw hinge axis to cause inaccurate positioning of that mark. Moreover, mere visual observation of the stylus in motion is hardly calculated to assure ascertainment of the position at which its inner end spins in place with any great degree of accuracy. This is particularly true where the stylus is short, or when its outer end wobbles or describes arcuate movements during the jaw hinge axis-locating procedure. Finally, the slowness of rotation of the stylus, due to the relatively slow movement of the patients lower jaw, coupled with the limited range of his jaw movement, adds to the difficulty of precisely determining the spinning location of the inner end of the stylus.

SUMMARY OF THE lNVENTlON The jaw hinge axis locator of this invention is a simple, lightweight device of streamlined shape having a minimum of cooperating parts. in its preferred form the device has a wirelike frame of extremely light weight, adapted to fit rather closely around (but in nontouching relationship with) a dental patients face without the cumbersome bulk of the conventional face bow. By virtue of its design and manner of use and functioning, the locator requires virtually no hand manipulation or adjustment of any of its parts beyond an initial coarse" adjustment of the utmost simplicity. As will be seen, no fine" adjustment of the device is ever necessary, visual observation alone being adequate to determine the precise location of a dental patients jaw hinge axis from the coarse setting of the instrument. The device, moreover, is designed to function in such a way as to permit doublechecking of its findings with ease and rapidity, and quick correction of the latter, where necessary or desirable, to a high degree of accuracy. Finally, my novel jaw hinge axis locator does not depend upon visual observation of the end of a pointer or stylus, with its inherent imprecision, for the pinpointing ofjaw hinge axis locations, but utilizes a different, and much more accurate pinpointing technique for this purpose.

It will be apparent from the foregoing that my new jaw hinge axis locator is sufficiently different in design, manner of use and manner of functioning from prior art jaw hinge axis locators, at least in its preferred form, to avoid all of the abovenoted shortcomings of the latter. Even in embodiments other than its preferred one, moreover, my novel locator is so unique in its structure and use capabilities as to be absent all or most of these shortcomings of the prior art locators.

In its preferred form, my novel jaw hinge axis locator comprises a frame having a pair of thin, wirelike arm segments (hereinafter referred to as arms) designed for attachment, through an adapter, to the handle of a mouthpiece in such fashion as to extend curvingly around the sides of a dental patients face when the mouthpiece is secured to his lower jaw in the below-described manner. The frame is rotatably adjustable in the adapter, so that its arms can be made to angle upwardly from front end positions near the patients mouth to rear end termination in the vicinity of the jaw hinge axis area either side of his face. This positional adjustment of the arm angles, coupled with a simple fore-and-aft adjustment of the arms, hereinafter to be described, comprises the coarse locator adjustment previously referred to.

Each of the arms of the frame of my jaw hinge axis locator is, in turn, made up of two segments, a stiff forward segment, shaped to curve around the forward part of the patients face, and a second segment, constructed of a dead-soft metal or alloy. The second segment of the arm is preferably of smaller cross section than its forward segment, and serves to extend the arm from the rear end of the latter to the vicinity of the patients jaw hinge axis, the two segments being joined together for this purpose in any convenient manner, as, for example, by means of a cylindrical connector with a pair of oppositely directed, aligned sockets, sized to receive the ends of the segments, and a pair of cooperating setscrews adapted to lock the segments in place in the sockets. Fixedly secured to the rear end of each of the second (dead-soft) segments of the arms of the jaw hinge axis locator is a square plate of a transparent material such as, for example, plexiglass. The plate is marked with crossing lines, which form a grid pattern thereon, and is sized to cover the general area of the patients jaw hinge axis on one side of his face when the locator is adjusted to its coarse setting on the patient.

When the locator is positioned as indicated above on a dental patient, and the patient opens and closes his mouth, the square plates on the ends of its arms rotate reciprocally about respective center points. The center of rotation of each plate can be easily spotted by the naked eye, with the aid of the grid markings on that plate. This center of rotation coincides with the patients jaw hinge axis and overlies the position of the latter on the patients face. It is an easy matter to spot this position on the patients skin, through the rotating plate, after which the plate can be moved out of the way, by bending the dead-soft segment of the locator arm to which it is attached, and the jaw hinge axis location marked on the patients face in some manner. Repetition of this procedure either side of the patients head results in the emplacement of marks on his face at the two ends of his jaw hinge axis. If greater accuracy in locating these marks is desired, the locator can be made to serve in a doublechecking capacity by placing a mark at the center of rotation of each of the plastic plates, after that center has been visually determined in the above-described manner; moving the plate out of the way by bending the deadsoft segment of the arm of the locator to which it is attached; lightly marking the position of the patients jaw hinge axis on his face; moving the plastic plate back over the jaw hinge axis area of the patients face and aligning the mark on the plate with that on his skin; and, finally, observing whether the two marks remain in coincidence as the patient opens and closes his mouth. If correction of the location of the mark on the patient's face is necessary, as a result of this procedure, it is a simple matter to once again move the plastic plate out of the way, and make the correction. The plate-moving steps of the doublechecking procedure can be repeated as often as neces sary to achieve maximum accuracy, although such repetition is generally not required for satisfactorily precise results.

It is thus a principal object of the invention to provide an extremely lightweight device, of simplified construction, for the rapid determination of a dental patients jaw hinge axis location with minimal discomfort to the patient.

It is another object of the invention to provide such a device which requires only simplified coarse adjustment, and no fine adjustment, of its parts when being fitted for use on a dental patient.

It is still another object of the invention to provide such a device which yields inherently accurate results with a minimum of effort on the part of the operator.

Yet another object of the invention is to provide such a device having an inherent capability for use in a self-checking capacity.

Other objects, features and advantages of the invention will become apparent in the light of subsequent disclosures herein.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a preferred embodiment of a jaw hinge axis locator in accordance with this invention in a fully assembled position of use.

FIG. 2 is a somewhat enlarged front view of the jaw hinge axis locator positioned for use on a dental patient, a part of the patient's face being depicted in phantom lines.

FIG. 3 is a side view of the jaw hinge axis locator so positioned, the locator being shown in solid lines in an exaggerated lower position, and in phantom lines in an upper position, of use, and the location of the center of rotation of a plate member forming an important part of the locator being shown by means of an index mark thereon.

FIG. 4 is a slightly enlarged side view of a fragmentary portion of the locator, showing a length of dead-soft wire forming an end segment of an arm member thereof, and showing additionally a connector joining the dead-soft wire to a stiff segment of the arm, two different positions of the length of deadsoft wire being illustrated by solid and phantom lines, respectively, to demonstrate an important functional feature of the locator.

DESCRIPTION OF THE PREFERRED EMBODIMENT Considering now the drawing in greater detail, there is shown generally at 10 a preferred embodiment of a jaw hinge axis locator in accordance with this invention. Jaw hinge axis locator 10 comprises a mouthpiece 11, including an impression tray 12 of conventional design, and a flat handle 14, having a crescent-shaped end 13 which is fixedly secured to the bottom of the impression tray by soldering, or equivalently suitable, means, as illustrated in FIG. I, and a flat, elongate, longitudinal segment 15, extending outwardly from said crescent-shaped end, again as illustrated in FIG. 1; a stiff, curving wire 22; an adapter 16 for fastening the stiff, curving wire to handle 14 in the manner illustrated in FIG. I; a pair of dead-soft wire segments 24; a pair of connectors 26, for holding the ends of the stiff curving wire and the dead-soft wire segments together in the aligned relationship illustrated in the drawing; and a pair of transparent plastic plates, or squares, 36, of identical size, fixedly secured to the rearwardly disposed ends of the dead-soft wire segments by means of a pair of sleeve holders 34, again in the manner illustrated in FIG. 1. As the drawing shows, each of the plates 36 is marked with a grid pattern of crossing lines. Although these plates can be of any suitable size, they are preferably five-eighths inch square.

Adapter 16 is simply a metallic block, having the general form of a rectangular parallelpiped, through which run perpendicularly disposed slideways for the handle of mouthpiece 11 and the midsection of stiff wire 22, respectively. The slideway for the handle of the mouthpiece is a T slot 17 running transversely through the lower portion of the adapter, as illustrated in FIG. 2, and sized to receive the mouthpiece handle in its upper, wider portion, again as illustrated in FIG. 2. As will be apparent, the adapter is slidably movable along the handle of the mouthpiece, for fore-and-aft adjustment of the position of the connected curving wire and dead-soft wire segments of the locator assembly (which parts, as will also be apparent, form a pair of arms-designated hereinafter as arms 2l-adapted to fit around the sides of a dental patients face). An illustrative outline of such a face is shown in phantom lines, at 19, on the drawing. Adapter 16 is adjustable along the handle of mouthpiece 11 with the aid of a pair of setscrews 18 mounted in two tapped openings running perpendicularly to the handle through the adapter, in the manner illustrated in the drawing. FIG. 3 shows one of these setscrews in locking engagement with the mouthpiece handle.

Running perpendicularly to T-slot 17, at a higher level, through adapter 16, is a round bore 23, sized to receive the midsection of stiff wire 22 in freely sliding relationship. While stiff wire 22 is, as previously indicated, of curving configuration, it has a straight segment in the middle to permit its sliding interfit with bore 23 of the adapter in the above-indicated manner. Adapter 16 is provided with a pair of setscrews 20, threadedly engageable with a pair of tapped openings so positioned as to permit tightening of the screws against the straight midsection of stiff wire 22 to lock the latter in place, all as illustrated in the drawing, particularly FIG. 2. The stiff wire portions of arms 21 are curved to fit around the sides of a dental patients face, in relatively close, but nontouching relationship, when jaw hinge axis locator is positioned for use on the patient as taught herein.

Each of the dead-soft wire segments 24 of the locator arms 21 is formed of a metallic material of dead-soft character, sub stantially lacking in resiliency and adapted to remain in any position into which it is bent without spring-back to its original shape. Such segments may be formed from extruded aluminum, gold, soft solder or other metal (pure or alloyed) having the necessary properties of dead softness taught herein. Preferably, the dead-soft wire segments are of smaller cross section than stiff wire 22, to increase their flexibility and make them easier to bend.

Connectors 26 are metallic members of cylindrical shape having aligned, counterbored recesses in their ends sized to matingly receive the rearwardly extending ends of stiff wire 22 and the forwardly disposed ends of dead-soft wire segments 24, respectively, in the manner best illustrated in FIG. 4. A pair of setscrews 32 are mounted in a pair of tapped openings running radially into each of the connectors 26 sufficiently far to permit the screws to lock the stiff wire and dead-soft wire segments in place in the connectors, again as best illustrated in FIG. 4.

Press fitted onto the rearwardly disposed ends of each of the dead-soft wire segments 24 is a sleeve holder 34. Each of sleeve holders 34 is of generally tubular shape and pushed partway onto a separate one of the dead-soft wire segments (in the above-indicated press-fit relationship) to leave a rearwardly disposed portion of its hollow center unobstructed. Running from the rearwardly disposed end of the sleeve holder, for substantially the length of the unobstructed portion of its hollow center, is a straight slot 35, adapted to receive one of the plates 36 and hold it sufficiently tightly to provide adequate support for the latter during usage of the locator.

As will now be apparent, each of the dead-soft wire segments 24 is rotatable within its mating recess, or socket, in

connector 26, and can be secured therein at varying angles of rotation, by means of the rearwardly disposed pair of setscrews 32, to permit generally parallel positioning of plates 36 with respect to the sides of a dental patients face. The resulting parallelism between the plates and the, patients face permits a dentist, or dental technician, to look squarely at either side of the patients head through one of the transparent plastic plates and obtain an undistorted view of the surface of the patients skin, for accurate pinpointing of the location of his jaw hinge axis from a sight point on the plate determined in accordance with the below-described axis-locating procedure.

To prepare jaw hinge axis locator 10 for use, the impression tray 12 of mouthpiece 11 is first filled with a suitable impression material, such as alginate, and then fitted over the lower teeth of the patient as the latter holds his mouth open, in a position generally as indicated (although in exaggerated formfor better illustrative effect) in solid lines in FIG. 3. The patient is instructed to close on the tray and thereby bring it into the phantom line position shown in FIG. 3, whereupon the impression material will, upon setting, firmly anchor the tray to his lower jaw and permit it to move coactively therewith. The anchoring of mouthpiece 11 to the patients jaw in this fashion can be carried out with or without attachment of adapter 16 and arms 21 to the mouthpiece handle. In any event, the maximum locator adjustment generally necessary, after mouthpiece 11 has been mounted on the patients jaw, is a simple sliding adjustment of adapter 16 along handle 14 of the mouthpiece (for proper fore-and-aft positioning of arms 21 relative to the patients face), and rotational manipulation of stiff wire 22 in bore 23 of the adapter, to assure proper positioning of plates 36 over the jaw hinge axis areas either side of the patients face. If any additional adjustment is required, as, for example, to compensate for misalignment of the sides of a patients face, it is a simple matter to bend one, or both, of the soft wire segments of the arms 21 to the extent necessary for the purpose. This adjusting capability permits use of the locator on practically anyone (regardless of the shape of his face) with essentially the same ease and lack of difficulty, and constitutes an important feature of my invention.

After jaw hinge axis locator 10 has been fitted to the head of a dental patient in the above-described manner, it is ready for service. All that is now necessary is for the patient to engage in rotational jaw movement, usually under the manipulation of a dentist. While this movement is occurring, the dentist looks through each of the plastic plates 36 to the underlying skin of the patient. The patients jaw movement causes plates 36 to rotate reciprocally about a dead center point, or center of rotation, as the point will hereinafter be referred to. This center of rotation is in alignment with the patients jaw hinge axis, and the observer can easily spot it (with the aid of the grid markings on the plate) then pinpoint the corresponding location of the jaw hinge axis on the patients face. Once such pinpointing of the axis has been accomplished, it is a simple matter to move the overlying plate 36 out of the way, by bending its supporting dead-soft wire segment in the previously indicated manner, and mark its location on the patients skin. This procedure is followed on each side of the patients face for delineation of each end of his jaw hinge axis. Doublechecking of the accuracy of the jaw hinge axis location determination either side of the patients face can be accomplished by placing a mark at the center of rotation of the corresponding plate 36, such a mark being shown at 38 on FIG. 3, before moving that plate out of the way to mark the patients skin, then proceeding in accordance with the doublechecking procedure previously described herein.

From the foregoing description, considered conjunctively with the drawing, it will be evident that jaw hinge axis locator 10 is, by virtue of its extreme lightness of weight, absence of structural complexity, and simplicity of use and functioning, operable in such a way as to achieve all of the above-noted advantages over presently known jaw hinge axis locators. Thus,

the lack of structural complexity of the locator makes for rapid fitting of the device to a dental patients face, and determination of the jaw hinge axis location with a minimum of time and effort. The lightness of weight of the locator contributes greatly to a minimization of patient discomfort during utilization of the instrument, by comparison with the discomfort accompanying usage of the heavy and bulky jaw hinge axis locators of more conventional types. Because of its unique design and manner of functioning, the device yields results of a high degree of accuracy and has an inherent selfcorrecting capability to permit upgrading of those results, where possible, to an even higher degree of accuracy. A particular feature of locator 10, not heretofore mentioned but perhaps evident from the foregoing description, is that it can be used with a conventional alginate impression tray, rather than requiring a custom-made clutch adapter. The advantages of increased versatility and decreased manufacturing expense attributable to this utilization of a standard part in the locator assembly of my invention will be readily apparent to those skilled in the dental arts in the light of present teachings.

The present invention has been described in considerable detail in order to comply with legal requirements for a full public disclosure of at least one of its forms. Such detailed disclosure is not, however, intended to unduly limit the scope of the patent monopoly sought to be granted. Accordingly, while my novel jaw hinge axis locator has been herein illustrated and described in what is considered to be a preferred embodiment, it is emphasized that departures may be made therefrom within the scope of my invention. Exemplary of such departures are noncritical variations of the shapes of the component parts of the jaw hinge axis locator; the use of substitute, for preferred, materials of construction for the locator parts; the elimination of certain structural, or other, features of the locator not critically essential to its proper use and functioning; the addition of useful, but noncritical, components to the locator; etc.

More specifically illustrative of those modifications of jaw hinge axis locator 10 within the scope of my invention are such changes as the substitution of a pair of stiff wire members, extendible from the ends of bore 23 in adapter 16, for stiff curving wire 22; the substitution of longer connecting elements for connectors 26 (to permit adjustment of the length of the locator arms to a greater extent than is possible with arms 21); the substitution of glass, or other suitably clear, plates for clear plastic plates 36; the substitution of plates other than square ones for plates 36; the substitution of equivalently suitable center of rotation-indexing markings for the grid markings on plates 36; the substitution of permanent connecting means between the stiff and dead-soft portions of arms 21 for connectors 26; and other modifications of similarly noncritical character.

While usage of the jaw hinge axis locator of this invention has been heretofore discussed in terms of reference to patients with teeth, I wish to make it clear that the locator is equally applicable for use on patients who have lost their teeth. In the latter connection, the wirelike frame of the locator can be attached to the lower jaw of an edentulous patient by means of a lower, or mandibular, baseplate and bite rim. More specifically, the lower baseplate can be clamped or secured to the mandibular edentulous arch of such a patient, after which the patients lower jaw can be subjected to rotational movement and his hinge axis located in a manner similar to that described above for the location of the jaw hinge axis of a patient having an impression tray secured to his lower teeth.

I wish to emphasize, in final summary, that the scope of my invention includes all of its variant forms encompassed by the language of the following claims. In the claims, the term mouthpiece" includes the above-mentioned baseplate-bite rim-type of mouthpiece apparatus for use on edentulous patients, as well as the impression tray-type of apparatus for use on patients with teeth.

I claim:

1. Jaw hinge axislocating means comprising:

thin, elongate means, so sized, shaped and securable to the handle of a mouthpiece as to extend from said handle partway around at least one side of a dental patients face to termination near the area of his jaw hinge axis, when the mouthpiece is mounted for use on his lower jaw; and

at least one flat, transparent plate member having center of rotation indexing markings thereon;

said thin, elongate means having said fiat, transparent plate member affixed at each end near said area of the patients jaw hinge axis in such fashion as to overlie that area;

at least a portion of said thin, elongate means extending from each end to which said flat, transparent plate member is affixed being of dead-soft character to permit bending thereof and movement of said plate back and forth between positions of overlie and exposure with respect to said patients jaw hinge axis area;

all parts of said jaw hinge axis-locating means serving to permit the rapid location of said patients jaw hinge axis either side of his face through observation of said flat, transparent plate member as the patients lower jaw is subjected to rotational movement, and notation, with the aid of said center of rotation-indexing marking thereon, of the center of rotation of said plate member, and to permit subsequent movement of said plate member out of the way and easy marking of the location of the appropriate end of the patients jaw hinge axis on his face.

2. Jaw hinge axis-locating means in accordance with claim 1, in which said thin, elongate means comprises a pair of wirelike arms adapted to curve from the vicinity of the handle of said mouthpiece around each side of said patients face in relatively close, but nontouching, proximity thereto, when said locating means is mounted for use on the lower jaw of the patient.

3. Jaw hinge axis-locating means in accordance with claim 2, including an adapter for connecting said wirelike arms to the handle of said mouthpiece, said wirelike arms being joined together by means of a straight wire segment of round cross section, integral to both, and said adapter having a transverse bore, of round cross section, adapted to receive said straight wire segment, in freely rotatable relationship, and setscrew means for locking the straight wire segment in position in the bore, whereby angular adjustment of the positions of said arms relative to said handle is readily achievable.

4. Jaw hinge axis-locating means in accordance with claim 2, in which each of said arms has a rigid arcuate segment consisting of a piece of stiff curving wire, sufficiently long to extend, in a position of use on a dental patient, from the vicinity of the handle of said mouthpiece to a point short of the area of said patients jaw hinge axis on one side of his face; a dead-soft segment consisting of a piece of dead-soft wire of a length sufficient to extend from a point near the rearwardly disposed end of said rigid arcuate segment, when the latter is in the above-indicated position of use, to termination near the patients jaw hinge axis, and a connector having counterbored recesses, serving as receptive sockets for adjacently disposed ends of the rigid and dead-soft segments of the arm, and cooperating means for locking the adjacently disposed ends of said segments in said counterbored recesses in generally aligned relationship.

5. Jaw hinge axis-locating means in accordance with claim 3, in which each of said arms has a rigid, arcuate segment consisting of a piece of stiff, curving wire, sufficiently long to extend, in a position of use on a dental patient, from said adapter to a point short of the area of said patients jaw hinge axis on one side of his face; a dead-soft segment consisting of a piece of dead-soft wire of a length sufficient to extend from a point near the rearwardly disposed end of said rigid, arcuate segment when the latter is in its above-indicated position of use, to termination near said patients jaw hinge axis; and a connector having counterbored recesses, serving as receptive sockets for adjacently disposed ends of the rigid and dead-soft segments of the arms, and cooperating means for locking the adjacently disposed ends of said segments in said counterbored recesses in generally aligned relationship.

8. Jaw hinge axis-locating means in accordance with claim 1, including, as a structural element, said mouthpiece.

9. Jaw hinge axis-locating means in accordance with claim 5, including, as a structural element, said mouthpiece.

l0. Jaw hinge axis-locating means in accordance with claim 7, including, as a structural element, said mouthpiece.

Claims (10)

1. Jaw hinge axis-locating means comprising: thin, elongate means, so sized, shaped and securable to the handle of a mouthpiece as to extend from said handle partway around at least one side of a dental patient''s face to termination near the area of his jaw hinge axis, when the mouthpiece is mounted for use on his lower jaw; and at least one flat, transparent plate member having center of rotation indexing markings thereon; said thin, elongate means having said flat, transparent plate member affixed at each end near said area of the patient''s jaw hinge axis in such fashion as to overlie that area; at least a portion of said thin, elongate means extending from each end to which said flat, transparent plate member is affixed being of dead-soft character to permit bending thereof and movement of said plate back and forth between positions of overlie and exposure with respect to said patient''s jaw hinge axis area; all parts of said jaw hinge axis-locating means serving to permit the rapid location of said patient''s jaw hinge axis either side of his face through observation of said flat, transparent plate member as the patient''s lower jaw is subjected to rotational movement, and notation, with the aid of said center of rotation-indexing marking thereon, of the center of rotation of said plate member, and to permit subsequent movement of said plate member out of the way and easy marking of the location of the appropriate end of the patient''s jaw hinge axis on his face.

2. Jaw hinge axis-locating means in accordance with claim 1, in which said thin, elongate means comprises a pair of wirelike arms adapted to curve from the vicinity of the handle of said mouthpiece around each side of said patient''s face in relatively close, but nontouching, proximity thereto, when said locating means is mounted for use on the lower jaw of the patient.

3. Jaw hinge axis-locating means in accordance with claim 2, including an adapter for connecting said wirelike arms to the handle of said mouthpiece, said wirelike arms being joined together by means of a straight wire segment of round cross section, integral to both, and said adapter having a transverse bore, of round cross section, adapted to receive said straight wire segment, in freely rotatable relationship, and setscrew means for locking the straight wire segment in position in the bore, whereby angular adjustment of the positions of said arms relative to said handle is readily achievable.

4. Jaw hinge axis-locating means in accordance with claim 2, in which each of said arms has a rigid arcuate segment consisting of a piece of stiff curving wire, sufficiently long to extend, in a position of use on a dental patient, from the vicinity of the handle of said mouthpiece to a point short of the area of said patient''s jaw hinge axis on one side of his face; a dead-soft segment consisting of a piece of dead-soft wire of a length sufficient to extend from a point near the rearwardly disposed end of said rigid arcuate segment, when the latter is in the above-indicated position of use, to termination near the patient''s jaw hinge axis, and a connector having counterbored recesses, serving as receptive sockets for adjacently disposed ends of the rigid and dead-soft segments of the arm, and cooperating means for locking the adjacently disposed ends of said segments in said counterbored recesses in generally aligned relationship.

5. Jaw hinge axis-locating means in accordance with claim 3, in which each of said arms has a rigid, arcuate segment consisting of a piece of stiff, curving wire, sufficiently long to extend, in a position of use on a dental patient, from said adapter to a point short of the area of said patient''s jaw hinge axis on one side of his face; a dead-soft segment consisting of a piece of dead-soft wire of a length sufficient to extend from a point near the rearwardly disposed end of said rigid, arcuate segment when the latter is in its above-indicated position of use, to termination near said patient''s jaw hinge axis; and a connector having counterbored recesses, serving as receptive sockets for adjacently disposed ends of the rigid and dead-soft segments of the arms, and cooperating means for locking the adjacently disposed ends of said segments in said counterbored recesses in generally aligned relationship.

6. Jaw hinge axis-locating means in accordance with claim 4, in which the center of rotation-indexing markings on the flat, transparent plate members affixed to each of said arms consist of square grid markings.

7. Jaw hinge axis-locating means in accordance with claim 5, in which the center of rotation-indexing markings on the flat, transparent plate member affixed to each of said arms consist of square grid markings.

8. Jaw hinge axis-locating means in accordance with claim 1, including, as a structural element, said mouthpiece.

9. Jaw hinge axis-locating means in accordance with claim 5, including, as a structural eLement, said mouthpiece.

10. Jaw hinge axis-locating means in accordance with claim 7, including, as a structural element, said mouthpiece.

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