Dental prosthetic structures and connectors for use in such prosthetic structures

A dental prosthetic construction comprising a pontic and a connector limb attached to the pontic, the connector limb having a joint portion received in a socket of an abutment tooth to retain the pontic in an intended position, the joint portion of the connector limb being introduced into the socket in the abutment tooth along a path of insertion which is substantially parallel to the dental arch containing the abutment tooth and having bearing surfaces engaging bearing surfaces in the socket such that there is limited freedom of angular movement of the connector limb about the joint portion so as to permit stress-breaking relative movement between the connector limb and socket while maintaining contact between the connector limb and socket.

THIS INVENTION relates to improvements in or relating to the construction 
of both fixed and removable dental prosthetic structures, such as bridges 
and partial dentures. 
A dental bridge comprises an artificial tooth or teeth, a so-called 
"pontic", supported on either side by a suitably prepared sound natural 
tooth called "an abutment tooth" in the art. 
A number of different methods of providing a patient with a fixed dental 
bridge are currently in use, the majority of these methods involving a 
one-piece bridge construction made of a suitable dental material and 
incorporating the pontic and attachments for securing the pontic to the 
abutment teeth. 
Providing the patient with a dental bridge by the known methods is achieved 
by first carrying out dental preparation work on the abutment teeth and 
then fabricating and installing the bridge construction consisting of the 
pontic and the appropriate attachments. 
In one currently popular form of dental bridge, radical surgery is first 
carried out on both abutment teeth in order to form these into 
substantially parallel pillar--like structures which have a substantially 
constant cross-sectional area over a significant height. Once this surgery 
has been performed, casts are taken of the prepared abutment teeth for use 
in preparing cast sockets made of a dental metal for incorporating in the 
attachments of the dental bridge construction which is constructed as a 
unitary item consisting of the pontic and integrally cast attachments 
containing the metal sockets which fit accurately over the prepared 
abutment teeth. Installation of such a dental bridge construction is then 
performed by applying dental cement to the prepared abutment teeth and 
fitting the attachments of the dental bridge construction over the 
respective abutment teeth. 
The preparation of the cast metal sockets and the unitary bridge 
construction including these involves a very high degree of skill, and 
additional difficulties are involved by the need for the attachments to be 
applicable to the prepared abutment teeth along parallel paths. 
The bridge construction itself is necessarily made and assembled in a 
laboratory by a skilled technician, so that each bridge is individually 
made and is a unique piece of high precision work. 
The unitary nature of the bridge construction described above also means 
that such bridge construction can be subjected in use to considerable 
bending moments and is liable to break or become detached under the forces 
encountered in the mouth. 
Moreover, the surgery which is required to be performed on the abutment 
teeth is radical and may involve the destruction of considerable 
quantities of healthy tooth material. 
A further disadvantage of the described known bridge construction is the 
fact that, in installing the bridge construction, the attachments are 
applied to the prepared and cemented abutment teeth in a path of 
application along with bi-directional forces commonly occur in the mouth. 
Consequently, the bridge construction is subjected to forces which tend to 
dislodge it and can be readily withdrawn along this path as a result of 
loss of adhesion between the bridge construction and the abutment teeth 
following shearing of the relatively thin layer of dental cement holding 
the abutment teeth and the bridge construction together. 
It is an object of the present invention to provide an improved method of 
constructing a dental prosthetic structure and, to this end, there is 
provided a method of constructing a dental prosthetic structure, 
comprising providing an abutment tooth with a socket and retaining a 
pontic in an intended position by means of a connector limb attached to 
the pontic and having a joint portion received in the socket, the joint 
portion of the connector limb being introduced into the socket along a 
path of insertion which is substantially parallel to the dental arch 
containing the abutment tooth and fitting in the socket with a freedom of 
movement such as to permit stress-breaking relative movement between the 
connector limb and socket. 
In another aspect, the invention provides a dental prosthetic construction 
comprising a pontic and a connector limb attached to or for attachment to 
the pontic, the connector limb having a joint portion for reception in a 
socket of an abutment tooth to retain the pontic in an intended position, 
the joint portion of the connector limb being introducible into the socket 
in the abutment tooth along a path of insertion which is substantially 
parallel to the dental arch containing the abutment tooth and fitting into 
the socket with a freedom of movement such as to permit stress-breaking 
relative movement between the connector limb and socket. 
According to a further aspect, the invention provides a dental prosthetic 
connector for use in attaching a pontic to an abutment tooth, which 
connector has a first part including a limb and a second part defining a 
socket, the two connector parts having bearing surfaces at places of 
contact when engaged, which bearing surfaces are so arranged that there is 
complete freedom of movement of the limb within the socket along a path of 
insertion of the limb into the socket. 
In another aspect, there is provided a dental prosthetic connector for use 
in attaching a pontic to an abutment tooth, which connector consists of a 
part including a limb constructed to fit a prepared socket-like cavity 
within the substance of the abutment tooth. 
The invention further provides a dental prosthetic connector consisting 
entirely or in part of a limb which is arcuate in shape and movable along 
an axis thereof in a passage in the pontic in order to engage or disengage 
the connector. 
In a further aspect of the present invention, there is provided a dental 
prosthetic construction comprising a pontic and a connector for attaching 
the pontic to an abutment tooth, the connector having a first part for 
attachment to the abutment tooth and a second part carried by the pontic, 
the connector parts fitting together so as to permit a degree of movement 
therebetween, in which construction one of the connector parts has 
retaining projections extending therefrom in more than one plane to assist 
in attaching the connector part to the pontic or abutment tooth. 
The retaining projections of the one connector part need not be constructed 
from the same material as the rest of the connector part and could, with 
advantage, be capable of slight modification to suit particular 
installation requirements, for instance, by bending. In a preferred 
embodiment, the one part of the connector is the socket part. 
In yet another aspect of the invention, there is provided a dental 
prosthetic contruction comprising a pontic and a connector for attaching 
the pontic to an abutment tooth, the connector having a first part for 
attachment to the abutment tooth and a second part carried by the pontic, 
the connector parts fitting together so as to permit a degree of movement 
therebetween, in which construction the part of the connector attached to 
the abutment tooth is attached to a restoration for fitting to the 
abutment tooth. 
The term restoration is intended to cover laboratory-made items, such as a 
crown or inlay, and the connector part may be attached to the restoration 
by embedding in a matrix of filler material in an oversized cavity within 
the restoration, or may be attached by some other suitable means, such as 
welding, soldering, intrical casting, or the use of suitable bonding 
agents. 
In accordance with another aspect of the present invention, there is 
provided a dental prosthetic construction comprising a pontic and a 
connector for attaching the pontic to an abutment tooth, the connector 
comprising a first part for attachment to the abutment totooth and a 
second portion carried by the pontic, the connector parts fitting together 
so as to permit a degree of movement therebetween, in which construction 
at least limited vertical movement of the pontic is permitted by the 
connector. 
In the case of a socket and limb connector, such vertical movement is 
enabled by making the vertical dimension of the socket greater than the 
corresponding dimension of the joint portion of the limb. 
In a preferred embodiment, both horizontal and vertical movement of the 
pontic is permitted by the connector. In the case of a socket and limb 
connector, this is achieved by making both the horizontal and vertical 
dimensions of the socket greater than the corresponding dimensions of the 
joint portion of the limb part. 
In dental prosthetic constructions which permit vertical and/or horizontal 
movement of the pontic springs or magnets may be used to stablise the 
pontic in a resting position when chewing forces are not being applied, 
and also in order progressively to transfer a part of those forces to the 
abutment tooth, following movement of the joint portion of the limb within 
the socket. 
In some embodiments which allow vertical or horizontal movement of the 
pontic and which employ socket and limb connectors, one or more of the 
walls of the socket may be omitted. 
According to still another aspect of the present invention, there is 
provided a dental prosthetic construction comprising a pontic and a 
connector for attaching the pontic to an abutment tooth, the connector 
having a first portion attached to the pontic and a second portion carried 
by the pontic, the connector parts fitting together so as to permit a 
degree of movement therebetween, in which construction the first and 
second connector parts are disengagable from one another to permit removal 
of the pontic. 
Such a construction enables the provision of removable constructions, such 
as bridges or partial dentures which can be inserted and removed at will. 
In the case of a socket and limb connector, the limb part, or in certain 
circumstances the socket part, may be arranged to slide axially to 
withdraw the limb from the socket and enable removal of the pontic. 
Where the limb part of the connector is slidable, the limb may be a 
straight member, guided for linear movement, preferably along the line of 
withdrawal from the socket. The limb could, however, slide along on 
arcuate path, being a rigid member of arcuate shape, or at least partly 
constructed from a flexible material. 
Any suitable means, such as friction, spring pressure, a spring catch, or 
magnetic force, may be employed to retain the movable connector part in 
its position of engagement with the other connector part. 
In the case of a socket and limb connector, the slidable part is preferably 
the limb part and such a slidable limb part may be operated in diverse 
ways. Examples of suitable operating arrangements include projections 
extending from the limb part beyond the pontic through a suitable hole or 
slot so as to be operable to engage or disengage the limb from the socket. 
Such projections may have holding extensions to make them easier to 
manipulate and they may also have covers to help prevent the access hole 
in the pontic filling with debris. 
Magnetic force may also be used to move a movable connector part made of 
magnetisable material. In one embodiment, an operating tool could be 
magnetically coupled to the movable connector part, so that by 
subsequently manipulating the tool the required movement can be 
transmitted to the movable connector part. 
Another possible operating arrangement involves the application of pressure 
to a flexible or mobile part of the surface of the pontic, such pressure 
being translated into the required movement of the connector part, either 
directly or by way of linkage. 
A further possibility for actuating a movable connector part is the use of 
hydraulic pressure, advantages of which include the possibility of 
applying pressure remote from the movable connector part to be actuated 
and the possibility of simultaneously operating a plurality of movable 
connector parts in the same prosthetic construction. 
Conveniently, a movable limb of a socket and limb connector is movable by 
means of a tool mechanically engaging the limb part. For instance, the 
limb part may be provided with indentations or projections with which the 
tool is engageable. In such embodiments, slots or notches may be provided 
to the guide tool into correct engagement with the limb part. 
Locating devices may be provided to help align a limb part with its 
respective socket during installation and also to align a tool with an 
appropriate portion of the limb part during removal of the prosthetic 
construction. 
The socket parts of a socket and limb connector may have suitable 
cross-sectional shape, such as more or less rectangular or triangular 
shapes, which may be best suited to posterior teeth and incisor teeth 
respectively.

Referring now to the drawings, FIG. 1 shows a fixed dental bridge 
construction embodying the present invention, in which an artificial tooth 
or pontic 3 is supported in a gap between two abutment teeth 1 and 2 by 
respective bridge connectors 4 and 5. 
The bridge connector 4 is shown schematically in FIG. 1 as comprising a 
first or socket part 6 which is embedded in a matrix of filler material 8 
received in a prepared, oversized and under-cut cavity 7 formed in a 
vertical surface of the abutment tooth 1. A second or limb part 9 of the 
connector 4 has a portion 10 at one end thereof received in a fixing 
cavity in the form of a slot 11 formed in the pontic 3, the said portion 
10 being embedded in a matrix of filler material 12. A projecting joint 
portion 14 at the other end of the limb part 9 projects from the filler 
material 12 and fits into the socket part 6 with sufficient play to enable 
relative movement of the pontic 3 relative to the abutment tooth 1 for 
stress-breaking purposes. 
The bridge connector 5 is a unitary structure and consists of a dihedral 
strip 15 having a horizontal arm 16 and a vertical arm 17. The strip 15 
fits into an L-shaped surface groove or cavity cut for this purpose in 
adjacent horizontal and vertical surfaces of the abutment tooth 2. Fingers 
18 formed integrally with the arm 17 of the strip 15 project into the slot 
of the pontic 3 where they are embedded in the matrix of filler material 
20 filling the slot. Each of the fingers 18 is covered with a layer of 
resilient material 19 which permits limited stress-breaking movements of 
the pontic 3 relative to the abutment tooth 2. 
FIGS. 6 to 8 show on example of a configuration which may be adopted in the 
case of the bridge connector 4. As shown in these Figures, the limb part 9 
of the connector 4 for embedding in the matrix of filler material 12 in 
the slot 11 of the pontic 3 may have its projecting joint portion 14 
fitting quite snugly into the socket part 9 in the abutment tooth with a 
flat end surface 21 of the joint portion 14 spaced from the floor 22 of 
the socket part 6. The bearing surfaces 23, 24 of the joint portion 14 
within the socket part 6 are rounded to form a kind of universal joint, 
permitting stress-breaking movement of the pontic 3 in the required 
directions, including longitudinally of the limb part 9, but precluding 
rotation around the longitudinal axis. 
In some circumstances it may be desirable to provide a construction which 
permits rotational movement on one side. In this case, one connector could 
be constructed as illustrated in FIGS. 6 to 8 and the other connector 
could be of similar form but modified to permit such rotation about the 
longitudinal axis. 
The bridge connector components can be standard items made of any suitable 
material, such as stainless steel or titanium or a composition including 
carbon fibres. The pontic may be made of dental metal or a non-metallic 
dental material. Those parts of a connector component which are to be 
covered by the filler material may also be treated, for example by having 
the surface thereof roughened, so as to make the filler material adher to 
the component. 
The filler material used to fill the cavities in the abutment teeth and the 
pontic, and thus attach the component to the tooth or pontic, may be any 
suitable material, such as a composite dental filling material. 
Whilst, in the above described embodiment, the connectors 4 and 5 are 
embedded in filler material in cavities in the abutment teeth and the 
pontic, it is envisaged that, in appropriate cases, a connector embodying 
invention could be attached entirely or in part to a prepared surface of 
an abutment tooth. In such a case, a procedure such as acid etching may be 
used to prepare the surfaces of the tooth and connector to be attached to 
one another by filler material or the like placed between the surfaces. 
It is envisaged that a range of different types and sizes of standard 
bridge connectors may be provided for different circumstances and a range 
of pontics may also be provided with suitable fixing cavities for use with 
the various connectors. 
In providing a patient with a dental bridge construction as hereinbefore 
described, a dental procedure is first carried out to prepare the abutment 
teeth by forming the required cavities or otherwise preparing the surface 
of the tooth to receive the standard bridge connectors selected for the 
particular construction involved. 
The bride construction is then installed by attaching the corresponding 
bridge connectors to the abutment teeth using the filler material, 
introducing the relevant portions of the bridge connectors into the groove 
of a suitable standard or custom-made pontic and thereafter fillng the 
groove in the pontic with a matrix of filler material to embed and retain 
the connector. 
The advantages of the proposed bridge construction are seen in the fact 
that the bridge connectors can be ready made components which are not 
intended to fit accurately either the abutment tooth or the artificial 
tooth. Consequently, high precision laboratory work is eliminated and the 
dental preparation work to enable the construction of such a bridge is 
simplified and does not involve carrying out radical and accurate surgery 
on the healthy abutment teeth. 
The proposed bridge construction also allows a bridge connector to be so 
arranged that the path of withdrawal of the connector, or separation of 
its parts, is transverse to the forces encountered in the mouth, thereby 
reducing the chances of the pontic becoming detached from the abutment 
teeth. This construction further permits effective stress-breaking 
structures to be incorporated into the bridge with consequent reduction in 
the likelihood that the bridge will break. Moreover, the forces 
encountered in the mouth will not subject the bridge construction to 
shearing forces tending to break the connection between the bridge 
construction and abutment teeth as in the prior art, but will subject the 
structure to more readily resisted compression forces. 
Whilst the above embodiment of the invention has been described with 
reference to fixed dental bridges, it is envisaged that, connectors 
embodying the invention could be used as denture retainers, provided a 
two-part connector structure is employed and the coupling of the connector 
parts is effected in a direction transverse to the forces encountered in 
the mouth. For example, the connector of FIGS. 6 to 8 is thought to be 
specially suitable for use in the case where a denture is to be provided 
to replace teeth at the back of the mouth behind sound front teeth to 
which a connection can be made. 
FIGS. 9 to 11 show another embodiment of a socket part of a socket and limb 
connector for use in attaching a pontic to an abutment tooth. The socket 
part comprises a socket 31 attached to a perforated base plate 32 from 
which extend upper substantially horizontal limbs 33 which have an arcuate 
configuration in the horizontal plane. To attach the socket part to an 
abutment tooth 35, the socket part is positioned in an oversized cavity in 
the tooth 35 and the remaining space 34 is later filled with a suitable 
material. Part of the socket may protrude from the left side wall of the 
tooth. Such a means of attaching the socket part and abutment tooth 
enables the socket part to occupy a cavity resulting from the removal of a 
pre-existing mesio-occlusal or disto-occlusal filling, whilst at the same 
time acting as a reinforcement for the matrix of filler material. 
FIG. 12 illustrates diagrammatically how a joint part of a limb 36 of the 
connector may be afforded limited vertical movement within the socket 31. 
In FIG. 12, the limb 36 is shown near the upper limit of its permitted 
vertical movement. 
The dental bridge construction shown in FIG. 13 comprises a pair of 
integrally formed pontics 37 each connected to a respective abutment tooth 
35 by means of a respective connector consisting of a socket 31 and a limb 
36, such that limited vertical moement of the pontics 37 is permitted. In 
the upper resting position shown in FIG. 13, the gum 38 is in light 
contact with the pontics but is uncompressed. FIG. 14 shows the bridge of 
FIG. 13 when subjected to an occlusal load. In this state, the pontics 
have moved vertically downward a little, with coresponding movement of the 
limbs 36 within the sockets 31. The gum 38 has been compressed and is 
providing resistance to the occlusal force. This type of arrangement would 
be advantageous in those instances in which it is desirable to reduce the 
forces transmitted to an abutment tooth by a pontic. 
As shown diagrammatically in FIG. 15, a limb 36 of a socket and limb 
connector may be permitted both vertical and horizontal movment. FIG. 15 
shows such an arrangement with the limb 36 positioned at the upper limit 
of vertical movement within the socket part 31 and near the centre of its 
range of horizontal movement. Such a connector transmits a minimum of 
chewing forces from the pontic to the abutment teeth, provided that the 
pontic is adequately supported by either the gum or other teeth. Movement 
of the pontic is an occlusal direction (arrow 39) is prevented, so that 
the pontic is held in position in the mouth. Such a connector arrangement 
would be a especially useful in the case of a partial denture coupled to 
weak or loose natural teeth. 
The removable bridge construction shown in FIG. 16 comprises a pair of 
integrally formed pontics 37 through which extends a horizontal sleeve 41 
containing freely slidable connector limb parts 40. A spring 42 disposed 
between the limbs 40 biases the limbs apart into engagement with the 
respective socket parts 31. 
The limbs 40 are formed with notches 44 with which a tool may be engaged 
through slots extending through both the pontic and sleeve, and indicated 
by dotted lines 43, in order to move the limbs to a retracted position in 
which they are disengaged from the sockets 31 as shown in FIG. 17. With 
the limbs thus withdrawn from the sockets, the pontics are no longer 
attached to the abutment teeth and the bridge may thus be removed from the 
mouth. A removable bridge has a number of advantages when compared to a 
fixed one, including simplified hygiene procedures for the wearer, as well 
as improved access for the dentist for inspection and maintenance. 
As shown in FIG. 18, the limbs 40 may have an arcuate shape and be received 
in respective sleeves 41 in the pontics 37. The end 46 of the limbs 
furthest from the joint part 36 are more or less flush with the palatal 
surface of the pontics 37. Notches 45 in the pontics facilitate engagement 
of an actuating tool in notches 44 in the limbs. 
Arrows 47 in FIG. 19 illustrate the direction of the force applied to 
retract the limbs from the sockets in the FIG. 18 embodiment. In this 
retracted condition of the limbs, the ends 46 now protrude from the 
surface of the pontics. Re-engagement of the limbs with the sockets 31 may 
be achieved either using a tool or by pressure on the ends 46 following 
alignment of the joint part 36 with the socket parts 31. 
A curved connector limb has an advantage in that the end furthest from the 
joint may be situated at the surface of the pontic facing the tongue, 
cheek or chewing surface, where it is readily accessible. 
FIG. 20 illustrates how two curved connector limbs 40A and 40B may be 
accomodated in different planes in respective sleeves 41 within the same 
narrow pontic. The sleeve 41 are confined to short lengths guiding the 
limb close to the joint portions thereof, the remainder of the limbs 
sliding within a tunnel formed by the matrix of filler material 34. FIG. 
21 shows the limbs 40A and 40B in the region where they are simply placed 
in filler material. There is sufficient latitude between the materials of 
the connector limb and the filler material to allow the connector limb to 
slide. 
End stops (not illustrated) may be provided in order to prevent movement of 
a sliding connector limb beyond determined limits, which would normally be 
fully engaged and fully retracted positions. 
FIGS. 22, 23 and 24 illustrate the use of a locating device for aligning 
pontics relative to abutment teeth and for assisting in the manipulation 
of sliding connector limbs. This locating device takes form of a cap 48 
constructed so as to be a tight fit over the pontics, abutments and as 
much of the dental arch as desired or necessary. Like a common type of 
sportsman gun shield, the cap 48 is designed to engage undercuts and so to 
stay firmly in place following insertion. However, the cap is constructed 
of a material which is sufficiently flexible to allow the device to be 
removed and reinseted fairly easily. Actuating rods 49 are positioned so 
that, during insertion of the cap they will slide along grooves 45 in the 
pontic so as to be guided into notches 44 in the bolts, clearing away any 
food debris in the process, so that, when the cap is fully located, the 
rods 49 will be engaged in the notches 44. In order to insert a removable 
bridge using the described locating device, the connector limbs are moved 
into the extended socket-engaging position and the bridge is placed fully 
into its location in the cap. The rods 49 are now used to slide each bolt 
into the retracted position, the movement of the rods and connector limbs 
being made possible by the flexible nature of the cap material. The cap 48 
containing the bridge is now inserted into the mouth and slipped into 
position. The pontics are thus correctly aligned with the abutment teeth 
and the limbscan be moved to the extended position so as to enter the 
socket parts of the connectors in the abutment teeth, following which the 
cap 48 can be removed, leaving the bridge in position. The above procedure 
may be reversed in order to remove the bridge. 
It is envisaged that, in some embodiments of the cap 48, a space may be 
provided into which the ends 46 of the connector limbs can move during 
retraction without them having to distort the cap (see FIG. 24). 
Caps used as aids in positioning pontics and operating devices for 
connector limbs need not be flexible. If made of a rigid material, such as 
acrylic resin, they may be designed to avoid undercuts to the path of 
insertion, whilst at the same time conforming to sufficient of the surfacs 
of both the natural and artificial teeth to make location of a prosthetic 
construction easy and accurate. In the case of such rigid caps, springs or 
other catches may be fitted to engage undercuts both in the natural 
dentition and in the pontics in order to help keep the cap in place during 
operation of a sliding connector limb and also to hold the prosthetic 
construction in the cap during insertion or removal from the mouth. 
A connector limb operating rod attached to a cap may be designed to engage 
the appropriate parts of the limb during insertion of the cap. However, in 
a preferred arrangement, the pontic is first fully inserted into the cap. 
Subsequent operation of a mechanism first engages the rod and then moves 
it in order to operate the sliding connector limb. Such a sequential 
movement may be readily achieved by means of levers, incline planes, cams 
and the like. Preferably, an operating lever would be arranged to project 
from the mouth so as to be easily manipulated, possibly in conjunction 
with a second reciprocal lever which could further simplify use. One or 
other of the operations of engaging or retracting the sliding limbs may be 
spring-assisted. 
Referring now to FIGS. 25 and 26 of the drawings, which illustrate a 
particularly simple embodiment of the present invention, it will be seen 
that a socket part 50 of a connector for a dental prosthetic construction 
is fashioned from a sheet of material by forming a substantially 
rectangular aperture adapted to receive a connector limb 52 as shown in 
FIG. 26. The edges 51 of the aperture which are to support the limb 52 may 
be shaped, if desired, to allow for both a snug fit of the limb and 
limited stress-breaking movements. The socket is embedded in a matrix of 
filler material 53 and those surfaces of the socket part which are to 
contact the filler material 53 may be treated to provide good adhesion. 
The connector limb 52 partially within the pontic 56, has a parallel-sided 
portion where it passes through the aperture of the socket part, the 
required limited stress-breaking movements in this case being provided by 
the shape of the socket, rather than that of the bolt. 
The illustrated socket part 50 has an essentially rectangular 
cross-section. This may be positioned in any convenient plane. For 
example, in posterior teeth, the longer side of the pocket aperture would 
be horizontal, as illustrated. When used for incisor teeth, a more 
vertical arrangement may be advantageous. 
In some embodiments of the present invention, all or parts of a connector 
socket may be constructed of filler material. For example, the side wall 
54 or 55 could be omitted. 
It will be appreciated that the movements which need to be permitted 
between the socket and limb parts of a connector are very small and it is 
envisaged that such connectors may be supplied with the limb as a tight 
fit within the socket, the required freedom of movement to suit any given 
circumstances then being introduced by carrying out modification of the 
connector parts, such as by grinding or the like, at the time of 
installation. 
The limb and socket connectors described above are mainly intended to 
connect artificial teeth to adjacent natural ones. However, when dentures 
ae to be constructed it is common practice to anchor artificial teeth to 
natural ones which may be some distance from the gap--the intervening 
space being spanned by a plate or a bar. Clasps and rests are commonly 
used for attachment but have many disadvantages. Limb and socket 
connectors could be used in many of these situations, the sockets being 
oriented with the long axis more or less parallel with the plane of the 
dental arch and facing a convenient direction--for instance, towards the 
palate. It is envisaged that the limbs would be mounted on movable 
arms--or the like--to enable engagement of the limbs and sockets. One such 
embodiment will now be described, by way of example, with reference to 
FIGS. 27 to 30 of the drawings. 
The mechanism is based on a connector limb attached to a kinged arm which 
is spring loaded to keep it in its correct (closed) position. Large 
components of the forces imposed on the limb from the denture are 
transmitted through the surfaces of the arm adjacent to denture material, 
rather than through the hinges. The arm is extended beyond the hinges for 
ease of spring application and operation. 
Referring now to FIGS. 27 to 30, the connector has an arm 101 which in this 
case is "L" shaped, and fits loosely into a correspondingly shaped slot in 
the denture 102. Hinge-like projections 103 from the arm fit into 
depressions 104 (FIG. 30) in the dental material. Further hinge-like 
projections 105 fit depressions 106 on the inner aspect of the denture. 
The position of hinges 103 and 105 which are out of the section in FIG. 29 
are indicated by dotted lines, as is the hinge 105 which is out of sight 
in FIG. 27. Rests 107 project from arm 101 and fit depression 108 in the 
denture material. In FIG. 28 the connector limb 109 can be seen engaged in 
a socket 110 of the natural tooth 111. A part of the arm 101 on the 
opposite side of the hinges to the connector limb is made of a spring 
material 112 and, for ease of operation, is bowed so as to project in part 
above the surface of the denture material. The end 113 of the spring rests 
on a platform 114 of the denture. Spring tension is adjusted so that the 
spring end 113, hinges 105 and rests 107 are held in contact with the 
corresponding parts of the denture. When the denture is in position the 
connector limb 109 is engaged in the socket 110. In order to withdraw the 
limb from the socket, pressure--for instance finger pressure)--may be 
applied to the bowed part of the spring 112 in the direction of the arrow 
115 (FIG. 29). This would bend the spring, causing the arm 101 to pivot on 
hinges 103, thus moving the limb out of the socket. 
The embodiment of FIGS. 27 to 30 would be extremely simple to incorporate 
into a denture. It is envisaged that a range of standardised shapes and 
sizes of the arm with its projections would be produced together with aids 
to enable the necessary slots and depressions to be easily incorporated 
into the denture when it is made. 
Whilst the above described embodiments of the invention employ abutment 
tooth socket defined by connector parts, it is envisaged that all or part 
of such sockets could be fashioned as suitably prepared cavities in the 
substance of the abutment tooth or in a matrix of filler material. 
In those instances when it is desired to fit a slidable connector limb to a 
pontic in the laboratory, the socket part may be fitted to its abutment 
tooth either before or after the pontic is constructed. 
When a socket has been fitted first one way making a pontic with its 
connector limb in the correct position is as follows: 
A curved connector limb is fitted into the socket and held steady while 
being embedded in a small mass of impression material, such as a rubber 
base material, about the size of the pontic but without undercuts to the 
line of withdrawal, and with the material flush with the `working end` of 
the connector limb. After this has set, a second impression, of a type 
which will not adhere to the first, it taken over the top of it to include 
the abutment teeth. When set this is removed. The first impression will be 
left behind, anchored by the enclosed connector limb. The connector limb 
is now withdrawn a little way through the first impression material in 
order to disengage it from a socket, when the first impression may be 
removed from the mouth. The connector limb is now pushed back into its 
original position in the impression material and the first impression is 
replaced into its correct position within the second impression. A model 
prepared from this composite impression will have the connector limb 
embedded in it its correct location in the model abutment tooth. Following 
withdrawal of the connector limb from the model this, in turn, will have a 
correctly located socket. 
It is envisaged that a series of aids would be provided to assist in the 
construction of sockets. They may be made of a translucent material to 
facilitate the use of light-cured filler matrix material such as 
`composite` materials. It is envisaged that these aids would include 
gauges to define the minimum size and depth of a cavity, formers to 
compact and shape the filler matrix deep into the socket part, and aids to 
both hold the socket part steady while the surrounding matrix was inserted 
and also correctly shape the matrix. 
In addition, a range of burrs with shoulders may be provided as a help to 
achieving correct cavity depth. also suitable curved connector limbs and 
sockets may be provided for the construction of models as previously 
described. 
Any of the connector parts may be suitably coloured--for instance, tooth or 
gum coloured.