Mechanically retained fixed partial denture

A mechanically retained fixed partial denture is a three part device which is assembled to form the pontic. The three parts to interlock in a non-displaceable manner as follows: 1) a buccal element engages the buccal surfaces of the abutment teeth 2) a lingual element engages the lingual surfaces of the abutment teeth; 3) part of the buccal element is within the body of the lingual element; 4) and an incisal attachment element then connects the buccal and lingual elements. The incisal attachment element comprises an elongated member which, upon assembly, extends through a linear aperture located within the body of both the buccal element and the lingual element both simultaneously and continuously, to form an interlocking system resulting in one functional unit made up of the three elements. The advantages of this mechanical retention are 1) conservation of tooth structure; 2) efficiency due to time savings; 3) low expense; and 4) no complications of tooth preparation. The devices is adaptable to replace several adjacent teeth.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention pertains to fixed dental prosthetics, and more particularly, 
to devices for restoring dentulous spaces in the dentulous arch. 
2. Prior Art 
One of the most common problems faced in the field of dentistry is loss of 
teeth. Tooth loss may range in severity from one tooth to all teeth in the 
mouth. Missing teeth cause problems in speech, chewing, personal 
appearance, malocclusion, and the temporo-mandibular joint. When a limited 
number of teeth are missing the restorative options include replacement of 
the missing teeth with a prosthesis called a fixed partial denture 
(bridge). 
Fixed partial dentures are usually fabricated in the following manner: 
a. The teeth on both sides of the space caused by missing teeth are ground 
down (prepared). 
b. Impressions are made of these teeth and the space between them. 
c. A metal framework (retainer) is fabricated to fit over the prepared 
teeth (abutments) with a false tooth (pontic) between the retainers. 
d. Dental porcelain is fused to the metal framework to simulate the 
appearance and function of natural teeth. 
e. The bridge is permanently cemented onto the prepared teeth. (Dental 
Clinics of North America 1987, July; 333-346 and 505-528). 
This method, though usually successful, does not take into account certain 
circumstances that would dictate a more conservative approach. For 
example: 
a. When healthy teeth are prepared for bridges the teeth are more 
susceptible to decay if the bridge is faulty, or if the bridge becomes 
loose during function. 
b. This method of bridgework is expensive, precluding its use in certain 
socioeconomic groups. 
c. The procedure is time consuming, involving many hours of the dentist's 
time, and the patient must return several times. It may take several weeks 
to complete. 
d. The procedure usually involves injection of local anesthesia. 
e. Complications of tooth preparation may occur causing pulpal death and 
then endodontics or even tooth extraction. 
Several inventors have addressed these aforementioned problems. U.S. Pat. 
No. 4,556,388 to Hader discloses a method of fixing dental prostheses with 
pins and fitted sockets. This method is adaptable to many situations. 
However, it differs substantially from the devise described herein. The 
structural components are based upon a sleeve type mechanism, as opposed 
to retentive elements or the interlock principle. 
Another disclosure which furnishes background information is U.S. Pat. No. 
4,163,318 in the name of Tigani which discloses a method of restoring 
edentulous spaces by means of an adjustable device whose central mechanism 
is a screw. This screw extends arms which engage abutment teeth. This 
design is novel but does not resemble the invention described herein in 
all methods of structure or design. 
A similar device, with the U.S. Pat. No. 4,431,415 awarded to the same 
inventor Tiqani, differs from Patent No. 4,163,318 in certain details, but 
is of the same basic mechanical principle and thus does not resemble in 
structure or concept the device described herein. 
U.S. Pat. No. 3,422,534 to Bahm deviates from the conventional art in that 
the pontics are mounted upon a sleeve which embraces a bar suspended from 
the abutment teeth thus filling the space caused by the missing teeth. 
This design employs abutment teeth that have been prepared in the 
conventional manner, thus exposing those teeth to the same aforementioned 
detrimental consequences. The sleeve/bar apparatus serves indeed to 
support the pontics, but is very dissimilar in concept and design to the 
system of this invention. 
An apparatus of U.S. Pat. No. 3,423,827 awarded to Bahm and Andrews employs 
similar technology to U.S. Pat. No. 3,422,534 in that the basic principle 
relates to a bar which supports the pontics. This device also differs 
conceptually from the invention described herein. 
U.S. Pat. No. 4,744,757 to Adair et al. discloses a fixed partial denture 
which attempts to alleviate problems of error in the conventional art by 
utilizing crowns resting upon the abutment teeth which have male/female 
attachments connected to them. These attachments then are joined with a 
medium cured with visible light radiation. This system again relies upon 
substantial preparation of the abutment teeth with the attendant problems. 
The concept and design are very different from the invention described in 
this application. 
U.S. Pat. No. 4,877,400 is based upon a bar extending between abutment 
teeth which supports a porcelain bridge. This design has laudable goals in 
terms of esthetics. However, the preparation of the teeth, with the 
aforementioned problems associated therewith, renders this design 
inadequate to prevent harmful sequelae to the abutment teeth. The 
structural design resembles, in no way, the invention described herein. 
U.S. Pat. No. 4,950,162 awarded to Korber et al, also utilizes a 
longitudinal bar which extends between the abutment teeth. The framework 
can be adjustable and also depends upon substantial preparation of the 
abutment teeth. Thus the structural concept and design can be seen to be 
considerably different from the invention proposed herein. 
U.S. Pat. No. 5,007,836 to Gayso discloses a method of replacing missing 
teeth with a groove lock system. There is some utility to this concept but 
it is limited by its application to replace only one tooth. There are many 
conceptual and structural differences between this invention and the one 
proposed herein. For example, there is a one-piece pontic suspended 
between two teeth, and there are no retentive elements in U.S. Pat. No. 
5,007,836. These differences, among others, differentiates the Prior Art 
from the invention proposed herein. 
The Related Art includes an entire class of dental restorations called the 
Resin-Bonded Retainers. These restorations are successful in limited 
applications, but there are serious inherent problems in their structural 
concepts that preclude usage in many applications. The resin-bonded 
retainers are not advisable in patients with heavy occlusion because of a 
tendency to dislodge; the resin-bonded retainers are contraindicated on 
teeth with short clinical crowns; and the teeth must often be prepared in 
an elaborate fashion to generate a path of insertion. (Dental Clinics of 
North America, April, 1985, pp. 393-402). 
All of the techniques cited, and all those that this inventor is aware of, 
do not employ the central design concept of the invention described 
herein. That design concept is the three part device having an 
interlocking attachment which passes through two opposing and retaining 
elements simultaneously thus supporting the pontics between the abutment 
teeth. The Prior Art, and though successful in many instances, still 
leaves a large number of concerns yet to be adequately addressed. The 
invention described herein addresses those concerns in the following 
manner: 
a. Regarding the preparation of teeth which leaves the teeth susceptible to 
decay, the present invention relies upon extremely minimal tooth 
preparation, which extends only into the enamel. The teeth are thus 
preserved, for the most part, in their natural anatomical form. The chance 
for increased rate of decay is thus obviated. 
b. The expensive standard method of fabricating fixed partial dentures, 
precluding its use in many people, is definitely an inadequate feature of 
that technique. The invention described herein is by far much less 
expensive for the patient. The technique will allow people with less 
available income to enjoy the benefits of fixed partial dentures. 
c. The invention described herein is far less time consuming to fabricate 
and insert than the standard methods. It is possible to complete the 
replacement of many teeth in just one day. The patient's time is saved and 
the dentist's time is saved. 
d. The standard procedures and many of those described in the Prior Art 
necessitate local anesthetic injections which are uncomfortable for the 
patient. This invasive procedure also may lead to injury to the patient or 
the dentist because of the sharpness of the needle. The proposed invention 
does not require local anesthetic thus precluding such injuries. 
e. There are complications associated with tooth preparation in the 
conventional manner, such as intense heat generated by the high speed 
dental drill, and inadvertent exposure of the nerve during drilling. Both 
of these complications are further time consuming, often painful, and 
expensive. The invention described herein, will not cause either of these 
complications, because this procedure does not involve extensive grinding 
of the teeth. 
f. The deficiencies in the resin-bonded retainer technique are also 
overcome with the mechanically retained fixed partial denture. In contrast 
to the resin-bonded retainer, the mechanically retained fixed partial 
denture may be used in patients with heavy occlusion, and on teeth with 
short clinical crowns. The structural concept of this invention which 
involves engaging the tooth from opposite sides (buccal and lingual) 
eliminates the need for a path of insertion and the tooth preparation 
attendant thereto. 
The invention described herein addresses several of the most important 
concerns regarding the deficiencies of the Prior Art. The device disclosed 
herein has a unique structural concept which embodies strength and a 
conservative approach. The invention enables missing teeth to be replaced 
painlessly and expeditiously with fixed partial prosthodontics. 
SUMMARY OF THE INVENTION 
The principal object of the present invention is to replace teeth which are 
missing in a person's mouth by utilizing remaining teeth as anchoring 
mechanisms or abutments. 
Another object of the present invention is to use these remaining teeth as 
abutments by preparing them in such a manner as to remove only minimal 
tooth structure. 
Another object of the present invention is to fabricate these tooth 
replacements in such a manner as to cost much less than fixed partial 
dentures fabricated in the conventional manner. 
These and other objects of the present invention are achieved by the 
mechanically retained fixed partial denture disclosed herein. 
The mechanically retained fixed partial denture is comprised of three parts 
which, when placed together, lock onto abutment teeth and resist forces of 
displacement of the prosthesis in all directions. 
To mechanical principle which forms the basis for this invention is the 
interlock. The interlock is defined as: to engage or interrelate with one 
another: lock into one another: interlace firmly; 1) to lock together: 
unite closely; 2) to connect in such a way that the motion of any part is 
constrained by another part: to arrange the connections of to ensure 
successive movement in proper sequence. (Webster's Third international 
Dictionary--Unabridged, Merriam-Webster Inc. 1986, U.S.A.) 
This invention utilizes the interlock principle to engage and interrelate 
the three parts of the invention, to lock them into one another, united 
closely; and connected in such a way that the motion of any part is 
constrained by another part; and further, the connections of the device 
are so arranged that it can only be assembled or disassembled in the 
proper sequence. 
The three parts of the invention are: a) a buccal element which is placed 
onto the abutment teeth from the buccal side, and utilizing retentive 
elements placed buccal to the buccal line angles of the abutment teeth, 
thus preventing lingual displacement; b) a lingual element which is placed 
onto the abutment teeth from the lingual side, and utilizing retentive 
elements placed lingual to the lingual line angles of the abutment teeth 
thus preventing buccal displacement; additionally, these retentive 
elements are placed within grooves cut into the tooth in a horizontal 
direction thus preventing superior and inferior displacement; and c) an 
incisal attachment element which comprises horizontal and vertical 
components so fabricated as to fit closely over the aforementioned buccal 
element and lingual element when the three elements are in close 
proximity. 
Furthermore, the buccal element comprises a projection so fabricated as to 
fit within the body of the lingual element; the lingual element comprises 
an indentation so fabricated as to accept the same projection from the 
buccal element; both the same projection and the same indentation 
comprising a longitudinal aperture within them which are so matched as to 
provide a continuous longitudinal aperture extending through both 
simultaneously. Finally, the incisal attachment element comprises an 
elongated structure which extends from the inferior surface of the 
horizontal component of that element so as to pass through the 
aforementioned continuous longitudinal aperture of both the indentation 
and the projection when the three parts are closely opposed and fitted. 
This is the last step in the assembly of the device, and the device cannot 
be fully assembled unless the sequence of assembly includes this same last 
step. Conversely, the device may not be disassembled unless removing the 
incisal attachment element is the first step in the disassembly. 
The three part structure, when fully assembled, will completely fill the 
space between two teeth, closely approximating both the mesial surface of 
the distal abutment and the distal surface of the mesial abutment. It can 
therefore be appreciated that there is no movement possible for each of 
the three aforementioned elements once they are engaged upon the tooth by 
the retentive elements, and the elongated structure from the incisal 
attachment element extends through both the lingual element and the buccal 
element, thus connecting all three elements in a mechanically interlocked 
system. Dental porcelain simulating the appearance and function of the 
natural teeth will be placed upon the incisal attachment element prior to 
final assembly. Thus the principle object of the invention is fulfilled. 
One object of the invention is to place the grooves in as shallow a 
position as possible upon the teeth to avoid entering the dentin. The 
grooves for the retentive elements are prepared by a dental bur, 
appropriate for the thickness of enamel in that tooth to be prepared, 
which is held so that the long axis of the bur is held in the same plane 
as the long axis of the abutment tooth. The shape of the bur may vary 
according to tooth morphology or certain clinical situations, however, the 
bur must be of sufficient size to allow visible grooves following tooth 
preparation. The shank of the bur serves as a limiting mechanism to 
prevent deeper grooves than are necessary for the prosthesis. While 
holding the bur in this position, the operator will use the high speed 
turbine handpiece with water coolant to place a continuous groove 
extending from a point buccal to the buccal line angle of the abutment 
tooth into the interproximal region and thence to a point lingual to the 
lingual line angle of that same abutment tooth. These grooves will thus be 
nearly perpendicular to the long axis of the abutment teeth. The grooves 
on each of the abutment teeth will also be placed nearly parallel to each 
other. 
Due to the latitude of accuracy afforded by this particular design it is 
possible to have grooves which are non-perpendicular to the long axes of 
the abutment teeth; and which are not exactly parallel to each other. This 
may be the situation when tooth position or rotation does not permit the 
ideal. However, the device can be so positioned as to accept many possible 
groove placements and still fulfill the requirements of the design. 
Another object of this invention is to restore edentulous spaces with fixed 
partial prosthodontics in such a manner as to be far less expensive than 
the currently widely accepted methods. This is accomplished in the 
following manner: 
a. The aforementioned three part device can be pre-fabricated industrially, 
such that the individual sizes and shapes of the various teeth, which are 
to be replaced, are readily available. Mass production techniques are far 
superior, in this regard, to the current method of having the dental 
laboratory technician fabricate, in wax, the tooth forms, which are then 
cast in metal using the lost wax technique. The standard fabrication of 
tooth forms or the "wax up" is time consuming, and may take several 
minutes to complete. In the preferred embodiment the three part device is 
prefabricated in acrylic resin (wax, plastic or any number of materials 
suitable for burnout and casting using the usual and standard lost wax 
technique are acceptable) and need only be minimally adjusted before 
insertion into the edentulous space, followed by addition of the retentive 
elements, and then casting. It is also possible to pre-cast this device in 
metal industrially, and add the retentive elements with solder, which 
decreases laboratory time even more. Thus a savings of many dollars, per 
unit, is realized. 
b. Far more significant, in this regard, will be the time saved by the 
dentist. In the standard technique, the dentist must prepare the abutment 
teeth with a succession of burs, drilling, water spray and suction, to 
render the tooth in the correct form to accept the standard retainer. The 
tooth, thus prepared, must then be covered by a device known as the 
"provisional crown" to protect it from the oral environment. Additionally, 
the space between the teeth must be filled with an artificial tooth to 
prevent drifting of the teeth while the permanent bridge is fabricated. 
This is known as the "provisional bridge". The provisional crowns and 
bridges may require one half hour, or more to fabricate and cement upon 
the patient's teeth. The provisional prostheses often fall out, are 
uncomfortable, or unsightly, and may necessitate yet another visit to the 
dentist's office for correction. 
For each tooth that must be prepared in this manner, there will be at least 
one hour of the dentist's time. Also, the fitting of the retainers, 
adjustments, and related procedures give a cumulative time effort of at 
least one and one half hours of dentist time per tooth prepared in the 
standard manner. 
The invention will significantly reduce the dentist's time necessary to 
replace a missing tooth. The actual preparation of the teeth with the 
aforementioned grooves will take approximately one minute. The fitting and 
adjustments in the patient's mouth, after the dental laboratory has 
completed its phase of the procedure, will take only about ten minutes. 
Therefore it will be seen that the time savings of at least one hour and 
fifteen minutes will be realized for each tooth involved in the 
restorative procedure. Additionally, provisional crowns or bridges are 
unnecessary because the complete final prosthesis can be fabricated in 
just a few hours, ideally on the same day. It is anticipated that even 
more rapid reconstructions will be possible as the operator becomes 
familiar with the technique. 
The cumulative time savings on the part of the dental laboratory and the 
dentist will result in a significant reduction in the fee that the patient 
will have to pay to receive this method of fixed partial dentures. 
Although the present invention has been discussed in the context of 
replacing only single teeth with prefabricated tooth forms, it is to be 
appreciated that multiple teeth may be replaced as well. This is 
accomplished in the following manner: 
a. Single units of the assembled three part device are luted together prior 
to casting by combining all of the buccal elements to each other; and 
combining all of the lingual elements to each other. 
b. The incisal attachment elements are removed and cast separately. 
c. The combined buccal elements are removed and cast together thus forming 
multiple combined buccal elements. 
d. The combined lingual elements are removed and cast together thus forming 
multiple combined lingual elements. 
e. After casting in metal the device is reassembled into the form that was 
established prior to casting. 
d. The incisal attachment elements and their porcelain coverings are 
prepared singly, and inserted into their respective apertures. 
Perhaps the most advantageous feature of this proposed invention is its 
conservative nature. Conservation of tooth structure is always preferable 
to removal of tooth structure when clinical circumstances permit. This 
proposed invention will markedly decrease the amount of tooth structure 
which would otherwise be lost in the conventional preparation. Also, the 
grooves placed in the tooth for the retentive elements are located far 
above the gum line, which allows for easy inspection for caries. 
Conversely, in the conventional preparation, the margin of the preparation 
is the usual place for caries to begin, and often this area is very 
difficult to inspect as it is usually at or below the gumline. 
This invention eliminates many of the problems associated with conventional 
fixed partial prosthodontics. The procedures necessary to fabricate the 
mechanically retained bridge save time and effort for the laboratory 
technician and for the dentist. The amount of tooth structure that must be 
removed for the mechanically retained bridge is far less than tha 
necessary for conventional fixed partial prosthodontics. Additionally, 
there is a much larger chance of new tooth decay associated with the 
conventional techniques than with the mechanically retained bridge. The 
patient needs no injection of anesthesia and the complications of tooth 
preparation are obviated.

DETAILED DESCRIPTION OF THE INVENTION 
Refer now to FIGS. 1,2,3 which are overall drawings of the invention in the 
unassembled phase. In the preferred embodiment as in FIG. 1 the buccal 
element 5 is the part of the three-part device which will be located 
toward the buccal side of the teeth. It comprises: the outer face 10 which 
is the buccal surface, and a projection 15 which is located upon an inner 
planar surface 20. Projection 15 further comprises an aperture passing 
therethrough best seen in FIG. 4 at 60. The inferior surface of the buccal 
element 5 is contoured to abut the gingival surface upon which it rests, 
as illustrated in FIG. 6 at 400. 
FIG. 2 shows the lingual element 35 which is contoured on the lingual side 
40 to conform to the lingual contours of the abutment teeth, whereas the 
inferior surface is contoured to abut the gingival surface upon which it 
rests, as illustrated in FIG. 7 at 400. 
The buccal surface 30 of the lingual element 35 and the inner face 20 of 
the buccal element 5 are shaped and contoured such that when placed upon 
one another during assembly there is no discrepancy, void or irregularity 
between the two elements. The indentation 25 is so formed in size and 
shape as to accept, without hindrance, projection 15 when the buccal 
element 5 and lingual element 35, as depicted in FIGS. 1 and 2 
respectively, are closely opposed and fitted. 
FIG. 3 shows the incisal attachment element 50 from the side, with the 
elongated member 45 extending in a vertical direction from the inferior 
horizontal surface 55. 
FIG. 4 shows a cross section through the middle of the invention, when 
assembled, prior to the addition of the retentive elements. As will be 
appreciated, projection 15 fits within indentation 25. Aperture 60 extends 
from the superior surface of the lingual element 35 to within the body of 
that element, through the aperture in indentation 156, and then ends 
within the body of lingual element 35 at a point below the level of 
projection 15. In the preferred embodiment, upon assembly, the elongated 
member 45 extends, in a continuous manner, through the length of aperture 
60. Thus, the elongated member 45 is seen within the aperture 60. 
the mechanical arrangement of the linear aperture 670, extending through 
both the buccal and lingual elements simultaneously, is further 
illustrated FIG. 5 which is a sagittal section of the assembled device at 
its midline. This is the concept upon which this invention is based, for, 
when the elongated member 45, which extends vertically from the inferior 
horizontal surface 55 of the incisal attachment element 50, passes through 
this aperture 60, when the device is assembled, there is created an 
interlocking of the three parts of this device. The elongated member 45 
ends at the point 65 in the preferred embodiment. Thus the three elements 
are mechanically fused to the extent that they are functionally one unit. 
Each of the three elements 5, 35, and 50 are united closely and interlaced 
together. According to the aforementioned definition they are interlocked. 
This design is adaptable to any tooth morphology, in terms of height, width 
or depth. The preferred embodiment is the placement of this device as a 
pontic(s) in a fixed partial denture. This is accomplished as follows: 
a. The dentist prepares the abutment teeth within the patient's mouth, 
without anesthesia, using the appropriate instruments, especially 
including a bur which will, when held against the long axis of the tooth, 
place a groove that will lie within the tooth to a depth that it is only 
within the enamel. Of course, the size of that bur will vary, based upon 
the tooth that is to be prepared. The grooves are prepared as close to 
parallel to one another, and as close to perpendicular to the long axis of 
the tooth, as is possible by the operator. The groove will extend from 
buccal to the buccal line angle of the tooth, which will place it upon the 
facial surface of the tooth; thence into the interproximal area; thence 
lingual to the lingual line angle of the tooth, which will place the 
groove upon the lingual surface of the tooth. The outlines of those 
grooves are illustrated by 70 in FIG. 6 which is the buccal view of the 
device (part 50 visible) positioned between the abutment teeth 100 and 
200; and groove 80 as seen in FIG. 7, which is the lingual view of the 
device. The lingual surface of the lingual element 40 is visible in this 
illustration as well as is 50. 
b. The dentist makes an impression of the teeth after this preparation, in 
the standard manner, and sends it to the dental laboratory. The dental 
technician prepares a model of this impression and then selects a 
prefabricated, assembled device which is the proper size and shape for 
that particular tooth which is to be replaced. The technician then 
contours the inferior surface of the device and positions it into the 
space by means of affixing it to the underlying gingival surface. It must 
be noted here that in the preferred embodiment, the device will be made of 
a solid dental material suitable for investment, burnout and casting such 
as acrylic resin. Other dental materials suitable for investment, burnout 
and casting are also possible. In the preferred embodiment, and for 
purposes of description, the device at this stage is fabricated in acrylic 
resin. 
c. The technician then flows a labile material such as acrylic resin into 
the grooves and from thence to the device. Thus it will be appreciated in 
FIG. 8, which is a cross-section through the middle of the assembled 
device attached to the acrylic resin within the grooves, that the buccal 
element 5 and the acrylic resin within groove 70 have become one 
contiguous unit as depicted by 75. Similarly, it will be appreciated that 
lingual element 35 has become one contiguous unit with the acrylic resin 
within groove so as depicted by 85. Of course grooves 70 and 80 have 
matching opposite grooves on the other abutment tooth. There is a thin 
sheet of a separating material extending from between elements 5 and 35 
that extends to also separate the acrylic resin in grooves 70 and 80. This 
is illustrated by 90. 
d. The technician then separates the device by removing, first, the incisal 
attachment element 50, then the buccal element 5 and the lingual element 
35 with their attached acrylic resin retentive elements 75 and 85 
respectively. It should be noted here that, although not noted in the 
figures, there may be a "removal button" attached to any or all of the 
aforementioned elements to facilitate handling, as is standard practice in 
many dental laboratories. These elements are then separately invested, 
burnt out and cast into metal in the standard and accepted manner. 
e. The technician finishes the castings in the normal manner and then 
reassembles the device upon the abutment teeth upon the model. In the 
preferred embodiment the reassembled casting is so accurate that the 
pieces fit together tightly enough so that cement is unnecessary. The 
friction of the combined elements is sufficient for retention. 
f. In the preferred embodiment the incisal attachment element 50 is to be 
covered with dental porcelain that will simulate the natural anatomy, 
esthetics and occlusal function of the natural tooth that was missing. The 
dental porcelain is fused to the incisal attachment element 50 in the 
standard manner with an opaque base underlying the porcelain. 
g. The technician returns the finished assembled device with the porcelain 
in place to the dentist who then affixes the device to the patient's 
abutment teeth in the mouth and examines the device for accuracy in every 
detail according to the proper and accepted principles of dentistry. In 
the preferred embodiment the now metal retentive elements 75 and 85 are 
opaqued on their outermost surface with a composite opaquer and then 
covered with a composite resin restorative material to completely cover 
those elements such that the device is not visible from the buccal side as 
illustrated in FIG. 9. This procedure of covering exposed metal, for 
esthetics, with composite opaquer and restorative materials is well known 
in the art. The porcelain covering the incisal attachment element 50 is 
illustrated by 300. FIG. 10 illustrates the lingual side in the preferred 
embodiment where the lingual surface 40 is visible as well as the 
porcelain 300. Thus it will be appreciated that the prefabricated device 
combined with the added retentive elements forms a very effective method 
of restoring the edentulous space in the dentulous arch. 
The above description is the preferred embodiment of this invention, but 
there are many variations possible. For example, the device is adaptable 
for the restoration of more than one tooth. In FIG. 11 two of the 
assembled devices are shown placed between abutment teeth 500 and 600. The 
incisal attachment element 50 is illustrated on two adjacent teeth as 
shown from the buccal side. The groove outline 70 is visible. This 
arrangement is possible when the individual units are joined together with 
acrylic resin or other suitable material prior to casting in metal. The 
prosthesis is cast in metal and then finished with the porcelain and 
composite resin as in the case of the aforementioned individual tooth 
replacement situations. 
Another variation is to make the entire prosthesis in metal without 
porcelain. In this case the superior surface of the incisal attachment 
element 50 would be contoured prior to casting to simulate in form and 
function the occlusal surface of the tooth that is to be replaced. After 
casting there would therefore be a metal occlusal surface, which is 
acceptable in the art and science of dentistry. The retentive elements 
would be covered with opaque and composite resin restorative material at 
the discretion of the operator and the patient. 
Yet another variation is to cement the finished device together, and to the 
abutment teeth with an accepted dental cement. Although the device in the 
preferred embodiment is designed to stay affixed to the teeth without 
cementation, it will e appreciated that cementing the finished device to 
the abutment teeth will result in an extremely stable restoration. The 
cementing media and procedures are standard aspects of the practice of 
dentistry. 
In summary, the invention is designed to fasten onto the abutment teeth 
from the buccal and lingual sides of those teeth. This invention comprises 
three parts: the buccal element, the lingual element, and the incisal 
attachment element. There are retentive elements attached to both the 
buccal element and the lingual element respectively. These retentive 
elements prevent movement of the device by engaging grooves placed within 
the butment teeth. The principle supporting the invention is an 
interlocking of the buccal element, the lingual element and the incisal 
attachment element by means of an elongated member that extends from the 
incisal attachment element through both the buccal element and the lingual 
element simultaneously to form a unitary functional unit. The occlusal 
surface of this invention is contoured to follow the proper functional 
patterns of the detention either by covering the incisal attachment 
element in porcelain or by creating the occlusal pattern in a labile 
material prior to casting, thus creating the occlusion in metal. The 
latter two procedures are standard techniques in the art. 
The invention can be seen to fulfill the objects aforesaid the and 
advantages among others by replacing missing teeth in the mouth utilizing 
remaining teeth as anchoring mechanisms. Another object is fulfilled 
because the preparation of those teeth requires the removal of minimal 
tooth structure as compared to the standard methodology. Another object is 
fulfilled because the present invention utilizes prefabrication technology 
to decrease the time, effort, and expense necessary to replace missing 
teeth. 
The foregoing description of the preferred embodiments of the invention has 
been presented for the purposes of illustration and description. It is not 
intended to be exhaustive or to limit the invention to the precise form 
disclosed. Many modifications and variations are possible in light of the 
above teaching. It is intended that the scope of the invention be limited 
not by this detailed description, but rather by the appended claims which 
should be broadly construed and should not be limited by their literal 
terms.