Forceps having replaceable tips for removing a dental prosthetic

A pair of dental forceps, whether configured for anterior, premolar or molar teeth, includes a pair of tips having removable cushioning and gripping inserts for conformingly gripping and frictionally retaining a respective dental prosthetic device, such as a crown or bridge, to be removed without imposing stress concentrations sufficient to mar or damage the dental prosthetic device.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to dental implements and, more particularly, 
to forceps and gripping elements for removing dental prosthetic devices. 
2. Description of the Prior Art 
Dental forceps, particularly configured for use upon the anterior, premolar 
or molar teeth have been available for years for purposes of extracting a 
tooth. These forceps have jaws particularly angled and of a length to 
facilitate grasping a particular tooth. During tooth extraction, it is 
very important that a firm grip of the tooth be achieved and it is of no 
consequence if the enamel of the tooth cracks or if the tooth is otherwise 
damaged. 
The forceps used for extracting teeth have been developed over a period of 
many decades to provide an effective combination of gripping a tooth and 
ease of manipulation of the gripped tooth to effect the extraction 
process. Primarily, the developmental work has been directed to the length 
and angulation of the gripping jaws. 
To remove a crown for purposes of reattaching it more securely to develop a 
better seal or for adjustment purposes, it is very important that the 
crown not be aesthetically damaged or physically distorted. To use a 
conventional pair of extraction forceps for this purpose presents a real 
problem for the following reasons. The jaws of the forceps may damage the 
surface of the crown even though a good firm grip is established. If the 
forceps are only lightly squeezed to avoid damage to the crown, the jaws 
may slip from the crown and cause injury to the patient or damage to other 
teeth or restorations. For these reasons, many dentists use their fingers, 
and particularly their fingernails, to grasp the cervical ridge of the 
crown to dislodge and extract the crown. Since not all dentists have 
sufficient power in their fingers for this purpose, crown removal is a 
problem. Similarly, not all dentists have sufficiently robust fingernails 
to withstand the forces imposed without bending and causing substantial 
pain to the dentist. A potential problem of fungal infection also exists. 
Various devices have been developed over the years to attempt to solve the 
above enumerated problems. In the 1920s, a clamp forceps was developed 
which cooperated with a detachably attached rubber dam to minimize damage 
to a crown while retaining sufficient gripping and extracting force. 
Regrettably, this device was difficult and awkward to use as a practical 
matter. Some time later, a pair of forceps was developed which included a 
pair of opposed curved surfaces lined with resilient material for gripping 
a crown. These forceps were very difficult to use for all teeth due to the 
different requirements of grip and manipulation imposed by the placement 
of each tooth within the mouth. 
A yet further device was developed which is of a plier like configuration 
having one jaw of the pair of jaws oriented to contact and bear against 
the proximal edge of the crown while the second jaw was penetrably 
inserted through a passageway cut in the top of the crown to bear against 
the underlying tooth. In situations where the underlying tooth is little 
more than a post, this device is ineffective. Moreover, the requirement 
for a passageway through the cusp of the crown necessitated repair and 
reconstruction of the crown prior to remounting. 
SUMMARY OF THE INVENTION 
A pair of extraction forceps includes detachably attachable differently 
angled jaws selected to correspond with the tooth supporting the crown or 
bridge to be removed. Removable inserts are disposed in the jaws for 
gripping with sufficient force to permit removal of the crown or bridge 
while preventing damage or disfigurement to the surface and structure of 
the crown or bridge. The replaceabilty of the inserts permits autoclaving 
or other sterilizing procedures of the forceps and jaws; the inserts are 
intended to be for one time use and to be disposable. The jaws can be 
selected for a particular configuration compatible with the type and 
location of the prosthetic device to be removed and they are detachably 
attached by a snap fit to permit rapid exchange. 
It is therefore a primary object of the present invention to provide 
apparatus for grasping and removing a dental prosthetic device without 
damaging it. 
Another object of the present invention is to provide an extraction tool 
for extracting a dental prosthetic device. 
Still another object of the present invention is to provide a resilient 
conformable insert for the jaws of a pair of forceps to grasp and remove a 
prosthetic device. 
Yet another object of the present invention is to provide a selection of 
jaw elements interchangeably replaceable upon the jaws of a pair of dental 
forceps for grasping and extracting a dental prosthetic device. 
A further object of the present invention is to provide a removable insert 
for use with removable jaws of dental forceps to extract dental prosthetic 
devices. 
A still further object of the present invention is to provide a method for 
extracting a dental prosthetic device without damaging the device during 
extraction. 
A yet further object of the present invention is to provide a method for 
firmly grasping but not damaging a prosthetic device to be removed. 
These and other objects of the present invention will become apparent to 
those skilled in the art as the description thereof proceeds.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
To assist a dentist in extracting teeth, numerous extraction forceps have 
been developed for groups of teeth which represent similar or related 
accessibility, direction of extraction and manipulation impediments. These 
forceps can generally be categorized as being suitable for anterior, 
premolar or molar teeth. It is to be understood that further gradations 
also exist. As shown in FIGS. 1 and 2, a pair of forceps 10 includes 
handles 12,14 pivotally attached to one another by pivot means 16. Jaws 
18,20 associated with handles 12,14, respectively, may extend generally 
planar with the handles or may be slightly bent, as shown in side view in 
FIG. 2 or substantially bent as shown in side view in FIG. 3. Female 
fittings are disposed at the ends of each of jaws 18 and 20, respectively. 
Each of these fittings includes a cavity (26,28) defined by a cylinder 
(30,32) extending from the respective jaw 18,20. A pair of opposed slots 
34,36 and 38,40 is formed in diametrically opposed sections of cylinders 
30,32, respectively. As shown in FIG. 2, the cylinders extend 
perpendicularly to the major axis of the respective jaws. 
FIGS. 3 and 4 illustrate variant orientations of the fittings to assist the 
dentist in extracting particular anterior, pre molar or molar dental 
prosthetic devices. For example, fittings 44, shown in FIG. 3, are 
oriented at an angle of approximately 45.degree. with respect to the major 
axis of jaws 46,48. Fittings 50, shown in FIG. 4, are oriented in general 
alignment with the major axis of jaws 52,54. To accommodate overlap of 
jaws 18,20, as shown in FIG. 5, fittings 30,32 may be of different length 
to place their respective ends in a common plane. The degree of angular 
orientation of the fittings primarily dictates the type of tooth with 
which the pair of forceps is to be used. 
For tooth extraction purposes, the jaws of a pair of forceps are of 
surgical steel or similar material which permits a very firm rigid grip of 
a tooth to be extracted. Whether the act of gripping and manipulating the 
tooth during extraction results in damage to the tooth enamel or the 
structure of the tooth is generally not of significance. 
When a crown is to be removed in the event the seal for the crown has been 
compromised, to repair the crown or to adjust the crown, it is important 
to prevent damage to the crown during the act of removal. Were such damage 
to occur, reconstruction or replacement of the crown would result in 
substantial expense which should be avoided. Because of the fragility of 
crowns, a dentist often must rely upon the strength of his fingers to 
effect removal since implements for this purpose and which have a low 
probability of causing damage to the crown do not exist. All dentists do 
not have sufficient strength in their fingers to effect removal of a 
crown. Furthermore, the space or volume available within the oral cavity 
to manually grip a crown may be a limiting factor of the ease with which a 
crown can be removed. 
Referring to FIG. 6 there is illustrated a representative jaw 60 (like jaws 
18,20) having a fitting 62 extending perpendicularly therefrom. The 
fitting includes a cavity 64 formed in a cylindrical element 66 of the 
fitting. A pair of diametrically opposed slots, of which slot 68 is shown, 
are in communication with cavity 64. A tip 70 includes a scoop 72 having a 
generally elongated recess 74 formed therein. Recess 74 has a geometric 
cavity contour of the labial/buccal or lingual surface relating to the 
crown to be removed. A support element 76 extends from one end of the 
scoop. It includes a cylindrical member 78 configured for penetrable 
engagement with cavity 64. A groove 80 circumscribes cylindrical member 
78. Upon insertion of cylindrical member 78 into cavity 64, groove 80 is 
coincident with the slots (68) in fitting 62. A clip 82 is configured to 
penetrate the opposed slots in the fitting and partially engage groove 80. 
The engagement between clip 82 and groove 80 will create an interfering 
fit to preclude withdrawal of cylindrical member 78 from within cavity 64. 
By having the groove cylindrical, tip 70 may rotate about the axis of 
cylindrical member 78 in response to forces imposed. 
An insert 86 is configured to mate with and nest within recess 74. It also 
includes a tang 88 for penetrable insertion into passageway 90, which 
passageway may be coincident with the longitudinal axis of the tip. As 
particularly illustrated in FIG. 7, insert 86 includes a face 92, which 
face extends above, or is displaced from perimeter 94 of tip 72. 
The displacement of face 92 of insert 86 will tend to preclude physical 
contact between tip 70 and the crown or other dental prosthetic to be 
removed whereby damage due to pressure exerted by the hard surface of tip 
70 would be precluded. 
Insert 86 can be relatively easily removed from the supporting tip by 
simply grasping the extending portion and pulling the insert out of recess 
74. Thereafter, the pair of forceps and tips may be autoclaved or 
otherwise sterilized without concern for damage to the insert. It is 
contemplated that each pair of inserts would be used only one time and 
would be disposable. 
Preferably, insert 86 is of resilient flexible material, such as a rubber 
composition or a plastic composition, which is suitable for molding or 
other fabrication. Sufficient resistance to compressibility must be 
present to prevent the pressures exerted by pair of tips (70) from coming 
into contact with the dental prosthetic to be removed. Furthermore, the 
insert must exert sufficient friction upon the surface of the dental 
prosthetic, such as a crown to prevent slippage without the application of 
sufficient compressive forces which might collapse or otherwise damage the 
crown upon disengagement from the underlying supporting tooth. 
Under certain circumstances, it may be preferable to inhibit rotation of 
tip 70 about its longitudinal axis. By substituting a pair of opposed 
indentations (of which indentation 100 is shown) for groove 80 and by 
incorporating an essentially rigid clip 102 for clip 82, rotation of the 
tip will be inhibited. That is, interior edges 104,106 of clip 102 will 
nest within opposed indentations 10 and inhibit rotation of cylindrical 
member 78 due to the resulting interference with the longitudinal edges. 
The configuration of each of tips 70 and inserts 86 is preferably 
commensurate with the surface of the dental prosthetic to be grasped by 
the respective tip/insert. Such correspondence will tend to distribute 
uniform forces along the contacted dental prosthetic to minimize the 
likelihood of damage or deformation. Moreover, a greater effective 
gripping area of essentially uniformly applied forces will result and 
extraction of the dental prosthetic will be eased. 
A representative tooth mounted premolar and anterior crown 110 is 
illustrated in FIGS. 9a and 9b. Outward surface 112 is generally referred 
to as the labial surface while inward surface 114 is referred to as the 
lingual surface. These are the two surfaces contacted by the jaws of 
forceps during extraction. Furthermore, it is generally 60% of these 
surfaces which is gripped. This portion of the lingual surface is 
identified as the area within the limit of lines 116,118 (the cavity rim 
associated with the radius R5 in FIG. 10). To promote and ensure a non 
slipping grip, the forceps jaws preferably conform with the various 
curvatures depicted by designations R1, R2, R3, R4 and R5 in the cervical, 
mid and incisal portions of the crown. 
FIG. 10 illustrates a cross section of a typical recess or depression 74 
(see FIGS. 6 and 7) formed in a tip 70. The depression illustrated is 
representative of the curvature of the lingual surface 114, it being 
understood that the curvature of the depression used in conjunction with 
the labial surface 112 would be commensurately configured. More 
particularly, the curvature or radius at each of locations R1, R2, R3, R4 
and R5 would be specifically contoured to the mating curvature of the 
crown. That is, R1 would be equivalent with the lower lingual profile, R2 
would be equivalent to the upper lingual profile, R3 would be equivalent 
to the cavity sidewall, R4 would be equivalent to the tooth gum line in 
the cervical area and R5 would be equivalent to the curvature of the rim 
of the depression commensurate with the contact area of the lingual 
surface extending longitudinally along the tooth generally proximate lines 
116,118 (see FIG. 9b). 
Referring jointly to FIGS. 11a, 11b and 11c, further views of depression 74 
in tip 70 are illustrated. Terminal end 122 includes a curved edge 124 
conforming in general to the curvature attendant R1 of crown 110. The 
remaining curvatures and contours of depression 74 generally conform with 
that of the mid third section of the lingual surface of tooth 110. 
The insert to be fitted within the tip and its depression depicted in FIG. 
10 and in FIGS. 11a, 11b and 11c will compressingly conform with the 
depression to receive the commensurate lingual or labial surface of a 
crown and exert uniform forces thereagainst upon gripping of the crown by 
the forceps. Such uniformity of gripping forces will reduce stress 
concentrations to minimize damage or deformation to the crown and minimize 
the likelihood of slipping while providing a high degree of control to 
manipulation of the crown during extraction. 
The tip depicted in FIGS. 10, 11a, 11b and 11c may include a passageway 126 
for penetrably receiving a tang extending from the approximate center 
bottom of the insert. This tang assists in installing the insert by 
pushing the tang into the passageway and pulling on the protruding tang 
until the insert becomes seated. Simultaneous pushing on the insert will 
assist the seating of the insert. Preferably, the insert extends above and 
across edge 94 of tip 70 to preclude contact between the crown to be 
gripped and the tip. 
FIGS. 12a and 12b partially illustrate a variant 70a of tip 70 for 
accommodating anomalies of the dental prosthetic to be removed. In tip 70, 
edges 94 join with terminal edge 124 at locations which define relatively 
sharp points. Depending upon the structure and configuration of both the 
tooth and associated dental prosthetic, there may be anomalies in the area 
of the cervical ridge and primarily in the mesio/distal length. The 
presence of sharp points 96,98 on tip 70 may create difficulties in 
effecting facile gripping and removal of the dental prosthetic. To 
eliminate such cause for difficulty, variant tip 70a may be used. In the 
area of one of the pair of sharp points identified within circle 130 in 
FIG. 12a, segments of edges 94,124 extending from the junction to 
locations identified by 132,134 are removed. The resulting edge, 
identified by numeral 136 in FIG. 12b, eliminates point 96 present in tip 
70. A similar modification is performed on edges 94,124 forming point 98 
to replace this point with an edge equivalent to edge 136. Such 
modification to tip 70 will not negatively affect the efficacy of edge 124 
in engaging the cervical ridge of the dental prosthetic as a functional 
equivalent of a dentist's fingernail and it will accommodate the 
aforementioned possible anomalies. 
While the principles of the invention have now been made clear in an 
illustrative embodiment, there will be immediately obvious to those 
skilled in the art many modifications of structure, arrangement, 
proportions, elements, materials and components used in the practice of 
the invention which are particularly adapted for specific environments and 
operating requirements without departing from those principles.