Method and apparatus for carving and contouring dental restorations

The finishing of dental restorations is disclosed with use of dental instruments of the present invention including instruments having concave surfaces shaped to conform to external convex tooth anatomy. External carving and contouring is accomplished by first carving the distal, mesial, lingual and facial convex surfaces using an interproximal carving instrument of the present invention, followed by carving of adjacent marginal ridges and contact areas, and embrasures with an intermarginal carver. Internal carving and contouring is accomplished by first making the areas of fossae and basic occlusal grooves with the ball end of the intermarginal carver, followed by carving and contouring tooth cusps and cuspal inclines, and then supplemental or developmental grooves with an occlusal-incisal carver.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to finishing of dental restorations. More 
particularly, the invention discloses a method for external and internal 
carving and contouring of convex surfaces of tooth anatomy, as well as 
ridges, contact areas, embrasures, fossae and grooves. The invention also 
includes instruments for carrying out the method of finishing dental 
restorations, including an interproximal carver, an occlusal-incisal 
carver, and an intermarginal carver, the latter two of which have concave 
surfaces constructed to match the convex surfaces of external tooth 
anatomy. The position of the plane of the concave carving edges varies in 
different embodiments of the invention, to allow the operator to select 
instruments appropriate to the particular quadrant. 
2. Description of the Prior Art 
Many general background references pertinent to the field of dentistry 
embraced by the present invention are available from state dental 
associations and publishers of scientific material. 
A dental tool is disclosed in U.S. Pat. No. 1,497,749, issued June 17, 
1924, to Diack, where a method for working the occlusal contour of a 
single tooth is disclosed, along with instruments for accomplishing 
burnishing of dental surfaces by a V-edge. U.S. Pat. No. 1,875,680, issued 
Sept. 6, 1932, to Van Horn, shows a carving instrument for shaping a wax 
model of a tooth, specifically adapted for pushing and pulling in 
following the tooth form. 
U.S. Pat. No. 1,953,584, issued Apr. 3, 1934, to Bronner, mentions that the 
dental tool described therein has an operative surface or cutting edge of 
suitable contour. 
Other patents describing dental instruments for various purposes are the 
following: 
U.S. Pat. Nos. 
550,508--Nov. 26, 1895--How 
888,071--May 19, 1908--Dodez 
1,109,924--Sept. 8, 1914--Hoffman et al. 
1,382,401--June 21, 1921--Zurbrigg 
3,023,501--Mar. 6, 1962--Schmitt. 
SUMMARY OF THE INVENTION 
Prior dental tools for contouring or carving of dental restorations have 
typically been designed in a convex shape, pointed shape, or other shapes 
not conforming to the convex surfaces characterizing all external tooth 
anatomy. Moreover, prior dental implements have not been specifically 
adapted for intermarginal carving of two adjacent teeth. Furthermore, a 
method for carving and finishing dental restorations has not been 
described making use of the advantages of the instruments of the present 
invention. 
Accordingly, it is an object of the present invention to provide a dental 
carving instrument having concave surface for conformingly carving or 
shaping convex outer surfaces of dental restorations. 
Another object of the invention is to provide a dental instrument for 
intermarginal carving of two adjacent teeth. 
Yet another object is to provide a dental instrument for occlusal-incisal 
carving of a single tooth. 
Still another object of the invention is to provide a method for external 
carving and contouring of dental restorations, as well as a method for 
internal carving and contouring of dental restorations. 
A further object of the invention is to provide a method for dental carving 
relying upon guiding of a dental carving instrument by the unprepared 
tooth structure. 
Yet a further object of the invention is to provide a method for use of the 
interproximal, intermarginal and occlusal-incisal dental instruments of 
the present invention. 
These together with other objects and advantages which will become 
subsequently apparent reside in the details of construction and operation 
as more fully hereinafter described and claimed, reference being had to 
the accompanying drawings forming a part hereof, wherein like numerals 
refer to like parts throughout.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
External tooth anatomy consists of elevations or projections and 
depressions. The elevations consist of cusp tips or peaks, cuspal inclines 
or slopes, marginal ridges and marginal inclines, while the depressions 
consist of grooves or sulci, pits, and fossae, which occur where three 
grooves intersect. A pit is a small depression with a fossa, and grooves 
or sulci occur at the base intersection line of two adjacent inclined 
surfaces. Teeth consist of a series of multiple convex surfaces, as can be 
seen in FIG. 1. Each and every tooth is distinctly different in its 
surface convex anatomy. It has been found that a convex surface of a 
dental restoration can be best carved, contoured and finished by a 
substantially matching concave edge of a dental instrument, such as 
concave distal edge 72 and concave side edges 73 and 75 on head 74 of 
instrument 70 shown in FIG. 1. The finishing of dental restorations is 
accomplished more adequately when carving, rotary and finishing 
instruments are designed and used for maximum surface contact. 
The direction of carving should be parallel to the cavosurface margin in 
its total outline. As is illustrated in FIG. 1, head 74 of instrument 70 
should be directed at right angles to the cavosurface margin along the 
groove and fossa pattern of tooth 78 and restoration 20 within tooth 78. 
The ideal technique for carving or finishing involves use of unrestored 
surfaces for guiding instrument 70 by contact with an instrument surface. 
For instance, in FIG. 8, surface 22 is used in guiding carver 70 in 
carving restoration 20. Only one unprepared guide surface is usually 
possible in this technique. Each and every surface forming part of 
restoration 20 must be carved. Three surfaces must be carved within the 
area of a fossa, and two surfaces must be carved within the area of a 
groove and cuspal incline. For maximum visibility of the tooth during 
carving and finishing, work on restoration 20 should proceed generally 
from distal surface 24 toward mesial surface 26, and from lingual surface 
28 toward facial surface 30. The margins should reflect the correct convex 
contour of the tooth, and choice of the carving instrument should be 
selected to most closely match the curvature of the concave edge of the 
instrument to the curvature of the convex surface to be carved. For 
instance, the greater degree of curvature of edge 72 of head 74 of 
instrument 70, as shown in FIG. 7, most closely matches a tooth surface 
having a sharply curving convexity, while the lesser degree of curvature 
of the concave edge 31 of wide instrument head 32, as shown in FIG. 5, 
more closely matches a convex tooth surface of lesser curvature. As 
illustrated in FIGS. 5 and 7, the longitudinal direction of side edges 33 
and 35 or 73 and 75 is substantially perpendicular to the longitudinal 
direction of distal edge 31 or 72. Other concave edges 33 and 35 can also 
be used for carving of the tooth surfaces and are approximately the same 
length as edge 31. Adjacent proximal margins should be in harmony with 
respect to their four embrasure spaces. The proximal contact area should 
be placed about one millimeter gingival to the occlusal surface. 
External carving and contouring is accomplished by carving the distal, 
mesial, lingual and facial surfaces using the concave edge 72 of head 74 
of occlusal-incisal instrument 70. If restoration 20 extends to the margin 
between adjacent teeth, adjacent marginal ridges are placed in contact 
with the concave end 36 of intermarginal carver 38, as shown in FIG. 2, 
using the unrestored ridge as a guiding surface. For example, if ridge 34 
is to be restored, concave edge 40 of intermarginal carver 38 is used for 
carving the convex surface of tooth 42 in substantially its original form, 
while unrestored ridge 37 of tooth 44 is used as the guiding surface. 
Intermarginal carver 38 is constructed so that by virtue of the design of 
carver 38 its contact area is about one millimeter gingival to the 
occlusal surface. Included in the external carving and contouring 
operations should also be development of the four embrasures (occlusal, 
facial, lingual and gingival). 
Internal carving and contouring proceeds first by marking of the fossae, 
including the distal, central and mesial, falling within the region of the 
restoration. This marking is accomplished with ball end 46 of 
intermarginal carver 38, or, alternatively, with a separate instrument 
having a ball end. The basic occlusal grooves are then marked in the 
region of the restoration with the same ball end, including the buccal, 
lingual, distal and mesial grooves, such as distal groove 50, lingual 
groove 52, mesial groove 54 and buccal groove 56. Cusps and cuspal 
inclines are then carved by one of the concave edges 72, 73 or 75 of 
occlusal-incisal carver instrument 70, such as cusp 58. Next, carving and 
contouring of supplemental or developmental grooves, such as supplemental 
groove 60, is accomplished with the concave edge 72 of head 74 of 
instrument 70. 
Proper interfitting of the restored tooth is evaluated through hinge and 
translatory jaw movements both under and not under the dentist's control 
to determine overfilling or overcontouring of the restored surfaces. Both 
centric occlusion and eccentric occlusion are considered. Finally, all 
margins are checked to insure complete coverage, carving and contouring, 
as well as a smooth blending of restoration to tooth and tooth to 
restoration. Contact areas must be in the correct facial, lingual and 
occlusal gingival proportions, and positive contact with extra-fine dental 
floss should result. 
Additional structural details of intermarginal carving instrument 38 are 
shown in the edge seen in FIG. 4, and the sectional view of the 
occlusal-incisal instrument 70 shows in FIG. 6 details of construction of 
head 74. FIGS. 5 and 7 point out instruments having differing degrees of 
concavity in a pair of occlusal-incisal dental carving instruments. 
While intermarginal carver instrument 38 has been illustrated in the form 
of a double-ended carver having a concave end and a ball end 46 as seen in 
FIG. 3, it is within the scope of the present invention to provide other 
instruments having the ball end 46. Preferably, however, the ball end is 
associated with the intermarginal carver for reasons of convenience in 
operation according to the method of the invention. While the present 
invention is concerned primarily with instruments having concave edges 
suitable for carving substantially conforming convex tooth restoration 
surfaces, the ball end 46 not per se forming a distinctly independent part 
of the present invention, the combination of a concave edged instrument 
end with a ball end is contemplated within the scope of the present 
invention, as well as a method utilizing such an instrument. 
In FIG. 9 the relative orientation of each end of intermarginal carver 38 
is pointed out, including concave end 36 and ball end 46. FIG. 10 shows 
the same features from a different direction of view, where the instrument 
of FIG. 9 has been rotated through 90.degree.. Similarly, FIGS. 11 and 12 
show features of instrument 82, distinguished from instrument 38 by the 
orientation of concave end 84, and FIGS. 13 and 14 show features of 
instrument 86 in a somewhat different orientation of concave end 88. p 
FIGS. 15 and 16 show interproximal instrument 90, bringing out the twisted 
nature of the pointed heads 92 and 94. 
FIGS. 17 and 18 show occlusal-incisal instrument 70, including wide 
instrument head 32 and narrower instrument head 74 on the opposite end of 
instrument 70. Heads 32 and 74 are seen to lie in a plane passing through 
the axis of instrument handle 71. FIGS. 19 and 20 show occlusal-incisal 
instrument 96, with details of construction and orientation of wide head 
98 and narrower head 100. Similarly, FIGS. 21 and 22 show occlusal-incisal 
instrument 102, with wide head 104 and narrower head 106; and FIGS. 23 and 
24 show occlusal-incisal instrument 108 with wide head 110 and narrower 
head 112. 
Various head orientations are provided in order to permit a skilled 
operator to choose the instrument appropriate for a particular quadrant of 
the mouth of the patient on whom dental restoration work is performed. The 
Table discloses recommended instruments by mouth quadrant for use by a 
right-handed operator. 
TABLE 
______________________________________ 
Recommended Instruments for Right-Hand Operators 
Mouth Quadrant Instrument Number 
______________________________________ 
Upper right 70, 102, 86 and 90 
Upper left 102, 108, 82 and 90 
Lower left 70, 96, 86 and 90 
Lower right 70, 102, 38, and 90. 
______________________________________ 
Instrument numbers in the Table correspond to the reference numerals 
applied to the instruments of FIGS. 9-24. Instruments, of course, can be 
used by left-handed operators by interchange of instruments 82 and 86, by 
interchange of instruments 96 and 102, and by an appropriate modification 
of interproximal instrument 90. 
The foregoing is considered as illustrative only of the principles of the 
invention. Further, since numerous modifications and changes will readily 
occur to those skilled in the art, it is not desired to limit the 
invention to the exact construction and operation shown and described, and 
accordingly, all suitable modifications and equivalents may be resorted 
to, falling within the scope of the invention.