Dental tool

A dental apparatus for cleaning teeth includes a metallic scaling element formed to receive a slender, rigid, smooth plastic sheath. The scaling element is vibrated by a sonic generator, causing its outer sheath to vibrate as well. The sheath or tip is composed of a material such as polysulfone having good thermal stability for covering the tip of the metallic scaling element. The small diameter free end of the sheath is especially useful in the removal of plaque from an individual's teeth or titanium implants while preventing damage to the surface of the teeth or implants.

FIELD OF THE INVENTION 
This invention relates to dental apparatus and, particularly, to an 
instrument for cleaning teeth and dental implants in a non-abrasive 
manner. 
BACKGROUND ON THE INVENTION 
Currently, teeth are primarily cleaned by dental hygienists and dentists 
utilizing hand-operated cleaning tools or a mechanized tool wherein the 
cleaning element is vibrated at sonic frequencies. A disadvantage of 
present tools is that their typically metal, cleaning elements have 
relatively sharp edges that can damage or scrape away enamel or dentin 
from the tooth. Also, sharp edges can chip crown or composite resin 
margins. 
Recently, tooth implants have been developed wherein a missing tooth is 
replaced by a prosthesis which is implanted in the jaw. The composition of 
the implant is such that the bone tissue will actually attach to the 
implant so that it is firmly anchored. This eliminates the need for a 
bridge wherein an artificial tooth is not positioned within the jawbone 
but, instead, is anchored to adjacent teeth. 
It is necessary to clean plaque and scale from the implant, just as a 
natural tooth, particularly beneath the gum line. Unfortunately, the 
material employed for the implants is damaged by conventional scaling 
tools. Commonly, the implant is made of titanium and is highly polished. 
The sharp metal edge of the scaling tool roughens and mars the surface of 
the implant, thereby increasing the surface area available for the 
adherence of unwanted plaque. 
Accordingly, a need exists for a tool which will properly clean tooth 
implants, as well as natural teeth, without damaging the surface of the 
teeth, and clean crown and restoration margins. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an improved tooth-cleaning tool 
which will not scratch the surface of tooth implants or natural teeth. 
According to the present invention, a metallic scaling element attached to 
a sonic vibrator is covered by a thin, replaceable, nonmetallic sheath or 
tip. In a preferred embodiment, the tip of a metallic scaling element is 
made shorter than a conventional element; and, rather than having sharp 
edges, it is smooth and generally frusto-conical in shape with a slight 
taper towards the free end. The configuration of the non-metallic tip is 
complementary to the metallic scaling element, being formed with a socket 
having mating tapered surfaces which provide considerable contact with the 
metal element. As a result, the non-metallic tip is securely attached to 
the metallic element simply by pressing it into position. Preferably, the 
included angle on the tip of the metallic element and on the interior of 
the mating socket on the non-metallic sheath is about 3.degree., or about 
11/2.degree. with respect to the axis of the components. 
The exterior is preferably cylindrical in the area of the socket, but then 
is generally conical or frusto-conical tapering to a small-diameter, 
smoothly-rounded free end. It is this tapered surface which contacts a 
tooth and provides the cleaning surface. Preferably, the tip exterior 
tapers at an angle of about 6.degree., with respect to the axis, to a free 
end of about 0.030 inches in diameter, rounded on the end with a radius of 
about 0.015 inches. 
The non-metallic tip is preferably composed of a rigid but strong plastic 
such as polysulfone. The smoothly curved vibrating tip is somewhat 
resilient and does not mar the surface of teeth. Polysulfone offers useful 
properties, such as maintaining thermal stability and rigidity at 
temperatures up to 300.degree. F. This feature is of great significance 
since dental devices acting at sonic frequencies generate excessive heat 
which, if not addressed, may distort the properties of a thermally 
unstable device. Yet, it has been found that an all-plastic tool cannot 
satisfactorily support itself, even if cooling is provided. The plastic 
tip on a metal tool works very satisfactorily with cooling. 
Since the plastic tip is quite small and, therefore, not easy to handle, a 
preferred method of removal is accomplished by employing a special tool. 
This tool includes a notch for receiving the removable tip with the shank 
of the metal-supporting element positioned in a slot open to the notch. 
Upon pulling this special tool away from the cleaning tool, the plastic 
tip is captured within the confines of the notch, thereby removing the tip 
from the cleaning tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown a sonic toothcleaning device 10, 
including a cylindrical housing 12, shown in phantom lines, and attached 
on one end to a sleeve or base 16, which supports a metallic scaling 
element 14. The external threading on a rearwardly extending portion 20 of 
the base 16 is used to connect the scaling element to a source of coolant 
(not shown) and a schematically-shown sonic generator 21. Such a device is 
not illustrated in detail in that it is well known that the sonic 
generator provides sonic vibrations to produce vibratory movement to the 
metallic scaling element 14 in the removal of plaque from teeth. 
The present invention provides a plastic or nonmetallic sheath or tip 26 
positioned on the tip of the cleaning element 14. The tip 26 is preferably 
made of a rigid, thermally stable plastic material, such as polysulfone. 
In utilizing the tool, the polysulfone material engages the tooth during a 
cleaning operation and, thus, prevents the metallic scaling element from 
scraping the surface of teeth or polished titanium implants which are 
easily scratched. Polysulfone is a desirable material to use for this 
purpose due to its high strength and its ability to withstand significant 
heat. 
FIG. 1 illustrates a metal scaling element, which is similar to a 
conventional one except for its having a special tip. As seen in FIG. 1 
and FIG. 2, the element includes a hook-shaped section 30 consisting of a 
front or free end section 32 which meets an adjoining rear section 34 at 
an angle of about 100.degree.. This angle is desirable in that it enables 
the dentist to better manipulate the tool for difficult-to-reach areas 
inside the mouth. Section 34 merges with a shank portion 36, which is 
shaped to be received within an elongated cavity or bore 38 in the base 
16, as seen in FIG. 3. A groove 35 is shown in FIG. 2 in the top portion 
of the sections 36 and 34 to conduct coolant to the tip. The rear portion 
of that groove is connected to a source of coolant (not shown) through the 
housing 12. 
Referring to FIGS. 2 and 3, the free end of the scaling element section 32 
has a smooth frusto-conical shape with approximately a 3.degree. 
converging taper extending in the direction of its free end. That is, the 
exterior of the free end forms a 11/2.degree. angle with the longitudinal 
axis of the element 14. This is in contrast to the sharp edges formed on 
the conventional scaling elements which typically have a square or 
triangular shaped cross-section. Also, the free end is shorter than a 
conventional element since it is to support a tip which, when combined 
with the metal element, is comparable in length to a conventional element. 
The non-metallic tip 26 has a bore or socket in its rear end, which also 
has an included angle taper of approximately 3.degree., that mates with 
the taper on the metallic tip 48. The components are dimensioned such that 
the extreme end of the metallic tip 48 does not normally bottom out or 
engage the end of the socket in the tip 26. This ensures that the exterior 
of the metallic tip 48 engages the socket walls of the non-metallic tip 
26, providing good frictional engagement, such that the non-metallic tip 
is firmly attached to the metallic element and will not slip or become 
unattached during operation. 
The socket in the non-metallic tip extends for a little less than half of 
the length of the tip 26. Thus, the free end of the tip 26 relies upon its 
own rigidity for support. As indicated above, an all-plastic scaling 
element becomes too hot during the operation of the sonic cleaning tool 
such that it does not maintain sufficient rigidity. However, with the 
combination illustrated, the metal tip provides the necessary strength and 
further assists in conducting heat away to the coolant, which flows 
through the groove 35 to bathe the tool tip during operation. 
The dimensions of the plastic tip 26 in a preferred form of the invention 
illustrate the small size of the tip. The rear portion of the plastic tip 
is substantially cylindrical, with a diameter approximately 0.090 inch, 
with the wall thickness increasing towards the closed end of the overall 
length of the plastic tip is about 0.50 inches, with the socket being a 
little less than half of that length and the remaining free end of the tip 
26, therefore being a little more than half. The exterior of the free end 
of the tip tapers at about 6.degree. from the cylindrical portion to a 
diameter of about 0.30 inches at its closed end in a preferred 
arrangement. The free end is substantially rounded in a radius of about 
0.015 inches in a preferred system. The small size enables the free end to 
fit into crevices between adjacent teeth and to extend between the gum and 
the base of the tooth. As indicated above, the smooth surface of the 
non-metallic tip 26, which is softer than the metallic element, does not 
mar or otherwise damage the exterior of the tooth or an implant, and yet 
the surface is effective for removing plaque. Although the non-metallic 
tip is possibly durable enough to withstand more than one use, its cost is 
such that it is practical to dispose of it after each use. This is highly 
desirable because of the concern of orally communicable diseases. 
To assist in the removal and replacement of the non-metallic tip 26 in the 
dentist's office, there is provided a special tool 46, as illustrated in 
FIGS. 4a and 4b. The tool has a generally cylindrical shape. However, a 
large notch 49 is formed in the top half of the front portion of the tool, 
as viewed in the drawings. This notch 49 extends axially sufficiently far 
to receive the length of plastic tip 26 of the tool 10, as seen in FIG. 
4a. The end wall 50 of the tool, forming one boundary for the notch 49, 
has a vertically extending slot 52 that opens outwardly or upwardly as 
shown. The width of the slot 52 is sufficient to receive the metallic 
scaling element in the area adjacent the rear of the non-metallic tip, but 
the width is less than the rear diameter of the non-metallic tip. With 
this relationship, the non-metallic tip may be positioned within the notch 
49, and the adjacent portion of the metallic element can fit within the 
slot 52. The non-metallic tip is thus captured within the notch 49. By 
pulling on the cleaning device and the tip tool in a manner to separate 
the components, the metallic scaling element 14 is separated from the tool 
and the non-metallic tip 26, which remains captured within the tip tool 
notch 49. 
As another feature, the tip tool 46 is useful to install the tiny tip on 
the metal element. A cylindrical bore or socket 60 is formed in the other 
end of the tool, opening to the end surface 62. This socket 60 is 
dimensioned to receive the non-metallic tip, and the length of the 
non-metallic tip is greater than the length of the socket such that the 
tip end engages the inner end of the socket 60 while the rear of the tip 
extends beyond the rear face, as shown in FIG. 4b. The diameter of the 
socket 60 is sized to properly support the non-metallic tip within the 
recess, but at the same time it is large enough so that friction does not 
result between the non-metallic tip and the interior surface of the socket 
60. Thus, by positioning a non-metallic tip in the socket 60, the tip of 
the metallic scaling element 14 can be readily inserted into the 
non-metallic tip. 
As a further feature, the tip tool 46 is also designed for use as a small 
wrench in separating the base 16 from the cylindrical housing 12. A 
cut-out 70 is formed in the side wall of the forward portion of the tool 
46. The width of the cut-out is dimensioned to fit onto the flats 44 of 
the exterior of the housing portion 42.