GB2171296A - Interdental toothbrush - Google Patents

Abstract

An interdental toothbrush has a handle (20) made from a mixture of a thermoplastic elastomer and a general purpose polypropylene. A twisted wire brush (26) projects from the handle in axial alignment therewith. The toothbrush can be held within a loosely clasped fist, with one end of the brush held between a thumb and an index finger. By manipulating the thumb and index fingers, the angle at which the brush projects may be changed at will. In this way, the insertion of the brush in more difficult to reach spaces in or around teeth is more easily performed. <IMAGE>

Description

1 GB 2 171 296 A 1

SPECIFICATION

Interdental toothbrush This invention relates to toothbrushes and, more particularly, to interclental brushes.

An interclental brush is one which fits into spaces between and around the teeth. This kind of brush is generally used by people who have special brushing needs. For example, some bridges are suspensions which run between adjoining teeth. The biting surface is present, but there is nothing under that surface and above the gum line. Therefore, there is a problem of how best to clean under the bridge and against adjacent teeth. Of course, there are many other places where similar interdental brushing problems may occur. Such 10 brushes are shown, for example, in U.S. Patent Nos. 3,559,226; 4,222,143; 4,387,479, and others.

When traveling or away from home, it is often inconvenient to carry and use long handled interdental brushes of the types shown in the above cited patents. Therefore, small portable devices are available which fit easily into a pocket or purse. These devices often have two parts which include a handle, a brush integral with the handle, and a cover that slips over the brush. Usually, the brush and handle are about two-inches long, with a twisted wire brush projecting out the end of the handle. One such product is marketed by Denticator Company, Inc., of Brisbane, California, under the name "SPIREX V" compact bridge and space brush.

The handle and brush of the prior art devices are generally a rigid unit; therefore, use of the unit is similar to holding a pencil of a comparable length and projecting it into the back of the mouth, while trying to fit the 20 point into a gap under a bridge or between adjacent teeth. This kind of rigidity may require an extension of the cheek or the use of two hands.

Once the gap is found, the brushing must occur without a loss of gap orientation unless one is willing to go through the process of finding the gap again. Also, if one brushes too vigorously and loses the gap while doing so, he may jab himself in the gum or tooth and also bend the wire stem brush. Thus, interdental cleaning may be difficult to perform, especially where visual contact is not easy to achieve.

Accordingly, an object of the invention is to provide new and novel interclental brushes and, more particularly, to provide small and portable units which may be carried in pocket or purse.

Another object of the invention is to provide an interdental brush which may be guided into a brushing position responsive to the user's sense of touch. Yet another object is to provide such a brush which may be 30 guided into position by a slight change in the attitude of the tip of a finger. Here, an object is to provide a brush with a handle which may be flexed at the tip end, especially so that it may be used more easily in the back of the mouth and other hard to reach places in the mouth. In this connection, an object is to provide a brush which is benclable to a proper angle during use and which can be straightened when not in use.

A further object is to provide a brush where very small movements at the tip of the finger may be used to 35 brush in the interclental spaces, thereby reducing the possibility of jabbing the gum responsive to a loss of brush-to-tooth contact.

In keeping with an aspect of the invention, these and other objects are accomplished by providing an interdental brush having a handle with a selected amount of flexibility in a neck region at a junction between the handle and brush, while being substantially rigid in the handle. The dimensions of the brush and handle 40 are such that a small amount of finger pressure upon the neck region causes the tip of the brush to deflect, bend or flex to a convenient brushing angle. After use, the neck may be straightened from the deflected position. The brush may be repeatedly bent and straightened for repeated use. Furthermore, it may be bent at different angles to afford access to different areas of the mouth. Thus, during brushing, one side of the interclental space may be brushed by slightly increasing the deflection responsive to an added finger pressure and the other side of the space may be brushed responsive to decreasing the deflection by reduced finger pressure. If need be, the brush may be rolled between the fingers to enable the finger tip to help straighten or to change the angle of the tip. Thus, the brushing itself may be accomplished by slight movements of the finger tip and thumb.

A preferred embodiment of the invention is shown in the attached drawing in which:

Figure 1 is a side elevation of the inventive brush and cap, as it might be viewed by the user; Figure 2 is a side elevation, partly in cross-section, showing the inventive brush and cap; Figures 3 - 6 are end views taken along lines 3-3 to 6-6, respectively, of Figure 2; Figure 7 is an assembled showing of the cap and brush, as they appear while the brush is being carried in packet or purse, for example; Figure 8 shows the brush in operation, illustrating how the brush is deflected responsive to finger pressure; Figure 9 shows an alternative embodiment of the invention shown in Figures 1-7; Figure 10 is a side elevation of an embodiment of the invention, with the top partially broken away to show internal grooves within the cap, with the cap closed over the handle; Figure 11 is a side elevation also showing the embodiment of figure 10 with the cap on the bottom of the handle extending the length thereof; and Figure 12 is a cross-sectional view of the cap of Figure 1 also showing an enlarged portion showing internal longitudinal ribs.

The brush of Figures land 8 include a handle 20 and a cap 22. The cap 22 is a cylindrical member, having 65 2 GB 2 171 296 A 2 one end 23 closed. The other end 24 is open and slips over the brush handle 20 with friction fit (as best seen in Figure 7). Optionally, one or more vents 21 may be provided in the cap to facilitate drying of the brush after use. A reduction in internal diameter, such as annular stop 25, limits the distance which the cap 22 may be slipped overthe end of handle 20 and, therefore, protects the brush 26 from the cap being jammed downwardly internal ribs 29 (Figure 12) run longitudinally within the cap 22 to provide added friction for holding the cap in place on the handle 20. The added holding forces occur because it is impossible to mold plastic with a completely circular interior to close enough tolerance to always fit snuggly. With the longitudinal ribs, the cover will stretch slightly between the ribs on undersized tolerances and yet the unstretched cap still holds on oversized tolerances. This holding force is especially important if it is necessary to coverthe brush after use and while it is still wet, when there could be a tendency for the cap to 10 slip off the handle.

In the embodiment of Figure 2 the internal diameter of the cap is uniform throughoutthe distance from the step 24 to the closed end 23 to give a smooth internal wall. It is desirable for the outside of the handle 20 and cap 22 to be serrated with longitudinal ribs so that they may be better manipulated by a person with wet hands. These ribs add friction, in the mold between the cap 22 and walls of the cavity in which it was formed. 15 Therefore, when the male member of the mold parts is opened, it often slipped out of the cap 22 with the smooth internal wall, thus leaving the cap 22 trapped inside the female member of the mold. This required a knock-out pin which would leave unslightly marks on the cap. To avoid this problem the male mold part is given a plurality of circumferential grooves to form a number of ribs 25a, inside the cap 22. When the male part of the mold is open, these ribs and grooves are engaged to provide enough holding forces to overcome 20 the friction between the cap 22 and the female mold part. Thereafter the cap 22 may be knocked off the male part since the depth of the grooves (or the height of the ribs 25a) is very shallow. To help with the knock-off without causing a blemish on the cap, a smooth surfaced flange 24a is provided for the bottom of the cap.

This flange also provides a controlled amount of resistance to a flaring of the open end (i.e. it acts somewhat as a rubberband would act to hold the cap 22 in place).

Handle 20 has a twisted wire brush 26 of any suitable design projecting longitudinally therefrom. The opposite end 27 of handle 20 is solid. When the cap 22 is in place on the handle 20, the brush 26 is kept clean and sanitary. When the cap 22 is placed on the opposite end of the handle 20, the handle is made longer. The internal ribs 29 help secure the cap 22 on the opposite end of the handle 20 so that, together, they provide a more secured tool which may be gripped with greater ease within the hand and braced against the palm at 30 the fleshy fold 34 between the thumb and the index finger. The stop 25 limits the distance that the end of the handle 20 extends into the cap 22.

The handle 20 is a solid member which is approximately a quarter-inch in diameter, for a distance A, which may be about one-inch. Beginning at shoulder 28, the diameter of a tip end 30 gradually reduces over a distance, which may be about one-quarter inch, to an outertip 31. which is also approximately one-quarter 35 inch in length and an eighth-inch in diameter. The wire stem 32 is exposed over a distance between the top of tip end 31 and the bottom of brush 26 which is about one-sixteenth of one-inch.

The wire stem 32 of brush 26 extends through and is embedded in the tip end and handle of the molded part. This wire stem continues for a substantial distance into the full diameter section of handle 20, as shown, for example in Figure 2. Preferably, the brush stem 32 is molded into the plastic of the handle at the time when the handle is made. To aid in preventing the brush from being pulled out of the handle, the end of the wire may be bent or crimped, as shown at 36 in Figure 9.

Longitudinal ribs 38 are provided in the handle 20 and the cap 22. These ribs enhance the esthetic appearance of the product and give the handle and cap a better feel to the user. The ribs also aid in removal of the cap from the handle, particularly after the brush has been used.

In order to achieve a desired flexing characteristic, the handle 20 is preferably made from a mixture of a thermoplastic elastomer, polymer material and a polypropylene of a general purpose homopolymer grade.

More particularly, in one embodiment which was constructed and found satisfactory, the handle was made of approximately 80% "C-Flex" and 20% "Polypropylene 5820".

The "C-Flex" material is manufactured by Concept Polymer Technologies, Inc. of 12707 U.S. 19 South, Clearwater, Florida 33546. In its technical data sheets, the manufacturer reports that "C-Flex" has the following properties:

3 GB 2 171 296 A 3 Mechanical ASTM C-Flex C-Flex C-Flex Properties Method 42-3500 42-3510 42-3515 Durometer Hardness D-2240 50A 65A 70A Tensile Str. Break 5 PSI @23'C D-412 1650 1780 1900 Tensile Modulus PSI at 100% D-412 175 330 340 PSI at 300% D-412 310 540 650 Tensile - Set 10 %(5) after Break D-412 55 100 43 Elongation % at Break @23'C D-412 850 800 790 Compression Set 15 at 700C D-395 72 66 70 Tear Strength - Method-Die C lbs/in D-624 130 183 220 Specific Gravity:t.02 D-792.90.90.90 Water Absorption (5) at 20 73'F 1 week at 50% RH D-570.14.27.30 1 week at 100% RH D-570.42.26.17 Thermal 25 Properties Brittle Temperature Melt Index-Cond. E D-746 - 100'1 - 1 00'F - 1 00'F D-1238.25 1.9 1.8 Electrical Properties Dielectric Strength Rolts/Mil) 450 740 800 35 Volume Resistivity (1016 ohm-cm) 1.2 3.0 0.8 Surface Resistivity (101' ohm) 3.6 3.6 2.6 Dielectric Constant 40 (102 Hz) 2.33 2.27 2.27 (103 Hz) 2.33 2.27 2.27 (106 Hz) 2.31 2.27 2.15 Dissipation Factor (1 O'Hz) 0.0004 0.0002 0.0002 45 (103 Hz) 0.0006 0.0002 0.0002 (106 Hz) 0.0022 0.0008 0.0008 Polypropylene #5820 (12 melt) is manufactured by the Shell Chemical Company, having an address at 50 1415 West 22 Street, Oak Brook, Illinis 60521. The manufacturer of this product describes its physical properties as follows:

4 GB 2 171 296 A Traditional si ASTV Property Units Units Test 4 Melt Flow 12g/10 min 12g/10 min D 12381 Density at 23'C 0.903 g/cc 0.903 g/cc D 1505 5 Tensile yield strengthr at 2.0 in/min 5100 psi 35 MPa D 638 2 Yield elongation at 2.0 intmin 10% 10% D 6382 10 1% Secant modulus, at 0.2 in/min 200,000 psi 1375 MPa D 638 2 Flexural modulus, at 0.05 in/min, 2 in span 220,000 psi 1500 MPa D 790A 2 15 Notched Izod impact strength, at 73'F/23'C 0.5 ft-lb/in 27 J/m D 256 2 at 0"F/- 1 80C 0.4ft-lb/in 20 J/m D 256 2 Hardness, Rockwell R95 R95 D 785 20 Heat deflection temp at 66 psi/ 455kPa 220OF 1040C D 648 Vicatsoftening temp 305OF 1520C D 1525 25 1 Condition L, 230'C, 2160g 2 ASTM Type 1 specimen, 1/8" thick (injection molded) 0 Shell further describes this product as being a high flow, general purpose material suitable for injection molding of intricate parts where long flow paths are involved. An antistat component reduces electrical charges during processing and subsequent storage, thereby reducing dust pickup. The manufacturer claims thatthe product has an excellentflex life, good chemical and solvent resistance, high strength-to-weight ratio, and exceptional stress cracking resistance.

Both of these materials meet exacting Federal standards for bio-medical use and for making direct contact 35 with food.

To further control the amount of flexing which may occur in the neck region 30, 31, the diameter of wire stem 32 may be either increased or decreased somewhat and the diameter and length of the neck region 30, 31 may be modified. It is thought that those who manufacture the inventive brush will determine the best diameters and lengths for themselves and for their own particular needs. In general, the wire stem of a conventional interdental brush may be increased in diameter in the approximate range of 10-50%.

The method of using the inventive brush is shown in Figure 8. The length of handle 20 is such that, when the tip end 30 is held between the thumb and index finger, the opposite end of the handle is captured and stabilized along the length of the finger. Or, if the cap is in place on the end of the brush, its end might be captured in or near the palm of the hand, as in the fleshy fold 34, which is between the thumb and index finger. By pressing the index finger against the tip end 30 while holding the handle 20 by the thumb, it is possible to deflect, bend, or flex, the brush to point, more or less, in line with the finger tip. If the user wishes to point the brush in another direction, the handle may be rolled between the thumb and index finger or a small amount of thumb pressure may be applied to the brush to straighten it or bend it to the other position.

Thus, the flexed angle of the brush may be varied, at the will of the user.

It is relatively easy to point one's finger at an object since the sense of touch tends to assist the pointer.

This makes the invention easy to use. On the other hand, it is more diff icult to point an instrument with a relatively long handle since the instrument may be held at almost any angle and since the user cannot always take advantage of the sense of touch to tell the user where the tip end of the long handled brush is located. Moreover, none of the existing long-handled or other interdental brushes have flexible tip ends similar to the inventive brush so their tip ends cannot be deflected as in the inventive brush. While the tip end is held and deflected, as seen in Figure 8, use of the instrument is much more like pointing a finger since the method of bending inherently tends to align the brush with the finger. This is an important advantage over the prior interclental brushes.

Anotherfactor is that, when the brush is held in the hand as seen in Figure 8, it is much easier to place the 60 brush in the space between the teeth in the back of the mouth as compared to attempting to position it when the brush is straight, as seen in Figure 1, because the natural curvature of the hand in this position is most appropriate to reaching into that back of the mouth space. An advantage is that the portion of the wire brush encased in plastic is more resistant to breaking from repeated or excessive bending than would be the case if the wire were exposed.

GB 2 171 296 A 5 The claims are to be construed to cover all equivalent structures which fall within the scope and of the invention.

Claims (15)

1. An interdental toothbrush comprising a handle having a first portion atone end with a flexing capability which maybe controlled by being held between a thumb and index finger, and a second portion which is relatively rigid and of a length which enables the opposite end of the handle to be captured and stabilized in the hand, brushing means having a brush with a twisted wire stem embedded in at least said first portion of the handle and projecting from said first portion in axial alignment with the handle, said controlled flexing of said handle being such that when said first portion is held between said thumb and index finger a small amount of thumb and finger pressure flexes said first portion of the handle to project said brush from said handle at an angle responsive to a manipulation of the thumb and index finger which enables said brush to be inserted into hard to reach places.

2. The toothbrush of claim 1 wherein the length is such that said second portion of said toothbrush 15 handle is captured along the length of the finger when said first portion is held by the thumb and index finger.

3. The toothbrush of claim 1 wherein the length is such that said second portion of said toothbrush handle is captured in approximately the palm of the hand when said first portion is held by the thumb and index finger.

4. The toothbrush of claim 2 wherein said first portion is approximately one-half inch long and tapers for approximately one-quarter inch diameter near said second portion to about one-eighth inch diameter, and said first portion has a tip at the outer end which is about one-eighth inch in diameter and approximately one-quarter inch long.

5. The toothbrush of claim 4 wherein said twisted wire brush has a diameter which is selected to provide 22 5 said controlled flexibility.

6. The toothbrush of claim 5 and cap means for covering said first portion and said twisted wire brush.

7. The toothbrush of claim 6 wherein the cap means includes at least one internal longitudinal rib for adding friction to secure the cap when in place over the handle.

8. The toothbrush of claim 6 or7 wherein the cap has at least one internal circumferential rib.

9. The toothbrush of anyone of claims 6 to 8 wherein said cap means are adapted to receive the second portion of the handle when the cap is removed from the first portion and means are provided in said cap means for limiting movement of first and second portions when they are inserted in the cap.

10. The toothbrush of claim 7 wherein the second portion of the handle and the cap are provided with external longitudinal ribs extending along a major portion of their lengths.

11. The toothbrush of anyone of claims 1 to 10 wherein said handle is made from a composition of approximately 80% of a thermoplastic elastomer polymer and approximately 20% of a general purpose polypropylene.

12. An interdental toothbrush substantially as described herein with reference to and as illustrated in Figure 1 of the accompanying drawing.

13. An interdental toothbrush substantially as described herein with reference to and as illustrated in Figure 2 of the accompanying drawing.

14. An interdental toothbrush substantially as described herein with reference to and as illustrated in Figure 10 and 11 of the accompanying drawing.

46

15. An interdental toothbrush substantially as described herein with reference to and as illustrated in 45 Figure 1 and 12 of the accompanying drawing.

Printed in the UK for HMSO, D8818935, 7186, 7102. Published by The Patent Office, 25 Southampton Buildings, London. WC2A lAY, from which copies may be obtained.