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Title:
ORAL CARE IMPLEMENT HAVING A BRISTLE PATTERN
Document Type and Number:
WIPO Patent Application WO/2016/058923
Kind Code:
A1
Abstract:
The present invention relates to an oral care implement, particularly to a toothbrush having a bristle pattern providing enhanced conformity to the topography of the teeth and improved ability to reach the interdental spaces for better cleaning thereof. An object of the present invention is to provide an oral care implement which provides plaque removal. A further object of the present invention is to provide an oral care implement which easily penetrate into the interdental spaces. The present inventors have found that an oral care implement having groups of bristle tufts with free ends of the bristle tuft inclined at specific angle relative to the plane of the head on which the bristle are anchored provides for improved plaque removal from the inter-dental spaces of the tooth.

Inventors:
HILLIER ANTHONY PITMAN (SG)
REBETZKE DAVID BRIAN (GB)
Application Number:
PCT/EP2015/073377
Publication Date:
April 21, 2016
Filing Date:
October 09, 2015
Export Citation:
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Assignee:
UNILEVER NV (NL)
UNILEVER PLC (GB)
CONOPCO INC DBA UNILEVER (US)
International Classes:
A46B9/04; A46B9/02; A46D1/00
Domestic Patent References:
WO1999023910A11999-05-20
Foreign References:
US5392483A1995-02-28
EP1864589A12007-12-12
US5655249A1997-08-12
US20060099162A12006-05-11
JP2002325632A2002-11-12
US20030088932A12003-05-15
JPH03289906A1991-12-19
Attorney, Agent or Firm:
TANSLEY, Sally, Elizabeth (AT Vlaardingen, NL)
Download PDF:
Claims:
Claims

1. An oral care implement comprising a handle (4), a head (1) connected to and extending from the handle (4), plurality of bristle tufts (8a, 8b, 8c, 8d)) anchored to the bristle bearing face (6) of the head characterized in that the bristle tufts are grouped into;

(i) a rearwardly located group (11) proximate the handle (4) wherein the plane (15) defined by the free ends (10) of the bristle tufts (8a) forms a positive slope of 3 to 11.5 degree when viewed in a direction from the head to handle with respect to the plane of the bristle bearing face (6) of the head and further wherein the bristle tuft of the rearwardly located group is anchored at an angle of 80 to 86 degree relative to the plane of the bristle bearing face of the head measured in a direction towards the handle;

(ii) a forwardly located group (12) farthest from the handle (4) wherein the plane ( 6) defined by the free ends of the bristle tufts (8b) forms a negative slope of 3 to 11.5 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head and further wherein the bristle tuft of the forwardly located group is anchored at an angle of 80 to 86 degree relative to the plane of the bristle bearing face of the head measured in a direction away from the handle;

(iii) a first group (13) adjacent the rearwardly located group (11 ) wherein the plane (17) defined by the free ends of the bristle tufts (8c) forms a positive slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head;

(iv) a second group (14) intermediate the forwardly located group (12) and the first group (13), wherein the plane (18) defined by the free ends of the bristle tufts (8d) forms a negative slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head.

2. An oral care implement as claimed in claim 1 wherein bristle tuft of or the first group is anchored at an angle of 78 to 90 degree relative to the plane of the bristle bearing face of the head measured in a direction towards the handle.

3. An oral care implement as claimed in claim 1 wherein bristle tuft of or the second group is anchored at an angle of 78 to 90 degree relative to the plane of the bristle bearing face of the head measured in a direction away from the handle.

4. An oral care implement as claimed in claim 1 wherein longest perpendicular distance of the forwardly located group from the plane of the bristle bearing face of the head is at least equal to the longest perpendicular distance of the rearwardly located group from the plane of the bristle bearing face of the head.

5. An oral care implement as claimed in any one of the preceding claims wherein the bristle tufts of the first group adjacent the rearwardly located group extends farther from the bristle bearing face of the head than the bristle tufts of the rearwardly located group.

6. An oral care implement as claimed in any one of the preceding claims wherein the bristle tufts of the second group adjacent the forwardly located group extends farther from the bristle bearing face of the head than the bristle tufts of the forwardly located group.

7. An oral care implement as claimed in any one of the preceding claims wherein the longest perpendicular distance of the first group and the second group from the plane of the bristle bearing face of the head is equidistant.

8. An oral care implement as claimed in any one of the preceding claims wherein the bristle thickness is 0.15 to 0.25 millimetres.

9. An oral care implement as claimed in any one of the preceding claims wherein bristle tufts of the forwardly located group and the rearwardly located group comprises spirally twisted filaments.

10. An oral care implement as claimed in claim 10 wherein the spirally twisted filaments has a square cross section.

11. An oral care implement as claimed in claim 1 for use in providing improved plaque removal.

Description:
ORAL CARE IMPLEMENT HAVING A BRISTLE PATTERN

Field of the invention The present invention relates to an oral care implement, particularly to a toothbrush having a bristle pattern providing enhanced conformity to the topography of the teeth and improved ability to reach the interdental spaces for better cleaning thereof.

Background of the invention

Avoiding accumulation of dental plaque is considered essential for preventing common oral disease, in particular gingivitis. The most regularly used implement for controlling plaque is a toothbrush. Toothbrush serves to clean the teeth by removing plaque and debris from the tooth surfaces which includes the curved outer tooth surfaces and the inter-dental surfaces between the teeth. While most commercially available

toothbrushes clean the outer buccal face of teeth adequately, they fail to provide improved cleaning of plaque and debris from the gingival margin, inter-dental areas, and other hard to reach areas of the mouth. It is believed that toothbrushes having multi-level bristle contour allows better inter-dental penetration by the bristles and ensures effective plaque removal. Attempts have been made to provide inter-dental cleaning of the tooth.

One such attempt was made in EP1286608B1 (Colgate-Palmolive Company, 2008) which discloses a toothbrush bristle pattern for penetrating into the interproximal spaces between the teeth and for enhanced cleaning of the teeth surfaces. It discloses a bristle pattern including a trim profile in the form of an inverted "V" with its apex at the centre of the head. EP1097655 A2 (Colgate-Palmolive Company, 2001) discloses a toothbrush having a bristle profile for improved cleaning action and access to the teeth and gums. The bristle configuration includes a convex group of bristles located at the heel of the head, the teeth engaging ends of which lie in a convex line, another convex group of bristles located at the toe of the head and a group of concave bristles intermediate the two convex group of bristles and having its teeth engaging ends which lie in a concave line.

US5392483 A (Heinzelman et al., 1995) discloses a toothbrush which gives improved removal of dental plaque while massaging and stimulating the gums without injury to these tissues. Bristle tufts of said toothbrush has a special arrangement which arrangement includes a fan-shaped grouping of tufts along left and the right edges of the head; front end and rear end of the head includes groups of tufts whose free ends are trimmed to define respective planes which are slanting downwardly towards the interior area of the head; and a further grouping of tufts which is arranged in a saddle shape and positioned in an interior area between the fan-shaped tufts.

US5655249 A (Li, 1997) discloses a toothbrush for providing improvement in terms of dental cleaning and gum stimulation. Height of bristles in the toothbrush are arranged to create a concave cylindrical brushing surface at the free ends of bristles and height of bristles of the inner rows are shortened to follow a more concave cylindrical shape. This arrangement provides for a curvature which is similar to the user's frontal dental arch.

US2006099162 A1 (Moskovich et al., 2006) discloses an oral care implement having a handle and a head with tooth cleaning elements extending from fixed pods and additional tooth cleaning elements extending from one or more central pods suspended between the fixed pods through a bridge.

JP2002325632 A2 (Lion Corp, 2002) discloses a toothbrush which has bristle tufts that can fit with the shape of the teeth. Head of the toothbrush has two groups of bristle bundle, one in the front half and the other in back half closer to the neck each of which are implanted perpendicular to the face of the head. The tips of the bristle bundle in the front half when viewed from a side includes a set of bristle bundles with its peak nearer the front of the head which is forward leaning and a further set of bristle bundles of the front half which is nearer the neck are backward leaning. The tips of the bristle bundle in the second half when viewed from the side has a smoothly rising line towards the neck and goes up and down in every bundle. There is a need in the art for an oral care implement having a bristle pattern that easily penetrate into the inter-dental spaces and cleans deep in between the teeth without the need for application of excessive and deleterious brushing force. An object of the present invention is to provide an oral care implement which provides improved plaque removal.

A further object of the present invention is to provide an oral care implement which easily penetrate into the inter-dental spaces.

Yet another object of the present invention is to provide an oral care implement which cleans in between the teeth without the need for excessive brushing force.

The present inventors have found that an oral care implement having groups of bristle tufts with free ends of the bristle tuft inclined at specific angle relative to the plane of the head on which the bristle are anchored provides for improved plaque removal from the inter-dental spaces of the tooth.

Summary of the invention

According to an aspect of the disclosed invention provided is an oral care implement comprising a handle (4), a head (1) connected to and extending from the handle (4), plurality of bristle tufts (8a, 8b, 8c, 8d)) anchored to the bristle bearing face (6) of the head characterized in that the bristle tufts are grouped into;

(i) a rearwardly located group (11) proximate the handle (4) wherein the plane (15) defined by the free ends ( 0) of the bristle tufts (8a) forms a positive slope of 3 to 11.5 degree when viewed in a direction from the head to handle with respect to the plane of the bristle bearing face (6) of the head and further wherein the bristle tuft of the rearwardly located group is anchored at an angle of 80 to 86 degree relative to the plane of the bristle bearing face of the head measured in a direction towards the handle;

(ii) a forwardly located group (12) farthest from the handle (4) wherein the plane (16) defined by the free ends of the bristle tufts (8b) forms a negative slope of 3 to 11.5 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head and further wherein the bristle tuft of the forwardly located group is anchored at an angle of 80 to 86 degree relative to the plane of the bristle bearing face of the head measured in a direction away from the handle;

(iii) a first group (13) adjacent the rearwardly located group (11) wherein the plane (17) defined by the free ends of the bristle tufts (8c) forms a positive slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head;

(iv) a second group (14) intermediate the forwardly located group (12) and the first group (13), wherein the plane (18) defined by the free ends of the bristle tufts (8d) forms a negative slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head.

According to a second aspect disclosed is an oral care implement according to the first aspect for use in providing improved cleaning of interdental spaces of tooth. According to a further aspect disclosed is an oral care implement according to the first aspect for use in providing improved plaque removal.

Brief description of the drawing Figure 1 is a side elevational view showing the four groups of bristle tufts according to the present invention.

Detailed description of the drawings In the description like numbers refer to like features.

Figure 1 is a side elevational view highlighting the four groups of bristle tufts according to the invention and provides the best view of bristle tuft positioning on the head.

Shown is a head (1) with a rear end (2) and a toe end (3). Rear end (2) is connected to a handle (4). The head (1) is connected and extends along a longitudinal axis (a-a) from the handle. Head is defined by a bristle bearing face (6), an opposing face (not shown) and side surfaces (7a, 7b) joining the bristle bearing face (6) and an opposing face. Plurality of bristle tuft (8a, 8b, 8c, 8d) is anchored to the bristle bearing face (6) of the head (1). Each bristle tuft (8a, 8b, 8c, 8d) is made of plurality of bristles, the anchored end (9) of the bristle tuft is held within an aperture of the bristle bearing face of the head (6) and a free end (10) is distanced away from the bristle bearing face of the head.

A rearwardly located group (11) of bristle tufts (8a) is arranged proximate a handle (4). Another forwardly located group (12) of bristle tufts (8b) is arranged farthest from handle and is proximate to the toe end (3) of the head. A first group (13) of bristle tufts (8c) is arranged adjacent to the rearwardly located group (11) and a second group (14) of bristle tufts (8d) is arranged intermediate the first group (13) and the forwardly located group (12).

A plane (15) defined by the free ends of the bristle tufts (8a) of the rearwardly located group (11) forms a positive slope of 6.6 degree when viewed in a direction from the head to handle with respect to the plane of the bristle bearing face (6) of the head. Preferably the bristle tufts of the rearwardly located group (11) are anchored at an angle of 82 degree with respect to the plane of the bristle bearing face of the head (6) measured in a direction towards the handle.

In the forwardly located group (12), a plane (16) defined by the free ends of bristle tufts (8b) of the forwardly located group (12) forms a negative slope of 11.0 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face of the head. Preferably the bristle tufts of the forwardly located group (12) are anchored at an angle of 82 degree with respect to. the plane of the bristle bearing face of the head (6) measured in a direction away from the handle. In the first group, a plane (17) defined by the free ends of the bristle tufts (8c) of the first group (13) forms a positive slope of 18 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face of the head. Some of the bristle tufts of the first group (13) are arranged transversely across a substantially middle portion of the head and are preferably orthogonally anchored to the plane of the bristle bearing face of the head (6). Remaining bristle tufts of the first group (13) are preferably anchored at an angle of 82 degree with respect to the plane of the bristle bearing face of the head measured in a direction towards the handle.

In the same manner, some of the bristle tufts of the second group (14) are arranged transversely across a substantially middle portion of the head and are preferably anchored at an angle of 90 degree to the plane of the bristle bearing face of the head (6). Remaining bristle tufts of the second group (14) are preferably anchored at an angle of 82 degree with respect to the plane of the bristle bearing face of the head (6) measured in a direction away from the handle (4). In the second group, a plane (18) defined by the free ends of the second group (14) of bristle tufts (8d) forms a negative slope of 18 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face of the head.

The length of the bristle tufts (8), measured as the perpendicular distance between anchored end (9) and free end (10) of the bristle tuft, within the rearwardly located group is greatest for the bristle tufts proximate the handle (4) and the length of the bristle tufts progressively decreases as the positioning of the bristle tufts is distanced farther away from the handle. Within the rearwardly located group (11) the length of the longest bristle tufts measures 11.2 millimetres and the shortest bristle tufts measure 10.3 millimetres. Likewise, within the first group (13) the length of the bristle tufts progressively decreases with increase in the distance of the tuft from the handle (4). In the first group the length of the longest bristle tufts measure 12 millimetres and the shortest measure 10 millimetres.

Within the forwardly located group (12) the longest bristle tufts are arranged proximate the toe end (3) of the head and the length of the bristle tufts progressively decreases within the group with increase in distance of the tuft from the toe end of the head. Within the forwardly located group the length of the longest bristle tufts measure 12.0 millimetres and the shortest measure 10.5 millimetres. The bristle tufts within the second group (14) are also arranged in a manner such that the longest bristle tufts are closer to toe end (4) of the head and the length of the bristle tufts progressively decreases within the group with increase in the distance of the tuft from the toe end (3) of the head. In the second group the length of the longest bristle tufts measure 12.05 millimetres and the shortest measure 10.0 millimetres.

Detailed description of the invention

According to a first aspect disclosed is an oral care implement having a handle, a head having plurality of bristle tuft grouped into a rearwardly located group, a forwardly located group, a first group and a second group.

Bristle tuft

Disclosed oral care implement includes plurality of bristle tufts (8) anchored to the bristle bearing face of the head (6). Bristle tuft is made plurality of bristles.

Preferably the bristles are made of a material which is flexible, it is also preferred that the bristles are soft enough to penetrate the gingival margin and remove debris and plaque without causing irritation and bleeding of the gums. It is preferred that the free end of bristles is end-rounded. Preferably some of the bristles are spirally twisted. Preferably the spirally twisted filament has a round or square cross section, more preferably the spirally twisted filament has a square cross section. Preferably the spirally twisted filament has a diameter of 0.15 millimetres to 0.30 millimetres.

Preferably the bristle tufts of the forwardly located group and/or the rearwardly located group comprises spirally twisted filaments.

Preferably the bristles have a thickness of 0.15 to 0.30 millimeters more preferably the bristles thickness is 0.15 to 0.25 millimeters, still preferably 0.18 to 0.25 millimeters and still more preferably the thickness is 0.18 to 0.23 millimeters. Any conventional flexible bristle material may be used. Nylon and polyester are preferred bristle materials, with nylon being the most preferred. A preferred brand of nylon is 6, 12 nylon available from E.I. Du Pont de Nemours and Company marketed under the tradenamne of TYNEX(R). Bristles may be of any colour. Preferably the bristle tufts are of two different colors. Rearwardlv located group

Disclosed oral care implement includes a rearwardly located group proximate the handle. The plane defined by the free ends of the bristle tufts of the rearwardly located group forms a positive slope of 3 to 11.5 degree when viewed in a direction from the head to handle with respect to the plane of the bristle bearing face of the head.

Preferably the plane is inclined at an angle of 4 to 10 degree relative to the plane of the bristle bearing face of the head more preferably the plane is inclined at an angle of 6 to 8 degree relative to the plane of the bristle bearing face of the head.

The bristle tufts of the rearwardly located group is anchored at an angle of 80 to 86 degree, more preferably at an angle 82 to 84 degree relative to the plane of the bristle bearing face of the head measured in a direction towards the handle. Preferably the ratio of the length of the longest bristle tuft to the shortest bristle tuft of the rearwardly located group is 1.09:1.

Forwardly located group

Disclosed oral care implement includes a forwardly located group farthest from the handle. The plane defined by the free ends of the bristle tufts forms a negative slope of 3 to 11.5 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face of the head. Preferably the plane is inclined at an angle of 4 to 10 degree relative to the plane of the bristle bearing face of the head more preferably the plane is inclined at an angle of 6 to 8 degree relative to the plane of the bristle bearing face of the head.

The bristle tufts of the forwardly located group is anchored at an angle of 80 to 86 degree, more preferably at an angle 82 to 84 degree relative to the plane of the bristle bearing face of the head measured in a direction away the handle.

Preferably the longest perpendicular distance of the forwardly located group from the plane of the bristle bearing face of the head is at least equal to the longest perpendicular distance of the rearwardly located group from the plane of the bristle bearing face of the head.

Preferably the ratio of the length of the longest bristle tuft of the forwardly located group to the shortest bristle tuft in the forwardly located group is preferably 1.14:1.

First group

Disclosed oral care implement includes a first group adjacent the rearwardly located group. The plane defined by the free ends of the bristle tufts forms a positive slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face of the head, preferably at an angle of 12 to 20 degree, more preferably at an angle of 14 to 20 degree and further more preferably at an angle of 14 to 18 degrees and still more preferably at an angle of 16 to 18 degree relative to the plane of the bristle bearing face of the head.

Preferably the bristle tufts of the first group is anchored at an angle of 78 to 90 degree, more preferably at an angle 78 to 86 degree, further preferably at an angle of 80 to 86 degree, still preferably 82 to 86 degree and still more preferably at an angle 82 to 84 degree relative to the plane of the bristle bearing face of the head measured in a direction towards the handle.

Preferably the bristles tufts of the first group adjacent the rearwardly located group extends farther from the bristle bearing face of the head than the bristle tufts of the rearwardly located group.

Preferably the ratio of the length of the longest bristle tuft of the first group to the shortest bristle tuft of the first group is preferably 1.2:1.

Second group

Disclosed oral care implement includes a second group of bristle tufts intermediate the forwardly located group and the first group, the plane defined by the free ends of the bristle tufts forms a negative slope of 12 to 24 degree when viewed in a direction from the head to the handle with respect to the plane of the bristle bearing face (6) of the head, preferably at an angle of 12 to 20 degree, more preferably at an angle of 14 to 20 degree and further more preferably at an angle of 14 to 18 degrees and still more preferably at an angle of 16 to 18 degree relative to the plane of the bristle bearing face of the head.

Preferably the bristle tufts of the second group is anchored at an angle of 78 to 90 degree more preferably at an angle 78 to 86 degree, further preferably at an angle of 80 to 86 degree, still preferably 82 to 86 degree and still more preferably at an angle 82 to 84 degree relative to the plane of the bristle bearing face of the head measured in a direction away the handle.

Preferably the bristles tufts of the second group adjacent the forwardly located group extends farther from the bristle bearing face of the head than the bristle tufts of the forwardly located group.

Preferably the longest perpendicular distance of the first group and the second group from the plane of the bristle bearing face of the head is equidistant.

Preferably the ratio of the length of the longest bristle tuft of the second group to the shortest bristle tuft of the second group is 1.2:1.

According to a second aspect disclosed is an oral care implement according to the first aspect for use in providing improved cleaning of interdental spaces of tooth. According to a further aspect disclosed is an oral care implement according to the first aspect for use in providing improved plaque removal.

Process for making the oral care implement

Disclosed oral care implement can be made by any process which is generally understood by those skilled in the art. The bristles may be implanted in the bristle bearing face of the head in tufts using either typical staple technology or by means of fusion. In a staple set bristling process, a small group of bristles is folded over a nickel silver staple and forced into a cylindrical hole in the brush which forms a bristle tuft. After bristling, the tufts are polished by a series of sanding discs which removes any burrs or sharp edges. The toothbrush head in which the bristles are anchored using staple set bristling process requires deeper hole and comparatively thicker head. Alternatively the bristles may be anchored to the bristle bearing face of the head using other non-staple technology. One such process involves fusing the bristle tufts into the bristle bearing face of the head by heating both the bristle tufts and the head which are then brought together. In another known process the ends of the bristle tufts are pre- positioned in an injection mold prior to the introduction of the material forming the toothbrush head, the material is subsequently injected about the ends of the bristle tufts, locking the bristle tufts in place in bristle bearing face of the head. After tufting the bristles are cut to the desired profile in a trimming step followed by rounding the tip free end of the bristles. The toothbrush is then packaged.

Examples

Example 1 : Evaluation of plaque removal ability of a toothbrush having a bristle pattern according to the present invention and a comparative toothbrush with a flat trim profile.

The plaque removal ability of oral care implement was tested in-vitro using a method for determining dental crevice penetration efficacy. The method is based on model teeth profile of Nygaard-Ostby for measuring interdental cleaning potential. The method provides plaque removal under typical wet conditions using a representative brushing machine with elliptical movement.

Teeth model: A tooth model simulating interdental spaces between incisor and molar teeth was made of light green coloured pdlyurethane plate which measured 45 square millimeters and 8 millimeters in thickness. The model had four uniform crevices spaced apart and running across the length of the plate. Artificial plaque: 40 parts of liquid paraffin and 0.6 parts of stearic acid was warmed and stirred until the stearic acid was dissolved. 55 parts of precipitated chalk (3 to 4 microns particle size) was added slowly and stirred at low speed with high shear to obtain the artifical plaque. The artificial plaque had a viscosity of 14.000 mPa. A palette knife was used to fill and level off the cervices of the tooth model with the artificial plaque. The crevices on the teeth model were filled with artificial plaque which simulates humane plaque in its physical properties.

Aqueous brushing medium (artificial saliva): 5 grams of Sodium dodecyl sulphate was added to 600 mL of water and heated at 50°C with continuous stirring. 3 grams of xanthan gum was added to the above mixture slowly followed by addition of 1 litre of water and mixed until all the ingredients are completely dissolved. The mixture was allowed to rest for 12 hours before use.

In-vitro brushing: For conducting in-vitro brushing a WIRA machine produced by Good Brand Jeffrey's Ltd (Stockport) was used. The machine provided a simulation of a typical brushing motion with a frequency of 150 double strokes per minute. The machine provided a predominantly elliptical brushing movement having a combination of co-linear and cross-brushing.

Comparative toothbrush and the toothbrush according to the present invention were soaked in water for 5 minutes prior to the experiment. The brush was then placed in the gripping unit of the WIRA machine taking care that the tufts are not compressed during and after being placed.

The tooth model was placed in a container of the WIRA machine. The container was dipped in the aqueous brushing medium until the tooth model was just submerged in the medium. The container was placed in the machine holder. Weight was added to provide 190 grams of load on the brush head. The machine was switched on and 30 brushing strokes were made on the tooth model. The plates were washed with distilled water to remove the residual aqueous rinsing medium. The above process was repeated by applying 275 grams of load using the same toothbrush which was used for brushing with 190 grams load.

The above brushing was conducted on four samples of comparative toothbrush and similarly for four samples of toothbrush according to the present invention.

Method for plaque removal measurement:

Removal of artificial plaque from the crevices was monitored photometrically using a Minolta chromameter. A 4 millimetre aperture nose cone was used to illuminate and measure circular areas directly over the crevice.

An un-cleaned crevice filled with the artificial plaque appeared as a 4 millimeter wide white band; a partially cleaned crevice depending on the degree to which it was cleaned appeared as a white band of decreasing width and a proportional decrease in reflectance value.

The whiteness reading 'L' in the L* a* b* colour system was taken for an empty crevice prior to being filled with the artificial plaque (L* empty), the reading were similarly taken after the crevice was filled (L* fined with the artificial plaque and following brushing (L * after brushing). Six reading at each stage were taken and the average 'L' value was calculated.

The efficacy of plaque removal was expressed using the equation:

Av(L* filled) - Av( L* after brushing)

% Removal =

AV (L* fined) - AV (L* empty)

Samples tested: Two toothbrushes (Ex 1 , Ex 2) with a bristle pattern according to the present invention and as shown in Figure 1 were taken. Ex 1 had a bristle thickness of 7 microns and Ex 2 had a bristle thickness of 8 microns. Well known marketed toothbrush (Brand: Formula Trendy) with a flat trim pattern was taken as the comparative example. One comparative toothbrush (Ex A) has a bristle thickness of 6 microns and the second comparative toothbrush (Ex B) had a bristle thickness of 7 microns. The efficacy of plaque removal of the toothbrushes were determined and provided on Table 1.

TABLE 1

The results on Table 1 clearly shows that the toothbrushes according to the present invention (Ex 1 , Ex 2) remove plaque efficiently and are statistically better than the comparative brushes (Ex A, Ex B) having a flat trim profile.