Note: Descriptions are shown in the official language in which they were submitted.
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TOOTHBRUSH WITH LONG TAPERED BRISTLES AND SHORT NON-TAPERED
BRISTLES
This invention relates to toothbrushes, in particular to the bristle
configuration
of a toothbrush. Especially this invention relates to improved toothbrush
bristle
configurations comprising tapered bristle filaments.
Toothbrushes are well known articles generally comprising a head for
insertion in the user's mouth and a grip handle to be held during use, with
often a
neck region in between. The toothbrush head normally has a surface, termed
herein
the "bristle surface" from which bristles extend from a lower end closest to
the bristle
surface to an upper end distant from the bristle surface. Toothbrush bristles
are also
well known articles, generally comprising a filament of a stiff but flexible
material,
disposed in tufts of plural filaments extending from the bristle surface. The
polyamide
Nylon is very frequently used as a toothbrush bristle material.
Although in most toothbrushes the bristle filaments have the same cross-
section along their entire length from their lower to their upper end, it is
also known
to use tapered bristles which decrease in their cross section toward their
upper end.
Tapered bristles, being thinner at their upper end, have different bending and
flexibility characteristics to non-tapered filaments. In particular tapered
bristles are
known for efficacy in reaching into the spaces between the teeth, the so
called
"interproximal" spaces. For example such bristles are disclosed in EP-A-1 234
525,
EP-A-1 415 572, US-A-6,546,586, WO-A-97/42853, WO-A-97/42854, WO-A-
01/32053, WO-A-82741, EP-A-0 596 633 among others.
Particular relative dispositions of the tapered bristles on the bristle
surface are
also known. For example US-A-6,546,586 discloses a toothbrush head in which
each
tuft comprises plural bristle filaments made of polybutylene terephthalate in
the form
of shorter filaments of uniform cross section and longer filaments which taper
toward
their upper end. It is also known from other disclosures to combine long and
short
bristle filaments in a tuft e.g. US-A-3,103,679, WO-A-96/16571 and DE-A-35 28
596.
Generally there are two methods of producing such tapered bristles. One is to
chemically erode the ends of the bristle filaments; the other is to
mechanically abrade
them to a taper. It has been found difficult to accurately mechanically abrade
bristle
filaments in situ on a toothbrush head. A known toothbrush of the type
disclosed in
WO-A-96/16571 is known to have been unsuccessful commercially because of poor
mouth feel.
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It is an object of this invention to provide an improved toothbrush head
incorporating tapered bristle filaments, e.g. providing tooth cleaning,
particularly in
the interproximal spaces, at the gingival margin, in subgingival access, and
also
having manufacturing advantages. Other objects and advantages of the invention
will
be apparent from the following description.
According to a first aspect of this invention a toothbrush head is provided,
having a bristle surface from which tufts comprising plural bristles extend in
a bristle
direction, each tuft comprising shorter bristles having a cross section which
does not
taper from their lower end toward their upper end and longer bristles which
taper from
their lower end toward their upper end, the taper of the longer bristles
commencing
above the upper ends of the shorter bristles, and wherein the length of the
longer
bristles above the upper ends of the shorter bristles is from 4 mm up to 7mm.
It has been found that a toothbrush head with the length of the longer,
tapered
bristles, bristles above the upper ends of the shorter bristles being from 4
mm up to
7mm, facilitates manufacture of the toothbrush head by mechanical abrasion of
the
upper ends of the longer bristles, particularly in the case when the bristle
filaments are
made of the preferred polyamide, e.g. Nylon, particularly the material
TynexTM. This
is inter-alia due to the current state of optimization of available machines
capable of
abrading the ends of bristle filaments to a tapering profile, and the
properties of such
bristle filament materials as TynexTM
Preferably the length of the longer bristles above the upper ends of the
shorter
bristles is from >4 mm up to 7mm. Typically the length to which the shorter
bristles
extend from the bristle surface is 9+/- lmm and length to which the shorter
bristles
extend from the bristle surface is 13 +/- lmm.
Typically the filaments may be circular in cross section, typically 0.1 - 0.25
mm, e.g. 0.15 - 0.20 mm, at maximum. This is a typical standard dimension for
toothbrush bristle filaments. Typically the longer bristles may taper over the
entirety
of their length above the upper end of the shorter bristles.
According to a second aspect of this invention a toothbrush head is provided,
having a bristle surface from which tufts comprising plural bristles extend in
a bristle
direction, each tuft comprising shorter bristles having a cross section which
does not
taper from their lower end toward their upper end and longer bristles which
taper from
their lower end toward their upper end, the taper of the longer bristles
commencing
above the upper ends of the shorter bristles, and wherein each said tuft is
set in a tuft
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socket having a minimum dimension across the longitudinal direction of the
bristle
filaments in the range 1.7 - 2.4 mm.
It is found that using a tuft socket in this dimension range, typically being
circular and having its diameter in this range, is advantageous for the
combination of
shorter and longer bristles in the tufts. This is believed to be because such
a dimension
enables a packing density which enables the shorter bristles to support the
longer
bristles for an advantageous tooth-cleaning effect, longer filaments being
more
flexible than shorter filaments for the same applied force. In particular this
is found to
be the case with the tufts of the toothbrush head of the first aspect of this
invention.
Typically toothbrush tuft sockets have a standard depth of 3.4 - 3.8 mm. A
tuft socket depth of 3.6 mm has been found suitable for the tufts of the
toothbrush
head of the first aspect of this invention.
According to a third aspect of this invention a toothbrush head is provided,
having a bristle surface from which tufts comprising plural bristles extend in
a bristle
direction, each tuft comprising shorter bristles having a cross section which
does not
taper from their lower end toward their upper end and longer bristles which
taper from
their lower end toward their upper end, the taper of the longer bristles
commencing
above the upper ends of the shorter bristles, each tuft containing 2 -
121onger
filaments extending from the bristle surface. Preferably there are 20 - 30
shorter
bristle filaments and 2 - 12 longer filaments extending from the bristle
surface.
It is found that this range of numbers of bristle filaments in the tufts can
be
advantageous in providing an acceptable mouth feel and in getting the longer
bristles
in between the teeth. Too few longer bristle filaments may not feel
comfortable to the
user, too many and it may not be easy to get a larger number of the longer
filaments
between the teeth.
It has been found that 5 - 7 longer filaments, preferably 26 - 28 shorter
filaments and 5 - 7 longer filaments is a suitable number for an optimized
effect.
Consequently in a fourth aspect of this invention the first and third aspects
are
combined in a toothbrush head, and a toothbrush head is provided having a
bristle
surface from which tufts comprising plural bristles extend in a bristle
direction, each
tuft comprising shorter bristles having a cross section which does not taper
from their
lower end toward their upper end and longer bristles which taper from their
lower end
toward their upper end, the taper of the longer bristles commencing above the
upper
ends of the shorter bristles, and wherein the length of the longer bristles
above the
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upper ends of the shorter bristles is from 4 mm up to 7mm, and wherein each
tuft
contains 2 - 121onger filaments extending from the bristle surface.
In this fourth aspect, preferably there are 20 - 30 shorter bristle filaments
and
2 - 121onger filaments extending from the bristle surface.
In a fifth aspect of the invention all three of the above aspects are combined
in
the toothbrush.
Therefore this fourth aspect a toothbrush head is provided having a bristle
surface from which tufts comprising plural bristles extend in a bristle
direction, each
tuft comprising shorter bristles having a cross section which does not taper
from their
lower end toward their upper end and longer bristles which taper from their
lower end
toward their upper end, the taper of the longer bristles commencing above the
upper
ends of the shorter bristles, and wherein the length of the longer bristles
above the
upper ends of the shorter bristles is from 4 mm up to 7 mm, wherein each said
tuft is
set in a tuft socket having a minimum dimension in the range 1.7 - 2.4 mm, and
wherein each tuft contains 20 - 30 shorter bristle filaments and 2 - 121onger
filaments extending from the bristle surface.
In the said bristle tufts the shorter and longer bristle filaments may be
disposed
in various ways. For example the longer tufts may be disposed randomly among
the
shorter bristle filaments. Alternatively the longer bristles may be disposed
about the
central upper-lower axis of the tuft, e.g. as a central region comprising
predominantly
or entirely of the longer bristles.
In the toothbrush head of this invention the said tufts may be disposed on the
bristle surface in a pattern which is otherwise generally conventional.
However in preferred embodiments the said tuft comprising shorter bristles
having a cross section which does not taper from their lower end toward their
upper
end and longer bristles which taper from their lower end toward their upper
end, the
taper of the longer bristles commencing above the upper ends of the shorter
bristles
may be disposed on the bristle surface in a pattern comprising an inner
cluster of said
tufts flanked on each longitudinal side by tufts comprised only of said
shorter bristle
filaments. Further, in such a pattern the inner cluster of said tufts may be
surrounded
on all sides by tufts comprised only of said shorter bristle filaments.
On the bristle surface of the toothbrush head of this invention there may
additionally be bristle tufts of known types, e.g. of commonplace types made
of
known materials such as Nylon e.g. TynexTM. There may also be tooth- or gum-
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hygiene elements extending from the bristle surface, e.g. known types of
elastomeric
elements.
A sixth aspect of this invention provides a further relative configuration of
tapering and non-tapering bristle filaments.
According to this sixth aspect of this invention a toothbrush head is
provided,
having a bristle surface from which tufts comprising plural bristles extend in
a bristle
direction, the tufts being disposed in a pattern on the bristle surface
comprising a
relatively inner cluster of plural tufts each of which contains relatively
longer bristles
which taper from their lower end toward their upper end, and plural relatively
outer
tufts of relatively shorter bristles.
Tufts in the relatively inner cluster may consist entirely of the relatively
longer
bristles which taper.
The plural relatively outer tufts may be disposed as outer perimeter tufts
along
two or more outer sides of the pattern of tufts. For example the plural
relatively outer
tufts may be disposed as the outer tufts along two widthways opposite sides of
the tuft
pattern. For example the outer tufts may be disposed as a ring of perimeter
tufts
around all sides of the relatively inner tufts. At the end of the tuft pattern
furthest from
the toothbrush handle, the "tip end" the upper ends of the outer tufts may lie
in a
surface, e.g. a plane, that increase in its distance from the bristle surface
with
longitudinal distance away from the handle. For example at the tip end of the
head
there may be a cluster of the outer tufts e.g. a polygon of the outer tufts
with their
upper ends in such a surface.
The plural relatively outer tufts may comprise bristles which are of uniform
no-tapering cross section along their lower-upper length. The plural
relatively outer
tufts may consist entirely of tufts which consist of bristles which are of
uniform cross
section along their lower-upper length.
The difference in the length between the relatively longer bristles and the
relatively shorter bristles to which they respectively extend fro the bristle
face may be
2 - 7 mm, typically 2-4 mm. Typically the shorter outer tufts may be 9-11 mm
long.
All of the bristle filaments on the toothbrush head of this fifth aspect of
the invention
may be made of polyamide, e.g. Nylon, particularly the material TynexTM
The handle and other parts of a toothbrush provided with the head of this
invention may be otherwise conventional, and may be made of conventional
materials
such as the known polypropylene materials used for toothbrushes.
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The toothbrush head may be provided integrally attached to a toothbrush
handle e.g. by an intermediate integral neck, or may be replaceably attachable
to the
toothbrush handle. The toothbrush head of this invention may be provided
either for a
manual or a powered toothbrush.
The toothbrush head of this invention may be made by a process in which the
shorter bristles and longer bristles in a non-tapered state are inserted into
tuft socket
holes in the tooth brush head with the upper ends of the longer bristles
extending
above the upper ends of the shorter bristles, and the upper ends of the longer
bristles
are mechanically abraded into a tapered shape. Machines able to do such
mechanical
abrasion are known in the toothbrush manufacturing art.
Alternatively bristle filaments may be purchased in an already tapered form.
There are two main types of such commercially available tapering bristles.
Double ended bristle filaments are tapered at both ends and are normally
mounted in a toothbrush bristle surface by folding them in the middle into a
"U"
shape and setting the folded middle region of the "U" shape in a socket hole
in the
bristle surface using a conventional "anchor". In the toothbrush heads of this
invention the tapering and non-tapering bristle filaments may comprise such
double-
ended filaments, conventionally folded in a "U" shape with the bend of the "U"
inserted into the socket hole and retained therein by a conventional metal
anchor. In
such a construction each length of "U" shaped filament provides two bristles
extending from the bristle surface.
Single ended bristle filaments are tapered at only one end and are normally
mounted in a toothbrush bristle surface by folding them close to the non-
tapered end
into a "J" shape and setting the folded end region of the "J" shape in a
socket hole in
the bristle surface using a conventional "anchor".
Alternatively the bristle tufts of the toothbrush head of this invention may
be
mounted in the bristle surface using the known "anchorless" or "inmould"
process in
which the parts of the bristles to be set in the head are enclosed within an
injection
mould and the plastics material of the head in injected into the mould to
embed the
bristle filaments in the head.
The tapering tufts may be mounted in the toothbrush head of this invention in
these conventional ways.
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In the toothbrush head of the sixth aspect of the present invention such
single
ended filaments are preferred as providing a preferred bristle density in the
longer
tufts.
The invention will now be described by way of example only with reference to
the accompanying figures which show:
Fig. 1 a perspective view of a toothbrush head of this invention.
Fig. 2 a sectional view of part of a toothbrush head of this invention.
Fig. 3 a cross sectional view through a bristle tuft of the head of Fig. 2 cut
at
the line A-A of Fig. 2 looking in the direction of the arrow.
Fig. 4 a side view of another toothbrush head of this invention.
Fig. 5 a side view of another toothbrush head of this invention.
Fig. 6 a plan view of the bristle face of the toothbrush head of Fig. 5.
Referring to Figs. 1, 2 and 3, a toothbrush head 10 overall is shown, having a
bristle surface 11 from which tufts 12 (generally) comprising plural bristle
filaments
extend in a bristle direction `B' generally perpendicular to the bristle
surface. The
bristle filaments are made of the Nylon material TynexTM. The lower end of
each of
the tufts 12 is adjacent to the bristle surface; the opposite upper end is
distant from the
bristle surface.
Each tuft 12 comprises shorter bristles 13 having a cross section which does
not taper from their lower end toward their upper end and longer bristles 14
which
taper from their lower end toward their upper end. As seen more clearly in
Fig. 2 the
longer bristles 14 taper in a generally conical shape toward their upper end,
the taper
of the longer bristles 14 commencing above the upper ends of the shorter
bristles 13.
The length "d" indicated in Fig. 2 by which the length of the longer bristles
14
extends above the upper ends of the shorter bristles 13 is ca. 6mm. The length
to
which the shorter bristles 13 extend from the bristle surface is ca. 9 mm and
the length
to which the longer bristles 14 extend from the bristle surface is ca. 13 mm.
The
shorter bristle filaments 13, and the longer bristle filaments 14 over their
length below
the upper ends of the shorter bristles, are circular in cross section, 0.15 -
0.20 mm
diameter, a typical standard dimension for toothbrush bristle filaments.
Each of the tufts 12 is mounted in a respective tuft socket 15 having a
minimum dimension perpendicular to the length direction of the bristles in the
range
1.7 - 2.4 mm. The total depth of the socket holes 15 is 3.6 mm, being
cylindrical to a
depth of 3.3mm and shallow conical below that. This is a standard depth and
profile.
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Each tuft 12 comprises double ended bristle filaments folded over into a "U"
shape,
with the fold of the "U" inserted into the tuft socket 15 and is fixed in
place in the
socket hole 15 by a metal "anchor" 16 as conventionally used in toothbrush
construction. In this construction each bristle filament folded into such a
"U" shape
consequently provides two bristle filaments 13, 14 extending from the bristle
surface
11.
Each of the tufts 12 contain 20 - 30 shorter bristle filaments and 2 -
121onger
filaments extending from the bristle surface 11. In the tufts 12 shown in
Figs. 1- 3
the longer bristles 14 are disposed about the central upper-lower axis of the
tuft 12,
e.g. randomly disposed or as shown in Fig. 3 disposed in a central area
predominantly
of longer bristles 14 surrounded by an outer sheath of the shorter bristles
13.
The toothbrush head 10 of this invention is integrally formed with a neck 17
by which it is integrally connected to a grip handle (not shown). Between the
neck 17
and the head 10 is a flexible link 18 of known construction comprising a
thinned
region of the neck 17 surrounded by an elastomer sphere.
A toothbrush according to Figs. 1 to 3 above was experimentally evaluated in
comparison with two commercial toothbrushes having no tapered bristles as
described
below.
Test 1: Interproximal Access Efficacy, IAE
Methods.
Three toothbrush products, a toothbrush provided with a toothbrush head of
Figs. 1 to 3, now commercially available as the "Dr Best ZwischenzahnTM"
toothbrush (herein "test toothbrush"), and two other toothbrushes, being an
Oral-B
Cross Action 40 TM toothbrush (herein "toothbrush A") and an Oral-B Indicator
35 TM
toothbrush (herein toothbrush "B") both of medium texture bristles, were
evaluated in
this study. All test toothbrushes were provided by G1axoSmithKline Consumer
Healthcare GmbH & Co. KG, Buehl, Germany. Six toothbrushes from each product
group, i.e. the test toothbrush, and toothbrushes A and B, were tested four
times for a
total of twenty four tests on each toothbrush design. Toothbrushes were stored
in the
laboratory at a temperature of 67-70 F for more than 48 hours before testing.
The
laboratory equipment used was fabricated to the design of Nygaard Ostby,
Edvardsen
and Spydevold. The tooth brushing technique involved independent evaluations
of
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each toothbrush in a vertical and horizontal brushing motion, tooth shapes
simulating
anterior and posterior teeth and a brushing weight of 250 g. The brushing
apparatus
was set to brush 15 seconds at two strokes per second with a 50-mm stroke. The
maximum width of the artificial plaque removed (Interproximal Access Efficacy,
IAE) was recorded in cm using vernier calipers. The same examiner performed
all
evaluations. The analysis of variance (ANOVA) was performed on the mean scores
for each of the toothbrush products. Significant differences between the
toothbrushes
were identified using two-sample t-tests.
Objectives
A primary method used in the laboratory assesses the ability of toothbrush
bristles to penetrate between simulated teeth and remove artificial plaque,
i.e.
interproximal access efficacy (IAE), during the tooth brushing procedure. Both
vertical and horizontal brushing motions are evaluated on simulated anterior
and
posterior tooth shapes. The results are then combined to determine overall
efficacy of
the toothbrush products evaluated. Overall efficacy in the IAE assay has been
correlated with clinical plaque removal. The purpose of this study was to
evaluate the
test toothbrush and toothbrush A and B for efficacy in the IAE procedure.
Interproximal access efficacy on anterior or posterior shaped teeth with
horizontal brushing is shown in Table 1 below. The mean IAE is significantly
(p <
0.001) higher for the Test Toothbrush than for toothbrushes A or B.
Table 1
Tooth Shape Test toothbrush Toothbrush A Toothbrush B
Mean values (standard deviation)
Anterior 1.21 (0.06) 0.89 (0.06) 0.67 (0.07)
Posterior 1.29 (0.10) 0.99 (0.10) 1.03 (0.10)
Results.
Interproximal access efficacy on anterior or posterior shaped teeth with
vertical brushing is shown in Table 2 below. On both anterior and posterior
tooth
shapes with vertical brushing, the mean IAE is significantly higher (p <
0.001) for the
Test Toothbrush than for toothbrushes A and B.
Table 2
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Tooth Shape Test toothbrush Toothbrush A Toothbrush B
Mean values (standard deviation) [cm]
Anterior 1.35 (0.05) 0.84 (0.08) 0.78 (0.06)
Posterior 1.50 (0.02) 0.99 (0.04) 1.03 (0.04)
Overall performance meaning combining all brushing motions and teeth
shapes are shown in Table 3. The overall IAE mean for the Test toothbrush was
statistically (p < 0.001) higher than the overall mean values for the
toothbrushes A
and B.
Table 3
Test toothbrush Toothbrush A Toothbrush B
Mean values (standard deviation)
1.34 (0.12) 0.89 (0.10) 0.82 (0.16)
In all of the IAE assays conducted, the Test toothbrush was significantly
superior (p< 0.001) to toothbrushes A and B. The Test toothbrush is predicted
to be
more effective for clinical interproximal plaque removal than toothbrushes A
and B.
Test 2: Gingival Margin Cleaning.
Two laboratory methods have been developed to measure the gingival margin
and subgingival action of toothbrushes in these anatomical areas. The Gingival
Margin Cleaning method (GMC) utilizes wet plaque-covered pressure-sensitive
paper
placed over simulated posterior teeth, to compare toothbrush products for
their ability
to remove artificial plaque at the junction of simulated gingival tissues. The
second
method Subgingival Access Efficacy (SAE) utilizes an artificial plaque-covered
pressure-sensitive substrate to evaluate the ability of toothbrush bristles to
penetrate
below simulated gingival tissues around posterior tooth shapes and to remove
artificial plaque under wet brushing conditions. The maximum depth of the
plaque
deposit removed is defined as subgingival access efficacy (SAE).
The purpose of these studies was to evaluate the Test Toothbrush and
toothbrushes A and B for Gingival Margin Cleaning and Subgingival Access
Efficacy.
Methods and Materials.
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The products tested in this assay were the Test toothbrush, and toothbrushes A
and B as identified above. Six products from each group were tested four times
in
each individual assay for a total of 24 evaluations. The laboratory equipment
was
fabricated to the design of Nygaard-Ostby, Edvardsen and Spydevold. Simulated
gingivae were prepared from self-curing dental acrylic. The marginal anatomy
was
developed using dental textbook guidelines. The space between the acrylic
gingivae
and the tooth shapes was 0.2mm. -The brushing technique was a horizontal
brushing
motion, simulated posterior teeth and an applied brushing weight of 500 g.
Gingival Margin Cleaning.
The tooth brushing technique involved independent evaluations of each
toothbrush in a horizontal brushing motion, tooth shapes simulating posterior
teeth
and a brushing weight of 500g. The toothbrush to be tested was aligned with
the
papillae of the gingival margin and the brushing apparatus was set to brush
for 60
seconds at two strokes per second with a 15mm stroke. For cleaning at the
gingival
margin (GMC), the length of the artificial plaque deposit removed was recorded
at the
junction of the simulated gingivae and pressure-sensitive paper. Readings were
measured in mm with 3x magnification by one investigator. The data were
analyzed
using t-tests for statistical significance between the three groups, assuming
unequal
variances.
Subgingival Access.
Each toothbrush to be tested was aligned with the papillae of the gingival
margin, and the brushing apparatus was set to brush for 30 seconds at two
strokes per
second with a 15 mm stroke length. The maximum depth of the plaque deposit
removed (SAE) was recorded on an artificial plaque-covered substrate placed
under
the simulated gingivae and around the posterior-shaped teeth. Readings were
measured in millimeter units with 3x magnification by one investigator.
Descriptive
statistics (mean and standard deviation) were calculated for the toothbrushes
tested.
A comparison of mean SAE was conducted using two-sample t-tests assuming
unequal variances.
Results
The Test toothbrush was found to be statistically superior (p < 0.00 1)
compared to Toothbrushes A and B in GMC and SAE as shown in Tables 4 and 5
below.
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Table 4
Gingival Margin Cleaning (GMC)
Toothbrush Mean (standard deviation)
Test Toothbrush 9.6 (l.l)
Toothbrush A 4.5 (3.1)
Toothbrush B 1.4 (1.6)
Table 5
Subgingival Access Efficacy (SAE)
Toothbrush Mean (standard deviation)
Test Toothbrush 3.7 (0.5)
Toothbrush A 0.9 (0.5)
Toothbrush B 0.5 (1.4)
Conclusions.
These llaboratory studies were conducted to evaluate cleaning efficacy at the
gingival margin (GMC) and the depth of artificial plaque removal between a
toothbrush of this invention, and three toothbrush products. In these
laboratory
studies, the Dr Best ZwischenzahnTM toothbrush was found to be significantly
(p<0.001) more effective for the gingival margin cleaning and subgingival
access
efficacy area compared to Toothbrushes A and B.
Referring to Figs. 4, 5 and 6 another toothbrush head 20 overall is shown,
having a bristle surface 21 from which tufts 22 (generally) extend in a
bristle direction
"B". The head 20 is integrally extended longitudinally as a neck region 23
linking the
head to a grip handle 24. The head 20, neck 23 and handle 24 are made of a
plastics
material with a rubbery grip pad 25. The toothbrush shown in Figs 4, 5 and 6
is a
manual toothbrush.
The tufts 22 are disposed in a pattern comprising a relatively inner cluster
of
plural tufts 26 each of which contains relatively longer bristles which taper
from their
lower end toward their upper end, and plural relatively outer tufts of
relatively shorter
bristles 27. The tufts 26 consist entirely of relatively longer bristles which
taper. The
plural relatively outer tufts 27 are disposed as an outer perimeter ring of
tufts around
all sides of the relatively inner tufts 26. The plural relatively outer tufts
27 consist
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entirely of tufts which consist of bristles which are of uniform cross section
along
their lower-upper length.
The shorter outer tufts 27 are ca. 10 mm long, and the longer inner tufts 26
are
ca. 13mm long. The bristle filaments of the tufts 26, 27 are made of the
polyamide
material Nylon, typically that sold under the name TynexTM, and are typically
0.1 -
0.25 mm in diameter.
The longer tapered bristle filaments 26 are single ended tapered filaments.
Fig. 5 shows a toothbrush head in which at the end of the tuft pattern
furthest
from the toothbrush handle 24, being the "tip end" the upper ends of the outer
tufts 28
lie in a plane, that increases in its distance from the bristle surface 21
with
longitudinal distance away from the handle 24. These tufts 28 are disposed in
a
polygon of the outer tufts 28.
13
