Note: Descriptions are shown in the official language in which they were submitted.
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TOOTHBRUSH
Technical Field
[0001] The present invention relates to a toothbrush.
Background Art
[0002] Conventionally, a toothbrush has been proposed in which soft
bristles, such as polyester thermoplastic elastomer, are tufted in outer
portion in the width direction of a toothbrush head of the toothbrush and
hard bristles, such as nylon, are tufted in an inner portion in the width
direction of a toothbrush head of the toothbrush and which provides a
massaging effect to the gum by the outer soft bristles at the outer portion,
while maintaining a cleaning effect by the hard bristles at the inner portion
mainly in the case of horizontal brushing method (rolling-stroke method)
(e.g., Patent Document 1: Japanese Examined Utility Model Publication No.
6-12647 and Patent Document 2: Japanese Unexamined Patent Application
Publication (Translation of PCT Application) No. 2002-514946).
[0003] There are various brushing methods, such as a scrubbing
method and a Bass method, in addition to the rolling-stroke method. Thus,
it is necessary to employ the various methods while combining the
advantages of each method. In particular, the Bass method refers to a
method of finely vibrating a toothbrush while tilting the toothbrush by 45
angle to the gum line, and is a cleaning method having a relatively high
cleaning effect in the dental grooves where a dental plaque is easily
accumulated. However, when the above-described toothbrush is applied,
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the hard bristles at the inner portion damage the gum. Thus, the
above-described toothbrush cannot be used for persons with weak gum.
[0004] Moreover, although the above-described toothbrush can
massage the gum by the soft bristles at the outer portions when horizontally
brushed, such soft bristles are spread out in a short period of time in the
course of using, giving a problem with durability.
Disclosure of the Invention
Technical Problems to be Solved
[0005] In view of the above-described circumstances, the present
invention aims to provide a toothbrush which gives a high massaging effect
to persons with weak gum while reducing the stimulus and not damaging the
gum in various kinds of brushing methods, especially in the Bass method
and which is excellent also in durability
Means to Solve the Problems
[0006] The present invention is a toothbrush in which bristles are
tufted in a toothbrush head so as to solve the above-described problems.
The toothbrush is structured such that thermoplastic elastomer bristles
made of a polyester elastomer or a polyamide elastomer are tufted in the
inner portion in the width direction of a toothbrush head and bristles made
of synthetic resin harder than the thermoplastic elastomer bristles are tufted
in the outer portions in the width direction of a toothbrush head.
[0007] Here, it is preferable that the diameter of the thermoplastic
elastomer bristles be 0.1 mm to 0.4 mm. The number of bristle tufting rows
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(row of tufts) is not limited, and is preferably 3 to 5 rows, and particularly
preferably 3 rows. Among the above, in the case of thermoplastic elastomer
bristles, the number of bristle tufting rows is preferably 1 to 3 rows.
[0008] Moreover, it is preferable that synthetic resin bristles harder
than the thermoplastic elastomer bristles be tufted in the tip portion and the
base end portion in the longitudinal direction in the inner portion in the
width direction of a toothbrush head.
[0009] In particular, it is a preferable that, among tuft holes of a
toothbrush head, a tuft made of the thermoplastic elastomer bristles is
tufted in each tuft holes except tuft holes at the tip and the base end near
the
neck of handle in the longitudinal direction in a single inner row or a
plurality of inner rows, and a bristle made of the synthetic resin bristles is
tufted in the tuft holes at the tip and the base end of the inner row(s) and
in
each tuft hole in both outer rows.
[0010] Moreover, it is preferable that the synthetic resin bristle be
made of a polyester resin in which one or two or more members selected from
polyethylene terephthalate, polytrimethylene terephthalate, and
polybutylene terephthalate have been melt-mixed, or a polyamide resin, or
be a sheath-core type composite filament formed of a core filament made of a
polyamide resin and a sheath portion made of a polyester resin.
[0011] Moreover, it is preferable that the bristle length of each
bristle tufted in a toothbrush head becomes successively or stepwise shorter
from the inner portion to the outer portion in the width direction.
[0012] In particular, as viewed in a cross section, the angle of
inclination of a straight line, which passes through the tip of the bristles
at
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the central portion and the tip of the bristle at the outermost sides,
relative
to a tufting surface is preferably 5 to 400 angle, and most preferably 10 to
30
angle. Moreover, the bristle length of the bristles at the outermost side is
shorter than the bristle length of the bristles at the central portion by
preferably 0.5 to 2.5 mm, and more preferably 1.0 to 2.0 mm.
[0013] Specifically, it is preferable that the line passing through the
tip of each bristle substantially linearly incline from the central portion to
the outer portion in the width direction and the bristle length of each
bristle
become successively shorter from the central portion to the outer portion.
[0014] Moreover, according to another preferable example, the
bristles of the tufts tufted in each tuft hole have the same bristle length;
the
bristle length of the bristles of the tufts at the outer portions are shorter
than the length of the bristles of the tufts at the inner portion in the width
direction of a toothbrush head; and the length of each bristle becomes
stepwise shorter from the central portion to the outer portion.
[0015] The thermoplastic elastomer bristles are preferably made of
thermoplastic elastomer having a hardness of 30D to 100D.
Effects of the Invention
[0016] According to the toothbrush structured as described above of
the present invention in this application, the above-described thermoplastic
elastomer bristles are tufted in the inner portion in the width direction of a
toothbrush head which contacts sensitive portions of the gum or the
interproximal portions in the Bass method, and thus the gum or the
interproximal portions are hard to damage and massaging effect of the gum
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is provided. Moreover, since synthetic resin bristles harder than an
elastomer are tufted in the outer portion which contacts the tooth surface in
the Bass method, cleaning effect of the tooth surface, the interproximal
portions, and the gum can be improved; and the elastomer bristles at the
inner portion are supported by the synthetic resin bristles at the outer
portion to thereby prevent the elastomer bristles from spreading out,
accordingly resulting in increased durability and the improvement in the
cleaning effect by the elastomer bristles.
[0017] Moreover, since the diameter of the thermoplastic elastomer
bristle is set to 0.1 mm to 0.4 mm, narrow part cleaning effect with the
elastomer bristles for boundaries between the teeth and the gum and
interproximal gaps can be improved.
[0018] Moreover, since synthetic resin bristles harder than the
thermoplastic elastomer bristles are tufted in the tip hole and the hole
nearest to the neck of handle in the central row and the outer rows, the soft
elastomer bristles can be supported by the hard synthetic resin bristles from
the longitudinal direction and the width direction, i.e., all directions, to
thereby prevent the soft elastomer bristles from spreading out, resulting in
that the cleaning effect by the elastomer bristles and the durability can be
further improved.
[0019] Moreover, since the bristle length of each bristle tufted in a
toothbrush head becomes successively or stepwise shorter from the inner
portion to the outer portion in the width direction, the synthetic resin
bristles at the outer row opposite to the side contacting the tooth surface
can
be avoided from contacting the gum at the time of cleaning by the Bass
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method; a sufficient massaging effect and narrow part cleaning effect can be
obtained by the long elastomer bristles; and sufficient cleaning effect can be
maintained by the synthetic resin bristles at the side contacting the tooth
surface. Moreover, since the synthetic resin bristles at the outer rows are
short as described above, the contact between the synthetic resin bristles and
the gum is reduced at the time when horizontally brushed to thereby prevent
damaging the gum.
[0020] Since the thermoplastic elastomer bristles are made of a
thermoplastic elastomer having a hardness of 30D to 100D, outstanding
cleaning effect can also be obtained simultaneously with that the stimulus to
the gum is suppressed to thereby achieve a favorable massaging effect.
Brief Description of the Drawings
[0021]
Fig. 1 is a perspective view illustrating an essential part of a
toothbrush according to a first embodiment of the present invention.
Fig. 2 is a side view illustrating the same part as in Fig. 1 as viewed
from the tip side in the longitudinal direction.
Fig. 3 is a plan view illustrating the same part as in Fig. 1.
Fig. 4 is an explanatory view illustrating the usage manner of the
toothbrush according to the first embodiment of the present invention by
Bass method.
Figs. 5(a) and (b) are explanatory views illustrating modified
examples in the first embodiment, respectively.
Figs. 6(a) and (b) are explanatory drawings illustrating other
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modified examples.
Fig. 7 is a perspective view illustrating an essential part of a
toothbrush according to a second embodiment of the present invention.
Fig. 8 is a side view illustrating the same part as in Fig. 7 as viewed
from the tip side in the longitudinal direction.
Fig. 9 is a plan view illustrating the same part as in Fig. 7.
Fig. 10 is an explanatory view illustrating the usage manner of the
toothbrush according to the second embodiment of the present invention by
Bass method.
Figs. 11(a) and (b) are explanatory views illustrating an essential
part of a synthetic resin bristle in the second embodiment.
Figs. 12(a) and (b) are explanatory views illustrating modified
examples of the synthetic resin bristle in the second embodiment.
Figs. 13(a) to (e) are explanatory views illustrating other modified
examples of the synthetic resin bristle in the second embodiment.
Figs. 14(a) and (b) are explanatory views illustrating still other
modified examples of the synthetic resin bristle in the second embodiment.
Description of Reference Numerals
[0022]
1. Toothbrush
2. Toothbrush body
3. Brush part
4. Bristle
5. Tuft
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20. Toothbrush head
20a. Tuft hole
21. Neck of handle
41. Thermoplastic elastomer bristle
42. Synthetic resin bristle
60. Sheath portion
61. Core filament
63. Unit cross sectional element
0. Angle of inclination
hl, h2. Bristle-length difference
R1, R2, R3, R10, R11. Portion
Best Mode for Carrying Out the Invention
[0023] Hereinafter, embodiments of the present invention will be
described in detail with reference to the attached drawings.
[0024]
Fig. 1 is an explanatory view illustrating a structure of the
toothbrush according to the present invention. Figs. 1 to 6 illustrate a first
embodiment, and Figs. 7 to 14 illustrate a second embodiment. In Figs. 1 to
14, the reference numerals 1, 2, and 3 denote a toothbrush, a toothbrush
body, and a brush part, respectively.
[0025]
A feature of a toothbrush 1 according to the present invention resides
in that bristles 4 are tufted in a toothbrush head 20 as illustrated in Fig. 1
in
which thermoplastic elastomer bristles 41, ... are tufted in an inner portion
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R1 in the width direction of a toothbrush head 20 and synthetic resin bristles
42,... harder than the thermoplastic elastomer bristles are tufted in outer
portions R2 and R3 in the width direction of a toothbrush head 20.
[0026] First, the first embodiment of the present invention will be
described with reference to Figs. 1 to 6.
[0027] As illustrated in Fig. 1, the toothbrush 1 of this embodiment
is equipped with a toothbrush body 2 made of a synthetic resin and a brush
part 3 provided on a toothbrush head 20 of the toothbrush body 2. The
toothbrush body 2 is composed of a toothbrush head 20, a neck of handle 21,
and a handle (not shown) which have been integrally molded by injection
molding of a synthetic resin, such as polypropylene, for example.
[0028] As illustrated also in Fig. 2, the brush part 3 provided on a
toothbrush head 20 is obtained by two-folding a tuft 5 obtained by bundling a
plurality of bristles 4, ... into a U shape; inserting and fixing (driving)
the
tuft 5 in each tuft hole 20a of a toothbrush head 20 with an anchor wire (also
referred to as a metal wire material, a wire staple, etc.); and then trimming
the tip of each tuft 5 to the equal length.
[0029] In addition to the method using an anchor wire as described
above, employable as a method of fixing the bristles 4 to a toothbrush head
20 are the same bristle tufting methods as conventional bristle tufting
methods, such as an in-mold method which involves heat sealing the base
part of the tuft in which bristles are similarly bundled to form a fusion
lump,
placing the base part in a molding cavity at the time of shaping of a
toothbrush body, and fixing the bristles to the toothbrush head by integral
molding, and a fuse in method.
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[0030] In this example, three tuft rows are provided along the
longitudinal direction of a toothbrush head 20 in which one central row is a
tuft row of thermoplastic elastomer bristles 41, ... and each outer row
parallel thereto is a tuft row of the synthetic resin bristles 42,... harder
than
the thermoplastic elastomer bristles. It should be noted that it is a matter
of course that the number of tuft rows, the number of the tufts forming each
row, and the arrangement relationship are not limited at all in the present
invention.
[0031] Specifically, the thermoplastic elastomer bristles 41 are made
of thermoplastic elastomer having a hardness of 30D to 100 D, such as a
polyester elastomer or a polyamide elastomer, and the diameter is set to 0.1
mm to 0.4 mm. When the diameter is smaller than 0.1 mm, a sufficient
durability cannot be obtained. In contrast, when the diameter is larger
than 0.4 mm, the cleaning effect of gaps decrease. More preferably, the
diameter is set to 0.15 to 0.25 mm. Moreover, when the hardness is lower
than 30D, the cleaning effect cannot be obtained. In contrast, when the
hardness is higher than 100D, the stimulus to the gum is too strong.
Preferably, the hardness is set to 55 to 80D.
[0032] The thermoplastic elastomer is engineering plastic having
rubber elasticity. Usable as the thermoplastic elastomer are polyester
elastomers, such as 'Hytrel"TM (manufactured by Du Pont-Toray Co., Ltd.),
"Arnitel"Tm (manufactured by Akzo), !GaflexTM (manufactured by GAF), and
"Pelprene"TM (manufactured by Toyobo Co., Ltd.) and polyamide elastomers,
such as, GrilaxTM (manufactured by DIC Corporation) and "Pebax"Tm
(manufactured by Atochem).
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[0033] The synthetic resin bristles 42 are harder than the
thermoplastic elastomer bristles 41. Usable as a material thereof are
synthetic resins known as bristles of a toothbrush, such as: a polyamide
resin,
such as nylon or aramid; a polyester resin in which one or two or more
members selected from polybutylene terephthalate, polypropylene
terephthalate (polytrimethylene terephthalate), and polyethylene
terephthalate have been melt-mixed; and a polyolefin resin, such as
polypropylene and polyethylene.
[0034] In particular, a synthetic resin made of nylon or a polyester
resin in which one or two or more members selected from polyethylene
terephthalate, polytrimethylene terephthalate, and polybutylene
terephthalate have been melt-mixed is preferable from the viewpoint that
excellent cleaning effect can be obtained.
[0035] As illustrated in Fig. 2, each tuft 5 tufted in a toothbrush
head 20 is trimmed in such a manner that the bristle length of the bristles 4
becomes successively shorter from the inner portion to the outer portion in
the width direction. More specifically, the tufts of thermoplastic elastomer
bristles 41 at the central row are trimmed in such a manner that the length
of the bristles at the central portion is the highest and the length thereof
becomes gradually shorter towards both outer portions and the synthetic
resin bristles 42 at the outer rows are trimmed in such a manner that the
length thereof becomes gradually shorter from the inner portion to the outer
portion.
[00361 In this example, the line passing through the tip of each
bristle is trimmed in such a manner as to substantially linearly incline from
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the central portion to the outer portion in the width direction. The angle of
inclination 0 to the head surface is set to 5 to 400 angle. The bristle length
difference h1 between the bristles (thermoplastic elastomer bristles 41) at
the central portion and the bristles (synthetic resin bristles 42) at the
outermost side is set to 0.5 to 2.5 mm.
[0037] Thus, by reducing the length of bristles at the outer portions,
the following effects can be achieved in Bass method of finely vibrating a
toothbrush in the vertical direction while tilting the toothbrush to the gum
by 45 angle as illustrated in Fig. 4: a sufficient massaging effect and
narrow
part cleaning effect can be obtained by the long elastomer bristles 41;
sufficient cleaning effect can be maintained by the synthetic resin bristles
at
a side contacting the tooth surface; and the synthetic resin bristles at a
lower
part can be avoided from contacting the gum to damage the gum. When the
bristle length difference h1 is smaller than 0.5 mm, the feeling that the
toothbrush contacts the teeth and the gum is almost the same with a feeling
that the bristles having the same length (straight line) contact the teeth and
the gum, and thus the length difference is hard to recognize; the massaging
effect by the elastomer bristles cannot fully be obtained; a possibility that
the
synthetic resin bristles at a lower part contact the gum during cleaning
becomes high. In contrast, when the bristle length difference hl is larger
than 2.5 mm, the elastomer bristles become excessively long, and thus the
tip thereof are not sufficiently supported by the synthetic resin bristles,
resulting in that the massaging effect and narrow part cleaning effect
decrease, and also cleaning effect decrease because the synthetic resin
bristles at an upper part do not sufficiently contact the tooth surface. More
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specifically, only the central portion contacts the brushing target, and thus
cleaning effect to the tooth surface cannot be expected.
[0038] It should be noted that similarly preferable are a toothbrush
in which the bristles are trimmed in such a manner as to incline in a
substantially curved shape as illustrated in Fig. 5(a) and a toothbrush in
which only the synthetic resin bristles 42 at the outer rows are similarly
trimmed while inclining in such a manner that the synthetic resin bristles 42
at the outer rows are shorter than the thermoplastic elastomer bristles 41 at
the central row and the outer portions of the outer rows are shorter and that
the tip of the tuft of the thermoplastic elastomer bristles 41 at the central
row are horizontally trimmed as illustrated in Fig. 5(b). Also in this case,
the angle of inclination 0 of a straight line, which passes through the tip of
the bristles at the central portion and the tip of the tuft at the outermost
side,
relative to a tufting surface as viewed in a cross section is preferably
adjusted to 5 to 40 angle.
[0039] Moreover, a toothbrush is also preferable in which, in the
inner portion R1 in the width direction of a toothbrush head, the synthetic
resin bristles 42 harder than the thermoplastic elastomer bristles 41 are
tufted in a portion R10 at the tip in the longitudinal direction and a portion
R11 at the base end in the longitudinal direction as illustrated in Fig. 6(a).
In the illustrated examples, the tuft made of the synthetic resin bristles is
tufted in each tuft hole at the tip and the base end in the longitudinal
direction of the central row and each tuft hole forming both the outer rows
sandwiching the central row. Thus, the thermoplastic elastomer bristles
41,... are surrounded by the hard synthetic resin bristles 42 from all
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directions in the width direction and the longitudinal direction, resulting in
that the cleaning effect by the elastomer bristles 41 and the durability
further increase.
[0040] In this case, the synthetic resin bristles 42 in the portions
R10 and R11 may be the same in the bristle length as the thermoplastic
elastomer bristles 41. However, as illustrated in Fig. 6(b), it is preferable
that the synthetic resin bristles 42 in the portions R10 and R11 be trimmed
while inclining in such a manner that the tip of the tufts of the synthetic
resin bristles 42 in the portions R10 and R11 are shorter than the
thermoplastic elastomer bristles 41 and the outer portions, i.e., the tip and
the base end in the longitudinal direction of the central row, are shorter
than
the central portion similarly as in the synthetic resin bristles 42 at the
outer
portions R2 and R3, to thereby avoid the synthetic resin bristles 42 from
contacting the gum.
[0041] The tip of each tuft 5 is trimmed in such a manner as to
incline in the width direction, and may be trimmed in such a manner as to
form an uneven surface also in the longitudinal direction. Moreover, when
the tip of the thermoplastic elastomer bristle 41 or the synthetic resin
bristle
42 is processed into a tapered shape, the insertion properties to a narrow
part are improved.
[0042] Next, the second embodiment of the present invention will be
described with reference to Figs. 7 to 14.
[0043] In the toothbrush 1A of this embodiment, similarly as in the
above-described first embodiment, three tuft rows are provided along the
longitudinal direction of a toothbrush head 20 in which one central row is a
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tuft row of thermoplastic elastomer bristles 41, ... and each outer row
parallel thereto is a tuft row of the synthetic resin bristles 42, ... harder
than
the thermoplastic elastomer bristles, respectively.
[0044] As illustrated in Figs. 7 and 8, each tuft 5 is tufted in such a
manner that the tip of each tuft 5 becomes substantially horizontal or the tip
of each tuft 5 is substantially horizontally trimmed after tufting. The
trimming is performed in such a manner that the bristle length of the
bristles 4 becomes successively shorter from the inner portion to the outer
portion in the width direction (one level difference in this embodiment).
More specifically, the bristle length of the synthetic resin bristles 42
forming
the tufts at the outer rows is shorter than the bristle length of the
thermoplastic elastomer bristles 41 forming the tufts at the central row.
The bristle length difference h2 is set to 0.5 to 2.5 mm, and the angle of
inclination 0 of a straight line, which passes through the tip of the bristles
at
the central portion and the tip of the bristle at the outermost side, relative
to
a tufting surface as viewed in a cross section is set to 5 to 40 angle.
[0045] Thus, similarly as in the case of the first embodiment
described above, in the Bass method of finely vibrating a toothbrush in the
vertical direction while tilting the toothbrush to the gum by 45 angle as
illustrated in Fig. 10, a sufficient massaging effect and narrow part cleaning
effect can be obtained by the long elastomer bristles 41; sufficient cleaning
effect can be maintained by the synthetic resin bristles at a side contacting
the tooth surface; and the synthetic resin bristles at a lower part can be
avoided from contacting the gum to damage the gum.
[0046] In this example, with respect to especially the synthetic resin
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bristles 42 forming the tufts at the outer rows, the cross section is formed
of a
filament made of a synthetic resin having a sheath-core type composite and
three core filaments 61 are projected from the tip of a sheath portion 60 as
illustrated in Fig. 11. Such a synthetic resin can be produced by dissolving
the sheath portion 60 from the tip to thereby expose a core filament 61,
which is achieved by forming the core filament 61 using a material
containing a polyamide resin, such as nylon, as a main component; forming
the sheath portion 60 using a composite synthetic resin monofilament made
of a material containing a polyester resin, such as polybutylene
terephthalate, as a main component; immersing the above in a chemical
solution, such as caustic soda. In the case of such a synthetic resin bristle,
the dental plaque removing effect and cleaning effect in narrow parts, such
as the interproximal portions and the boundaries between the teeth and the
gum, are improved.
[0047] In the example shown in Fig. 11, three core filaments are
projected. The number of projected core filaments may be 1 (as illustrated
in Fig. 12), 2, or 4 or more. Moreover, the tapered shape at the tip of the
sheath portion 60 or the exposure length of the core filament 61 can be
suitably adjusted by the concentration of the chemical solution, immersion
time, speed of pulling the resultant from the chemical solution, etc. The
tapered shape at the tip of the sheath portion increases insertion properties
and accessibility into narrow parts in the mouth. The tip shape of the core
filament 61 is suitably determined, and can be processed into proper shapes,
such as the shape of a hemisphere.
[0048] In addition to the sheath-core type composite, by immersing,
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in a solution, such as alkali or acid, the tip of a filament made of a
synthetic
resin having a cross sectional shape in which a plurality of unit cross
sectional elements 63a are connected as illustrated in Figs. 13(a) and 13(b),
a
tapered bristle in which tapered branch bristles in the number according to
the number of the connected unit cross sectional elements are formed on the
tip of the bristle can be formed as a tapered bristle used as the synthetic
resin bristle 42. The shape and the length of the branch bristles can be
suitably adjusted by the concentration of a chemical solution, immersion
time, speed of pulling up the resultant from the chemical solution, etc.
[0049] Similarly, Fig. 13(c) illustrates a tapered bristle formed of two
unit cross sectional elements; Fig. 13(d) illustrates a tapered bristle formed
of three unit cross sectional elements which are arranged in one row; and Fig.
13(e) illustrates a tapered bristle formed of four unit cross sectional
elements.
Similarly, a tapered bristle in which a tapered branch bristle(s) is(are)
formed on the tip of the bristles can be formed. Moreover, as illustrated in
Fig. 14, a core filament is formed in the central part of each unit cross
sectional element, and each branch bristle can be formed into the same
sheath-core type composite as the above.
[0050] By mounting the toothbrush described in each embodiment
described above to a toothbrush body having a shortened handle and a
driving unit, the toothbrush can also be applied to a brush of an electric
toothbrush which vibrates the brush part 3.
Examples
[0051] Hereinafter, each embodiment of the present invention was
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subjected to a cleaning effect test, a durability test, and a sensory test,
such
as feeling of use, and the test results will be described.
[0052] Toothbrushes of Examples 1 to 6 and Comparative Examples
1 to 5 are as shown in Table 1. Each toothbrush is formed of three tuft rows
(the central row and both outer portion rows). An "elastomer filament" is a
bristle having a diameter of 0.2 mm made of a thermoplastic polyester
elastomer ("Hytrel", manufactured by Du Pont-Toray). A "polyester bristle"
is a bristle having a diameter of 0.15 mm made of a melt-mixture of
polytrimethylene terephthalate and polybutylene terephthalate. A
"sheath-core" is a bristle having a diameter of 0.19 mm formed of a core
filament made of nylon and a sheath portion made of polybutylene
terephthalate in which three core filaments are projected from the tip. A
"roof shape" is a shape in which the tip of the bristles are trimmed in such a
manner as to substantially linearly incline from the central portion to the
outer portion in the width direction; the angle of inclination is set to 25
angle; and the bristle length difference of the bristles between the central
portion and the outer end is set to 1.5 mm. A "(high inclination)" refers to a
state where the angle of inclination is set to 40 angle and the bristle
length
difference between the bristles at central portion and the bristles at the
outer portion is set to 2.5 mm. A "convex shape" refers to a state where the
bristle length of bristles at outer rows is further shortened as compared with
the bristle length of bristles at the central row; the bristle length
difference
(level difference) is set to 1.0 mm; and the angle of inclination of a
straight
line, which passes through the tip of the bristles at the central portion and
the tip of the bristle at the outermost side, relative to a tufting surface is
set
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to 25 angle. A "(large level difference)" refers to a state where the bristle
length difference is set to 2.5 mm, and the angle of inclination of a straight
line, which passes through the tip of the bristles at the central portion and
the tip of the bristle at the outermost side, relative to a tufting surface is
set
to 40 angle.
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[0053] [Table 1]
Central row Outer row Shape
of trimmed bristles
Examplel Elastomer bristles Polyester bristles Roof shape
Example2 Elastomer bristles Sheath-core filaments Convex
shape
Roof shape
Example3 Elastomer bristles Polyester bristles
(high inclination)
Convex shape
Example4 Elastomer bristles Sheath-core filaments
(large level difference)
Example5 Elastomer bristles Polyester bristles Straight
shape
Example6 Elastomer bristles Sheath-core filaments Straight
shape
Comparative
Polyester bristles Elastomer bristles Straight
shape
Examplel
Comparative
Elastomer bristles Elastomer bristles Straight
shape
Example2
Comparative
Polyester bristles Polyester bristles Roof shape
Example3
Comparative Roof shape
Polyester bristles Polyester bristles
Example4 (high inclination)
Comparative
Polyester bristles Polyester bristles Straight
shape
Example5
[0054] (Cleaning effect test)
An artificial plaque is adhered to an upper second premolar of a jaw
model, and the jaw model is attached to a brushing simulation machine.
Each toothbrush of Examples and Comparative Examples is placed in such a
manner that one end of a bristle tufting part contacts the upper second
premolar and a bristle tufting part covers the second premolars. Brushing
is performed for 3 seconds while setting a stroke in the transverse direction
to 20 mm and applying a load of 150 g. The area of the artificial plaque is
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measured and calculated in each part with an image analyzer. Then, a ratio
of the area where the artificial plaque is removed to the area where the
artificial plaque was adhered was defined as a plaque removal ratio. The
results are shown in Table 2.
[0055]
(Plaque removal ratio (%))
C); 90% or more,
0; 70 to lower than 90%,
50 to lower than 70%
x; Lower than 50%
[0056] [Table 21
Tooth surface portion Cervical margin
Plaque Plaque
Standard Standard
removal Evaluation removal
Evaluation
deviation deviation
ratio (%) ratio (%)
Examplel 99.34 0.48 @ 94.02 0.25 @
Example2 99.09 0.47 @ 91.62 1.57
Example3 67.65 0.95 A 90.45 1.56 @
Example4 71.03 3.57 0 94.39 0.57
Example5 93.69 0.27 @ 92.57 0.89 CD
Example6 94.67 1.28 92.37 0.89 @
Comparative
81.46 1.68 0 85.21 4.10 0
Examplel
Comparative
81.06 5.01 0 83.82 1.11 0
Example2
Comparative
96.27 0.43 @ 95.99 1.16 @
Example3
Comparative
96.92 0.33 @ 95.65 0.12 @
Example4
Comparative
92.68 2.30 @ 95.31 0.64 @
Example5
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[0057] Table 2 shows that Examples 1, 2, 5, and 6 (a roof shape and a
convex shape) have a cleaning ability (average) and a cleaning stability
(error) to the tooth surface portion which are equivalent to or more excellent
than the conventional polyester bristles (Comparative Examples 3 to 5) and
excellent cleaning effect both to the tooth surface portion and the cervical
margin in comparison with Comparative Examples 1 and 2 each having a
massaging effect.
In Examples 3 and 4, the cleaning effect of the tooth surface portion
decrease. This shows that when the bristle length difference (inclination
and level difference) is excessively large, the synthetic resin bristles at
the
outer portion cannot sufficiently contact the tooth surface.
[0058] (Durability test)
When the toothbrush was immersed in a warm water at 37 C and
reciprocated by 10,000 times while applying a load of 300 g, (A) the width of
the bristle tufting part in the minor axis direction of the toothbrush of an
initial state (width at the tip of the tufted bristles) and (B) the width of
the
bristle tufting part in the minor axis direction of the toothbrush in a state
where the bristles are spread out after the toothbrush was reciprocated by
10,000 times were measured. Then, the durability was evaluated according
to the following criteria based on the durability index (where the lower index
indicates that the durability is more excellent) determining the durability
baseline according to the following formula.
Durability index (%) = [(B)/(A)]/100
[0059] (Evaluation criteria)
c): 100 to 150%,
0: 150 to 200%,
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A: 200 to 250%,
x: Higher than 250%
[0060] [Table 3]
Durability
Evaluation
index (%)
Examplel 176 0
Example2 156 0
Example4 165 0
Example6 157 0
Comparative Example2 220 A
Comparative Example3 171 0
Comparative Example4 174 0
Comparative Example5 168 0
[0061] Table 3 shows that Examples 1, 2, 4, and 6 have a difficulty of
spreading out and durability which are equivalent to or higher than those of
conventional polyester bristles (Comparative Examples 2 to 5), although
Examples 1, 2, 4, and 6 use elastomer bristles.
[0062] (Sensory test)
Each toothbrush of Examples 1 to 6 and Comparative Examples 1 to
was subjected to sensory test in terms of the massaging feeling, existence
of a stimulus, feeling of use, and ease of contacting the cervical margin by
10
subjects, and evaluated according to the following criteria.
[0063] (Massaging feeling)
@; Remarkably sensible
0; Sensible
A; Hardly sensible
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x: Not sensible
[0064] (Existence of a stimulus)
(); No stimulus
0; Less stimulus
A; Slight stimulus
x: Strong stimulus
[0065] (Feeling of use and Ease of contacting the cervical margin)
@; Very Good
0; Good
A; Not so good
x: Bad
[0066] [Table 4]
Massaging Existence of a
Ease of contacting
Feeling of use
feeling stimulus
the cervical margin
Examplel @ @ @ @
, Example2 @ @
Example3 0 @ 0 @
Example4 0 0 @
Example5 , 0 @ 0 A
Example6 0 @ 0 A
Comparative
A A A A
Example 1 ,
Comparative
0 @ x A
Example2
Comparative
x x 0 0
Example3
Comparative
x x 0 0
Example4
Comparative
A, A 0 A
_ Example5
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[0067] Table 4 shows that Examples 1 and 2 have excellent brushing
comfortability, feeling of use, and ease of contacting the cervical margin as
compared with Comparative Examples 1 and 2 having a conventional
massaging effect and polyester bristles (Comparative Examples 3-5).
In Examples 3 and 4, brushing comfortability and feeling of use
decrease. This shows that when the bristle length difference (inclination
and level difference) is excessively large, the elastomer bristles of the
central
row is too long, resulting in uncertain feeling similarly as in Comparative
Example 2, and resulting in that sufficient cleaning feeling cannot be
obtained because the synthetic resin bristles at the outer portions do not
securely contact the tooth surface.
It is revealed that, in Examples 5 and 6 having a straight line, the
synthetic resin bristles at the outer portion contact the gum again. Thus,
Examples 5 and 6 are inferior to Examples 1 and 2 in terms of the ease of
contacting gum.
[0068] (Comprehensive evaluation)
Based on each evaluation of the cleaning effect, durability, and
sensory test, points were given and averaged according to the following
criteria, and the comprehensive evaluation was performed according to the
following evaluation criteria.
c); 3 points
0; 2 points
A; 1 point
x: 0 point
[0069] (Comprehensive evaluation criteria)
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@; 2.5 points or more
0; 2.0 to lower than 2.5 points
A; 1.5 to lower than 2.0 points
x: Lower than 1.5
[0070] [Table 51
Ease of
Cleaning effect
Existence
contacting Comprehe
Massaging Feeling of
Tooth Durability of a the
nsive
Cervical feeling use
stimulus cervical
evaluation
surface
margin margin
portion
Examplel @ @ 0 @ @ @ @
@
Example2 @ @ 0 @ @ BC, @
@
Example3 A @ 0 @ 0 @
0
Example4 0 g 0 0 @ 0 @
0
Example5 @ @ 0 @ 0 A
0
Example6 @ @ 0 0 @ 0 A
0
Comparative
0 0 - A A A A
x
Examplel
Comparative
0 0 A 0 @ x A
x
Example2
Comparative
@ @ 0 x x 0
0 A
Example3
Comparative
@ @ 0 x x 0
0 A
Example4
Comparative
@ @ 0 A A 0 A A
Example5
[0071] The scope of the claims should not be limited by particular
embodiments set forth herein, but should be construed in a manner
consistent with the specification as a whole.
