BACKGROUND OF THE INVENTION
1. Field of the Invention
-
The present invention pertains to a toothbrush with
excellent ability to clean, interdental spaces and a
cervical portion of a tooth, and excellent ability to clean
smooth surfaces, such as the tooth surface, etc.
2. Description of the Related Art
-
A toothbrush cleans, that is, brushes, teeth inside
the oral cavity using the resiliency of the monofilaments
of the tufts implanted in the tufting holes of the handle.
Since the cleaning results increase with an increase in
resiliency, there is a demand for a toothbrush with high
resiliency, basically in the direction of brushing.
Moreover, there is also a need for a toothbrush that can
adapt to the state of the site to be cleaned in order to
manifest cleaning activity specific for each individual
site. There are various types of cleaning capabilities in
response to the state of the site to be cleaned, but
typical examples are the ability to clean the tooth
surface, which is a smooth surface, and the ability to
clean the tight spaces of the tooth. The tight spaces
include the interdental spaces and the cervical portion of
the tooth, as well as the occlusal surfaces, etc., and of
these, food residue and plaque easily accumulate in the
interdental space, which is an interproximal site. This
is often a cause of caries and periodontal disease.
Therefore, the ability to clean interdental space is
particularly important. Thus, there is the general problem
of improving the resiliency of a toothbrush, and at the
same time, there is the problem of improving interdental
cleaning activity while retaining smooth surface cleaning
activity, and a toothbrush that can solve these problems is
needed.
-
The toothbrush disclosed by the present applicant with
a publication of unexamined application No. 9-149815 is an
example of that was developed in line with this purpose.
This toothbrush is characterized in that of the tufts
comprising the tufting part, one or more tufts has an
almost elliptic cross section, which spreads out in width
in the direction of handle length, with their end portions
converge in the shape of a roof. There is a major
advantage to this type of tuft in that the extent to which
the filaments aggregate together varies with their
direction and therefore, tuft stiffness changes with the
direction in which the tufts are pressed and thus, it is
possible to improve smooth surface cleaning performance by
making the direction of strong stiffness the same as the
brushing direction, and at the same time, since the end
portions of the tuft converge together, the ability to be
inserted to the tight spaces, such as the interdental
spaces is also excellent.
-
On the other hand, the structure whereby adjacent
fibers are inclined so that they support one another and
the tufts touch at their end portions to make a part where
the tufts converge together is a special technique for
improving insertion of tufts into Interdental space. This
tuft converging part has high density and a strong tuft
stiffness, and the tufts are not loose bundles.
Consequently, there is an advantage in that by designing
the toothbrush so that the direction in which the tufts
support one another corresponds to the brushing direction,
a toothbrush is obtained that has excellent capability of
being inserted into tight spaces, such as interdental space
and a cervical portion of the tooth, and improved
capability of cleaning these places.
-
Attempts are also being made to increase resiliency of
the monofilaments as a different means relating to this
type of tuft concept.
-
General countermeasures for increasing resiliency of
the monofilament are increasing the diameter of
monofilaments with a round cross section or using a harder
material for the monofilament, but improving cleaning
performance by these countermeasures only can hardly be
expected. The reason for this is that when the diameter of
the monofilament is increased or a harder material is used
for the monofilaments, it will feel as if there is too much
irritation of the tissues inside the oral cavity by contact
with the monofilaments, and there are also cases where the
bristle end portions will not reach into the tight spaces
between the teeth when only these measures are taken.
-
Incidentally, when discussing the cleaning power of a
toothbrush, it is necessary to also consider the
relationship with the brushing method. The scrubbing
method whereby the handle is moved back and forth, little
by little, in the lengthwise direction to clean the tooth
has recently become the main brushing method, replacing the
old rolling method whereby the handle is rolled in the
direction of width to clean the tooth. Therefore,
improvement of cleaning power should be considered focusing
on the scrubbing method.
-
There is a demand for a toothbrush with improved
cleaning activity and excellent smooth-surface cleaning
performance and tight-space cleaning performance that is
suitable for brushing by the scrubbing method, but good
appearance and durability as a toothbrush while having
excellent cleaning capability cannot be disregarded. For
instance, it is important that the monofilaments be
uniformly distributed over the tufting holes so that they
give a beautiful raised appearance to the toothbrush, while
the toothbrush must be durable enough that the end portions
of the tufts will not spread out (so-called "permanent set
in fatigue") and the tufting base will not crack or break
during the course of use of the toothbrush.
SUMMARY OF THE INVENTION
-
The toothbrush of the present invention is
characterized in that the tufting holes formed in the
tufting part are almost elliptic or almost rectangular and
these tufting holes are inclined toward the tufting
surface.
-
As in the past, the tufts are fixed in the tufting
holes using an anchor. However, in the present toothbrush,
the tufting holes are almost elliptic or almost rectangular
and are inclined toward the tufting and therefore, the
tufts that have been embedded become tufts with an almost
elliptic or almost rectangular cross section that are
inclined toward the tufting surface.
-
Since the inclination of the tufts is due to the
inclination of the tufting holes themselves, the inclined
state is retained, even after repeated use [of the
toothbrush].
-
In addition, the tufting holes are almost elliptic or
almost rectangular and the number of filaments that are
clustered together to form the tufts differs in the
direction of greater width of the tufts and in the
direction of narrower width of the tufts and therefore,
tuft stiffness is different depending on the direction.
Consequently, by designing the lengthwise direction of the
tufting holes taking the brushing method into
consideration, it is possible to obtain good tuft stiffness
and realize superior cleaning activity. The term tuft
stiffness used here Is the property that is realized from
the extent of resiliency (restitutive force) that comes
into play when pressure is applied and the tuft deforms.
-
Moreover, a converging part with high resiliency is
formed at the end portion in an converging block of tufts
that is formed when the inclined tufts themselves support
one another. This end portion part can be easily inserted
into tight spaces such as interdental space and a cervical
portion of the tooth, etc., and therefore, these spaces can
be firmly brushed by the inserted tufts.
-
When the tufting holes are almost rectangular, the
contact resistance when the tufts first touch the tooth can -
be minimized because the tufts are streamlined.
-
The direction of the tufting holes that are almost
elliptic or almost rectangular is determined in accordance
with the brushing procedure. For example, the lengthwise
direction of the tufting holes is along the direction of
handle length by the scrubbing method or the Bass method
that is mainly back-and-forth movement in the direction of
handle length. The term "along the direction of handle
length" here includes both the state of being parallel to
the direction of handle length and the state of slight
inclination to the direction of handle length.
-
When the lengthwise direction of the tufting holes is
along the direction of handle length, resiliency of the
monofilaments in the brushing direction can be increased
when teeth are being brushed by the scrubbing method.
Consequently, monofilament resiliency can be increased and
as a result, the teeth can be thoroughly polished by this
resiliency and cleaning activity can be improved when the
handle is moved back and forth, little by little, in the
lengthwise direction.
-
In particular, when the tufting holes that are formed
along the direction of handle length are almost elliptic,
both ends of the tuft in the direction of handle length
form a curved, narrow peak and therefore, the monofilaments
can easily penetrate interdental space, improving cleaning
activity even further, when teeth are brushed by the
scrubbing method.
-
It is preferred that the tufting holes be inclined
toward the inside, facing one another, to make tufts that
form pairs and that there be at least one of these tuft
pairs.
-
Inclination toward the vertical direction of the
tufting holes should be set within a range of 2 to 10°.
-
The monofilaments comprising the tufts embedded in the
tufting holes can also have a round cross section, but a
rectangular cross section is preferred. When monofilaments
with a rectangular cross section are used and are embedded
with the lengthwise direction of the cross section of the
monofilament, that is, the long side, being in the
lengthwise direction of the tufting holes, resiliency of
the monofilament when brushing is performed by the
scrubbing method can be further improved. Moreover, the
irritation that is felt in the oral cavity is related to
the cross sectional area of the monofilament. The
irritation can be reduced when the cross sectional area of
the monofilaments is small. When monofilaments with a
round cross section and monofilaments with a rectangular
cross section are compared, the cross sectional area needed
to obtain the same resiliency is smaller with monofilaments
with a rectangular cross section and therefore, irritation
of oral cavity tissues can be reduced with a toothbrush
that uses monofilaments having a rectangular cross section.
-
It is preferred that the tufts that are embedded in
the inclined tufting holes form a pair of converging blocks
where two tufts facing one another lean against one another
and that there be several of these converging blocks.
-
The end portion of each tuft should be worked into a
V-shape in order to improve tight-space cleaning
performance.
-
By making the end portion into a V-shape, tight-space
cleaning performance can be further improved. In
particular, when is a V-shape so that an inclined face is
formed on both sides perpendicular to the direction in
which adjacent tufts support one another, tight-space
cleaning performance in the direction of handle length and
tight-space cleaning performance in the direction of handle
width can be improved. Moreover, the number of filaments
per each tuft that comprises the V-shape is more than
conventional toothbrushes where 1 V-shape is formed from 2
tufts, and tuft resiliency is very strong.
-
The number and arrangement of converging blocks that
form a pair and are made with the tufts supporting one
another can be selected as needed, but it is preferred that
there at least be a converging block at the front end or
the back end in the direction of handle length.
-
It is preferred that the next row of converging
blocks be behind the space that is formed between the
converging blocks in the previous row in the direction of
handle length. When this is the case, areas that were
missed by the converging block in the previous row will be
brushed by the next row of converging blocks and therefore,
a smooth surface, such as a tooth surface, etc., will be
brushed over its entire area by the end portion of a stiff
converging block having excellent brushing power.
-
Tufts are folded in the middle in a lengthwise
direction and then embedded in the tufting holes with an
anchor that is as long as the cross section of this fold,
and the tufts are thereby fixed and supported in the
tufting holes. When the tufts are fixed in the tufting
holes with this type of anchor, the anchor is driven into
the tufting hole so that the opening surface area of the
tufting hole is divided into two equal parts, being almost
parallel to the long or the short side of the tufting hole.
Thus, it is possible to pack filaments into each area
delineated by the anchor uniformly and prevent the tufts
from falling out, which is caused by a packing density that
is too loose, and obtain a beautiful embedded appearance.
-
If the anchor is to be almost parallel to the tufting
holes in their lengthwise direction, the anchor should be
within ± 10° to the center line along the lengthwise
direction of the above-mentioned tufting holes.
-
Incidentally, when the anchors are driven [into
tufting holes] in this position, they will be in almost a
straight line [on the tufting base] and as a result, there
is a strong chance that cracks will be made starting where
the anchor is driven [into the hole]. In order to prevent
this from occurring, the tufting holes can be made so that
the centers of the tufting holes do not form a straight
line in the direction of handle length.
-
The tufting holes should account for 10 to 30 mm in
the direction of handle length and 5 to 15 mm in the
direction of handle width. By specifying how much space on
the handle is occupied by tufting holes, it is possible to
eventually specify the tuft brushing area. If the area
occupied by the tufting holes is within the above-mentioned
range, there will be an increase in the smooth surface,
such as anterior teeth, etc., that can be efficiently
brushed without any reduction in maneuverability inside the
oral cavity.
-
If the tufting holes are almost rectangular holes, the
short side of the tufting holes should be 0.8 to 2.0 mm and
the long side of the tufting holes should be 1.5 to 5.0 mm.
If the dimensions of one tufting hole are within this
range, the size of the end portion of the converging part
that is made when adjacent tufts support one another is
optimal for realizing both smooth-surface cleaning
performance and tight-space cleaning performance.
-
The distance between the base of the pair of tufts
that form a converging block should be within a range of
0.2 to 4.0 mm. By designing the angle of inclination of
the tufts comprising the converging block to within a range
of 2 to 10°, as previously explained, and setting the
distance between the base of the pair of tufts that form
the converging block at 0.2 to 4.0 mm, it is possible to
prevent the converging shape from collapsing, even with
long-term use.
-
Moreover, a toothbrush will be considered as an actual
toothbrush obtained in this way where there are 5 rows of
tufts in the lengthwise direction of the tufting base, with
Rows 1 and 5 forming one converging block in the center in
the direction of width of the tufting base, Rows 2 and 4
forming 2 converging blocks on either side sandwiching the
center in the direction of width of the tufting base, and
Row 3 forming one converging block at the center in the
direction of width of the converging block, and there is 1
independent tuft, each inclined so that it is in the same
direction as the tufts that form the above-mentioned
converging blocks, but its end portion does not touch the
converging blocks, to the outside of the above-mentioned
converging blocks.
BRIEF DESCRIPTION OF THE DRAWINGS
-
Figure 1 is a plane view showing the entire structure
of the toothbrush of the present invention, Figure 2 is an
oblique view showing the tufting part of a typical example
of the present invention, Figure 3 is a plane view of the
same tufting part, Figure 4 is a left view showing the same
tufting part from the front end. Figure 6 is a plane view
showing the shape and arrangement of the tufting holes made
in the tufting base, Figure 7 is the I-I cross section in
Figure 6, Figure 8 is the II-II cross section in Figure 6,
Figure 9 is the III-III cross section in Figure 6, Figure
10 is a IV-IV cross section in Figure 6, Figure 11 is the
V-V cross section in Figure 6, Figure 12 is the anchor
driven into the tufting holes and is a diagram explaining
how the holes into which this anchor is driven are
arranged, Figure 13 is a diagram that shows the anchor
driven Into the tufting holes and describes how the holes
into which this anchor is driven are arranged, Figure 14
is a diagram showing the anchor driven into the tufting
holes in a conventional toothbrush and explains how the
tufting holes into which this anchor have been driven are
arranged, Figure 15 is a diagram representing a V-shaped
tuft end portion, Figure 16 is a different type of V-shape,
Figure 17 is a different type of V-shape, Figure 18 is a
different type of V-shape, Figure 19 is a diagram showing
the rows of teeth, Figure 20 is a diagram explaining how
the tufting part comes into contact with the anterior
surface of the rows of teeth, Figure 21 is a diagram
showing the pattern of brushing the tooth surface and the
cervical portion of the tooth, Figure 22 is a diagram
showing the pattern of brushing a molar, Figure 23 is a
diagram explaining how molar teeth are cleaned in
succession by the tuft rows, Figure 24 shows other types of
tuft rows, Figure 25 is a diagram showing where smooth-surface
cleaning capability and tight-space cleaning
performance are evaluated, Figure 26 is a graph showing the
overall evaluation of smooth- surface cleaning performance
and interproximal-surface cleaning performance, Figure 27
is a graph showing evaluation of interproximal cleaning
capability, Figure 28 is a graph showing evaluation of
smooth-surface cleaning performance, Figure 30 is a cross
section of the tufting part in a second example where
monofilaments with a rectangular cross section have been
implanted in tufting holes that are almost elliptic, Figure
31 is a plane view of the tufting part when the number of
tufting holes and their arrangement was changed in the same
example, Figure 32 is a diagram showing rectangular
tufting holes in which monofilaments with a round cross
section have been implanted, Figure 33 is a diagram showing
elliptic tufting holes in which monofilaments with a
rectangular cross section have been implanted, Figure 34 is
a diagram showing oval-shaped tufting holes in which
monofilaments with a rectangular cross section have been
implanted, Figure 35 is a diagram showing the flow of
molten synthetic resin when rectangular tufting holes are
molded, and Figure 36 is a diagram showing the flow of
molten synthetic resin when elliptic tufting holes are
molded.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
-
The present invention will now be explained with
examples that illustrate its details. Unless otherwise
indicated, lengthwise direction in the following
description means the direction of handle length and
direction of width means the direction of handle width.
The direction of handle length is the same as the direction
of tufting base length and the direction of handle width is
the same as the direction of tufting base width.
-
Figure 1 shows the handle before the tufts have been
implanted. The toothbrush of the present invention is
characterized by the state of the tufting part shown by A
in the figure, and neck B and grip C can have any shape.
The structure of tufting part A is explained below.
-
The toothbrush of the present invention is
characterized in that the openings for the tufting holes
formed in the tufting part are almost elliptic or almost
rectangular and the holes are inclined toward the tufting
surface. What is important here is that the tufting holes
are almost elliptic or almost rectangular and as a result,
there is a difference in resiliency during brushing in the
direction of length and the direction of width of the
tufting holes and strong resiliency is obtained in the
direction of length of the tufting holes. Furthermore, in
addition to this, the tufting holes are inclined and the
end portions of the tufts that have been implanted in these
tufting holes converge in the direction of inclination,
improving the capability to clean tight spaces (referred to
below as tight-space cleaning capability).
-
The tufts implanted in the tufting holes are made from
bundles of monofilaments. There are no restrictions to the
cross section of the monofilaments. Monofilaments with a
round cross section that are normally used can be employed,
or the monofilaments with a rectangular cross section that
are described later can be employed. If monofilaments with
a rectangular cross section are used, resiliency of the
monofilament in the lengthwise direction of their cross
section will be increased. Moreover, since the cross
sectional area needed to obtain the same resiliency is less
than monofilaments with a round cross section, irritation
of the tissues inside the oral cavity is alleviated.
Examples of the toothbrush of the present invention will
now be explained. The first example describes the present
invention using monofilaments with a round cross section
implanted in rectangular tufting holes and then the next
example describes tile present invention using
monofilaments with a round cross section implanted In
elliptic tufting holes.
[Example of implanting monofilaments with a round
cross section in rectangular tufting holes]
-
Figure 2 shows the appearance of a tufting part of a
typical example, Figure 3 is a plane view of the tufting
part, Figure 4 is a front view, and Figure 5 is a side view
of the tufting part as seen from the front end. By means
of this example, tile tufting holes are rectangular and
monofilaments with a round cross section are used.
-
Tufts 11, 12, 21 to 24, 31 to 34, 41 to 44, 51 and 53
are arranged in 5 rows in the lengthwise direction in
tufting part A and there is at most 1 row of tufts in the
direction of width. Moreover, the vertical cross section
of the tufting holes in which these tufts have been planted
is represented by attaching an "a" to the symbols for the
corresponding tuft.
-
Each tuft is implanted in the direction of handle
length from rectangular tufting holes with their long sides
matching. Adjacent tufts that face one another are
inclined inward in the direction of width of tufting base 1
so that a pair of tufts facing one another forms a unit and
a block of tufts that converge at the end portions
(referred to a converging block R) is made. There are
several of these converging blocks R. The converging
blocks R are spaced so that these converging blocks R are
alternately formed at the front row and the back row in
order to uniformly clean the entire tooth surface, which is
a smooth surface, when the tooth is brushed by moving the
handle back and forth in the lengthwise direction.
Moreover, tufts 32 and 33 are inclined inward toward one
another at the center row of the handle in its lengthwise
direction and tufts 31 and 34 that are on the outside form
isolated tufts.
-
Here, tufts 31 and 34 are inclined toward the inside
somewhat, but they can also be standing straight up.
-
In addition, distance W between adjacent converging
blocks R and R In the direction of width of the tufting
base is somewhat narrower than the average width of a
tooth, and when brushing is performed by moving the handle
back and forth in the lengthwise direction, the tooth that
is to be cleaned is thereby sandwiched between converging
blocks R and the surface on both sides of the tooth can be
thoroughly cleaned.
-
Inclination of the tufts is accomplished by inclining
the tufting hole itself and then pressing and fixing the
tufts in the inclined tufting hole using an anchor. As a
result of inclining the tufting hole itself, the inclined
position of the tuft can be firmly maintained, even if
force that would collapse the inclined tuft is repeatedly
applied during brushing.
-
Figures 6 through 11 show the inclined state of the
tufting boles. Figure 6 shows how the tufting holes are
arranged in tufting base 1, and Figures 7 through 11 show
the cross section of each of 5 rows that are made in the
lengthwise direction of the tufting base.
-
The angle of inclination of the tufting holes should
be based on tuft stiffness that is to be obtained, but it
is usually set within a range of 2 to 10° with respect to
the vertical direction of the inclined holes. The bristles
must be extremely long for the end portion of the tufts
facing each other to come into contact if the inclination
is less than 2°, which is undesirable. On the other hand,
an inclination greater than 100 makes handle molding
difficult. The distance at the base between the tufts that
form converging blocks R should be within a range of 0.2 to
40 mm. If inclination and the distance are set at the
above-mentioned values, it will be possible to realize
sufficient durability to the pressure that is repeatedly
applied during the course of use of the toothbrush and the
converging shape of the tufts can be retained for a long
period of time.
-
The angle of inclination of the tufting holes can vary
with the position at which converging block R Is formed, or
it can be the same as in the present example.
-
The ability to penetrate the tight interdental spaces
can be improved further by making the end portion of the
tufts into a V-shape with an inclined face along the long
side of the tufting holes. When an end portion with a
sharp V-shape is employed, the ability of the toothbrush to
brush out plaque and food sediment that has penetrated
tight spaces is improved.
-
The dimensions of rectangular tufting holes are a
short side S of 0.8 to 2.0 mm and a long side L of 1.5 to
5.0 mm, as shown in Figure 2. The surface pressure applied
directly to the tooth surface is dependent on the shape of
the end portion of the tuft, but if the dimensions of the
tufting holes are smaller than the above-mentioned range,
insufficient force will be transmitted to the end portions
of the tufts.
-
The reason for using rectangular holes as the tufting
holes is that good stiffness In accordance with the
brushing direction can be obtained when there is a
difference in the number of filaments clustered together
depending on the direction and as a result, resiliency,
that is, stiffness, when pressure is applied to the tuft is
given directivity. By using the embodiment where the long
side of the tufting holes are along the direction of
handle length, good stiffness is obtained when brushing is
performed mainly by moving back-and-forth in the direction
of handle length.
-
The space occupied by the tufting holes is set at 10
to 30 mm in the direction of handle length and 5 to 15 mm
in the direction of handle width. If the tufting holes
account for less than this amount of space, the tooth
surface contact area will be small and there will be a
reduction in cleaning efficiency.
-
The tufts are fixed in tile tufting holes by driving an
anchor into the hole as with conventional toothbrushes.
The anchor is a 1.6 mm x 0.22 mm metal strip. This strip
is sandwiched with a tuft that has been folded into a U
shape and driven into the tufting hole with the tuft and
both ends of the anchor in its lengthwise direction are
wedged into the wall around the tufting hole to fix the
tuft in the tufting hole. Conventional toothbrushes have
round tufting boles and therefore, as shown in Figure 14,
tile anchor is driven into the tufting hole along its
diameter, but by means of the present invention, anchor P
is driven into the tufting bole so that it is parallel to
the long side of tufting hole H and so that it divides the
opening surface area of the tufting hole into two equal
parts, H1 and H2. Moreover, there is a possibility that
cracking will increase if anchors P that have been driven
into the tufting holes are in a straight line on the
tufting base, but this can be prevented by staggering the
position where the tufting holes are formed slightly in the
direction of width.
-
By driving the anchor In exactly so that the opening
surface area of the tufting hole is divided into two equal
parts, there will be no bias to the number of filaments
held in parts H1 and H2, which are delineated by anchor P.
and there will be a marked reduction In the number of tufts
that come loose. Moreover, a state can be realized where
the filaments are uniformly filled In the tufting holes and
therefore, the appearance after tufting will be beautiful.
-
Working the end portion of the tuft into a V-shape was
previously discussed. Figure 15 represents the end portion
of a tuft that has been worked into a V-shape. In this
example, inclined faces r and r along the peak are in the
direction of width of the tuft. The present example is
also characterized in that an angular peak is made by 1
tuft. Slopes r and r toward the angular peak intersect in
the direction in which the tufts support one another so
that inclined faces of a V-shape are obtained. As a
result, in addition to obtaining converging tufts where the
tufts support one another, the end portions are squeezed In
the direction in which they intersect the above-mentioned
direction of convergence from the V-shape and as a result,
the end portions can be inserted into tight spaces when
used for brushing by moving the handle up and down or to
the left and right, and a sharp, stiff end portion is
realized, making it possible to efficiently remove food
sediment and plague.
-
Although not illustrated, the slope toward the angular
peak can also be formed in the direction in which the tufts
support one another. This shape can be any shape as long
as it falls under the category of V-shaped.
-
For example, the embodiment in Figure 16 where the
front and back faces in the direction in which the tufts
support one another are the inclined faces that form
trapezoidal inclined face r1, the embodiment in Figure 17
where an isosceles triangle-shaped inclined face r2 is
formed, the embodiment in Figure 18 where a right triangle-shaped
inclined face r3 is formed, etc., can be used.
-
The structure of a first example, which is a typical
example, was discussed, and the effects of the toothbrush
of this example will now be discussed.
-
The toothbrush of the present Invention is excellent
in terms of its cleaning activity on smooth surface Z1, and
it has excellent cleaning activity for interdental site A2,
which is the part between adjacent teeth, occlusal surface
Z3 of a molar tooth, etc., and a cervical portion of the
tooth Z4 shown by Figures 20 and 21. However, particularly
good cleaning activity that should be emphasized is
realized at interdental part Z2.
-
For example, cleaning of the tooth surface with the
toothbrush of the present example is shown in Figure 20.
As shown by this figure, there is space SP between
converging blocks R and R comprising each row of the
tufting part, and the next row of converging blocks R is in
the position of the next row, which is behind space SP.
Consequently, when brushing is performed by moving the
handle back and forth in the direction of the arrows in the
figure, the teeth missed by the front row of tufts will be
brushed by the next row of tufts and even if the tooth
brush is moved up and down in the direction of handle
width, the entire tooth surface can be effectively cleaned
leaving any of the tooth surface unbrushed. Moreover,
since these surfaces are being brushed by the stiff end
portion of the converging block, cleaning power is
excellent. When the toothbrush is pressed on the tooth
surface, deforming force is applied to the tufts, but the
converging block has tufts facing one another that support
their inclined position and reinforce their shape and
therefore, even if they are deformed, the tufts can recover
and there will be no early reduction in brushing
performance during the use of the toothbrush.
-
Moreover, Figure 21 shows cervical surface Z4 being
cleaned. Food sediment and plaque that have deposited on
the cervical portion of the tooth can be effectively
brushed away because the end portion where the converging
block converges is pushed into the cervical portion of the
tooth, as shown in the figure.
-
Moreover, interdental space Z2 can be cleaned by
moving the toothbrush up and down, but it is also possible
to perform this back and forth movement so that the length
of the handle is along the direction of the tooth row or is
perpendicular to the direction of the tooth row. In the
former case, using a tuft end portion that has a V-shape is
very effective for improving tile ability to insert the tuft
end portion into interdental spaces.
-
On the other hand, in the latter case, the end portion
of the tuft can be inserted between the teeth and the
sediment between the teeth wiped away because the end
portion of the tufts that support one another converge.
-
Figure 22 is a figure showing occlusal surface Z3 of a
molar being brushed with the third row of tufts on the
tufting base. In this case, the tuft end portion where
converging block R, which is made from 2 tufts supporting
one another on the inside, converges is inserted deep into
the grooves formed in occlusal surface Z3 and the sediment
on occlusal surface Z3 is wiped away with the stiff end
portion, while the two tufts to the outside enclose around
the molar and brush off both sides of the molar. Brushing
of occlusal surface Z3 has been explained here using an
example where there is a third row for realizing the best
cleaning effects, but it is also possible to realize good
insertion of other rows of tufts into the occlusal surface
even if the effects are slightly different.
-
The toothbrush of the present example has the
following characteristic cleaning effects. For instance,
taking into consideration the case where molars, etc., are
to be brushed, the mechanism shown in Figure 23 comes into
play. For instance, when an occlusal surface is brushed
along the row of teeth, the molar is first touched by
converging block R1 of the first row at the first position
shown by P1 in the figure and the front surface in the
forward direction is cleaned. Once the occlusal surface
has been cleaned by converging block R1, which has run up
onto the occlusal surface, the second row of tufts moves to
second position P2 shown by the imaginary line in the
figure as it is pushed to either side of the molar to be
cleaned. In this position, the molar to be cleaned is
enclosed by tufts and the front surface in the forward
direction is cleaned by the converging block R3 in the
center of row 3, while the sides are cleaned by the second
row of tufts, which are pushed to either side in the
direction of handle width. The same effect is obtained
moving to next third position P3 and as a result, the molar
in question is thoroughly cleaned.
-
By means of the present example, the second, third and
fourth row of tufts comprising the tufting part have a
structure where there are 2 pairs of converging blocks, or
there is one pair of converging blocks in the center and
there is one tuft inclined slightly to the inside on either
side. However, the structure of the rows of tufts is not
limited to this example. For instance, as shown in Figure
24(a), the structure of some of each row of tufts can be
such that the tufts on both sides of the row are inclined
to the outside, as shown in Figure 24(a), or such that
there are no converging blocks and all 4 tufts are inclined
to the outside, as shown in Figure 24(b).
-
The present inventors confirmed the cleaning effects
of the toothbrush of the present example by comparison with
a conventional toothbrush using a dental study model to
study smooth-surface cleaning performance and tight-space
cleaning performance.
-
A toothbrush with the tufting pattern shown in Figure
2 (this is referred to below as Trial Product 1) was used
as the toothbrush representing the present invention in the
comparisons, while popular commercial toothbrushes were
used as the object of comparison. Commercial products A
and B were employed as the toothbrushes to be compared
(referred to be low as comparative product). Comparative
product A had almost rectangular tufting holes and a V-shape
formed by two tufts. Moreover, Comparative Product B
had almost rectangular tufting holes and tuft pattern of
steps of tufts with different lengths for each tufting hole
in the direction of handle length.
-
The lower right first molar was selected as the site
for comparison of cleaning activity. Although tight-space
cleaning performance means the ability to clean
indentations, such as spaces between the teeth, the
cervical portion of the tooth, an occlusal surface, etc.,
only interproximal-surface cleaning performance, which is
the ability to clean the interdental space, was evaluated.
The test method and test results are described below:
-
First, spray for checking for dental occlusion (brand
name "Occlude," Pascal Co., Ltd.) was applied to the dental
study model and then the buccal surface of the molar of the
dental, study model in a state of top and bottom occlusion
was brushed using the sample toothbrush and a brushing
simulator. Brushing was performed with the direction of
handle length along the row of teeth (almost parallel) and
the toothbrush being moved back and forth In the direction
of handle length. Brushing conditions were set at a weight
in a stationary state of 250 g, brushing time of 6 seconds,
amplitude of 10 mm, brushing speed of 37 mm / second, and 1
stroke time being 0.225 second.
-
Once the front teeth were brushed under these
conditions, performance in terms of cleaning the lower
right first molar, which was the site of the test, was
evaluated. As shown in Figure 25, 70% of the above-mentioned
molar surface was "smooth surface" (shown by F in
the figure) and 15% on each side of the "smooth surface"
was "interproximal surface" (shown by K In the figure, and
cleaning performance of both types of surfaces was
evaluated. Cleaning performance is represented by percent
and is the value obtained by subtracting "uncleaned surface
area after cleaning test" from "uncleaned surface area
before cleaning test" and then dividing this by "uncleaned
surface area before cleaning test." The results are shown
in Figures 1 and 2 and the mean values are plotted in
Figures 26, 27 and 28.
| Interproximal cleaning performance |
| | Trial product |
| 1 | Comparative Product A | Comparative Product B |
| 1 | 54.5 | 36.5 | 46.1 |
| 2 | 50.5 | 26.3 | 41.1 |
| 3 | 58.5 | 35.5 | 43.6 |
| Mean value | 54.5 | 32.8 | 43.6 |
| Smooth-surface cleaning performance |
| | Trial product |
| 1 | Comparative Product A | Comparative Product B |
| 1 | 84.8 | 64.6 | 59.5 |
| 2 | 88.0 | 66.7 | 73.3 |
| 3 | 81.6 | 62.4 | 58.7 |
| Mean value | 84.8 | 64.6 | 63.8 |
-
As is clear from the above-mentioned results, in
contrast to the fact that interproximal cleaning
performance was 32.8% for Comparative Product A and 43.6%
for Comparative Product B, the Trial Product of the example
of the present invent ion reached a high cleaning
performance of 54.5%, and in contrast to the fact that
smooth-surface cleaning performance of Comparative Product
A was 64.6% and that of Comparative Product B was 63.8%,
the trial product of the example of the present invention
reached a high cleaning performance of 84.8%. Only
interproximal cleaning performance was evaluated in the
evaluations of tight-space cleaning performance, but it is
estimated that the same excellent results obtained for
interdental space would be obtained in terms of the
cleaning activity on the cervical surface and occlusal
parts of the teeth.
-
A dental study model was used for the above-mentioned
comparative study, but the inventors also performed
clinical trials using the above-mentioned Trial Product and
the above-mentioned Comparative Product A at a university
school of dentistry in order to confirm in detail the
effects when actually used on the oral cavity. By means of
this test method, 21 subjects were obligated to brush their
teeth two or more times a day for 7 days and the amount of
plaque before and after brushing was measured and plaque
removal efficiency by brushing was evaluated.
-
Six teeth were selected as typical teeth within the
oral cavity in evaluations of plaque and the tooth to be
studied was stained with a plaque stain and height to which
the plaque was deposited was measured at 6 places on 1
tooth in units of 0.5 mm. The results are listed in Table
3.
| | Number n | Trial product | 1 | Comparative Product A | Difference between groups (p value) | Significant difference (p < 0.05) |
| | | Average | | Average | |
| Entire tooth | 21 | 63.1 | 19.5 | 50.5 | 17.0 | 0.00179 | ○ |
| Upper jaw | 21 | 61.6 | 22.0 | 47.4 | 19.3 | 0.00395 | ○ |
| Lower jaw | 21 | 63.3 | 20.5 | 55.1 | 23.2 | 0.06558 | X |
| Buccal side |
| | 21 | 72.4 | 20.3 | 56.3 | 20.8 | 0.00214 | ○ |
| Lingual side | 21 | 53.7 | 22.3 | 42.9 | 18.9 | 0.01373 | ○ |
| Center | 21 | 72.7 | 19.3 | 57.1 | 25.4 | 0.00562 | ○ |
| Adjacent | 21 | 59.1 | 20.3 | 48.5 | 15.4 | 0.00919 | ○ |
-
The difference between groups was studied by paired t
tests.
-
As shown in Table 3, the Trial Product of the present
invention provided better results than Comparative Product
A for all parts studied. Moreover, it was confirmed that
the difference between the toothbrushes was significant
(level of significance P < 0.05) for all parts studied
except the lower jaw.
[Example of implanting monofilaments with a
rectangular cross section into elliptic tufting holes]
-
Next, the inventors made a toothbrush where
monofilaments with a rectangular cross section were
implanted in tufting holes with an elliptic opening
inclined toward the tufting surface and studied this
toothbrush. The tufting part of this toothbrush is shown
in Figure 30. This toothbrush has 1 tufting hole 100, two
tufting holes 110 and 120, and three tufting holes 130, 140
and 150 from the end portion side in the direction of
length of the tufting base. Tufting hole 100 at the end
portion and tufting hole 140 in the middle of the 3 tufting
holes at the back are perpendicular holes, while 2 tufting
boles 110 and 120 of the second row face inside (toward the
center of the tufting base), inclined at an angle of 3°,
and tufting holes 130 and 150, on either side of above-mentioned
tufting hole 140 in the middle at the back end
are each inclined at an angle of 3° toward the inside and
monofilaments with a rectangular cross section are tufted
in these tufting holes. The small rectangular cluster in
each tufting hole is a cluster of monofilaments and an
anchor is seen intersecting along the lengthwise direction
in the center in the direction of width of each tufting
hole. By placing the tufts at either side in the
direction of tufting base width so that they are inclined
toward the inside with this toothbrush, it is possible to
prevent the filaments from separating to the outside in the
direction of tufting base width when teeth are brushed by
moving the handle back and forth in its lengthwise
direction and a reduction in resiliency that occurs when
the filaments separate to the outside can thereby be
prevented. This is an example of a toothbrush where the
number of tufting holes is relatively few and the size of
the tufting base is relatively small, but as shown in
Figure 31, a variety of embodiments can be used for a
toothbrush where monofilaments with a rectangular cross
section are implanted in elliptic tufting holes using the
same arrangement of tufting holes as in the above-mentioned
example.
-
The subject of the present example is a toothbrush
where the tufting holes are elliptic, but tufting holes
that are almost elliptic are included in the concept of
almost elliptic defined by the invention of the present
application, and in addition to elliptic tufting hole 110
shown in Figure 33, tufting hole 100' that is almost
elliptic shown in Figure 34 is included in the concept of
almost elliptic.
-
The present example differs from the above-mentioned
example in that in contrast to the fact that monofilaments
with a round cross section are implanted in rectangular
tufting hole 100'', as shown in Figure 32, in the above-mentioned
example, monofilaments with a rectangular cross
section are implanted in a tufting hole that is inclined
and has an elliptic or oval-shaped opening in the present
example.
-
It is possible to improve tight-space cleaning
performance even further and to all but eliminate cracking
of the tufting base and improve toothbrush durability by
using elliptic tufting holes and making the lengthwise
direction of the tufting holes along the direction of
handle length, that is making the lengthwise direction of
the tufting holes the same or almost the same as the
direction of handle length.
-
The reason why tight-space cleaning performance is
improved is that when the tufting holes are elliptic and
the lengthwise direction of the tufting holes is the same
as the direction of handle length, both ends of the tufts
that have been implanted in the tufting holes are
streamlined in the direction of handle length and are
narrow and therefore, insertion into tight spaces is
improved.
-
Moreover, there is no cracking of the tufting base and
durability of the toothbrush is improved for the following
reasons:
-
The toothbrush is molded using an injection molding
and the tufting base in which the tufting holes have been
formed is molded by filling molten synthetic resin into a
cavity for molding the tufting base in the mold. Pins for
forming the tufting holes are planted in the cavity and the
molten synthetic resin flows around these pins for forming
the tufting holes. Once the synthetic resin has cured, the
mold is opened and the pins for molding the tufting holes
are at the same time removed to form the tufting holes.
Tufting holes are molded in this way. Pins that correspond
to the shape of the tufting holes to be made can be used
for the pin for forming the tufting holes, but the state in
which the molten synthetic resin will flow around the pin
varies with the shape of this pin used to form the tufting
holes and this will affect cracking of the tufting base.
For instance, when tufting holes that are rectangular in
shape are used, pins 200 for forming tufting holes will
have angles 201, as shown in Figure 35. Nevertheless,
since it does have angles 201, the molten synthetic resin
that is supposed to flow around angle 201 and into space
205 between this pin and adjacent pin 210 for forming
tufting holes will not flow exactly along the surface of
pin 200 for molding tufting holes and as a result, the
resin will not firmly bond back together when it flows
around pin 200 for molding the tufting holes and then
merges again. Consequently, the part where the resin is
not thoroughly bonded together will easily crack. Since an
anchor will be driven into the part where the resin is not
firmly bonded together when an anchor is driven parallel in
the lengthwise direction of the tufting holes, cracks will
form even more easily. This is particularly obvious when
the center line in the direction of width of adjacent
tufting holes overlaps a line extending on the center line
in the direction of width of the tufting holes as shown in
Figure 35, that is, when the space between adjacent tufting
holes is narrow.
-
In contrast to this, as shown in Figure 36, when the
tufting holes are elliptic, the molten synthetic resin can
smoothly flow around the curved surface of the oval shape
of pin 300 for forming tufting holes and the molten
synthetic resin can firmly bond back together when it flows
around pin 300 for molding the tufting holes and merges
again. As a result, the part where the resin bonds back
together after splitting to go around the pin is
sufficiently strong. Consequently, the chance that the
tufting base will crack can be reduced dramatically and a
toothbrush can be obtained that shows no cracking and
excellent durability, even if the anchor is driven in
parallel to the direction of length of the tufting holes.
-
By means of the present example, the direction of
length of the rectangular surface was made the same as the
direction of handle length using monofilaments with a
rectangular cross section and therefore, when the method of
brushing by moving the handle back and forth in its
lengthwise direction is used, the resiliency of the tuft is
very high. Moreover, since the tuft on either side in the
direction of width of the tufting base is inclined toward
the inside, there is no separation of monofilaments during
brushing and resiliency of the monofilaments is efficiently
realized.
-
The inventors performed studies on how resiliency
during brushing is affected by inclination of the tufting
holes and by different cross sections of monofilaments in
toothbrushes with elliptic tufting holes. The experiments
were performed using
Trial Product 2 of this example and
Comparative Products C, D and E in which monofilaments with
a round cross section were implanted in order to compare
resiliency of the monofilaments of these toothbrushes. Of
the toothbrushes used in the study, the shape and
arrangement of the tufting holes of all but Comparative
Example 3 were the same as shown by Figure 30, and the
number of tufting holes used for Comparative Product C was
17. The tufting holes of Comparative Product C were
vertical holes with a round cross section having a diameter
of 0.190 mm , the tufting holes of Comparative Product D
were vertical holes with a round cross section having a
diameter of 0.160 mm , the tufting holes of Comparative
Product E were vertical tufting holes with a rectangular
cross section of 0.254 mm x 0.162 mm, and the tufting holes
of
Trial Product 2 of the present example were tufting
holes with a rectangular cross section of 0.254 mm x 0.162
mm. Four tufting holes placed on the outside in the
direction of tufting base width were inclined inside at 3°,
as shown by Figure 30. Resiliency was measured as
"resiliency per surface area in the direction of handle
length" and "resiliency per unit surface area in the
direction of handle width. These two types of resiliency
were compared and are represented as the "ratio of
resiliency in the direction of length and in the direction
of width." Resiliency of the monofilaments was calculated
by international standards (ISO). The reaction force that
was produced when resistance was applied to 1/3 the length
of the monofilament for elastic deformation was measured
and is represented In units newton (N). The results are
shown in Table 4.
-
As is clear from Table 4, when compared to Comparative
Products C, D and E, resiliency per unit surface area in
the direction of handle length is strong with Trial Product
2, the toothbrush of the present invention, and it was
confirmed that resiliency in the direction of handle length
was greater than that in the direction of width. Thus, it
was shown that the toothbrush of the present invention,
Trial Product 2, is ideal for brushing methods where the
toothbrush is moved in the direction of handle length,
typically the scrubbing method, and that the toothbrush of
the present invention provides excellent cleaning effects.
Moreover, as is clear from the fact that Trial Product 2 of
the present invention provides less resiliency per unit
surface area in the direction of handle width than did
Comparative Products C, D and E, there is not an absolute
increase in resiliency of the toothbrush of Trial Product 2
in comparison to Comparative Products C, D, and E, but
instead, an increase in resiliency in the direction of
handle length can be expected because distribution of
resiliency that is applied in the direction of handle
length and of handle width is changed and as a result,
cleaning effects are improved without increasing irritation
of the tissue of the oral cavity. Thus, it was shown that
the toothbrush of the present example is a toothbrush that
is ideal for the scrubbing method.
-
Moreover, since monofilaments were implanted in
tufting holes with an almost elliptic shape extending in
the direction of handle length of the toothbrush of Trial
Product 2 (this point was the same in Comparative Examples
C, D and E, both ends of the tufts in the direction of
handle length formed a peak that curved streamlined and the
width of this peak was narrow. Teeth can be touched using
this curved narrow peak and therefore, initial contact
resistance when the toothbrush touches the teeth can be
minimized. As a result, the monofilaments at both ends of
the tufts in the direction of handle length can be easily
inserted into interdental space when teeth are brushed by
the scrubbing method, and coupled with the fact that
resiliency of the monofilaments can be increased, cleaning
effects are improved even further.
-
Moreover, since the toothbrush of the present example
uses tufting holes that are elliptic, cracking of the parts
between adjacent holes in the tufting base will hardly
occur and there is therefore no fear of cracking, even if
an anchor is driven into this part. Consequently, as shown
in Figure 30, by means of the toothbrush of the present
example, an anchor can be driven into the tufting hole
along the lengthwise direction of the tufting hole at the
center of the tufting hole in its direction of width
extending along the direction of handle length and
therefore, tufts can be implanted symmetrically, to the
left and right of the center in the direction of width of
the tufting hole, as shown in Figure 33, making it possible
to realize uniform density of monofilaments on both sides
of the anchor. Consequently, all of the monofilaments can
be brought to face almost perpendicular to the tufting
surface to obtain a good raised effect and a beautiful
toothbrush.
-
The inventors studies how the raised effect
(appearance) of the monofilaments is affected by a
difference in the tufting hole shape and the cross
sectional shape of the monofilaments and a difference in
the direction in which the anchor is driven into the
tufting hole and evaluated the raised effect (appearance).
The results are shown in Table 5. a Through f in Table 5
are conventional toothbrushes, g is a toothbrush of the
present example, and h is an example where the shape of the
tufting hole is the same as in above-mentioned g, but the
anchor is inclined and driven into the hole at an
inclination of 15° to the direction of handle length.
| | Shape of tufting hole | Cross sectional shape of monofilament | Direction in which anchor is driven into tufting hole | Evaluation of raised effect |
| a | Round | Round | Parallel to direction of handle length | ○ |
| b | Round | Round | Inclined 15° to direction of handle length | ○ |
| c | Round | Rectangular | Parallel to direction of handle length | ○ |
| d | Round | Rectangular | Inclined 15° to direction of handle length | ○ |
| e | Elliptic | Round | Parallel to direction of handle length | ○ |
| f | Elliptic | Round | Inclined 15° to direction of handle length | Δ |
| g | Elliptic | Rectangular | Parallel to direction of handle length (including ± 10°) | ○ |
| h | Elliptic | Rectangular | Inclined 15° to direction of handle length | X |
Evaluation of raised effect with implanting
○ = no problems
Δ = somewhat poor raised effect
X = poor raised effect |
-
As is clear from Table 5, when the tufting holes are
round, the appearance of the toothbrush is unaffected by
the cross sectional shape of the monofilaments or the
direction in which the anchor is driven into the tufting
holes, and the appearance is good. Moreover, it is clear
that the raised effect (appearance) of the toothbrush is
good, even if tufts of monofilaments with a round cross
section are driven into elliptic tufting holes parallel to
the direction of length of the handle.
-
On the other hand, although the raised effect is good
when the anchor is driven into a elliptic tufting hole
along the direction of length of the handle, the raised
effect is somewhat inferior if the anchor is driven into
the hole so that it intersects the direction of length of
the handle at an angle of 15°. Moreover, when
monofilaments with a rectangular cross section were
implanted into elliptic tufting holes, the raised
appearance was poor if the anchor was driven into the hole
intersecting the lengthwise direction of the handle, but
the raised effect was good and appearance was good with the
toothbrush of the present example where the anchor was
driven parallel to the direction of handle length.
-
The toothbrush of the present invention can provide a
difference in tuft resiliency in the longitudinal and
latitudinal directions of the tufting holes because the
tufting holes are almost elliptic or almost rectangular and
therefore, cleaning effects can be improved by adjusting
the direction along the long side of the holes. Moreover,
since the tufting holes are inclined toward the tufting
surface, brushing power in a specific direction can be
improved by controlling the direction of inclination. In
addition, since the tufting boles themselves are inclined,
the above-mentioned inclined position will not collapse and
stable brushing force can be obtained over long periods of
time, even with repeated application of pressure with
brushing. Moreover, a toothbrush with both tight-space
cleaning performance for interdental spaces, the cervical
portion of the tooth and occlusal surfaces and smooth-surface
cleaning performance for a tooth surface can be
obtained by designing the lengthwise direction of the
tufting holes and the direction of inclination of the tufts
to match the brushing direction. In particular, when the
tufting holes are almost elliptic holes, the contact
resistance when the tufts first touch the tooth can be
minimized because the tufts are streamlined, and the narrow
monofilaments at both ends in the lengthwise direction of
the tufting holes can be easily introduced to interdental
space, improving cleaning effects even further.
-
When the lengthwise direction of almost elliptic or
almost rectangular tufting holes is alone the direction of
handle length the resiliency of monofilaments in the
brushing direction can be increased and excellent cleaning
results can be realized when teeth are brushed by the
scrubbing or Bass method with mainly back and forth
movement in the direction of handle length.
-
When there is at least one group of tufting holes that
are inclined to the inside and form a pair, the tufts
implanted in these tufting holes will support one another
and reinforce tuft stiffness. Moreover, their end portions
converge and as a result, a toothbrush can be presented
with which the tufts can be inserted into tight spaces,
including interdental spaces, the cervical portion of the
tooth, and the occlusal surface, and the food sediment and
plaque that has accumulated in these sites can be forcibly
removed.
-
By designing inclination to a vertical direction of
the inclined holes within a range of 2 to 10°, a toothbrush
is obtained with which optimum pressure can be applied to
interdental spaces, the cervical portion of the tooth and
occlusal surfaces, and the degree to which the end portions
of the tufts converge is optimized and there is excellent
insertion into interdental space, etc.
-
When the monofilaments comprising the tufts that are
to be implanted in the tufting holes have a rectangular
cross section and the direction of the long side of this
cross sectional shape is along the lengthwise direction of
the tufting holes, resiliency of the monofilaments in the
lengthwise direction of the tufting holes can be increased
and toothbrush cleaning power can be improved even further.
Moreover, since the cross sectional area for realizing the
same resiliency is small in comparison to monofilaments
with a round cross section, irritation of oral cavity
tissues is also minimized.
-
When converging blocks are made when a pair of tufts
that face one another support each other and a plurality of
this type of converging block is made, the tufting part
will have excellent tight-space cleaning capability and
there will be a plurality of places where tuft stiffness is
realized, resulting in more efficient brushing.
-
When the end portion of each tuft is worked to a V-shape,
tight-space cleaning performance is improved even
further. In particular, when a V-shape is made so that an
inclined face is formed to the front and the back where the
direction in which the adjacent tufts support one another
is intersected, tight-space cleaning performance in the
direction of handle length and tight-space cleaning
performance in the direction of handle width are both
improved.
-
By placing converging blocks at least in front and
behind the direction of handle length and positioning the
next row of converging blocks behind the space that is
formed between converging blocks in the front row in the
direction of handle length, the part of the tooth that has
been missed by the front row of converging blocks will be
brushed by the next row of converging blocks and as a
result, an entire smooth surface, such as a tooth surface,
can be brushed by the end portion of a converging block
that is very stiff and has excellent brushing power.
-
When an anchor that is used to drive the tufts into
the tufting holes is driven into the tufting hole so that
it is parallel to the long side or the short side of the
tufting hole and it divides the opening area of the tufting
hole into two equal parts, the filaments can be filled into
the hole uniformly and as a result, none of the tufts will
be lost, which ends in loose packing density, and the
appearance of the tufting part will be beautiful.
-
When the centers of the tufting holes are such that
they are not lined up on one straight line in the direction
of handle length, cracking can be prevented. Consequently,
the tufting holes can be big and adjacent tufting holes can
be close to one another.
-
When tufting holes account for 10 to 30 mm in the
direction of handle length and 5 to 15 mm in the direction
of handle width, a smooth surface can be efficiently
brushed with no reduction in maneuverability inside the
oral cavity.
-
When the tufting holes are almost rectangular and the
short side of these almost rectangular tufting holes is
designed to dimensions of 0.8 to 2.0 mm, while the long
side is designed to dimensions of 1.5 to 5.0 mm, the size
of the end portion of the converged part that is formed by
the tufts supporting one another is ideal in terms of
realizing both smooth-surface and tight-space cleaning
performance.
-
When the angle of inclination of the tufts comprising
the converging blocks is within a range of 2 to 10° and the
distance between the tufts [at their base] is 0.2 to 4.0
mm, as previously explained, collapse of the converged
shape with long-term use can be prevented.
-
Moreover, when there are 5 rows of tufts in the
lengthwise direction of the tufting base, with Rows 1 and 5
forming one converging block in the center in the direction
of width of the tufting base. Rows 2 and 4 forming 2
converging blocks on either side sandwiching the center in
the direction of width of the tufting base, and Row 3
forming one converging block at the center in the direction
of width of the converging block, and there is 1
independent tuft, each inclined so that it is in the same
direction as the tufts that form the above-mentioned
converging blocks, but its end portion does not touch the
converging blocks, to the outside of the above-mentioned
converging blocks, the front surface in the forward
direction of the site to be cleaned is brushed by Row 1 of
converging blocks, these tufts being run up on the tooth,
and then the tufts on both sides in the direction of width
comprising Row 2 are pushed to ether side of the tooth and
both sides are brushed by the tufts in Row 2. Then this
front surface is brought into contact with Row 3 and this
same state is repeated moving from Row 3 to Row 1. Thus, a
toothbrush with strong cleaning performance is obtained.
