Note: Descriptions are shown in the official language in which they were submitted.
~24~68Z
1 This invention relates to a dental prophylaxis pro ess
2 and a device for accomplishing the same. More particularly,
3 the invention relates to a dental flossing process and a mechani-
4 cal device for the flossing of dentition surfaces.
BACKGROUND OF THE I~VENTION
_ _
6 It is well known in the field of dentistry that failure
7 to remove plaque from dentition surfaces and debris from between
o dentitions is a principal cause of dental diseases, such as tooth
9 decay and gingivitis and the like. Removal of plaque and debris
by brushing is the commonest and easiest method known. However,
11 brushing is generally inadequate, especially when self-adminis-
12 tered. A more efficient and known technique is the cleaning of
13 the dentition surfaces and areas between such surfaces by using
14 a dental tape or floss which is moved reciprocally over and
between the dentition surfaces. Furthermore, the reciprocating
16 motion of the floss as it is manipulated over and between the den-
17 tiion surfaces is beneficial as a treatment for and prevention of
18 periodontal diseases, such as gingivitis and the like. This is
9 so since the free margin of the gingiva which is adjacent to the
individual teeth of the dentition and forms the gingival sulcas
21 can be readily reached by dental floss, although it is generally
22 inaccessible to a brush or other intruments, and the sulci are
23 subject to the invasion of plaque or colonies of bacteria which
24 cause diseases of these tissues. Thus, floss, in general, is
particularly beneficial in removing plaque and debris, as well
26 as serving, in addition, as a vehicle for the application of
27 medication. On the other hand, dental tape or floss is in-
28 convenient and awkward to handle.
2~ Consequently, much development has been undertaken in
the past to provide dental tape or floss in various forms which
-2~
~z
1 is more convenient to handle and use. In addition, much develop-
2 ment has taken place to provide mechanical devices for the flos-
3 sing of dentition surfaces. Therefore, past developments have
4 broadly involved the provision of dental tape or floss in various
forms to render the same more easy to use and the provision of
6 mechanical devices to support or hold the dental tape or floss in
7 a manner so that it can be employed with greater efficiency and
8 facility.
9 As an example of such developments, U.S. Patent
4,162,687 discloses a flossing device which is manipulated by
hand and provided with a pair of spaced, resilient arms having
12 fingers extending therafrom. The fingers are equipped with
13 knobs on their distal ends and a length of dental tape or floss
14 having a grommet on each end is disposed over the knobs on the
ends of the fingers. A somewhat similar device, but which is
16 power driven, is disclosed in U.S. Patent 4,Q14,354 in which the
17 dental tape or floss is tensioned between a pair of L-shaped ar~s
18 attached to a handle which is adapted to ~e driven by the power
19 element. On the other hand, U.S. Patent 3,927,686 discloses a
hand manipulated flossing device which includes a handle and an
21 adjustable head provided with a single strand or a plurality of
22 strands of dental tape or floss.
23 Still another dental cleaning device is disclosed in
24 U.S. Patent 3,835,872 in which a flexihle dental tape or floss
~:s dis-posed on a handle having a detachahle yoke for tautly
26 supporting a run of the tape, the tape ~eing attached to a
27 pair of anchor pins disposed on the handle and one of which is
28 dispased on a reciprocable trigger mounted in the handle for the
29 purpose of tensioning the tape. The tape per se is provided with
non-elastic loops at each end which are disposed over the previ-
~L4~
l ously mentioned pins. U.S. Patent 3,828,804 discloses still
2 another apparatus which is a hand manipulated device for clean-
ing teeth that includes a handle with a nub disposed thereon and
4 which is provided with extending, spaced arms having notches at
the ends thereof. An endless or circular elastomeric dental flos
6 or tape is disposed in the notches thereby passing across the
7 space between the arms and around the nub. In a variation of the
8 device a simple length of elastomeric band is anchored in the
9 notches of the arms by means of shims or heads.
0 A further dental cleaning instrument is disclosed in
U.S. Patent 3,759,214 in which a strand of dental floss is
12 mounted on an extended fork which supports the strand and permits
13 an oscillating movement which is imparted thereto by a drive
14 means. In addition, the device also includes a spool for carryin
the strand and for registering a new9 unused portion of the stran
16 for use in each subsequent cleaning cycle. A still further
17 dental cleaning device is shown in U.S. Patent 3,667,483 in
18 which the device includes a pair of pro;ecting arms disposed on
9 a support frame, the arms being provided with guides at their
outer ends to receive and permit relative movement of ~loss which
21 passes from a spool to a take-up reel ~ounted on the supporting
22 frame. The floss is driven in a reciprocating manner through a
23 drive means located in the support frame and the device is pro-
24 vided with means to alternately remove floss from the supply
spool and feed it to the take-up spool after each use.
26 In U,S. Patent 3,552,022 there is disclosed another
27 powered dental cleaning or polishing device in which a tool
28 having a conical stem portion is adapted to be inserted in and
29 re~oved from a handle in which a reciprocating socket is provided
therefor. The operating end of the tool is wedgelike and point-
~46~2
1 ed, two broad sides being rough in order to abrade dentition
2 surfaces and a third side thereof being narrow and smooth in
3 order ~o prevent injury to the gingiva. Another power driven
4 cleaning device is disclosed in U.S. Patent 3,534,745. The
S device includes a housing provided with spaced prongs and a
6 dental tape or floss holder and supply unit adapted to be re-
7 movably attached to a power unit which imparts reciprocating mo-
8 tion to the tape as well as permitting the feeding of new tape to
9 the unit after each use. Finally, U.S. Patent 3,421,524 dis-
closes a power driven dental cleaner including a power unit
which is adapted to receive a cleanin~ unit which includes an
12 elongated shaft provided with a pair of spaced tynes. A dental
13 tape or floss supply holding member is removably positioned on th~ .
14 power unit and the dental tape or floss i5 fed therefrom through
an eyelet in each of the tynes and back to the supply holding
16 member where it is taken up on a take-up spool.
17 While the various devices disclosed in the above-
18 mentioned patents are useful for cleaning dentition surfaces,
19 they still exhibit va~ous disadvantages. For example, many of
them are extremely complex in structure and consequently relative
21 ly expensive to manufacture. In addition, many of the known
22 structures are relatively difficult to employ, often being diffi-
23 cult to load and require complex ad~ustment to impart the requir-
24 ed tenseness to the dental tape or floss utili~ed therewith.
In addition,many of the known devices, such as those
26 referred to above, are not provided with means to automa~ically
27 stop the movement of the floss should it become caught or
28 jammed on the dentition surfaces. Furthermore, due to their
29 particular construction~ many of the known devices do not pro-
vide maximum contact of the floss with the dentition surfaces
to be cleaned and, in addition, due -to their construction,
necessitate the use of more than the needed amoun-t of dental
tape or floss for carrying ou-t a given cleaning operation.
There exists, therefore, the need for a den-tal prophylaxis
device and a process for dental prophylaxis which do not
exhibit the above-mentioned disadvantages. The present
invention fulfills this need.
BRIEF STATEMENT OF THE INVENTION
In accordance with one aspect of the invention
-there is provided a dental floss comprising a thread
segment having a non-elastic loop at one end and an
elastic loop at the opposite end, said elastic loop being
under positive tension at all times and providing tension
control of said floss and substantially eliminating point
to point contact of denti-tion and said floss when in use
to floss a dentition.
In accordance with another aspect of the inven~
tion there is provided a device for dental prophylaxis
which in its broadest terms comprises in combination housing
means provided with an axial cavity and having a pair of
spaced tynes provided with slotted openings disposed there-
on and projecting outwardly therefrom, stationary support
means on the housing in the vicinity of the base of each
of the tynes, and oscillating support means located on the
housing between the bases of the tynes and which is
supported on a cylindrical sleeve that is disposed axially
within the cavity of the housing, the housing means being
adapted to be connected to driving means to drive the
oscillating support means through the cylindrical sleeve.
-- 6
In a more detailed aspect, a deviee for dental
prophylaxis in accordance with the invention includes
second housing means removably connected to the above-
mentioned or firs-t housing means, -the seeond housing means
being provided with internal driving means including an
external, axially projeeting, oscillating drive shaft whieh
projeets axially into the first housing means and engages
the eylindrieal sleeve disposed in the eavity thereof.
In still further detailed aspeet, a dental
prophylaxis device in aeeordanee with the invention
further ineludes dental tape or floss eomprising a thread
segment having a non-elastie loop at one end and an elastic
loop at the opposite end, the dental floss being supported
in the slotted openings of the above-mentioned tynes and
aeross the spaee therebetween wi-th the elastic loop being
supported on the stationary support means and the non-
elastic loop being supportedon-the oscillating support
means.
Further, in accordance with the invention, the
dental prophylaxis process eomprising eontaeting dentition
surfaees to be
~6a2
l treated with a dental ~loss having ~thread segment which is
2 provided with a non-elastic loop at one end and an elastic loop
3 at ehe opposite end, reciprocating the thread segment over the
4 surfaces of the dentition to be treated, while expanding and
contracting the elastic loop in response to the application of
6 tensile force to the dental floss as it reciprocates over the
7 dentition surfaces and absorbing the tensile force which is
8 imparted to the dental floss when it encounters resistance as it
9 reciprocates over the dentition surfaces and the elastic loop
expands.
Expressed in more detailed terms, the dental prophy-
12 laxis process, according to the invention, comprises contacting
13 dentition surfaces to be treated with a dental floss having a
14 thread segment that is provided with a non-elastic loop at one
end and an elastic loop at the opposite end, reciprocating the
16 thread segment over the dentition surfaces and across the space
17 between a pair of spaced, stationary tynes which bracket the den-
18 tition surfaces while imparting oscillating movement to the den-
19 tal floss through ~e non-elastic loop along an axial line which
is sub~stantially at a right angle to the axis of reciprocation of
21 the thread segment and while expanding and contracting the elas-
22 tic loop in res-ponse to the application of a tensile force to
23 the dental floss as it reciprocates over the dentition surfaces,
24 and absorbing the tensile force imparted to the dental floss
when it encounters resistance as it reciprocates over the den-
27 tition surfaces and the elastic loop expands.
28
29
~24468~
THE DRAWINGS
1 In order to describe the device and process of this
2 invention more fully, reference is directed to the accompanying
3 drawings which are to be taken in conjunction with the following
4 description and in which drawings:
Fig. 1 is a view in perspective of a dental prophylaxis
6 device according to the invention;
7 Fig. ~ is a partial, elevational, exploded view of the
8 prophylaxis device illustrated in Fig. l;
9 Fig. 3 is a par~ial plan view of the prophylaxis
0 device shown in Fig. l;
11 Fig. 4 is a front end view in elevation of the device
12 of Fig. l;
13 Fig. 5 is a partial bottom view of the device illus-
14 trated in Fig. l;
Fi8. 6 is a partial elevational view of the device
16 shown in Fig. 1, partially in section, illustrating in detail
17 the c~lindrical sleeve disposed within the housing cavity and
1~ the oscillating drive shaft engaging the sleeve; and
19 Fig. 7 is a plan view of dental flossing thread in
2Q accordance with tbe invention having a thread segment ~ith a
21 non-elastic loop at one end and an elastic loop at the opposite
22 end
225
28
29
~2~4~
DESCRIPTION OF T~E PREF~R~D E~BOD~MENTS
1 Referring now to Fig. 1, a dental prophylaxis device
2 according to the in~ention comprises an elongated, generally
3 tu~ular housing 11 having a pair of tynes 13 and 15 disposed
~4 thereon at one end are provided with guide grooves 16 and 18,~5 respectively, on the shouldersthereof. At the opposite end, t~e
6 housing is adapted to be connected to a collar 17 6y any con-7 venient means, such as a screw 19 or the like. In turn, collar
8 17 is adapted to be snap-fitted or friction-fitted to second
9 housing means 21 containing suitable driving means to impart
oscillating motion to a drive shaft or the like as explained
more fully hereinbelow and, optionally, a power source such as
12 a rechangeable battery (not shown). Alternatively, the second
13 h.ous.ing may be adapted in a convenient manner to be connected
14 to an electrical outlet by means of a suitable electrical cord
and plug (not shown) in order to energize the device. The second
16 housing means is also provided with a s-~itch 23, more particular~ ,
17 seen in Fig. 5, for activating or deactivating the device.
18 Housing means 11 has a stationary support means 25,
19 such as 3 post, located on its upper surface substantially midway
bet~een the bases of the tynes 13 and 15, as more particularly
21 shown in Fig. 3. In addition, oscillating support means 27, such
22 as a post, is located on the front end of housing 11 between the
23 bas:es: of the tynes, as more particularly shown in Fig. 4. The
24 oscillating support means is attached in a convenient manner,
s~uch. as with a hu~ 28, to one end of a cylindrical sleeve dis-
26 posed axlally within the housing, as explained more fully here-
27 i~nafter,
28 As shown in Fig. 1. tynes 13 and 15 have slotted
2g openi:ngs 2q and 31, respectively, into which a dental tape or
.~0 floss, generally referred to by numeral 3~ and provided with
~ -10-
12446~Z
1 loops 35 and 37 at each end, is inserted and anchored on the
2 stationary and oscillating support means. Thus, the dental tape
3 or floss extends across the space between the slotted ends of
4 the tynes as may be seen particularly in Fig. 4.
As illustrated more particularly in Fig. ~, the dental
6 prophylaxis device of this invention comprises, therefore, two
7 fundamental or main elements. These are the housings 11 and 21
8 which are cooperatively joined to each other by collar 17.
9 In this connection, it is to be understood, however, that housing
11 may be shaped so that the collar 17 is an integral portion
1 thereof and adapted to be friction-fitted directly to housing 21,
12 thus eliminating the need for separate collar 17, screw 19 and
13 its mating nut 39.
14 As may be seen in Fig. 6, housing 11 has a genèrally
elongated internal cavity 41 in which a generallyelongated hollow
16 cylindrical sleeve 43 having oscillating support means 27 fixed
17 thereon is axially disposed, the sleevebeing of slightly smaller
18 overall diameter than the internal diameter o~ the cavity. Thus,
19 the sleevefreely oscillates in the cavity and imparts oscillating
motion to support means 27. As illustrated, sleeve 43 is also
21 provided with an internal cavity 45 which may extend either partl r
22 through the length thereof, as shown, or completely therethrough.
23 An oscillata~le drive shaft 47 projecting from housing 21 and
24 having dimensions sufficiently larg~ to be frictionally engaged
within cavity 45 of the sleeve is disposed in that cavity to im-
26 part oscillating motion to the sleeve when the driving means
27 is in motion.
28 Turning next to Fig. 7, dental tape or floss, generally
29 designated by numeral 33, in accordance with this invention com-
prises a thread segment 49, a loop 35 which is non-elastic at one
~Z4q6~
1 end and a second loop 37 which is elastic at the opposite. end.
2 In its disposition on the dental prophylaxis drive of the in-
3 vention, the thread segment 49 of tape or floss 33 is inserted
4 in the slotted grooves of the tynes and passes through the guide
grooves on the shoulders thereof with the non-elastic loop 35
6 being disposed on the oscillating support means 27 and the
7 elastic loop 37 6eing disposed on the stationary support means
8 25 of housing 11.
9 The various elements of the dental prophylaxis device
0 of this invention, excluding the tape or floss, may be made from
a wide variety of materials, either metals or plastics. In
12 general, plastica such as nylon, polyesters and the like are
13 preferred since they can be more readily shaped or molded at a
14 lower cost wh.ile still having the required strength.
Insofar as the tape or floss is concerned! it can be
16 made. from natural orsynthetic thread material, such as, for
17 example, cotton and nylon, and the like with a non-elastic
18 loop attached in any convenient manner to one end and an elastic
19 loop, such as, for example, a ruhber band, attached in any
convenient manner at the opposite end, ~lternatively, and pra-
21 ferab.ly, the tape or floss can be made from a synthetic thread
22 h.aving alternate non-elastic and elas.tomeric segments cut into
23 the desired premeasured lengths to provide individual lengths
24 of floss having a non-elastic segment and an elastomeric segment
at OppQs-ite ends and then forming the non-elastic loop and el-
26 astomeric loops at each end by employing the respective non-
27 elasti~c and elastomeric ends turned back upon themselves and
28 ~Qined in any convenient manner.
29 Due to the unique construction of the device of this
inventi:on, it can bemarketed for use by the ultimate consuming
l~Z446~Z
1 public as a wh.ole or in parts. For example, an initial pur-
2 chaser ~ill normally obtain the whole device 9 that is the housing
3 11, second housing 21 and at least one dental tape or floss. On
4 t&.e other hand, an ample supply of tapes can also be provided wit
S the initial purchase or sold separately a~ a later time. More-
6 over, a consumer who bas already undertaken the initial purchase
7 can, as needed, simply purchase at a subqequent time either the
8 housing 11 or housing 21 should replacement parts be needed or
9 desired for one reason or another. For example, where a device
is to be employed by a number of individuals in a household,
only one housing 21 may be purchased along with an adequate sup-
12 ply of tapes and a sufficient number of housings 11 to accommo-
13 date each individual member of the household.
14 In use, the dental prophylaxis device of this inven-
tion operates in the following manner. When the switch 23 on
16 h.ousing 21 is in the "on" position, the device is energized,
17 either through a battery or through electrical means as mentioned
18 above., imparting power to the driving means and oscillating the
19 drive shaft 47, In turn, drive shaft 47 imparts oscillating
motion to the crlindriral sleeve 43 and thus oscillates post 27
21 fixed to hu~ 28. As a result of such oscillating motion, the
22 thread segment 4q of dental tape or floss 33 disposed across the
23 space between the ends of tynes 13 and 15, and with its non-
24 elastic loop s.upported on oscillating post 27 and elastic loop
supporte.d on ~tationary post 25, reciprocates between the tynes.
26 Consequently, when the reciprocating thread segment 49 is placed
27 in contact ~ith dentition surfaces to be treated and reciprocates
28 ove.r those surfaces, tensile force is applled thereto by such
29 contact and the elastic loop of the tape e~pands and contracts
in resp~nse to such force. Moreover, because of the e~pansion
-13-
12~46t32
1 and co~traction of the elastic loop, the thread segment of the
2 tape is provided with the proper tension at all times, thus in-
3 suring that the thread segment adjusts to the contour of ehe
4 dentition surfaces at all times, thereby providing maximum con-
S tact of the dental tape with the dentition surfaces. On the
6 other hand, should the tape or floss catch or jam, the elastic
7 loop will further expand, becoming slack, and the reciprocating
8 movement of the tape or floss will cease, even though the power
9 is on and imparting oscillating motion to post 2? on which the
non-elastic loop is supported.
11 Therefore, expressed in other terms, a dental proph~-
12 laxis process in accordance with this invention comprises con-
13 tacting dentition surfaces to be treated with a dental tape or
14 floss ha~ng a thread segment providedwith a non-elastic loop at
one end and an elastic loop at the opposite end, reciprocating
16 the thread segment over the surfaces of the dentition while
17 expanding and contracting the elastic loop in response to the
lo application of tensile force to the tape or floss as it recip-
19 rocates over the dentition surfaces and absorbing the tPnsile
force imparted to the dental tape or floss w~en it encounters
21 resistance as it reciprocates over the dentition surfaces and
22 the elastic loop expands. It is to be noted in this respect that
23 as achieved in the inventive process, reciprocation of the dental
24 tape or floss takes place across the space between the spaced,
stationary t~ne~ of the device of the invention which bracket
26 the dentition surfaces being treated, Moreover, in this respect
27 it is to be further understood that the oscillating movement
28 imparted to the tape or floss, in accordance wiht the invention,
29 occurs along an axial line substantiall~ at a right angle to the
axis of reciprocation of the thread segment of the tape or floss.
12q46~2 ~
1 In utilizing the device and carrying out the process
2 of this invention, medication may, if desired, be applied to the
3 dental floss and transferred to the dentition surfaces over whic
4 the floss reciprocates. Consequently, in this respect, the pro-
cess of this invention in its more specific aspects also includes
6 the application of such medication to the dentition surfaces bein
7 treated.
8 The dental prophylaxis device and process of this
9 invention present numerous advantages. Among such advantages
are those resulting from the unique construction of the dental
11 tape or floss per se. For example, the provision of tape or flos
12 segments having loops at both ends allows easy positive attach-
13 ment of the floss to the stationary and oscillating posts of the
14 housing without any additional complex means of fixation such as
are needed in many of the known flossing devices. Moreover, the
16 tape or floss segments can be manufactured to one pre-measured
17 length sufficient to span the space between the tynes and be
18 arranged over the posts. Thus, a minimum amount of floss is uti-
19 lized. In addition, replacement tapes or floss can be manufac-
tured and marketed less expensively than tapes suitable for use
21 in known flossing devices.
22 The utilization of an elastic loop on one end of the
23 tape or floss segment provides "built-in" tension control of the
24 floss, as well as positive return to start position. The
positive '`built-in" tension control of the tape or floss assu-~es
26 maximum contact of the floss wieh the dentition surfaces being
27 treated at all times, thus substantially eliminatin~ point to
28 point c~tact of dentition surface and floss which occurs if the
29 tape is too tense, as is the case in many of the known devices
~0 or no action if the tape is too slack. At the same time, however
-15-
~ 6~3~
1 the proper positive tension provided by the use of the elastic
2 loop on the tape permits the floss to stop reciprocating even
3 though the power is on should the floss become caught or jammed
4 on the dentition surface heing treated. Still further, the
provision of proper positive tension on the floss by the use of
6 the elastic loop substantially eliminates irritation which often
7 occurs with known flossing devices due to excessive tension
8 imparted to the floss by such devices. Finally, the use of tape
9 or floss segments with looped ends and its ease of attachment or
0 fixing to the device eliminates extensive handling of the tapes
and is thus more hygienic.
12 Insofar as the housings and related elements of the
13 device are concerned, they are relatively easy and inexpensive
14 to manufacture with readily available materials and a plurality
of the housing portions provided with the tynes can be sold for
16 use with one driving means. Moreover, the housing portion
17 h,a~ing the tynes can also be sold separately and adapted for
18 attachment for use with equipment normally found in a dental
19 office. Furthermore, since the tynes are stationary and only
the tape or floss reciprocates, the device is easier to employ
21 without the danger of damaging dentition surfaces by contact
22 thereof with the tynes, as is the case with devices which have
23 to be manipulated by hand in the mouth of a user in order to
24 reciprocate or otherwise move the tape or floss.
It is to be understood that the device and process of
26 this invention provide a mechanical flossing means for the re-
27 moval o~ plaque on the inter-proximal surfaces of the teeth and,
28 as such, are much more efficient than hand flossing methods.
29 Moreover, the device and process of this invention eliminate many
of the problems inherent in previous devices since the tapes
~Z4468Z
l or floss can be attached to the mechanical portions of the device
2 in a matter of seconds and the unique structure of the floss
3 loop eliminates previous means of securing floss by winding and
4 the like. ~oreover, as mentioned hereinabove, the unique floss
segments of this invention can be manufactured in exact lengths,
6 which is usually 2 inches, in order to fit the device. With
7 the device and in accordance with the process the floss moves
8 rapidly and conforms to the contours of the dentition surfaces
9 without loss of speed or creating slack as often occurs in known
0 devices and the entire dentition surface can be flossed effi-
11 ciently in a matter of minutes. Furthermore the device and
12 process of this invention are harmless to tissue and the tape or
13 floss will stop moving if it beco~es jammed on a dental filling
14 or the like. Furthermore, as previously mentioned, the tynes
do not move as in some known devices, thus obviating the danger
16 of damaging tissue and dental surfaces by abnormally sharp
17 contact of th.e tynes therewith.
18 It is also to be noted that the device can be used
19 advantageous.ly hy all age groups, from pre-school age children
to adults. and moreQver, the device can be utilized with great
21 facility by a parent to floss a child's teeth. In addition,
22 the entire device is easily cleaned or sterilized, thus providing
23 hygienic henefits. The loops, due to their low cost,are dis-
24 pos.able after use, thus also providing increased hygienic stan-
dards~
26 The reciprocal action of the tape or floss is
27 benefi~cial in treating and preventing periodQntal disease, that
28 is gingivitIs since the sulci b.etween the teeth can be reached
29 easil~ hy the dental tape usedwith the device. ~oreover, the
me.chanical action of the device, in accordance with the process?
lZ44~Z
1 debrides the tissues of bacterial colonies, necrotic tissue and
2 organic debris, accomplishing this without irritation while at
3 the same time providing a stimulating effect which promotes the
4 formation of the hornified layer of cells that normally protects
the underlying tissues from trauma and bacterial invasion.
6 Numerous other advantages of the inventive device and process
7 will be readily apparent to those skilled in the art.
8 It is to be understood that the descriptive embodi-
9 ments of this invention set forth herein are illustrative only
0 and the concepts of this invention are not to be limited
ereby, e~ccept as defiDed in th~ tppeDd~d clal=s.
21
22
23
24
26
27
28
29
