Polytetrafluoroethylene therapeutic articles

Polytetrafluoroethylene surfaced articles can be coated with various adjuvants such as medicants and flavorants. The coated articles can be dental flosses, toothpicks, and tongue depressors. The dental flosses can be of a monofilament or a multi-filament type. Further, they can be a filament of polytetrafluoroethylene or have a coating of polytetrafluoroethylene.

BACKGROUND OF THE INVENTION 
The present invention is directed to polytetrafluoroethylene surfaced 
articles which contain thereon an adjuvant material. More particularly, 
the present invention is directed to polytetrafluoroethylene therapeutic 
articles for use in the oral cavity and which have thereon an adjuvant 
substance such as a medicant and/or flavorant. 
Polytetrafluoroethylene is a material which is well known for its surface 
lubricity. Polytetrafluoroethylene due to its compact carbon and fluorine 
structure has the property whereby the surface is highly resistant to the 
adhesion of most substances. In fact, it is this property of 
polytetrafluoroethylene that has been primarily utilized in the design of 
various articles. When it is desired to have a surface to which other 
substances will not adhere, it is common to coat that surface with a layer 
of polytetrafluoroethylene. The use of polytetrafluoroethylene is enhanced 
since it can withstand high temperatures. This is the case with regard to 
platens, pans, rollers, and the like. The lower degree of adhesion of 
polytetrafluoroethylene for most substances provides an effective 
technique for processing materials through machinery and not having such 
materials adhere to parts of the machinery and to otherwise create 
problems in the operation of such machinery. However, just as 
polytetrafluoroethylene has many effective uses where it is desired that 
other materials not adhere to its surface, it is difficult to 
intentionally adhere substances to its surface. 
In the design and construction of various articles for therapeutic use in 
the oral cavity, it is desirable to use polytetrafluoroethylene articles 
or polytetrafluoroethylene coated articles for this purpose. 
Polytetrafluoroethylene has many properties which are useful in the design 
and construction of the therapeutic articles. However, it is likewise 
desirable in many instances for such articles to have a coating of a 
medicant and/or a flavorant. This presents the difficulty of how to get a 
medicant and/or a flavorant effectively adhered to the surface of 
polytetrafluoroethylene. This problem is made all the more difficult when 
it is considered that the articles after being coated with the medicant 
and/or flavorant must be able to undergo subsequent processing, packaging, 
handling and usage without the medicant or flavorant unintentionally 
becoming detached from the polytetrafluoroethylene surface. 
One very useful therapeutic article that can be constructed from 
polytetrafluoroethylene is dental floss. This can be a monofilament or a 
multi-filament dental floss. It has been found that a monofilament of 
polytetrafluoroethylene is a very effective dental floss. This can be a 
monofilament of polytetrafluoroethylene or a nylon, dacron, or other 
filament coated with polytetrafluoroethylene. A polytetrafluoroethylene 
monofilament dental floss or a polytetrafluoroethylene surfaced 
monofilament dental floss will have a thickness to width ratio of at least 
about 1 to 10, and preferably about 1 to 50 to about 1 to 500. The width 
of the monofilament will be at least 10 times the thickness, and 
preferably about 50 to 500 times the thickness of the 
polytetrafluoroethylene monofilament. A polytetrafluoroethylene dental 
floss having such a thickness to width ratio can be easily inserted 
between teeth for the removal of substances adhering to the teeth as well 
as for removing food particles from between the teeth. When in the form of 
a multi-filament floss, each strand will be of a diameter of about 0.1 to 
0.001 millimeters and will consist of from about 10 to 1000 fibers. These 
fibers will be in a twisted arrangement. A problem is that it has not been 
possible to provide either a medicant or a flavorant coating on such a 
dental floss product. This is the case, since as discussed above, the 
surface of polytetrafluoroethylene has a high lubricity to which 
substances adhere only with difficulty. 
Most of the dental floss products that are available today are 
multi-filament materials. These multi-filament materials include nylons 
such as nylon 6 and nylon 66, rayons, dacron, acetate polymers, 
polypropylene polymers, cotton, wool and other natural fibers. Examples of 
such multi-filament dental flosses are set forth in U.S. Pat. Nos. 
3,897,795, 3,943,949, 4,033,365, 4,414,990, 4,548,219, 4,583,564 and 
4,638,823. These fibers that are usually used in producing multi-filament 
dental flosses have surfaces to which it is rather easy to adhere various 
medicants and/or flavorants. Further, the very nature of the 
multi-filament structure of such flosses also makes it easier to adhere a 
medicant and/or a flavorant. That is, the medicant and/or flavorant can be 
held within the interstices between the individual fibers which make up 
the multi-filament dental floss. The foregoing patents which have been 
cited to illustrate multi-filament dental flosses also disclose having 
various adjuvants as a part of the dental floss and techniques for 
adhering these various adjuvants to the multi-filament dental flosses. 
Monofilament dental flosses are known. In U.S. Pat. Nos. 3,800,812 and 
4,617,950, there are disclosed monofilament dental floss products. In U.S. 
Pat. No. 3,800,812, the dental floss is disclosed to be an elastomeric 
monofilament material. In U.S. Pat. No. 4,617,950, the fibers that are 
disclosed to be useful as a monofilament comprise the fibers that are 
conventionally used to make dental flosses. However, neither of these 
patents discloses a dental floss which is comprised of an effectively 
coated polytetrafluoroethylene monofilament. In U.S. Pat. No. 4,776,358 
there is disclosed a polytetrafluoroethylene dental floss. However, this 
dental floss is not a coated monofilament floss. In addition, the dental 
floss that is disclosed in this patent contains a paste which is 
sandwiched between two pieces of polytetrafluoroethylene. The objective in 
this patent is to have the dentifrice that is contained within the floss 
flow from the floss while the floss is being used. There is no disclosure 
in this patent with regard to adhering a medicant, flavorant or other 
substance to the surface of polytetrafluoroethylene. There is also 
available a monofilament, polytetrafluoroethylene dental floss. However, 
this floss is not coated with any medicants, flavorants or related 
substances. 
The problem of adhering a medicant, flavorant or related substance to the 
surface of polytetrafluoroethylene has now been solved. A composition has 
been found which will adhere to the surface of polytetrafluoroethylene and 
which will not be removed during any further processing, packaging or 
handling. That is, a medicant and/or flavorant will be substantially 
maintained on the polytetrafluoroethylene surface until the point in time 
that it is to be removed from the polytetrafluoroethylene surface. It is 
therefore now possible to provide polytetrafluoroethylene articles, or 
polytetrafluoroethylene surfaced articles, which have a coating of a 
medicant and/or a flavorant. Such articles, as previously noted, are 
effective for therapeutic purposes. In particular, such articles such as 
dental floss, tooth picks, dental tape, tongue depressors and the like can 
be more effectively used. 
BRIEF DESCRIPTION OF THE INVENTION 
The present invention is directed to polytetrafluoroethylene or 
polytetrafluoroethylene surfaced articles which have a coating adhered 
thereon. More particularly, the present invention is directed to 
therapeutic articles which have a coating of a medicant, and/or a 
flavorant and which can be utilized in the oral cavity. It has been found 
that as a part of a certain composition, a medicant and/or a flavorant can 
be adhered to the surface of polytetrafluoroethylene. This adhesion to the 
surface of polytetrafluoroethylene is sufficiently strong so that it is 
not removed frown the polytetrafluoroethylene surface during further 
processing, packaging or handling. However, during usage as a floss, the 
medicant and/or flavorant will be dissolved from the surface of the floss. 
A medicant and/or flavorant is applied to the surface of 
polytetrafluoroethylene from an aqueous emulsion which contains the 
medicants and/or flavorants ad other adjuvants and which, in addition, 
contains polyvinyl alcohol and polyethylene glycol. If the composition is 
to be a flavorant, it may also contain a sweetener, and preferably a 
non-carbohydrate sweetener. This composition is applied to the 
polytetrafluoroethylene surface from an aqueous emulsion. After the 
aqueous emulsion is applied to the surface of the polytetrafluoroethylene, 
the polytetrafluoroethylene is dried with the medicant and/or flavorant 
thereby adhering to the polytetrafluoroethylene surface. 
DETAILED DESCRIPTION OF THE INVENTION 
As has been noted above, it is difficult to adhere substances to the 
surface of polytetrafluoroethylene. This is the case regardless of the 
type of polytetrafluoroethylene. This can be an expanded or non-expanded 
polytetrafluoroethylene. It can also be a monofilament or a multi-filament 
polytetrafluoroethylene. Further, this is the case whether an article is 
constructed entirely of polytetrafluoroethylene or if it only contains a 
polytetrafluoroethylene surface. Due to the high surface lubricity of 
polytetrafluoroethylene, it is difficult to get substances to adhere to 
its surface. This applies to medicants and/or flavorants which include 
fluorides, anti-plaque, anti-caries, anti-bacterial and tartar control 
agents, coagulants, coolants, colorants and polishing agents. However, it 
has been found useful to have medicants and/or flavorants as a part of the 
surface of various therapeutic articles that are to be used in the oral 
cavity. That is, it has been found to be useful and desirable to have 
medicants and/or flavorants on the surface of therapeutic articles such as 
tooth picks, tongue depressors and dental floss. It has also been found to 
be useful to have such therapeutic articles constructed of 
polytetrafluoroethylene, or to have a polytetrafluoroethylene surface. 
This is particularly the case with regard to dental floss. This can be a 
multi-filament dental floss, but it has been found to be very effective to 
utilize a monofilament of polytetrafluoroethylene as a dental floss. This 
dental floss is highly resistant to breaking, has an inherent lubricity 
which makes it easier to insert between teeth, and due to its shape is 
very effective in removing substances from teeth as well as for removing 
food particles from between teeth. 
A useful polytetrafluoroethylene for a dental floss is an expanded 
polytetrafluoroethylene in a tape form. Such a polytetrafluoroethylene has 
a tensile strength of at least about 8000 pound per square inch (psi) 
(68,950 pPa) and a polymeric matrix strength in excess of about 100,000 
psi (689,500 kPa). Such a polytetrafluoroethylene also has a porosity of 
at least about 90 percent. However, a conventional extruded and calendered 
tape form of polytetrafluoroethylene can also be used. In addition, an 
essentially circular cross-section polytetrafluoroethylene filament can be 
used. 
Medicants, flavorants and other substances can be adhered to the surface of 
polytetrafluoroethylene through the use of a polymer which has an affinity 
for the surface of polytetrafluoroethylene and which is at least partially 
water soluble. The binder must be at least partially water soluble so that 
an effective amount of the medicant and/or flavorant can be released. 
Although any compositions which have a high degree of adherence to 
polytetrafluoroethylene and which are at least partially water soluble, 
can be used, a preferred composition consists of polyvinyl alcohol and 
polyethylene glycol as the adhering agents. It has been found that an 
aqueous emulsion containing polyvinyl alcohol and polyethylene glycol can 
be effectively utilized to adhere medicants and/or flavorants to the 
surface of polytetrafluoroethylene. In one embodiment, the medicants 
and/or flavorants are made a part of the aqueous emulsion of polyvinyl 
alcohol and polyethylene glycol. In such an instance, the medicants and/or 
flavorants must be at least partially soluble in the aqueous emulsion 
medium. In order to coat the polytetrafluoroethylene surfaced articles, it 
is only necessary to contact the article with the emulsion. After contact 
with the emulsion, the article is then dried to remove moisture and to 
thereby set the polyvinyl alcohol-polyethylene glycol composition onto the 
polytetrafluoroethylene surface. This dried polyvinyl alcohol-polyethylene 
glycol composition will also contain the medicants and/or flavorants which 
were a part of the coating emulsion. If the medicants and/or flavorants 
are not significantly soluble in the emulsion composition, other solvents 
can be added in order to increase the solubility of the medicants and/or 
flavorants in the emulsion composition. The most effective way to apply 
the medicants and/or flavorants to a polytetrafluoroethylene surface is by 
having the medicants and/or flavorants dissolved in the emulsion 
composition. 
The medicants that can be added include the K vitamins (1-4), calcium ions 
and blood factors which initiate the blood cascade. In addition, the 
medicant can include coagulants such as aminocaproic acid, tranexamic 
acid, adrenaline, alum, noradrenaline, iron salts, zinc salts and calcium 
alguate. Other coagulants and other medicants can also be used. Other 
medicants include antibiotics such as tetracycline, cetyl pyridinium 
chloride, benzethonium chloride and other quaternary salts, chlorhexidine, 
hexachlorophene and wound healing agents such as allantoin and zinc 
sulfate. In addition, the composition can contain a preservative such as 
sodium benzoate, citric acid, benzoic acid, ascorbic acid and erythrobic 
acid. 
The composition may also contain a dentally accept colorant such as FD&C 
red 3 and FD&C red 4. 
The fluoride agents that can be a part of the composition include sodium 
fluoride, sodium monofluoride phosphate and stannous fluoride. A dentally 
accepted cooling agent such as menthol or analogues such as 
N-ether-p-methane-3-carboxamide can also be a part of the composition. In 
addition, there can be present a polishing agent such as a water insoluble 
phosphate, amorphous silica, alumina or calcium carbonate. 
The anticalculus agents include the linear molecularly dehydrated alkali 
metal or ammonium salts of such as sodium hexametaphosphate, sodium 
tripolyphosphate, dissodium diacid phosphate, trisodium monoacid 
phosphate, tetrasodium polyphosphate and polyphosphates having the general 
formula of (NaPO.sub.3).sub.n where n is 2 to 125. This polyphosphate and 
other phosphates are preferably used in conjunction with synthetic anionic 
linear polymeric polycarboxylates. These include copolymers of maleic 
anhydride or acid with methyl vinyl ether having a molecular weight of 
30,000 to 1,000,000 and available under the tradenames Gantrez AN 139, 
Gantrez AN 119 and Gantrez S-97. 
A sweetener can also be a part of the composition. Preferably, such a 
sweetener is a non-carbohydrate sweetener such as sodium saccharin or 
phenylalanine. 
The preferred emulsion composition will contain from about 40 to 80% by 
weight water, about 5 to 20% by weight polyvinyl alcohol, about 10 to 40% 
by weight of the medicants, flavorants, and other additives, and about 1 
to 4% by weight of polyethylene glycol. Most preferably, the emulsion 
composition will contain about 67% by weight water, about 10% by weight 
polyvinyl alcohol, about 20% by weight of medicants, flavorants and other 
additives, and about 2% by weight of polyethylene glycol. 
The various adjuvants, amounts of the various adjuvants, that will be a 
part of a composition will depend on the particular adjuvant and the 
composition. An artificial sweetener will range in content from about 0.25 
to 1.0 percent by weight. A flavorant will be present in an amount of 
about 5 to 25 percent by weight depending on the flavorant. When present, 
an anti-calculus agent will be present in an amount of about 0.5 to 10 
percent by weight. The fluoride agent will be present in an amount of 
about 0.005 to 1 percent by weight. A polishing agent, if present, will be 
in a content of up to about 4 percent by weight. Each of antibiotics, 
coagulants, wound healing agents, preservatives, coolants and colorants 
will be present in an amount of up to about 2 percent by weight. 
The polytetrafluoroethylene therapeutic articles that can most usefully be 
coated with medicants and/or flavorants are dental flosses. In one 
embodiment, the dental floss is a monofilament strand of 
polytetrafluoroethylene, or a polytetrafluoroethylene coating on a base 
fiber. The base fiber can be nylon, dacron, acetate polymers, 
polypropylene, cotton, wool or other fiber. This monofilament strand has a 
thickness of about 0.001-0.003 mm and a thickness to width and a ratio of 
at least 1 to 10, and preferably a thickness to width ratio of between 
about 1:50 to about 1:500. That is, the dental floss is considerably wider 
than it is thick. In preparing this dental floss, the monofilament strand 
of polytetrafluoroethylene is fed through a bath of the above aqueous 
emulsion composition which contains the polyvinyl alcohol, polyethylene 
glycol, medicants and/or flavorants. As the strand of 
polytetrafluoroethylene passes through the bath, it picks up a sufficient 
amount of the emulsion composition and is then passed into a drying 
chamber. This drying chamber can be a tube surrounded by heating elements 
and having an inlet for the flow of air. Air that is flowed into the 
drying chamber will purge the drying chamber of moisture. The strand of 
polytetrafluoroethylene leaves the drying chamber with the non-water 
components of the emulsion coating composition adhered to the 
polytetrafluoroethylene surface. This now coated strand of 
polytetrafluoroethylene is wound on a spool and can be utilized for dental 
flossing. 
In addition to the dental floss being a monofilament of 
polytetrafluoroethylene, or a base fiber coated with 
polytetrafluoroethylene, it can also be a multi-filament dental floss. 
Each component filament can be a polytetrafluoroethylene filament or a 
base fiber coated with polytetrafluoroethylene. The base fiber can be 
essentially any fiber such as those set out above. Each filament that 
makes up the multi-filament strand of dental floss will be of a diameter 
of about 0.1 to 0.001 millimeters and will consist of from about 10 to 
1000 fibers. These fibers will be in a twisted arrangement. The coating on 
the polytetrafluoroethylene surface which serves to bond the medicants 
and/or flavorants to the fiber also will decrease the lubricity of the 
polytetrafluoroethylene surface to such a point that the fibers will 
maintain a twisted arrangement until used. When used, such a 
multi-filament dental floss will become splayed into a more flat shape. 
This will be a shape similar to that of the monofilament dental floss. 
Each filament of the multi-filament dental floss preferably will be coated 
with the medicant and/or flavorant using the method for coating the 
polytetrafluoroethylene monofilament dental floss. Likewise, any of the 
compositions used for coating the polytetrafluoroethylene monofilament can 
be use for coating the strands of the multi-filament floss. After coating 
the strands would then be formed into the multi-filament floss. However, 
it is also feasible to first form the multi-filament floss and then to 
apply the coating. The processing steps of applying the coating would be 
essentially the same. 
A particular advantage to the present coatings on a strand of 
polytetrafluoroethylene is that it serves to reduce the lubricity of the 
surface of the polytetrafluoroethylene whereby the polytetrafluoroethylene 
strand can more easily be wound and otherwise manipulated. An uncoated 
polytetrafluoroethylene strand due to its high lubricity presents 
difficulties in winding due to slippage of the fibers, one over another. 
This is an unexpected advantage with regard to these coatings. 
When it is desired to use these coated polytetrafluoroethylene as a dental 
floss, a segment of the polytetrafluoroethylene floss, whether a 
monofilament or a multi-filament, is removed from the spool and is used in 
the manner of other dental flosses. During flossing, the medicants and/or 
flavorants that had been coated onto the surface of the 
polytetrafluoroethylene are released and utilized in the oral cavity. 
These medicants and/or flavorants are released since the dried coating 
when in contact with saliva in a persons mouth will become redissolved and 
reemulsified and thereby stripped from the surface of the 
polytetrafluoroethylene.

The present invention will now be set forth in more detail with reference 
to the following examples. 
Examples 1-5 
These examples illustrate the coating of an expanded microporous 
polytetrafluoroethylene tape having a thickness of 0.001-0.002 mm and 
width of 2-3 mm with fluoride and an anti-calculus agent medicants. This 
tape is unwound from a spool and passed through a coating both which 
contains the coating solution. The polytetrafluoroethylene tape containing 
the wet coating is then passed through a drier maintained at above 
100.degree. C. The polytetrafluoroethylene tape is in a last step, wound 
onto a spool. The composition of the coating solution in grams for each of 
the examples is set out in Table 1. 
TABLE 2 
__________________________________________________________________________ 
Polyvinyl 
Polyethylene 
Sodium Gantrez 
Tetrasodium 
Example 
Alcohol 
Glycol 4000 
Fluoride 
Glycerine 
S-97 Polyphosphate 
Water 
__________________________________________________________________________ 
1 292.2 g. 
100.0 g. 
4.0 g. 
60.0 g. 
60.0 g. 
80.0 g. 1403.8 g. 
2 292.2 g. 
100.0 g. 60.0 g. 
60.0 g. 
80.0 g. 1407.8 g. 
3 146.1 g. 
50.0 g. 
2.0 g. 
30.0 g. 
60.0 g. 
40.0 g. 671.9 g. 
4 29.22 g. 
10.0 g. 
0.4 g. 
6.0 g. 
12.0 g. 
8.0 g. 67.19 g. 
5 68.05 g. 
25.0 g. 
1.0 g. 
15.0 g. 
20.0 g. 
30.0 g. 340.95 g. 
__________________________________________________________________________ 
Each of these compositions produced a suitable coating emulsion. The 
coating adhered to the polytetrafluoroethylene surface after drying and 
was an essentially continuous coating on the polytetrafluoroethylene tape. 
The polyphosphate content of the floss of Example 1 was 0.29 percent by 
weight and the fluoride content 104 ppm. The .flosses of Examples 2 
through 5 exhibited good coatings and had an acceptable uptake of 
fluoride and the anti-calculus component of polyphosphate and Gantrez 
S-97. 
Examples 6-8 
These examples illustrate the coating of an expanded 
polytetrafluoroethylene tape having the dimensions of Examples 1-5 with 
flavorants. The tape is unwound from a spool and passed through a coating 
bath which contains the coating solution. The coated 
polytetrafluoroethylene tape is then dried and wound onto a spool. The 
coating solution for each of the examples is set out in Table II. 
TABLE II 
______________________________________ 
Poly- Poly- 
Exam- vinyl ethylene Sodium Distilled 
ple Alcohol Glycol Flavorant* 
Saccharin 
Water 
______________________________________ 
6 25.0 g. 10.0 g. 100.0 g. 
2.5 g. 362.5 g. 
7 42.0 g. 15.0 g. 62.5 g. 3.75 g. 376.75 g. 
8 20.0 g. 4.0 g. 40.0 g. 1.0 g. 135.0 g. 
______________________________________ 
*Mint Flavorant 
Each of the examples yielded as essentially continuous coating on the 
polytetrafluoroethylene tape. There was also an acceptable degree of mint 
flavorant take-up and solvolysis during use. 
Examples 9-10 
Examples 9 and 10 set forth the coating of a polytetrafluoroethylene 
expanded tape floss having the characteristics of that of Examples 1-5 
with a wax which contains a flavorant. The wax is a microcrystalline wax 
Wico W-455. The wax is melted by heating to 180.degree. F. The flavorant 
was vigorously mixed into the molten wax so that it was dispersed in the 
wax. The polytetrafluoroethylene tape is run through the molten flavored 
wax bath and coated with the flavored wax. In Example 9, the flavorant 
content, of the wax 10 percent. In Example 10, the flavorant content of 
the wax was 20 percent. The flavored wax coated floss materials had an 
unacceptably low flavorant taste when used. Apparently, a sufficient 
amount of flavorant in the wax was not solvated so as to provide an 
acceptable taste. 
Examples 11-12 
In Examples 11 and 12, the polytetrafluoroethylene strand was first passed 
through a flavorant bath and then through a wax bath. In each example, the 
flavorant was mint. The wax was Witco W4-45 wax. In Example 11, the 
flavorant bath was maintained at room temperature and the wax bath at 
200.degree. F. The strand was passed through each bath at 3 ft. per 
second. In Example 12, the flavorant bath was maintained at room 
temperature and the wax bath at 160.degree. F. The strand speed was the 
same as in Example 11. Each of these floss products had an unacceptably 
weak mint flavor taste during use. Apparently, not a sufficient amount of 
flavorant is solvated from the wax in order to produce an acceptable 
taste.