The present invention is in the field of disposable dental floss holders commonly called dental flossers, and more particularly to injection molded dental flossers which each include a handle and a head part with two spaced-apart arms supporting a strand of dental floss extended between and fixed to the distal ends of the arms.
In more recent years dental flossers have become widely used for removing plaque from tooth surfaces, particularly from the generally facing surfaces of adjacent teeth and for removing food particles from the interstices between adjacent teeth. Such interstices may be empty space or may be merely the interface areas of contact between the surfaces of adjacent teeth. For many persons a dental flosser is substantially easier to use than a conventional strand of dental floss wrapped about fingers of both hands and manipulated between teeth, by having fingers of one hand in the mouth and fingers of the other hand outside the mouth.
Typical prior art flossers are disclosed in U.S. Pat. Nos. 5,538,023 and 4,006,750 to Chodorow, U.S. Pat. No. 7,487,785 to Dougan et al., U.S. Pat. No. 6,756,158 to Gwen, U.S. Application No. 2008/0149134 to Crossman, and U.S. Pat. No. 7,204,257 to Crossman.
Initially, many dental flossers employed nylon floss because it was well known, readily available, relatively inexpensive and relatively easy to use in multi-cavity injection molding machines. Over time better dental flosses have been developed, particularly polytetrafluoraethylene (“PTFE”) commonly known as TEFLON®, and ultra high molecular weight polyethylene (“UHMWPE”), the latter dental floss disclosed in U.S. Pat. No. 5,113,880 to Honda. Teflon® floss has a significantly lower coefficient of friction than nylon and thus is far more slippery and easier to manipulate into the interstices between two adjacent teeth, but its disadvantages are stretching, shredding and breaking in vigorous use. Nevertheless, PTFE flossers were considered to be a substantial and popular improvement over nylon floss flossers.
As compared to nylon, UHMWPE dental floss has (a) significantly greater strength to resist stretching, shredding and breaking, and (b) significantly lower coefficient of friction than nylon, but not as low as that of PTFE floss. Thus, UHMWPE flossers generally require greater effort, finger dexterity and strength than PTFE flossers when penetrating tight spaces, but UHMWPE flossers have the advantage of little to no stretching or breakage in use. In summary, while nylon dental floss is employed in some flossers in multi-cavity injection molding, for many the preference is either PTFE floss as the most slippery or UHMWPE floss as the strongest and still quite slippery.
Also, in the prior art are dual strand dental flossers, each having a pair of closely adjacent strands of dental floss extending across the flosser head or bow portion, as disclosed in U.S. Pat. Nos. 5,692,531, 5,829,458 and D401,701. In such dual strand flossers there typically is a lead strand that is most remote from the base of the flosser head, and a follower strand that is parallel and closely adjacent to the lead strand and closer to the base of the flosser head. The two stands are intended to provide more plaque-scrubbing surface area of the floss material so that for each stroke of the flosser in either the axial or transverse direction of the floss, more tooth surface area is scrubbed by two strands instead of by one strand. The follower strand, often spaced about one to five millimeters behind the lead strand, scrubs or wipes immediately after the lead strand.
Prior art dual strand flossers have two strands of floss, both strands being of the same material, such as nylon, PTFE or UHMWPE, the choice of material being based upon: (1) the floss characteristics of interest, (2) the theory that two strands produce twice the scraping surface of one of whatever floss was selected, and (3) the logical conclusion that it is easier in conventional manufacturing processes (which require engagement and stretching the strands across the multi-cavities of a mold), to apply the same stretching force and floss engagement apparatus to both adjacent strands. Thus, the prior art dual strand flossers have either two strands of PTFE floss, or two strands of UHMWPE floss, or two stands of nylon floss.
The present invention provides a multiple strand dental flosser wherein the features of each individual floss strand are selected to provide particular floss advantages.
In one embodiment, the present invention includes a dual strand flosser where the strands have different material characteristics. For instance, in one embodiment, the lead strand has a lower coefficient of friction than the follower strand. More particularly, the lead strand may comprise PTFE microfibers and the follower strand may comprise UHMWPE microfibers, the two strands being generally parallel and extending between and fixed to the end portions of the arms of a flosser head.
In another embodiment, the present invention provides a dual strand flosser where the follower strand is about 400 denier UHMWPE floss of about 120 microfilaments in a Z twist configuration. The UHMWPE strand may have about four twists per inch added to its natural condition, the additional twists maintained during injection molding and subsequent cooling and hardening of the plastic in the flosser head and handle.
The differences in material characteristics of the two strands, such as the lower coefficient of friction of the lead strand, may make it easier for a user to achieve insertion of the floss into a tight interspace between two adjacent teeth. The follower strand of UHMWPE provides higher strength and greater resistance to shredding or stretching during vigorous flossing. Also, the UHWMP follower strand being immediately behind and stronger than the PTFE strand, can support this lead strand from excessive stretching.
In another embodiment, the floss strands are arranged to provide an enhanced cleaning effect. For example, at least a portion of one of the floss strands may be positioned at a different location along the width of the arms than the other of the floss strands.
The floss strands may extend generally parallel to each other, with one floss strand being offset from the other floss strand along the width of the arms, such that the floss strands lie in a plane that extends at an angle to the longitudinal length of the flosser arms.
The floss strands may otherwise be arranged such that they are not parallel to each other. For example, the first end of one floss strand may be positioned closer to the front surface of the flosser arms than the first end of the other floss strand, with the second end of the one floss strand being farther from the front surface than the second end of the other floss strand. As a result, the floss strands may cross each other. In another arrangement, the floss strands may also be positioned such that the first end of one floss strand is positioned closer to the distal end of the arms than the first end of the other floss strand, and the second end of the one floss strand is farther from the distal end than the second end of the other floss strand, such that the floss strands cross each other in two directions. Optionally, the floss strands may contact each other at the location where the strands cross.
The arrangement of the floss strands, with at least a portion of one strand being offset from the other strand along the width of the flosser arms, enables increased engagement between the floss strands and the teeth as the floss strands are inserted between the teeth. In the embodiments wherein the strands cross each other, the strands may be moved back and forth to change the amount of engagement between the floss strands and the teeth.
Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.
A multiple strand dental flosser according to one embodiment of the present invention is shown in
Extending transversely between and fixed to the terminal end parts 20 of each flosser is a set of two adjacent generally parallel strands of dental floss, including lead strand 22 and follower strand 24. In one embodiment, the lead strand 22 is made of PTFE for its extremely slippery (low coefficient of friction) characteristic, and the follower strand 24 is made of UHMWPE for its greater strength and resistance to stretching or shredding. The UHMWPE strands may be 400 denier UHMWPE strands that include 120 microfilaments configured with a Z twist, as are available from Honeywell International Inc. or other commercial suppliers. The PTFE or Teflon® floss is also readily available from many commercial sources, and in one embodiment, the PTFE floss is 200 denier PTFE floss.
Manufacture of the flosser 10 may be conducted in a conventional manner, for instance, by injection molding the flosser 10 in a mold, with the strands of floss placed in the mold prior to molding, such that the arms 18 of the flosser 10 are molded about the strands of dental floss. In one embodiment, multiple flossers 10 may be formed simultaneously in a multi-cavity mold where the plurality of cavities are aligned so that each of the dual strands can be extended in a straight line transversely across all the arms of the aligned flosser cavities. Strands of floss are positioned in grooves in a mold surface between the cavities, so that on closing the mold parts the strands are not crushed. The strands are placed in tension, (a) to make sure they remain straight while traversing the arms of the flosser cavities and remain in the grooves between the cavities, and (b) to incorporate a pre-stretch in each strand to reduce the stretching that might occur in use. In this pre-injection stage the PTFE strand may be stretched about 15% and the UHMWPE strand may be stretched about 3½%. In one method of manufacture, the UHMWPE strands are given about four twists per inch by known twisting techniques to enhance the strength and resistance to stretching of the UHMWPE floss strand to about 3% as compared to a stretch of about 3½% without the further twists. In one embodiment, the flosser may also be manufactured such that the floss strands have differing amounts of tension. For example, the one of the floss strands (whether the strands are formed from the same or different materials) may be provided with a greater amount of pre-stretch than the other strand, or one of the floss strands may be placed in the mold cavity with a predetermined amount of slack.
A variety of different injection molded plastics may be used for form the handle part 12 and the head part 14. Current examples include polystyrene, polyethylene or polypropylene. Both of these plastics have melting temperatures below that of PTFE and/or UHMWPE, so that the dental floss will not be melted or otherwise damaged when the molten plastic for the arms of the floss head is injected around and about the outer surfaces of the portions of the floss extending across the arm portions of the flosser in the mold cavity.
Conventional multi-cavity injection mold and manufacturing techniques produce skeleton-connected aligned molded flossers, with a set of continuous dual strands of floss extending transversely through the end portion of the arms of the aligned flossers. These flossers may subsequently be separated by severing the segments of floss extending between the arms of adjacent flossers where the severing may be made by a hot knife, laser or flame. By this technique the exposed ends of the strands are melted and formed into beads having greater diameter or greater cross-sectional area than that of the original strands, thus restricting the portion of each strand embedded in the arm from pulling through during use of the flosser. The bead may be a single mass of the melted fibers of the strands or multiple tiny beads of the coalesced ends of the fibers and appearing somewhat like a cauliflower. In another embodiment, the adjacent flossers 10 may be separated by cutting the floss strands with a different cutting device that does not melt the strands. If necessary, the strands may be retained in the floss arms by knotting the ends of the strands, or by chemically bonding the floss material to the material used to form the flosser arms 18.
Use of the new dual strand flosser 10 is shown schematically in
In keeping with the general concept of employing two flosses having different material characteristics in the same flosser, it is also possible for a flosser to have the lead strand be of a stronger material, as UHMWPE and the follower strand to be of a more slippery material, as PTFE. This combination might be preferred for extremely tight interstices which may cause a lead strand of PTFE to stretch while a lead strand of stronger UHMWPE would not. In another embodiment, the floss strands may have other characteristics that are varied. For instance, one of the strands may be provided with a coating, such as a wax coating or another coating that changes the coefficient of friction of that particular strand, whereas the other strand may be uncoated. Other types of coatings may be provided to one of the floss strands, including, but not limited to, flavor agents, oral care agents and abrasives, and each floss strand may be coated with a different coating that cooperates with the coating of the other strand to provide enhanced cleaning effects.
A second embodiment of the dental flosser is shown in
A third embodiment of the dental flosser 200 is shown in
A fourth embodiment of the dental flosser is shown in
A fifth embodiment of the flosser is shown in
A sixth embodiment of the flosser is shown in
A seventh embodiment of the flosser 600 is shown in
An eighth embodiment of the present invention is shown in
The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US11/27529 | 3/8/2011 | WO | 00 | 1/17/2014 |