Drug – bio-affecting and body treating compositions – Dentifrices
Reexamination Certificate
1997-05-15
2001-12-18
Reamer, James H. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
C424S052000, C424S050000, C424S053000, C433S215000
Reexamination Certificate
active
06331291
ABSTRACT:
BRIEF DESCRIPTION OF THE INVENTION
A water-free (i.e., excluding intentionally-added water) creamy dental gel/paste product having the characteristics of a gel and a paste that contains a stable heterogeneous mixture of an essentially anhydrous organic polyol, a large quantity of amylopectin or a modified amylopectin and one or more thickening agents.
BACKGROUND TO THE INVENTION
Toothpaste, brushing gel and bleaching gel utilize a blended matrix material into which is provided a detergent, whiteners, plaque and/or tartar removers or inhibitors, flavorings, viscosity control agents, fluoridizers and the like. No particular toothpaste matrix material is utilized for a brushing gel or a bleaching gel. In most toothpastes and brushing and bleaching gel formulations, water is a critical component of the blended matrix material. Toothpastes come in various viscosities and their flow characteristics fluctuate depending on whether the paste is thixotropic or not. There is a paucity of information about the relative viscosities of toothpastes, the film forming qualities of dentifrices (pastes and gels), and the importance of such to the utility of the product. However, Fischer, U.S. Pat. No. 5,098,303; U.S. Pat. No. 5, 234,342 and U.S. Pat. No. 5,376,006, teach that the viscosity characteristics of a bleaching gel should be different from the viscosity characteristics of a brushing gel and takes the position that bleaching gels must possess extremely high viscosities in order to stick to the teeth during a bleaching period. To accomplish this, Fischer describes excessively high viscosity (e.g., >500,000 centipoises) water-based gels using high carbomer gelling agent concentrations (3.5 weight percent or greater).
A dentifrice may bring to the gums and teeth certain ingredients that affect gums and teeth. They include fluorides, hydrogen peroxide, enzymes, and special gum treatment agents. The respective utilities of such additives dependent on their residence time in contact with the gums and tooth enamel. The longer such additives remain in contact with the gum and teeth, that is, the longer the residence time in contact with the gums and tooth enamel, one can assume that they better contribute their special qualities. A dentifrice that disintegrates once it is brushed or otherwise exposed to the tooth and gum surfaces provides the minimum residence time. A dentifrice that does not readily disintegrate at the tooth and gum surfaces provides a higher residence time. The latter dentifrice can be expected to contribute more of the benefits to the teeth and gums of the additives in the dentifrice formulation.
Every dentifrice has some film forming qualities when applied to teeth and gums. The longer the dentifrice maintains a film while applied over the teeth and gums, the longer is the aforementioned residence time. Dentifrices that are water based typically form films on the teeth and gum that quickly disintegrate once the film is exposed to water (water added by the user or saliva carried to the tooth and gum surface). Water is an excellent solvent for a water-based dentifrice. Consequently, water-based dentifrices have relatively short residence times.
There are two basic fluid dental cleansing compositions marketed today. They are dental pastes (i.e., toothpastes) and dental gels (brushing gels and bleaching gels). Each is dispensed through a tubular orifice to the user's tooth brushing device or, in the case of some bleaching gels, to the user's dental tray (bleaching tray, stint or mouthguard). An important quality of a dental cleansing composition is its flow characteristics as it issues from the tubular orifice. If the composition is runny as it issues to and from the orifice, it is difficult to control the amount of composition to be applied to the brushing device or dental tray. If the composition is too viscous, then it is difficult to expel to and from the orifice and consequentially, the amount of composition to be applied to the brushing device or dental tray is difficult to control.
However, if the composition is neither runny nor too viscous but is unnecessarily sticky, it leaves a stringy tail as a blob issues from the orifice. When the tail separates from the orifice opening it falls to many places that the users wishes it would not, such on the brushing device handle and other non-brush head surfaces, or when deposited into a dental tray, over the tray's edges onto whatever surface exists outside of the tray. The flow characteristics of such compositions in the tube are also affected by the flow characteristics of the composition. If the composition is runny, it is more difficult to expel from the tube, but once it reaches the orifice opening, it is difficult to control its issuance from the tube's orifice. If the composition is too viscous, it is difficult o force it to the issuing orifice, and difficult to expel it from the orifice. If the composition is too sticky, it is extremely difficult to control the amount of composition that issues from the orifice because the stringy tail invariably causes more to issue than the user desires, or less to issue than the user desires, because the user is attempting to anticipate the extra amount issuing due to the composition's stickiness. There is another adverse flow category that involves neither runny, too viscous, nor sticky compositions; this flow has the appearance of a dry (non-glossy) mass while issuing from the orifice. The problem with such compositions is that the mass does not cleave well from the orifice, sometimes taking a few efforts of asserting the brush head or dental tray against the mass in order to dislodge it from the orifice. Frequently, when such composition is dislodged from the orifice, it fails to lie comfortably on the brush head or the dental tray. In the case of extrusion into a dental tray, such materials are difficult to distribute about the tray to assure uniformly distributed contact with the teeth.
On the whole, toothpastes are easier to formulate to control flow characteristics because they rely to a significant extent on simple filler loading to control flow. Dental gels, on the other hand, rely on the complex chemical interaction of a gelling aid to hydrogen bond with a matrix component of the dental gel formulation. Such chemical interaction is difficult to control in order to fine-tune the flow characteristics of the dental gel.
Dental gels are vehicles for dentifrices, bleaching aids and fluoride compounds. Gels are colloids in which the dispersed phase has combined with the dispersion medium to produce a semisolid material, such as a jelly. They are typically characterized as sticky, viscous liquids that have poor spreadability as their viscosity increases. This stickiness is sometimes averted in water-based gels by the addition of fillers that do not interfere with the water-white qualities of the gel.
Dental gels are used as a dental paste (toothpaste) substitute, as brushing gels that contain peroxide and as whitening gels that contain peroxide. The toothpaste substitute and the brushing gels are used with a toothbrush whereas the whitening gel is deposited in a dental tray and placed repeatedly over the patients teeth for extended periods of times, ranging from 30 minutes to 8 hours. Whitening is effected by the bleaching action derived from the oxygen generated by decomposition of the peroxide. A stable peroxide that fails to properly decompose provides no whitening oxygen, whereas a prematurely decomposed peroxide is ineffective because the bleaching oxygen is removed before the whitening treatment of the patient's teeth.
A dental paste (toothpaste) is a dentifrice that is in the form of a soft, smooth, thick mixture containing a filler material, typically in an aqueous liquid vehicle, that gives the mixture flow characteristics. A dental paste exhibits little of the chemical interactions that take place in forming a dental gel. Illustrative of a most desirable dental paste is found in Glace et al., U.S. Pat. No. 4,986,981, patented Jan. 22, 1991
Glace William R.
Ibsen Robert L.
Skoler George A.
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