US 2059396 A
Description (OCR text may contain errors)
Patented Nov. 3, 1936 PATENT- OFFICE nsu'rrrmcr: rnonuc'r Jean Ripert, Paris, France, assignor. to-Thibaud, Gibbs 8; Cie., Paris, France, arcorporation of France No Drawing.
Application July 12'. 1934, Serial No. 734,797. In France January 9, 1934 5 Claims. (01. 167-93) It is known that the abrasive substances currently employed in dentifrices are generally in crystalline or amorphous form divided into a plurality of fine particles having sharp angles 6 and many asperitiesvisible under the microscope.
Amongst the usual abrasives are calcium carbonate, precipitated chalk, powdered pumice stone, sodium sulphate, calcium phosphate, magnesium carbonate, zeolite, alum, cream of tartar,
l coral powder, talc, kaolin, sugar, milk sugar, potassium bitartrate, powdered cuttle fish bone, finely powdered sodium chloride,, infusorial earths (kieselguhr), zinc oxide, magnesium phosphate, barium carbonate, .calcium stearates of 15 magnesium or barium, calcium oxylate, glass silk,
potassium chlorate, hydrated. or colloidal alumina, colloidal silica, etc.
Now, it has been found that these various abrasives generally have a hardness superior or equal to that of the enamel, and greater than that of ivory, and also greater than that of the cement, such as exists at the neck of the tooth.
Consequently, they show under the action of the brush serious disadvantages; on the one hand they produce by wear the erosion of the neck of the tooth which contributes to shrinking away of the gums from the tooth and renders them very sensitive or even painful, on the other hand, instead of producing polishing of the tooth they produce in fact the reverse 'eifect by wear either 'of the prisms of the enamel or of the interprismatic substance. It may be remarked that there is never wear of the two at the same time which explains why the unpolishing action shows 35 itself by the production of a granular surface.
Teeth brought into this state show a quite particular susceptibility to caries; which may be explained by the retaining on the surface of the tooth which hasbecome rugged of scraps of 40 food, by the action of acids resulting from the decomposition of the scraps'and by the deposit of tartar.
In order to obviate these serious disadvantages of the abrasives currently employed it has alreadybeen proposed to employ in dentifrices as abrasives, flexible materials such as silica. or bentonite, in the form of colloidal gel (which bentonite is known as producing a favorable -detergent colloidal gel by addition of water), cel- 50 lulose and its esters,in the form of pulp and even paper in the form of paste. In fact these abrasives are too soft to produce the efficacious cleaning action which the teeth require. They act in fact upon the surface of the teeth like a 56 true washing cloth", no more, but they cannot after having removed the film exercise a true polishing action on the enamel.
The present invention has for its object. an improvement applied to the constitution of dentifrice products with the object of eliminat- 5 ing all these disadvantages and of permitting these products to have an efficacious polishing action leading to the production of a uniformly true surface while avoiding the excessive wear which is shown by the phenomena known as errosion abrasion etc.
For this purpose the invention employs as polishing. bodies substances having a hardness equal to that 'of the cement but which wear more rapidly than the body to be polished. In using such substances the sharp angles of the polishing particles, for example the edges of a cube,
that natural or industrial silicates, the'degree of hardness of which, measured on Mohs scale lies-between 2 and 3, satisfy all these conditions. In fact these substances while possessing a hardness substantially equal to that of the cement, wear in contact with this latter instead of wearing it, the sharp angles of their particles blunting themselves from the beginning of the cleaning action. My experiments have shown that this result is due to the lamellar crystalline structure of mica and the natural silicates constituting mica. powder, even one which passes through a .sieve of 300 meshes, presents a lamellar structure. Furthermore, it is important to observe that the fiat particles always offer a tendency to present their flat surfaces and not their sharp edges to the surfaces of the materials with which they come in contact. When, for instance, a quantity of mica powder is suspended in water or in glycerine, microscopic observations show that only the fiat surfaces are seen and not the sharp edges. 1 Accordingly, mica particles arrange themselves parallel to the surface of a plane on which the mica is rubbed in such a manner that Itis to be noted that a mica 40 I not contatt with the sharp edges of the particles. I have found, for example, that it is possible to rub a surface having a hardness far below 2.5
with mica powder having a hardness of 2.5, without producing any striations thereon, but on the contrary, the surface so rubbed was polished to a remarkable degree and had an appearance similar to that which would be obtained by polishing with a chamois skin or other material of very slight hardness. I have found that mica and silicates entering into the constitution of mica have properties which make such material particularly suitable for cleansing teeth.
Amongst the natural silicates envisaged by the invention it is convenient particularly to mention mica; the different varieties of mica having a degree of hardness of the order of that indicated above.
In fact the hardness of the different micas evaluated by means of Mohs scale is as follows:-
Muscovite 2 to 2.5
Paragonite 2.5 to 4 Lepidolite 2.5 to 4 Zinnwaldite 2.5 to 3.5
Biotite 2.5 to 3 Phlogopite 2.5 to 3 Amongst these micas those which are the easiest to procure commercially are those of which the hardness lies between 2.5 and 3.
The mica is used in the form of fine powder obtained by pulverizing and passing through sieves either mica in sheets or in scraps. This powder may be incorporated in a paste orin a dentifrice soap made according to the usual formulae as will be indicated by the examples cited below. One may also use the mica powder as the principal ingredient of a dentifrice powder mixing with this powder other suitable substances such as a taste corrector, perfume, colour etc.
Instead of using natural powdered mica one may use, under the natural lamellar crystalline forms which they show in the natural state, the silicates entering into the composition of micas,
and which are notably the double silicate of aluminium and potassium (muscovite), the double silicate of aluminium and sodium (paragonite) the triple silicate of aluminium, potassium and lithium (lepidolite) the double silicate of iron and lithium (zinnwaldite), the triple silicate of iron, magnesium and potassium (biotite), phlogopite or potassium and magnesium silicate combined with the double fluoride of potassium and magnesium, lepidomelane, of composition analogous to biotite but containing a large percentage of iron in the ferric form, roscoelite, analogous to muscovite but with about 30% of vanadium oxide.
The invention can be carried into effect according to the non-limiting examples which follow:
' Example 1.With '70 parts of a saponaceous paste made by emulsifying 5 parts of soap, parts of glycerine, 54 parts of water, by means of 1 part of gum tragacanth there are incorporated 30 parts of finely ground mica.
Example 2.-'To 12 parts of a mucilage of gum tragacanth formed into paste, 8 parts of glycerine are added. In this basis 2 parts of finely pulverized mica is incorporated. The consistency of the final product depends upon that of the mucilage of gum traga'canth employed and the quantity of mica incorporated. There is thus obtained a non-lathering tooth paste.
Example 3.--A solution of giycerine and gelatine is prepared with 7.5 parts of white gelatine, 120 parts of distilled water, 210 parts of glycerine. To 120 parts of this mixture there are incorporated 36 parts of finely powdered mica. If it is desired to render this paste lathering to the mass is added '7 .5 parts of powdered soap.
Example 4.-To a basis for dentrifrice soaps in cakes prepared in the usual manner there is incorporated a powder of mica or silicates consti-- tuting the natural mica as filling materials in a proportion of 20 to 25% for example.
Example 5.-Powdered mica or silicates of the P type indicated constitute the basis of a dentifrice powder to which other suitable products may be added.
In all the examples above the proportions may vary according to the end sought. Likewise other products such as antiseptics, bactericidal agents, astringents etc. may be added. The addition of perfume and colouring material is naturally permissible.
I claim: I
1. A dentifrice preparation having as a polishing constituent finely powdered silicates constituting the natural micas in their natural lamellar crystalline form and having a hardness not greater than about 3.
2. A dentifrice preparation having as a polishing constituent finely powdered silicates constituting the natural micas, which have a natural lamellar crystalline structure.
3. A dentifrice preparation having as a polishing constituent finely' powdered silicates consti-