Powder for powder blasting, powder mixture and method of use for the treatment of tooth surfaces

Abstract

A powder and a powder mixture, respectively, preferably for powder blasting with a powder-jet device, said device mixing the powder or the powder mixture with air to a powder / air mixture, wherein said powder and powder mixture is an alditol or contains such alditol. Preferably, mannitol and / or erythritol are used; because of the anti-cariogenic effect, xylitol is also well suitable for the cleaning of tooth surfaces, especially of less strongly mineralized tooth surfaces like dentine.

Description

BACKGROUND[0001]1. Field[0002]The disclosure relates to a powder for powder blasting with a powder-jet device or a powder mixture for powder blasting with a powder-jet device as described, for example, in EP 1 159 929. Furthermore, the disclosure relates to the use of such a powder and powder mixture, respectively, for the preparation of an agent or material for the powder-jet treatment, especially the powder-jet cleaning of tooth surfaces, preferably tooth root surfaces and dentine.[0003]2. Related Art[0004]FIG. 1 shows a dental abrasive spraying device disclosed in EP 1 159 929, incorporated by reference. It can be used not only with conventional tap water from a water supply (12), but also with other fluids. A dental abrasive spraying device has a hand-piece (4) nozzle for spraying a dental powder contained in a reservoir (1), together with a carrier gas and a fluid aiding mixing of the powder with the carrier. There are two separate pressure feeds (3,6). Pressurized air comes fr...

AI Technical Summary

Benefits of technology

[0020]Contrary to the hitherto known kinds of powder, like glycine, sodium gluconate or sodium hydrogen carbonate, mannitol has many advantages. In comparison to glycine, mannitol wears off the jet nozzle less; but shows, in comparison to glycine, a comparable abrasiveness in case of a similar particle size. Furthermore, mannitol cleans the tooth surface better than glycine, without adversely affecting the sensitive dentine. Simultaneously, it turned out that mannitol can be very well mixed with air in the powder receptacle, and that a uniform swirl takes place. Despite the small size of the particles, it raises less dust than, for example, glycine and thus can be better agitated and fed more uniformly to the nozzle of the powder-blasting device. This improves the evenness of the tooth treatment.

[0021]Furthermore, mannitol can be prepared as powder directly in the desired sizes and needs not, like, e.g., sodium hydrocarbonate or glycine, be grinded and sieved to the desired size. In addition, the tolerance of mannitol is significantly better. Glycine is cytotoxic and may, upon skin contact, cause irritations. Mannitol is a sugar substitute and can be used as food. It is water-soluble, does not clot and has a sweet taste.

[0023]The powder has a density of not more than 2.0 g / m3, preferably no more than 1.8 g / m3, and more preferred no more than 1.55 g / cm3. Much preferred densities range between 1.4 g / m3 and 1.5 g / m3. Furthermore, a special embodiment of the powder has a Mohs hardness of no more than 5, preferably no more than 3.5, much preferred no more than 2.5. Furthermore, the powder has a molar mass of no less than 90 g / mol, preferably no less than 110 g / mol, much preferred no less than 120 g / mol. Long-chain hydrocarbons thereby form particles of a lower density, i.e. with a larger contact surface at equal mass, leading to improved swirl properties in the swirl chamber.

[0025]Erythritol has two CH(OH) groups and is equally used a sugar substitute (E 968). It is solid at room temperature, has a density of 1.45 g / cm3 and is water-soluble. Like mannitol, erythritol has the aforesaid positive properties and has, in comparison to other alditols like sorbitol, maltitol, lactite and isomalt, the advantage of a very high digestive tolerance. The abrasion measurements have surprisingly shown that, despite the somewhat lower density vis-à-vis mannitol, the abrasiveness of erythritol at equal size of the particles has slightly increased. The reason for this is probably the different crystal morphology of erythritol, leading to the formation of a sharp-edged surface of the particles. Erythritol is very advantageous because, in the mixing chambers of conventional powder-jet devices, it can reliably be swirled to low particle sizes of app. 12 μm. Although the effectiveness during the cleaning of tooth surfaces is similarly good as in larger mannitol or glycine powders, there is significantly less abrasiveness than with a powder containing glycine with a mean grain size of 20 μm, or mannitol with a mean grain size of 23 μm. Hence, erythritol is especially gentle to dentine.

[0026]Furthermore, a powder containing xylitol is suitable; an uncoloured, sweet tasting crystal with a molar mass of 152.15 g / mol and a low density of 0.77 g / cm3. It can easily be dissolved in water and has the advantage of developing an anti-cariogenic effect. It is a natural sugar alcohol present in many sorts of vegetables and fruits (among others in plums, strawberries or raspberries). While metabolizing carbohydrates, xylitol is produced every day in the human body in the liver and has, because of its sweetish property, only positive characteristics of a dietary supplement. Xylitol is also suitable for diabetics.

[0031]It has also surprisingly been found possible to add to a very fine and light powder, like e.g. erythritol, having a mean grain size of 12 μm, fractions of another powder having a bit larger particles, like e.g. mannitol with a mean grain size of approximately 20 μm. Due to the deposition of the larger particles, the airstream in the powder chamber can more easily stir the powder; and the risk of getting more compact, i.e. the formation of densified areas within the powder chamber, will be minimized, i.e. the swirling of the used powder mixture is still good, whereas, at the same time, a particularly finely particled powder impinges on the tooth surface, wherein the sensitive tooth root surfaces, in particular, are treated with care. In doing so, the abrasiveness of the powder mixtures increases only insignificantly, because the fraction of the added larger particles is not that high, and the powder with the larger particles, due to the morphology of the particle surface, has a less abrasive effect.

Problems solved by technology

These powders, however, have the disadvantage that, due to one or several grinding and sieving steps, the preparation or manufacturing thereof is expensive and laborious.

This can only be ensured when the powder is uniformly stirred by the airstream and when the pourability, for example, is restricted by the formation of densified areas.

Smaller particles tend more to form such densified area than larger particles which, due to their mostly larger mass, are often less suitable for being stirred by the airstream.

Furthermore, a powder for powder blasting should have a corrosion tendency as low as possible and wear out the jet nozzle as little as possible.

Glycine is cytotoxic and may, upon skin contact, cause irritations.

While glycine, with a particle size of less than 20 μm in the powder chamber of customary devices, can no longer be reliably swirled, and forms densified areas, even if materials for the increase of pourability, like pyrogenic silica, are added, and hence does not allow the airstream to be sufficiently enriched with the blasting material, this does not appear when using a powder made, for example, of erythritol.

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