COATED POWDER FOR POWDER JET CLEANING OF TEETH

Abstract

A powder for use in a powder jet device for cleaning tooth surfaces by powder spraying, where the powder comprises at least 90 wt.-% of particles of a first material and 0.1-10 wt.-% of a second material, where the second material is coated on a surface of the particles of the first material and a solubility of the first material in water is ≥1 g/L.

Claims

1. Powder for use in a powder jet device for cleaning tooth surfaces by powder spraying, the powder comprising: at least 90 wt.-%, based on a total weight of the powder, of particles of a first material; and 0.1-10 wt.-%, based on the total weight of the powder, of a second material, wherein the second material is coated on a surface of the particles of the first material and a solubility of the first material in water is ≥1 g/L.

2. Powder according to claim 1, wherein the powder comprises at least 93 wt.-% of the first material and 0.2-7 wt.-% of the second material, based on the total weight of the powder.

3. Powder according to claim 1, wherein the second material covers at least 80% of the surface of the particles of the first material.

4. Powder according to claim 1, wherein the solubility of the second material in water is ≥1 g/L.

5. Powder according to claim 1, wherein the particles of the powder have an average particle size (d.sub.50) of 5-75 μm.

6. Powder according to claim 1, wherein the first material is selected from the group consisting of glycine, sodium hydrogen carbonate, tagatose, trehalose, alditols, cyclodextrin and mixtures thereof.

7. Powder according to claim 6, wherein the first material is an alditol.

8. Powder according to claim 1, wherein the second material is selected from the group consisting of glycine, sodium hydrogen carbonate, tagatose, trehalose, cyclodextrin, alditols and mixtures thereof.

9. Powder according to claim 1, wherein the second material is selected from the group consisting of amino acid, alditol, sugar, cyclodextrin and mixtures thereof.

10. Powder according to claim 9, wherein the second material is selected from the group consisting of asparagine, arginine, alanine, erythritol, tagatose, trehalose, rhamnose, cyclodextrin and mixtures thereof.

11. Powder according to claim 1, wherein the second material is selected from the group consisting of asparagine, arginine, cyclodextrin and mixtures thereof.

12. Powder according to claim 1, wherein maximum particle size (d.sub.100) of the powder is ≤150 μm.

13. Powder according to claim 1, wherein the powder further comprises 0.5 to 2 wt.-% amorphous silicon dioxide.

14. Process for cleaning tooth surfaces, wherein a powder according to claim 1 is sprayed with a powder jet device onto a tooth surface together with a gaseous carrier medium and/or liquid carrier medium.

15. Powder according to claim 1, configured to be used in a powder jet device for cleaning tooth surfaces by powder spraying.

Description

DESCRIPTION AND EXAMPLES

[0041] The following examples provide preferred embodiments according to the disclosure.

EXAMPLES

Example 1: Erythritol Coated with 1 wt.-% Asparagine

[0042] The experiment was carried out in a pilot batch fluidized bed of conical shape. Initial particle mass 1 kg, inlet air temperature 60-90° C., liquid feed rate 10 ml min.sup.−1 and relative air spraying pressure 2-3.5 bar were chosen as process parameters. A solution of 2.5% L-asparagine was sprayed for 40 min onto the erythritol particles. During the experiment, all process parameters (air inlet temperature, air flow rate, liquid feed rate and spraying pressure) were kept constant. At the end of the experiment the coated powder was removed and the solid content checked to be more than 98%. The amount of asparagine added to the powder was about 1%. The resulting mean particle size was 20 microns.

Example 2: Erythritol Coated with 0.5 wt.-% Collagen Type II

[0043] The experiment was carried out in a pilot batch fluidized bed of conical shape. Initial particle mass 1 kg, inlet air temperature 60-90° C., liquid feed rate 10 ml min.sup.−1 and relative air spraying pressure 1-2.5 bar were chosen as process parameters. A solution of 2% Collagen was sprayed for 20 min. During the experiment, all process parameters (air inlet temperature, air flow rate, liquid feed rate and spraying pressure) were kept constant. At the end of the experiment the coated powder was removed and the solid content checked to be more than 98%. The amount of collagen added to the powder was about 0.5%. The resulting mean particle size was 15 micron.

[0044] The two powders according to Example 1 and Example 2 were tested regarding cleaning efficiency and abrasiveness, together with an erythritol powder coated with 10 wt.-% erythritol. The results are shown in FIGS. 1 and 2 in comparison to erythritol powder.

[0045] The efficiency or cleaning efficiency is the surface that is cleaned per gram of the powder.

[0046] The abrasiveness is determined by projecting powder with a powder jet device directly on a surface at 45° and 2 mm of projected distance using an EMS Airflow® prophylaxis master device. This surface is made of pure aluminium (99.5%). The application time is 30 seconds. The plate is put on an elevator to reach the distance of 2 mm. The nozzle is fixed in a resin mould in order to fix well the nozzle position. The mass is known by weighing the powder chamber before and after the test. Every measurement is repeated at least three times and the average is taken as abrasiveness. The depth of the holes was measured by a laser profilometer.

[0047] The average particle size of the powders according to the disclosure was determined in a Malvern Mastersizer 2000 (Malvern Instruments Ltd., Malvern, United Kingdom) with a scirocco dispersing unit at a dispersion pressure of 1.5 bar.

Example 3: Erythritol and Glycine with Different Coatings

[0048] In accordance to the above experiments, erythritol and glycine were coated with different coatings as shown in FIGS. 3 and 4. The abrasiveness was determined as above described.

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The disclosure is described further below with reference to FIGS. 1 to 4.

[0050] FIG. 1 shows the cleaning efficiency [mm.sup.2/g] of erythritol, compared to erythritol coated with 10% erythritol, erythritol coated with 1% asparagine and erythritol coated with 0.5% collagen.

[0051] FIG. 2 shows the abrasiveness [μm/g] of erythritol powder compared to erythritol powder coated with 10% erythritol, erythritol coated with 1% asparagine and erythritol coated with 0.5% collagen.

[0052] FIG. 3 shows the abrasiveness of erythritol powder coated with different coatings of arginine, cyclodextrin, arginine+cyclodextrin, asparagine, collagen, vitamin C, erythritol, alanine and rhodamine relative to erythritol powder without coating. It can be seen that erythritol coated with erythritol, arginine, alanine, cyclodextrin, arginine+cyclodextrin and asparagine have a reduced abrasiveness compared to erythritol as such and compared to erythritol+collagen, erythritol+vitamin C and erythritol+rhodamine. This reduced abrasiveness is advantageous, for example over erythritol coated with collagen, erythritol coated with vitamin C and erythritol coated with rhodamine.

[0053] FIG. 4 shows the abrasiveness of glycine coated with cyclodextrin relative to glycine powder without coating.

[0054] It has been demonstrated that the powders according to disclosure, wherein a second material is coated on particles of a first material show a reduced abrasiveness compared to powders without coating and still have a good cleaning efficiency. The ratio of efficiency vs. abrasivity makes the coated powders according to the disclosure more powerful than standard erythritol or glycine powders.