| 摘要 |
<p>Oral compositions, such as oral gels and toothpastes, containing a novel abrasive. An amorphous silica abrasive composition comprising: a) a precipitated silica, said precipitated silica being a low structure precipitated silica having a narrow particle size range distribution of soft particles and having a mean value (MV) particle size ranging from 8 to 14 microns, an oil absorption ranging from 60 to 120 cc/100g, and a mercury intrusion (HGI) void volume of 1.0 to 4.0 cc/g; said precipitated silica, when formulated into a dentifrice, having a Pellicle Cleaning Ratio (PCR) of from 70 to 140 and a Radioactive Dentin Abrasion (RDA) value of from 60 to 130; and wherein the ratio of said PCR to said RDA is at least 1.1; and wherein, as the particle size in microns increases in said silica, the RDA value remains substantially constant; and b) a gel silica comprising particles, preferably having: i) a mean particle size of from 5 to 11 microns (s.d. < 9); ii) an Einlehner hardness of from 3 to 15 for abrasive to brass screen and from 8 to 20 for abrasive to polyester screen; iii) an oil absorption of from 60 ml/100 gm to 130 ml/100 gm; and iv) a radioactive dentin abrasion of from 80 to 200 wherein at least 70 percent of all of said particles have a diameter of below 25 microns and wherein the pellicle cleaning ratio is from 90 to 135 and the radioactive dentin abrasion is from 60 to 100 with a pellicle cleaning ratio/radioactive dentin abrasion ratio of from 1.20 to 1.60 and wherein the ratio of precipitated silica to gel silica is from 90:10 to 60:40, respectively.</p> |
