Stain control with two experimental dentin hypersensitivity toothpastes containing spherical silica: a randomised, early-phase development study

To determine in human participants whether toothpastes containing small quantities of a novel spherical silica, added to provide enhanced cleaning properties, could achieve similar or greater extrinsic dental stain removal compared to toothpastes containing standard dental abrasive silica concentrations. One hundred and twenty-three adults with extrinsic dental stain were randomised to one of four parallel groups for 8 weeks’ twice-daily brushing with an experimental toothpaste containing either 0.5% or 1% spherical silica (with relative dentin abrasivity [RDA] of ~38 and ~58, respectively), or marketed toothpastes containing either 6% (RDA ~ 36) or 16% (RDA ~ 166) standard abrasive silica. The objective was to evaluate the ranking order in extrinsic dental stain removal at Week 8, as measured by MacPherson modification of Lobene stain index Area × Intensity. Small treatment differences were observed between toothpaste formulations. The ranking order in extrinsic dental stain removal was: experimental 1% spherical silica toothpaste >16% standard abrasive silica toothpaste >6% standard abrasive silica toothpaste >experimental 0.5% spherical silica toothpaste. Toothpastes were generally well tolerated. This early-phase development study suggests that toothpaste formulations with low concentrations of a novel spherical silica abrasive with high-cleaning capability are generally well tolerated and appropriate for further development.