Randomized Clinical Dose-Response Study to Evaluate Plaque Removal by Three Experimental Sodium Bicarbonate...

This randomized, examiner-blind, crossover clinical study compared the plaque removal efficacy of three experimental toothpastes containing 20%, 35%, and 50% w/w sodium bicarbonate (NaHCO3) with commercial toothpastes containing 67% and 0% w/w NaHCO3 (positive and negative controls, respectively).

Fifty-six adults with a mean Turesky Modification of the Quigley-Hein Plaque Index (TPI) score of = 2.00 at screening and at the first treatment visit (pre-brushing) were randomized to a supervised single, timed (one minute) brushing with a 0%, 20%, 35%, 50%, or 67% w/w NaHCO3-containingtoothpaste. TPI was measured pre- and post-brushing. Participants completed five treatment visits, separated by a four- to six-day washout, and brushed once with each toothpaste. The primary efficacy analysis was change in whole mouth TPI score from pre- to post-brushing between the positive and negative control toothpastes (validation step). Secondary analyses were comparisons between each experimental toothpaste and the control toothpastes. Change in TPI score was analyzed using a mixed effect analysis of covariance.

The difference in adjusted mean TPI change from pre- to post-brushing between the 67% and 0% w/w NaHCO3 toothpastes was -0.01 points (95% CI -0.06, 0.04), with no statistically significant difference between them (p = 0.6674). As such, study validity was not attained. Differences in adjusted mean change from pre- to post-brushing between each experimental toothpaste and the positive and negative controls ranged from 0.00 to -0.02 points. Twenty-two treatment-emergent, treatment-related adverse events, all oral, were reported by 17 participants (30.4%). These were spread uniformly across test toothpastes and controls. No serious adverse events were reported.

There was no statistically significant difference in change in mean TPI score between toothpastes containing 67% w/w NaHCO3 and 0% w/w NaHCO3 following a single timed brushing. This unexpected observation may be attributed to lower than expected reduction in overall plaque and a possible Hawthorne effect. As study validation was not met, no further conclusions can be made. The study products were generally well tolerated.