The effects of load and toothpaste on powered toothbrush vibrations

Objectives The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). Methods Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. Results Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p < 0.003) except for the Sonicare (p > 0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p < 0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p < 0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. Conclusions Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.