Quantitative evaluation of the oral biofilm-removing capacity of a dental water jet using an electron-probe microanalyzer
This study was conducted to evaluate the oral biofilm-removing capacity of a dental water jet (DWJ) by measuring biofilm thickness using an electron-probe microanalyzer (EPMA).
Thirty consenting subjects wore in situ plaque-generating devices, which consisted of a pair of 4 mm2 enamel slabs attached to the upper molars for 2 days. Each device removed from the mouth was clamped, and one of the slab surfaces was treated with the DWJ, irrigating it for 5 s. The devices were randomly assigned to three different pressure settings of 707, 350 or 102 kPa. Another slab with no treatment served as a control. Each slab was freeze-dried, sputter-coated with platinum, and examined using secondary-electron imaging. The slabs were then embedded in methacrylate and cross-sectioned in the centre. Their surfaces were polished, coated with carbon, and examined using backscattered electron compositional (COMPO) imaging. The area between the enamel and the outer biofilm surface, indicated by a thin platinum layer, was measured by COMPO imaging to calculate the average thickness of the biofilm on the specimen.
The removal capacity of biofilm by irrigation was estimated using a reduced rate of biofilm thickness, which was calculated from the differences between a pair of treated and control slabs. The reduced rates were 85.5% at 707 kPa, 85.1% at 350 kPa and 63.4% at 102 kPa, indicating that biofilm thickness was significantly reduced at every pressure setting.
The results suggest that irrigation using a WaterJet Flosser would be an effective means of plaque control.