Objectives: The purpose of this study was to evaluate the effect of different toothpastes on dentin permeability after multiple applications and thermocycling in presence or absence of saliva.
Methods: Pulp-facing surfaces of bovine incisor dentin slices (200µm) were etched (30s, 50% citric-acid), other surfaces were ground (600grit). Dentin permeability (hydraulic conductance, Lp, m3/Ns) using aqua bidest at 1.4m H2O was measured at baseline (t0), after a first treatment (t1), and after thermocycling (5°C-55°C,100cycles,30s/cycle)(t2) using a commercially available measurement unit (Flodec, DeMarco-EngineeringSA, Switzerland). Permeability measurements after two more cycles of material application and thermocycling followed (t3-t6). Each slice served as its own reference.
Test materials: (BR) (BioRepair, Dr. Kurt Wolff, Germany: zinc-carbonate-hydroxyapatite-preparation); (BR-II) BR with double amount of zinc-carbonate-hydroxyapatite; (SP) Sensodyne Proschmelz (GlaxoSmithKline-Consumer-Healthcare, Germany); (EO) Elmex Sensitive Professional in office, and (EH) Elmex Sensitive Professional Zahnpasta [home use] (GABA, Germany: Pro-Argin Technology). Controls: (AL) Adper Prompt L-Pop (3M ESPE, Seefeld, Germany), and (C) slices without treatment. All test materials and C were tested in presence and absence of human saliva. Test parameter Lp-REL was the percentage of fluid flow (100%=Lp at t0) for t1-t6. Non-parametric statistical analysis (a=0.05).
Results: Median Lp before treatment was 0.12-0.49e-10 m3/Ns. Over time: Lp-REL significantly increased to 280% for C and decreased to 22%-56% for AL; without saliva, BR and EO stayed below 100%. At t6 saliva significantly decreased/increased Lp-REL for EH/EO, respectively. No effect of saliva on SP was detected. By tendency Lp-REL of BR-II was higher than of BR. Thermocycling had a significant increasing effect on Lp-REL with or without saliva.
Conclusions: The zinc-carbonate-hydroxyapatite-preparation was able to reduce dentin permeability during multiple applications without saliva to the level not significantly different from the Dentin Adhesive Control. The Pro-Argin Technology seems to need saliva to be effective.
Keywords: Blood, Dentin, Pulp, Pulpal disease and Root