Long-Term In Vitro Effectiveness of A Bioglass Desensitizing Agent Investigated Using Electrochemical Impedance Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy

Objectives: To compare the long-term in vitro effectiveness of a newer desensitizing agent containing bioactive glass and two other commercial products employed for dentin hypersensitivity. Methods: Fifty occlusal dentin disks from extracted sound human third molars were treated with 0.5M ethylenediaminetetraacetic acid for 2 min then randomly divided into five groups (n=10). Specimens were brushed for 2 min twice daily with Actimins Paste (Group1), Lesening Super Desensitizing Toothpaste (Group2), Colgate Sensitive Pro-Relief Desensitising Polishing Paste (Group3) and distilled water (Group4) at 9:00 am and at 5:00 pm. Specimens in Group5 had no brushings. All specimens were immersed sequentially for 5 min into coffee (pH=5.4) at 10:00 am and undiluted cola (pH=2.5) at 6:00 pm. Dentin permeability was measured weekly over one month using electrochemical impedance spectroscopy (EIS). Data were analyzed using two-way repeated measures ANOVA and post hoc LSD tests. Dentin microstructures were observed at one month by atomic force microscopy and scanning electron microscopy. Results: The three desensitizing agents significantly reduced dentin permeability over one month. Post hoc LSD tests of the EIS values indicated that brushing with Actimins showed no significant difference from Colgate Sensitive (P=0.32), and that both agents had significantly less permeability than Lesening (P<0.05). Conclusions: The three desensitizing agents were effective in occluding dentinal tubules and reducing permeability to varying extents over one month, with Actimins and Colgate Sensitive being the most effective. Actimins might be initially, a faster-working desensitizing agent. Clinical significance: Actimins, a newer desensitizing agent containing bioactive glass, has the potential to relieve dentin hypersensitivity in the presence of long-term daily acidic beverage ingestion.