Zinc and silica are active components to efficiently treat in vitro simulated eroded dentin

Abstract

Objectives: Biomaterials for treating dentin hypersensitivity and dentin wear were evaluated to efficiently occlude the dentinal tubules and to increase dentin resistance to abrasion.

Materials and methods: Twenty-four dentin surfaces were treated with EDTA to expose dentinal tubules and were (1) non-brushed, (2) brushed with distilled water, or with pastes containing (3) monetite, (4) brushite, (5) Zn-monetite, (6) Zn-brushite, (7) Silica-brushite, and (8) NovaMin®. Topographical, nanomechanical, and chemical analysis were assessed on dentin surfaces (n = 3) after artificial saliva immersion for 24 h, and after citric acid challenge. Twenty-one further dentin specimens were created to evaluate dentin permeability after brushing, saliva storage, and acid application (n = 3). ANOVA, Student-Newman-Keuls (p < 0.05), and Student t test (p < 0.001) were used.

Results: Particles containing major proportion of silica attained intratubular occlusion by carbonate crystals (Raman carbonate peak heights 15.17 and 19.24 au; complex modulus 110 and 140 GPa, at intratubular dentin). When brushing with pastes containing higher proportion of silica or zinc, phosphate calcium compounds were encountered into tubules and over dentin surfaces (Raman intratubular phosphate peak heights 49 to 70 au, and at the intertubular dentin 78 to 92). The formed carbonated apatite and calcium phosphate layer were resistant to citric acid application. Zinc compounds drastically increased tubule occlusion, decreased dentin permeability (up to 30%), and augmented mechanical properties at the intertubular dentin (90-130 GPa); it was maintained after acid challenging.

Conclusions: Zinc-containing pastes occluded dentinal tubules and improved dentin mechanical properties.

Clinical relevance: Using zinc as an active component to treat eroded dentin is encouraged.

Keywords: Dentin; Mechanical properties; Raman; Silica; Zinc.