# Exploring the anti-erosive potential of film-forming polymers and fluoride on salivary pellicle modification

## TL;DR

This study explores how certain polymers and fluoride can modify the salivary pellicle to protect against dental erosion, finding that chitosan offers the best protection.

## Contribution

The study introduces chitosan as a promising polymer for modifying the salivary pellicle to enhance erosion resistance when used with or without fluoride.

## Key findings

- Chitosan provided the best protection against erosion, especially when not combined with fluoride.
- Carbopol and LPP showed minimal protective effects, with high calcium release and surface hardness loss.
- The presence of a pellicle increased wettability but hindered the adsorption of negatively charged polymers.

## Abstract

To investigate the effect of solutions containing film-forming polymers on salivary pellicle modification for protection against dental erosion.

Three polymers were tested: Chitosan, Carbopol, and Linear sodium polyphosphate (LPP), each with or without sodium fluoride (F). Control groups were deionized water, F only, and tin/fluoride (Sn/F, positive control). Bovine enamel specimens underwent 10 cycles consisting of: 1 min salivary pellicle formation, 1 min modification with experimental solutions (n = 15/solution), 28 min salivary pellicle formation, and an erosive challenge (1 min for the first 5 cycles, 5 min for the last 5 cycles, totaling 30 min). Relative surface hardness (rSH), surface loss (SL), and calcium release (CaR) were analyzed after 5 and 30 min of erosion. The wettability of enamel in the presence and absence of the pellicle promoted by the solutions was also evaluated.

Chitosan showed a protective effect, with best results in rSH after 30 min in the no F subgroup, and when combined with F, it had similar performance to Sn/F. Carbopol showed the least protection, with the greatest loss of rSH and highest CaR, while LPP performed similarly to Carbopol whether combined or not to F. All polymer solutions exhibited higher wettability in the presence of the pellicle.

Only Chitosan modified the pellicle and improved its protective effect against erosion. The pellicle may hinder the adsorption of negatively charged polymers, reducing their protective potential.

Chitosan may be a promissing agent for incorporation into erosion-preventive oral care products.