Title : Multifunctional oral care agent evaluating remineralization acid resistance and hemostatic properties of chitosan hydrochloride
Abstract:
Enamel demineralization remains a persistent clinical challenge. Current approaches face significant limitations: fluoride-based therapies risk fluorosis, while fluoride-free alternatives suffer from poor solubility, complex formation, calculus deposition, and limited enamel penetration. Moreover, existing approaches fail to meet consumer demand for multifunctional oral care products that not only remineralize enamel but also enhance acid resistance, provide sustained protection, and address gingival bleeding. Natural polymer derivatives offer promising solutions, therefore, this study evaluated the remineralizing, acid-resistant, and hemostatic properties of chitosan and its water-soluble modifications.
Acid-resistance and remineralizing properties were assessed on bovine enamel blocks in vitro. Enamel blocks were demineralized at pH 4.5 for 60 minutes, treated with test solutions of chitosan and chitosan hydrochloride for 16 hours at pH 6.5, and then exposed to 8 ml of citric acid for 1 hour at 37°C. The percentage of surface microhardness recovery (%SMHR) and the percentage of relative erosion resistance (%RER) achieved by the test products was calculated and used to compare the ability of the test products to repair the demineralized enamel samples. Hemostatic activity of chitosan derivatives (chitosan hydrochloride, carboxymethyl chitosan, and chitosan oligosaccharide) was evaluated by measuring blood coagulation time.
Remineralization efficacy of 0,5% chitosan hydrochloride, assessed by mean percentage surface microhardness recovery (%SMHR), was comparable to 1450 ppm fluoride (3,4 ± 4,26 versus 3,74 ± 6,87, respectively). Native chitosan showed no protective effect against enamel demineralization (-1,2 ± 3,27 %SMHR). Relative acid resistance (%RER) measurements demonstrated that chitosan hydrochloride provided significant protection against acid erosion at 0,25% and 0,5% concentrations, achieving -41,9 ± 11,8 and -30,67 ± 16,34 %RER, respectively. Unmodified 0,5% chitosan offered lower protection (-50,99 ± 30,06), comparable to 1450 ppm fluoride (-44,44 ± 15,89), while deionized water (negative control) resulted in substantial demineralization (-91,25 ± 30,01). Additionally, microscopic evaluation revealed notable adhesive properties of 0,2% chitosan hydrochloride, which remained adherent to enamel following exposure to deionized water flow for 1, 5, and 30 minutes.
Hemostatic activity was evaluated by measuring blood coagulation time after mixing with 0,2% and 0,5% chitosan hydrochloride and 0,25% water-soluble chitosan derivatives (chitosan oligosaccharide, carboxymethyl chitosan, chitosan hydrochloride) and comparing with positive and negative controls: Capramine (aluminum chloride and cetrimonium bromide solution) and 0,9% NaCl solution, respectively. In the first assay, the blood sample containing 0,5% chitosan hydrochloride achieved a mean clotting time of 5,73 s, while 0,2% chitosan hydrochloride averaged 9,45 s. The positive control showed average clotting time of 2,76 s, while the negative control did not clot within 60 s. A subsequent experiment compared the hemostatic efficacy of three chitosan derivatives: chitosan hydrochloride (38,34 s), carboxymethyl chitosan (27,94 s), and chitosan oligosaccharide (33,74 s), versus Capramine (9,26 s). The 0,9% NaCl control remained unclotted whithin 120 s.
The results of this study demonstrate that natural polymer derivatives offer promising multifunctional solutions, with chitosan hydrochloride demonstrating remineralization and acid-resistance properties alongside hemostatic activity.
