Chitosan as protection against dental erosion

Dental erosion is the demineralization of the hard tooth substance caused by acids. Particularly in industrialized countries this is an increasing problem due to changes in drinking and eating habits in recent decades. Additionally, the teeth surface is eroded by mechanical interaction like brushing. To substantially reharden demineralized enamel, the development of appropriate prophylaxis and therapy is important. HMC presents two studies that tested toothpaste and mouth rinses containing chitosan.

The goal in prophylaxis/therapy is to reduce acid exposure for reduction of demineralization, decrease surface hardness and susceptibility to mechanical wear. In addition, the solubility of tooth tissue should be reduced if acid exposure cannot be eliminated. It is well known that the use of fluorides reduces the demineralization of enamel.

Viscosity Of Chitosan Impacts The Efficacy Of F/Sn Containing Toothpastes Against Erosive/Abrasive Wear In Enamel

The primary mode of action of F/Sn preparations is the retention of tin ions (Sn2+) and the incorporation of tin into the enamel. For mouth rinses containing fluorine and tin, it has already been shown in situ that tissue loss can be reduced by up to 70%. When used as a toothpaste, there is the problem that toothbrushing causes loss of enamel. Chitosan has promising properties to improve the effectiveness of F/Sn toothpaste, as the biopolymer forms a protective layer on the tooth surface. The aim of the study was to investigate whether chitosan increases the anti-erosive efficacy of fluorine/tin-containing toothpastes and the influence of viscosity. For this purpose, 192 teeth from human donors were randomly divided into 2x 6 groups with 16 samples each. Chitosans by Heppe Medical Chitosan with a deacetylation degree of 80% were used for the study. The stated viscosities (mPas) describe the viscosity groups (more information see specifications).

Treatment groups:

1. F/Sn (500 ppm F-, 800 ppm Sn2+) -toothpaste with 0.5% Chitosan (Viscosity 50)
2. F/Sn-toothpaste with 0.5% Chitosan (Viscosity 500)
3. F/Sn-toothpaste with 0.5% Chitosan (Viscosity 1000)
4. F/Sn-toothpaste with 0.5% Chitosan (Viscosity 2000)
5. negative control (toothpaste without F/Sn/Chitosan)
6. positive control (F/Sn-toothpaste without chitosan)

The study was conducted in two experimental branches (E1/E2). The enamel samples were cyclic demineralized (10 days, 6x 2 min per day with 0.5% citric acid). Half of the group (E1) was exposed to toothpaste (2x 2 min) and the second half (E2) was additionally brushed with a machine (2x 15s per day). The loss of tissue was determined and elemental analysis of the sample surface and the toothpastes particulate fraction was performed. In addition, SEM was used to analyze the sample surface.

RESULTS

• Highest tissue loss in the negative controls with 4.96 µm ± 1.55 (E1) and 12.76 µm ± 2.45 (E2)
• E1: toothpaste with active ingredients
  
  • reduction of tissue loss
  • formation of distinct precipitates
  • formation of significantly thicker layers with chitosan 80/500
• E2: toothpaste with active ingredients
  
  • reduction of tissue loss compared to negative control
  • tissue loss due to tooth brushing
  • higher efficacy compared to positive control with Chitosan 80/1000