Evaluation of AmF on Dentine Tubule Occlusion — In–vitro Study

Objective: The aim of this study was to determine the effectiveness of an amine fluoride dentifrice and dental rinse to occlude dentine tubules, and to characterize the nature of the occlusion in an in-vitro study. Methods: Human dentin samples from unerupted third molars were prepared into 1.5 mm dentinal discs with a diamond saw, and etched. The discs were then allocated to the following groups: control (artificial saliva), elmex® Sensitive Plus dental rinse (250 ppm F^- from Olaflur and potassium fluoride) and elmex® Sensitive Plus toothpaste (1400 ppm F^- from Olaflur). The rinse was applied using 10 ml diluted with 10 ml artificial saliva for 2, 20 and 120 minutes. The toothpaste was applied by brushing for 2 minutes with a power toothbrush using a pea-sized amount. Samples were assessed for tubule occlusion by scanning electron microscopy (SEM) equipped with Elemental Detector. Raman spectroscopy for chemical analysis was used to identify the composition of the occlusive material. Results: In this hypersensitivity-treatment in-vitro model comparison of the test discs with the control discs demonstrated visually a blocking of 80±5% of the dentine tubules by toothpaste. After the dental rinse application the most pronounced effect was visible after 120 minutes: 70±4% tubules occluded in comparison with 20±5% after 2 minutes and 40±7% after 20 minutes. Microspectral and elemental analysis showed different chemical composition of precipitated intra-tubular plugs depending on what was applied, toothpaste or dental rinse. Conclusions: Amine fluoride dental rinse and dentifrice effectively occluded dentin tubules (partially or totally) and therefore may reduce patients' hypersensitivity symptoms in-vivo. The AmF products adhered to an exposed dentin surface and reacted with it to form a mineralized layer rich in elements. Supported by GABA.