Biomimetic transformation of polyphosphate microparticles during restoration of damaged teeth

Abstract

Objective: In the present study, we investigated the fusion process between amorphous microparticles of the calcium salt of the physiological polymer comprising orthophosphate units, of inorganic polyphosphate (polyP), and enamel.

Methods: This polymer was incorporated as an ingredient into toothpaste and the fusion process was studied by electron microscopy and by synchrotron-based X-ray tomography microscopy (SRXTM) techniques.

Results: The data showed that toothpaste, supplemented with the amorphous Ca-polyP microparticles (aCa-polyP-MP), not only reseals tooth defects on enamel, like carious lesions, and dentin, including exposed dentinal tubules, but also has the potential to induce re-mineralization in the enamel and dentin regions. The formation of a regeneration mineralic zone on the tooth surface induced by aCa-polyP-MP was enhanced upon exposure to artificial saliva, as demonstrated by SRXTM. Energy dispersive X-ray analysis revealed an increase in the calcium/phosphorus atomic ratio of the enamel deposits to values characteristic for the particles during the treatment with polyP applied in the toothpaste, indicating a fusion of the particles with the tooth mineral.

Significance: Our results suggest that toothpaste enriched with aCa-polyP-MP is a promising biomimetic material for accelerating enamel and dentin restoration.

Keywords: Alkaline phosphatase; Caries; Coavervate; Dentifrice; Enamel/dentin damage repair; Inorganic polyphosphate; Microparticles; Regeneration.