Novel hybrid chitosan/calcium phosphates microgels for remineralization of demineralized enamel - A model study

Dental caries remains one of the most prevalent bacteria caused diseases affecting both adults and children. It is a dynamic process which progress depends on the interplay between demineralization, caused by the bacteria produced acids from the consumption of sugars, and remineralization that takes place due to the saliva protective qualities/functions. The acids start to dissolve calcium and phosphate from the enamel (demineralization) and at the initial stage, when the tooth damage is not significant, the opposite process - the calcium and phosphate deposition (remineralization) could arrest the caries development thus making the caries a preventable disease. The development of new materials for enhancing the remineralization process is one of the main approaches of the non-invasive dentistry and also one of the main challenges of the advanced dental materials science. In the present study, hybrid chitosan/calcium phosphates microgels were developed for the first time. Their potential and effectiveness as remineralizing agent, enhancing the nucleation and growth of calcium phosphates on a model demineralized enamel surface, was revealed. The hybrid microgels formation was guided by the chitosan macromolecules which acted as a template for the calcium phosphate deposition and resulted into in situ formation of amorphous to poorly crystalline non stoichiometric hydroxyapatite. These newly developed hybrid materials have several advantages as remineralizing agent, including bio-adhesiveness, antimicrobial properties as well as continuous supply of calcium and phosphate ions to ensure the successful remineralization of the model initial caries lesions. Thus, the study reveals a simple and easy to apply remineralization procedure based on the newly developed hybrid materials that could be effectively used for arresting and enhancement of the remineralization of early-stage caries development taking advantage of the night regime of the oral cavity habits. This simple approach has been tested and proved to be effective for remineralization of initial enamel demineralization.