Chitosan bio-active designer materials and orthodontics: development and evaluation of novel materials as enamel protective agents

The aim of the investigation is to further develop and evaluate a versatile designed chitosan based bio-active materials for the prevention of demineralization around the orthodontic brackets, while maintaining acceptable shear bond strength and not leave any residual adhesive on the tooth surface after removal of the brackets from the enamel surface and compare the performance of the Clinpro and Tooth Mousse as commercially available protective agents in vitro. The bio-active chitosan containing were prepared by dispersion of the corresponding component in glycerol and acetic acid with the additon of chitosan gelling agent. Mechanical performance such as shear bond strength of attachment between the orthodontic bracket and enamel on the extracted premolar teeth were measured, as well as bio-adhesive studies were investigated in order to assess the suitability of these designer materials. The adhesive remnant index (ARI) and failure site assessment was completed immediately after each shear bond strength de-bonding under x20 magnification. The bioactive modified hydrogels showed a high adhesive force and significantly lower shear bond strength was recorded when Clinpro was used before bonding using the self-etching adhesive system. The bioactive chitosan containing group showed the lower ARI scores to be more frequent, while Clinpro, Tooth Mousse and control groups showed higher ARI scores more frequently. The adhesive remnant was not different between the self-etching and the conventional etching subgroups. In this study we demonstrated that the newly prepared bio-active modified hydrogels which demonstrate the beneficial for the prevention demineralization around the orthodontic brackets, while maintaining the appropriate shear bond strength and inhibition as alternative materials and compare the performance of the Clinpro and Tooth Mousse as commercially available protective agents.