Nanomaterials for functional repair of enamel microfractures. A SEM Study

OBJECTIVES: To evaluate the ability of a biocompatible and acid resistant natural gel containing nanocrystals to occlude microfactures occurring in human enamel specimens.

METHODS: A precipitation process was followed using a mixture of active ingredients containing rhubarb and spinach having traces of potassium oxalate, manipulated to contain glycerol-viscarin. Nanocrystals of 50 and 300 nm size were produced. Ten caries-free human enamel fragments and dentin disks were used. Specimens' microfractures were mechanically induced in order create the testing sites. A single application of a 2% potassium-oxalate gel (ABOCA S.p.A., Italy, Patent), created by a combination of natural extracts of spinach and rhubarb, was applied on each specimen for 3 full minutes. After treatment, each human enamel specimen was rinsed for 10 seconds under tap water. Specimens were dried and SEM was performed for each disk.

RESULTS: SEM analysis on all specimens showed that after a single 3 minutes application of the 2% potassium-oxalate natural gel nano-particles have formed into the mechanical-induced microfacture and adhered to the wall of the dentinal tubules. Dimensions of the nano-particles appeared to be of 50 and 300 nanometers. The crystalline reticule forming the walls of the fracture, appeared disordered and defective, suggesting high availability to release calcium ion for a kelating reaction.

CONCLUSIONS: Nanomaterial crystals can form and adhere to the wall of dentinal tubules after a short-term single application of a 2% potassium-oxalate natural gel allowing a complete filling of the microfactures space and imperfection of enamel structure.