Biomimetic Growth of HA Nanorods for Tooth Repair

Objectives: Dental decay and caries are prevalent as that 92% of adults (20-64) have dental caries and each adult has more than 10 permanent teeth affected in the United States (NHANES, 1999-2004). Conventional technologies to fill the cavities with bioinert restorative dental composites are usually used for large cavities and usually lead to leackage. Remineralization of enamel is essential to maintain tooth integrity and provide protection against dental caries. This study is to develop a biomimetic technology which can grow large area of hydroxyapatite (HA) nanorods under an ambient condition, so that it may provide inspiration for enamel regeneration.
Methods: In presence of soluble additives, HA nanorods were crystallized from aqueous soluton at room temperature. The effect of ion concentration, supersaturation, solution pH and crystallizing substrates on the control of crystallization of HA were fully investigated.
Results: Scanning electron microscope (SEM) shows that the well-organized HA nanocrystals were successfully grown on the surface of HA substrate. Crystallizationrate, diameter, length, morphology and orientation of HA nanorods were effectively and cooperatively controlled by the concentration of additive and ions.
Conclusions: Our developed biomimetic technology could grow well-organized HA nanocrystals, which are similar to the structure of tooth enamel, on the surface of enamel-like HA substrate, The crystal morphology, size and crystallization rate can be effectively controlled by multiple variables. This study may provide an inspiration on how to develop new technology for tooth repair.