Nanoscale structure and phase composition of sound and carious enamel

Tooth decay (caries) occurs when the rate of demineralization mediated by acids produced in plaque biofilms exceeds that of remineralization from saliva. While the development of caries at the histological level is well understood, the highly complex 3D architecture and nanocomposite nature of tooth enamel have hindered in-sight into the fundamental processes of dissolution and remineralization. We propose to investigate these changes of enamel nano- and microstructure using atom probe tomography (APT), a chemical imaging tech-nique with unrivaled spatial resolution (<0.4 nm). In combination with well-established quantitative imaging ap-proaches, the subnanometer resolution of APT will advance our understanding for the progression of atomic-to-nanoscale structure and composition of enamel, in particular very early changes that occur before caries is detected by current technology in the clinic. This knowledge will help 1) clarify biological strategies to harden enamel against acid corrosion; 2) provide high resolution information integral to developing early caries detec-tion schemes; 3) aid in the development of minimally invasive caries prevention; and 4) guide remineralization approaches that supersede current surgical management of tooth decay.