Methods: Six volunteers with good oral health participated in the study. A removable orthodontic appliance with a custom-made retainer was fabricated for each patient. Ge and Au disks were mounted in the retainers and were placed intraorally for 8 h in each volunteer. The surfaces of another series of disks treated with the CPP-ACP agent were placed intraorally as above. The intraorally exposed Ge surfaces were examined by Atomic Force Microscopy (AFM), whereas the Au surfaces with reflection FTIR miscroscopy and molecular mapping.
Results: AFM images (2D, 3D topography and 2D amplitude modes) showed that the retrieved specimens after CPP-ACP treatment demonstrated a smoother surface texture (lower Ra, Rq) than the controls, from the adsorbed agent's film at 10 and 30 ìm scan size. The adsorbed CPP-ACP film showed nanoporosity, apparently due to dissolving species. FTIR microspectroscopy and molecular mapping showed that the retrieved CPP-ACP films still retained calcium phosphates (1064 cm-1) more evenly distributed than the amide components.
Conclusions: In situ adsorption of the CPP-ACP agent after 8h intraoral exposure retained both film forming characteristics and calcium phosphate releasing capacity relevant to expression of a protective effect to demineralization