The Effect Of Demineralization And Remineralization On Dentine Surface With Different Surface Conditioner Treatment: Atomic Force Microscopy Study

ObjectivesThe aim of this study was to investigate the crystal formation and roughness alteration of dentine surface when submitted to different conditioner treatment and remineralization, using atomic force microscopy (AFM).Materials and MethodsThe central parts of thirty-six human upper first premolars crown were cut, ground and polished into plano-parallel dentine slides. Twelve of the thirty-six samples were randomly assigned into three experimental groups: no treatment as control group (U);37%phosphoric acid treatment for 40s (P);37% phosphoric acid treatment for 40s and then following with 10% sodium chloride(NaClO) treatment for 200s (PN). After surface treatment, six samples from each group received remineralization with mineralizing solutions similar to human saliva for 1 hour. Atomic force microscopy (AFM) was used to study the microstructure and microroughness at the dentine surface before and after remineralization.ResultsAfter treatment with phosphoric acid, dentinal tubule was enlarged and roughness was increased. In phosphoric acid /sodium hypochlorite group, the roughness of dentinal surface was increased significantly. Statistical difference was found between any tow groups. The results indicated that surface conditioners treatments produced a significant alteration of roughness (p<0.05 for any two subgroups; independent-sample T test) and surface topography at dentine surface after remineralization. dentinal surface roughness was showed as PN> U> P before remineralization and U> P > PN after remineralization.ConclusionsPhosphoric acid treatment increases dentinal surface roughness through demineralization of dentinal tubule, while phosphoric acid/sodium hypochlorite treatment produces uniform pores on surface of dentin, and increases surface roughness enormously. Our data provide a new strategy to guide our clinical application for dentin surface treatment. Surface treatment with conditioner at the dentine surface would influence the process of dentine remineralization, at least in the crystal orientation and surface roughness.