Proteomic evaluation of salivary acquired pellicle on restorative material surfaces

Abstract

OBJECTIVES: The aim of this study was to analyze salivary protein adsorption behavior onto restorative material surfaces. It was hypothesized that the acquired pellicle formation is material dependent. METHODS: Dental restorative material specimen blocks were prepared of (5×5×1 mm, n=20 each) nano-hybrid resin composite, glass ionomer cements (GIC), resin-modified GIC, GIC containing casein phosphopeptide–amorphous calcium phosphate (CPP-ACP), or human dentine. All specimen surfaces were polished with 1200-grit abrasive paper. The material surface micro morphology and surface roughness (100×100 µm2, n=10) were measured with atomic-force microscopy. After alcohol disinfection, all specimens were incubated in unstimulated, filtered, sterilized saliva for two hours at 37°C. The quantity of adsorbed protein on each material specimen was measured using a bicinchoninic acid assay. Relative acquire pellicle proteomics for each material group was characterized using liquid chromatography – mass spectrometry (LC-MS/MS). Institutional Review Aboard approval was obtained for saliva collection. RESULTS: The surfaces of polished resin-modified GIC, GIC and GIC containing CPP-ACP exhibited a greater micro surface roughness than resin composite or human dentin (P<0.05). The quantity of protein adsorbed varied between materials, with the resin composite (5.74 µg/specimen) and resin-modified GIC (4.67 µg/specimen) adsorbing the most protein (P<0.01), no significant differences were found between dentin (2.74 µg/specimen), GIC containing CPP-ACP (2.15 µg/specimen), and GIC (1.99 µg/specimen). CONCLUSIONS: The data demonstrated that there are noteworthy variations among acquired pellicles protein quantity and in a subtle fashion quality on various material surfaces, which may affect the subsequent biofilm formation on restorative surfaces.