Morphology and Elemental Composition of Salivary Pellicles after Brushing

The tongue is sensitive to changes in lubricating properties of teeth. Different modes of brushing yield a different sensory perception of the teeth, possibly because of their effects on the salivary pellicle surface. Objective: To investigate the roughness and elemental composition of pellicle surfaces in vitro after manual, rotary or sonic brushing. Methods: Glass surfaces were coated with reconstituted human whole saliva for 16 h at room temperature in order to create a pellicle and subsequently brushed with a manual toothbrush (Braun Oral-B advantage soft compact 35) under a weight of 200 g, a rotary (Braun Oral-B Professional Care 7850 DLX) under a weight of 150 g or sonic (Sonicare Elite; HX 7300 Philips Oral Healthcare) brush under a weight of 90 g, weights being typical for each brush. Surfaces were brushed in a wetted state (with a thin film of water on the pellicle) or with the bristles immersed in demineralized water for 30 s involving 30 single strokes back and forth each over a length of 3 cm. Roughness measurements were performed by atomic force microscopy (AFM) and surface chemistry was determined using X-ray photoelectron spectroscopy (XPS). Results: Unbrushed pellicles had a roughness of about 1.1nm by AFM, and both manual (roughness 1.7 and 2.4nm) and rotary (1.8 and 1.6nm) brushing of film-wetted and immersed pellicles, respectively yielded a significantly rougher pellicle. Sonic brushing yielded smoother pellicles under wetted (0.9nm) and immersed (0.8nm) conditions. XPS and AFM images indicated that sonic brushing caused a smooth and thin pellicle, and rotary and manual brushing gave a rougher pellicle surface, with more patchy coverage. Conclusion: This paper is the first to describe nanoscopic morphological features of pellicles after different modes of brushing, possibly with relevance to the sensory perception of teeth by the tongue. Supported by Philips Oral Healthcare.