Salivary conditioning films (pellicle) form the interface between teeth and the oral environment. The wettability of oral surfaces in part dictate biological adhesion phenomena such as plaque formation, calcification and staining and additionally clean mouth perception. Objectives: This study compares effects of sodium hexametaphosphate chewing gums on the wettability of salivary conditioning films in vitro and in vivo with those of a sodium hexametaphosphate containing dentifrice. Methods: In vitro studies follow protocols detailed by Busscher et al. J Clin Dent 13: 38-43. In laboratory studies, pellicle coated bovine enamel surfaces were prepared by 16 hour immersion in reconstituted saliva buffer. Toothpaste (1 min.25 wt. % slurry) or chewing gum treatments (immersion 15 minutes or 1 hour in ‘chewing gum stimulated saliva’ were followed by contact angle assessments of surface energy changes and pellicle film thickness via vacuum drying followed by photoelectron spectroscopy (XPS). In vivo, subjects brushed with Crest Regular for one week and then single treatments were carried out with chewing gum containing or absent hexametaphosphate. Water contact angles were then assessed on facial incisors. Results: Hexametaphosphate gum stimulated saliva produced significant reactivity on oral surfaces, reducing pellicle thickness post treatment by 59 % (15 min. – sig. p < 0.05) and increasing water contact angles + 4 degrees. Placebo gum stimulated saliva had no effect on film thickness but did decrease contact angles (-2 to -6 degrees). In vivo, hexametaphosphate gum produced a dramatic reduction in water contact angles (n=5) –23±15° compared to a –10±4° for placebo gum and –14±6° for wax stimulation. These changes correlate with those observed for hexametaphosphate dentifrice which is shown effective in chemical stain prevention and removal. Conclusions: Hexametaphosphate chewing gums were shown to produce marked surface chemistry changes on conditioning film coated surfaces both in vitro and in vivo.