Medicated chewing gum has been recognised as a new advanced drug delivery method, with a promising future. Its potential has not yet been fully exploited because currently there is no gold standard for testing the release of agents from chewing gum in vitro. This study presents a novel humanoid chewing robot capable of closely replicating the human chewing motion in a closed environment, incorporating artificial saliva and allowing measurement of xylitol release from the gum. The release of xylitol from commercially available chewing gum was quantified following both in vitro and in vivo mastication. The chewing robot demonstrated a similar release rate of xylitol as human participants. The greatest release of xylitol occurred during the first 5 minutes of chewing and after 20 minutes of chewing only a low amount of xylitol remained in the gum bolus, irrespective of the chewing method used. Saliva and artificial saliva solutions respectively were collected after 5, 10, 15 and 20 minutes of continuous chewing and the amount of xylitol released from the chewing gum determined. Bioengineering has been implemented as the key engineering strategy to create an artificial oral environment that closely mimics that found in vivo. These results demonstrate the chewing robot with built-in humanoid jaws could provide opportunities for pharmaceutical companies to investigate and refine drug release from gum, with reduced patient exposure and reduced costs using this novel methodology.

To evaluate the ability of a modified in situ model to differentiate dentinal tubule occlusion properties of toothpaste formulations over 10 days of treatment. This was a single-centre, three-treatment period, crossover, randomised, single-blind study with healthy participants wearing two lower oral appliances, each retaining four dentine samples, for 10 treatment days during each period of the study. Samples were power-brushed ex vivo twice on each treatment day with a Test toothpaste containing 0.454% stannous fluoride, a Control fluoride toothpaste containing 0.76% sodium monofluorophosphate, or mineral water. Dentine samples were subjected to in situ acid challenge (orange juice) on Days 9 and 10. Scanning electron microscopy images obtained at baseline and after 1, 4, 8 and 10 days of treatment were graded for degree of surface coverage by four calibrated examiners; the primary study endpoint was Day 8. After 4, but not 8, days' treatment, the degree of tubule occlusion increased in the dentine samples treated with the Test or Control toothpastes compared with the water-treated samples (p < 0.01 and p < 0.05, respectively). Following the acid challenge (Day 10), there was a statistically significantly greater degree of occlusion in the Test toothpaste-treated dentine samples compared with those treated with water (p < 0.01). No other comparisons were statistically significant. All study treatments were generally well-tolerated. This modified in situ model was unable to demonstrate statistically significant between-treatment differences in dentinal tubule occlusion after 8 days. Conversely, there are recognised developments that could be made to better identify product differences. Clinicaltrials.gov: NCT02768194. Dentine hypersensitivity can be managed through brushing with stannous fluoride toothpastes, which occlude patent dentine tubules. Clinical studies measure pain but in situ models are needed to demonstrate occlusion intra-orally. However, this study did not demonstrate superior occlusion with stannous toothpaste; further methodological development is required to investigate its mode of action.