Ex vivo approach to studying tribological properties of artificial salivas for oral dryness (Xerostomia)

摘要

Chemically, saliva is a very complex substance that has excellent lubricant properties [1]. This lubricant property of saliva is an essential factor for maintaining good oral health. It plays a dominant role in speech, friction between teeth and between food and the teeth, in transporting food in the body, and in the mechanism protecting the internal surface of the mouth [2]. The lubricity of saliva can evolve as a function of the food and liquids absorbed, food diets, medical treatments and certain infections. A modification of the lubricant capacity of saliva can lead to modifications of taste, tactile perception inside the mouth, and quite serious oral-dental problems [3,4]. Xerostomia is a disease characterised by a reduction or the disappearance of salivary flow, leading to severe dryness of the oral cavity [5,6]. This disease favours the risk of oral infection, the occurrence of dental carries and gingivitis, and it also leads to difficulties in chewing and swallowing, speaking [7] and can favour polydipsia. The treatments used most frequently in the case of xerostomia are salivary substitutes (oral lubricants) whose efficacy requires improvement. From the bio-tribological standpoint, an ideal salivary substitute must present good bio-adhesion and good lubricity. In this work, we propose an analysis method for measuring both the bio-adhesive and tribological properties of substances designed for use in the buccal medium (products A, B, C and D). To illustrate this method, the bio-adhesive and tribological characteristics of four salivary substitutes on the market and human saliva were compared. To imitate reality as closely as possible, this study was performed on pig tongues ex vivo. Pig tongue was chosen as the medium in this work as its characteristics are quite close to those of the human tongue [8].