Casein and Dental Erosion

Dental erosion is an increasing problem in many countries around the world, and research in this field has increased dramatically in recent years. Dental erosion is the dissolution of tooth tissues (enamel and dentine) by acids that are not of bacterial origin; most commonly these originate from the diet. Recently, protein-based technologies including casein and casein phosphopeptide (CPP) have been investigated and found to have erosion-inhibiting properties. The aim of this chapter is to summarize recent studies by the authors’ research groups to investigate the use of casein and casein-derived proteins as agents to inhibit dental erosion. A number of in vitro techniques and models are employed to investigate erosion, including non-contact optical profilometry, atomic-force microscopy (AFM) nanoindentation and hydroxyapatite dissolution rate experiments (hydroxyapatite is the main mineral component of teeth). Evidence is given for an almost instantaneous ‘protective’ effect afforded by casein, preventing demineralization of enamel under erosive conditions. Aqueous solutions of casein of 0.5 % w/v applied topically before an erosive challenge are shown to afford between 39 to 45 % reduction in demineralization over a range of clinically relevant timescales. The mechanistic aspects of the ‘protective effect’ afforded by casein are investigated using AFM and X-ray reflectometry (XRR). Data from both of these techniques show the formation of a thin (~ 6.6 nm) film of casein proteins on mica, a molecularly smooth mineral used as a model substrate.