How about the following: 1. Find a substance that is chemically tooth-like 2. Split it into predefined volumes (little cubes or spheres) 3. Add the beverage

How about the following: 1. Find a substance that is chemically tooth-like 2. Split it into predefined volumes (little cubes or spheres) 3. Add the beverage and saliva to the "tooth", wait a month, and measure the decrease in "tooth" volume. 4. Use regression to estimate the coefficients for sugar, pH, and whatever else.