Adding milk or cream to coffee alters the beverage's chromogens and modifies how the stain adheres to tooth enamel, thereby reducing staining.
The retrieved literature includes in vitro studies specifically evaluating the staining potential of beverages with and without milk. Both paper [0] and paper [9] establish that introducing milk into staining beverages like coffee and tea modifies the stain layer, changes adhesion dynamics, and reduces the resulting discoloration on tooth enamel.