Many abnormalities can be understood by considering the effect of the horse’s natural diet on dental function and tooth wear.  Along with resilient structural components such as lignin, grasses contain variable amounts of silicates.  Silica is mildly abrasive (like very fine sandpaper), so grazing results in continuous wear of the incisors as the horse snips off stalks of grass.

Horses fed hay as their primary roughage source do not use their incisors to prehend food to the same extent or even in the same way, so incisor wear in non-grazing horses is less than in grazing horses.  As a consequence, the incisors may become OVERLONG relative to the molar arcades, which can reduce molar occlusion, altering masticatory efficiency and contributing to abnormal wear of the molar arcades.