Copyright Peter Borgdorff 2001

The schematic representation on the left shows that the upper and lower incisors match properly but the length of individual molars varies greatly creating a bite which resembles a wave.  Because of the uneven bite the feed moves much less efficiently up towards the back of the mouth as it is being chewed.  That is the reason horses with this condition eat more slowly than other horses.  Weight loss can also be a factor.  Wavemouth can be caused by retained caps (milk teeth) at a young age and is subsequently made worse by the development of overbite.  Wavemouth is also frequently caused or aggrevated by badly distributed excessive filing of the molars. Filing is quite a delicate operation and needs to be done accurately.  The illustration shows one example of wavemouth; there are many variations of this abnormality.
The condition of wave mouth often gives rise to gum disease and more serious periodontal disease, especially in older horses when the crowns wear down to gum level in some areas.  Correction of this condition needs to be carefully done in stages as excessive filing will impede the horse's ability to grind feed even more.