Horses are born with "dental stock" which grows throughout their life.
Adult horses should have regular dental check-ups, just like humans, i.e. at least once a year.
Horses with dental problems are unable to chew their food properly.
Food which has not been sufficiently chewed will not be properly digested.
Hence the daily ration will lose its value.
In certain cases, a dental problem may be noticed if you find “small hay balls” in the stable; horses chew hay into small balls to form a sort of padding lodged between the jaws and cheeks to avoid injury, caused by irregular teeth for example.

It is essential to arrange an annual check-up with your equine dentist.