I've introduced you to the basic problems seen in every horse, but there are more serious dental disorders that can also cause problems, if delt with at an early age, these problems can be effectively treated before they cause a habit (evading, head throwing) or before weight loss or eating problems are caused. I will outline these below.

Hooks

Hooks are caused when molar arcades are not meeting correctly and the part of the tooth that is not meeting an opposing tooth creates a hook, they can be found on the second premolar (106/206/306/406) or the last molar (111/211/311/411). This is often caused by an overbite or under bite. If left, they will grow down (if on the uppers) or up (if on the lowers) and they can start to wear into the opposing gum causing lacerations (sores) and pain,  which means the equine won't eat or will eat very slowly. It will also prevent free movement of the jaw. They can also be sharp and when the equine is bitted pressure points can be found on the flesh causing unnecessary pain leading to head tossing etc.

Ramps 

Ramps form on molars on a more gradual slope on the upper or lower 6/7's or 10/11's similar to hooks. If left they will wear down the opposing teeth, sometimes to the root in older horses, but treated at an early stage can be easily rectified. Ramps will also prevent the free (anterior/ posterior) movement of the jaw.  

Waves 

With this case, the whole of the arcade has become uneven and develops what is described as a wave. This happen for many reasons, missing teeth, retained caps, impacted molars, large hooks or ramps. These cases can be treated better at a younger age with regular care, taking down the high parts and giving the opposing teeth time to erupt back into occlusion. However older horses have to be treated suitably as to leave as many teeth in occlusion as the eruption rate of teeth is much slower in older horses.

Step mouth
 
Steps are overlong molars that are found within the arcade, they grow long due to nothing opposing it (i.e. a missing tooth or a misshaped tooth) so it gets overlong. Therefore with dental care the tooth can be reduced by floating or burring and be realigned into the arcade and free up the movement of the jaw, also giving the opposing tooth time to recover and erupt (not always the case).
 
Excessive Transverse Ridges 
 
ETR's are ridges that are found on the grinding surface of the teeth, in most horses there are natural ridges found on the surface of the teeth but if these ridges become to large they will restrict the movement of the jaw and therefore the horse will find it difficult to masticate its food effectively. In order to correct this I would reduce the ridges and try to free up the jaw.

Fractured or loose teeth 

When horses get to an older age, their teeth have erupted all the way through their life and the roots become shorter. This may cause teeth to become loose and causes discomfort when eating. Food can get impacted which may lead to infection and/ or rotting teeth. I work alongside vets to remove such problems and create comfort back to the horse. In younger horses if they cause damage to their teeth (being kicked, fall over, chew something they shouldn't! etc) then the teeth may become loose or damaged, more serious operations may need to be performed by a vet. Also part of the tooth may become fractured and in this case part of the tooth can be removed and the rest of the tooth can remain and not cause any problem, but each case must be assessed and treated suitably.

Sheer Mouth

This is when the angle of the tooth is basically steeper than normal. It is more often seen in donkeys, but horses suffer this problem also. It can be caused by poor mastication, and will get considerably worse overtime, it can effect one or both sides of the mouth and restricts how much food is broken down before the horse swallows. This is treated by reducing the angle of the teeth but is a serious problem.