NTED - Common Incisor Abnormalties
1. Overbites and Underbites (parrot mouth) - Prevents horse from grinding feed freely from side to side resulting in improper and excessive molar wear. Prevent normal anterior, posterior moverment of the lower jaw. Front and back hooks, tranvers ridges, wave complexes and sheared molar table angles will become more severe as the horse is forced to grind incorrectly over time. Overbites and underbites will cause dysfunction and pain of the TMJ which results in poor performance levels, attitudes, training abilities, etc. Since the lower incisors are unable to be worn away, sever tissue damage can be caused to the upper palate. This condition can be found in any age horse.
2. Ventral Curvature (smile) - Prevents horse from grinding feed freely from side to side resulting in improper and excessive molar wear. Can occur if deciduous caps (baby teeth) on upper corner incisors are not shed properly preventing normal growth of permanent incisors. Can also occur due to abnormal grinding secondary to molar malocclusions. This condition is usually seen in older, mature horses.
3. Dorsal Curvature (frown) - Inhibits horse from grinding feed freely from side to side resulting in improper and excessive molar wear. Can occur when deciduous caps (baby teeth) are retained on the lower corner incisors, preventing normal growth of permanent incisors. Often occurs with cribbing, wood chewing and abnormal grinding secondary to molar malocclussions. This condition can be seen in young to geriatric horses.
4. Offset, Wedge or Diagonal Incisor Bites - Causes horse to excessively wear molars on one side of the mouth. Opposite side molars become excessively long resulting in a sheared molar table angle. Sets horse up for disfunction and pain of the TMJ. Can develope over time as horse grinds more in one direction, from cribbing and woodchewing. May occur secondary to molar malocclussions or as a result of a missing incisor or incisor damage causing opposing incisors to become excessively long. This condition can be seen in mature to geriatric horses.
5. Overjet and Underjets - Is a partial displacement of the margins of the incisor teeth, front to back, in which the incisor teeth do not wear or occlude properly creating an incisor rim and or steep angle. This condition can be seen in younger to geriatric horses.
6. Wry Nose - Is a congenital deviation of the maxilla, incisive bone and nasal septum of newborns. This affects the upper and lower incisors, suckling ability and breathing.
7. Cleft Palate - Is a congenital defect in the hard and soft palate of newborns. It can be present in one or the other, or both. Aspiration of milk, coughing and pneumonia are serious problems associatied with a cleft palate.