Modern Equine Dentistry

1. Modern Equine Dentistry

2. Why Equine Dentistry? Routine dental care and oral health are important for your horse’s health. Periodic examination for dental problems, correction of wear problems and maintenance of healthy teeth and gums is highly beneficial • Poor dentition can lead to poor nutrition, weight loss, impaction colic and reduced athletic performance (pain on riding) • Diets of many modern horses result in chewing patterns which are different to natural grassland • We demand more performance and keep horses over a wider age range than ever before • Breeding of horses has not selected for good mouth conformation especially in particular breeds

3. Your horse’s teeth • Horse’s teeth are continually worn down at the grinding surface and the teeth emerge gradually throughout life so that they stay the same length in the mouth • This mechanism requires that the teeth are in perfect contact with each other, otherwise growth is uneven and some teeth become overgrown • Circular chewing motion in horses means that many horses develop some sharp edges over time, which can injure the cheeks, tongue or gums and make chewing or contact with the bridle uncomfortable.

4. Dental Anatomy • Foals are born with deciduous incisors and molars • These milk teeth are replaced with 36-44 adult teeth between 2 and 5 years • Aged horses teeth wear out from 25-30 years of age – become smooth or fall out • Surfaces of teeth have enamel ridges which slow the rate of wear • Damaged enamel cannot repair itself • Dentine is a tissue inside the tooth which is laid down to protect the live tissues – blood and nerve supply

5. Dental Anatomy • The periodontal ligament and membrane attaches the tooth to the jaw. • Dentine, pulp and periodontal membrane all contain nerves which make them sensitive. • The pulp and periodontal tissues contain blood vessels • Because dentine is laid down close to the surface of the tooth, and contains nerves, it cannot be assumed that horses do not feel tooth rasping

6. Diet and Dentition • Horses have evolved to eat grass (which is often fed as hay or haylage now) • Grass contains silicates which causes wear at the grinding surface • Concentrate feeds cause less wear and in some cases reduced wear may contribute to abnormal wear patterns • Horses pick up food including grass with the lips and incisors • The tongue pushes the food towards the cheek teeth • Food is crushed on one side of the mouth at a time in a circular motion Alteration in the chewing pattern due to pain or overgrown teeth can contribute to abnormal angle of the grinding surface of the teeth - creating a greater problem over time (shear mouth)

7. Dental Problems

8. Common Dental Disorders • Developmental disorders • Abnormal number of teeth – too many or few • Abnormally placed teeth • Abnormally shaped teeth • Abnormalities caused by uneven wear • Acquired diseases • Trauma

9. Incisor Disorders • Significant incisor disorders are less common than cheek teeth disorders • This is because the incisors are less integral to the horse’s health and ability to eat - • The lips and tongue can be used to pick up food • Therefore horses which have abnormal incisor wear alone are unlikely to lose weight • It is now known that incisor reductions (used to be done by cutting top off tooth) can open into live tissues and potentially kill the tooth. • Significant removal of incisor tissue is rarely warranted as incisor problems are unlikely to affect chewing efficiency (and are often secondary to cheek tooth abnormalities which require correction)

10. Abnormal incisor wear Smile mouth Cribbing wear

11. Cheek Tooth Abnormalities • Significant abnormalities more common than with incisors - • Important to maintain cheek teeth to optimise feed utilisation • Abnormal wear and sharp points can cause painful ulcers of the cheeks and tongue • Tooth fractures are relatively common • Diastema (spaces between the teeth) can allow food packing at gum surface leading to painful gum disease (periodontal disease) • Tooth root abscesses are painful and can lead to facial/jaw swelling or sinusitis • Interestingly they often don’t cause chewing problems • Dental decay (caries) are likely to cause pain and may lead to tooth root abscesses (27-39)

12. Signs of Dental Disease • Difficulty chewing (+/- weight loss) • Chewing only on one side • Signs of pain when ridden • Resistance to the bit • Head tossing (8-12)

13. Modern Dentistry What’s new? Can my horse be treated? Does he need treatment or management?

14. What’s new in Equine Dentistry? • Interest among vets in producing quality research in the field and evidence based medicine • Improved regulation of and qualifications for Equine Dentists (see BAEDT for info) • Peer reviewed research must inform our diagnosis and treatment in dentistry as in every other field of equine medicine • Historical dogma is no substitute for science

15. What does this mean? • Better understanding of dental anatomy • E.g. we must understand where blood vessels and nerves extend to in teeth - to avoid damaging them through inappropriate reduction of tooth overgrowths • Better understanding of dental disease • We now understand that dental disease is painful and can affect overall health • Understand the way in which diseases progress over time – • Put in place disease prevention strategies – from regular checks, to management of overgrowths and diastema

16. Advances in Dentistry • Improved Diagnosis • Experience in equine digital dental radiography • Use of mirrors and endoscopic cameras • Allows earlier diagnosis, better treatment plans and more accurate prognosis • Treatment evaluation • E.g. methods of removing cheek teeth have been refined over last 20 years • Some new treatments such as root canal treatments are still being evaluated • It is important to choose the correct treatment and the correct person to perform it – as with any other type of surgery or procedure

17. Modern Equine Dentistry • Advances in diagnostic equipment and techniques • New equipment and safer use of equipment • Improved knowledge of diseases and anatomy • Keep in mind chewing cycles and grinding surfaces • Improved knowledge of the effects (potential consequences) of dentistry • Avoid risks associated with inappropriate treatments – DO NO HARM

18. Modern Dental Examination • Take complete relevant history (41-61) • Examine head and mouth (and other body systems where indicated) • Teeth • Fracturesand caries • Food packing, periodontal pockets and diastema • Abnormal wear • Loose teeth or loss of enamel ridges in aged horses • Normal eruption times, shape and number of teeth • Rest of mouth and head • Ulcers, sores or other lesions of the lips cheeks and tongue • Swellings indicating possible tooth root abscess • Nasal discharge due to sinusitis associated with abscess

19. Result! • Many horses when examined at an annual teeth check do not require any intervention at all • This does not mean your vet is too tired to rasp teeth! • It means you are lucky enough to have a horse with good mouth conformation who is grinding food well and maintaining his own teeth • In a survey of vets: Of 4925 equines examined 1483 needed no dental treatment

20. Some Dental Treatments

21. Removal of Overgrowths • Sharp points on the sides of teeth can be removed with hand rasps or power rasps • Care must be taken with power tools as it is easy to remove more tooth than intended and it is also possible to damage soft tissues if proper care and restraint of the horse are not undertaken • Grinding surface of the tooth should not be touched unless the individual tooth is causing a problem

22. Removal of Overgrowths • Hooks due to parrot mouth, and overgrowths due to uneven wear are usually removed using power rasps unless very small • It is important to be aware that the live tissues can be near the surface. It is safe to remove only 2mm • Further work can be done after about 12 weeks – the live tissues will recede away from the surface and dentine is laid down to protect them. • This is a normal response of the tooth which also occurs as the tooth is ground down naturally

23. Fractured Teeth • Commonly ‘slab’ fractures of cheek teeth in older horses may not involve vital tissues • They may be found incidentally – no clinical signs • Sometimes the displaced fragment may become sharp and will then require rounding with a power rasp, or removing if loose • Fractures of incisors or other types of cheek tooth fracture may require more complicated treatment to try to save the tooth, or the tooth may require removal

24. Tooth Removal • Diseased teeth may need to be removed if fractured or if a tooth root infection (abscess) is present • In young adult to middle aged horses this can be a very difficult task as the roots are long and are usually still well attached by the periodontal ligament • It can take hours to remove teeth in young adult horse • Teeth are usually removed from the mouth under sedation. Sometimes anaesthesia is required and occasionally repulsion (punching out) from the jaw is used • Once a tooth is removed its opposite number will require management with power rasping over time, to prevent overgrowth affecting the chewing action

25. Tooth Removal • Removal of cheek teeth in younger horses is avoided where possible due to the necessary ongoing management required for the rest of the horse’s life • Complications can occur particularly in the back 4 upper cheek teeth on either side as the roots of these extend into the bony walls of the sinuses of the head, therefore care must be taken to avoid leaving a hole between the mouth and sinus • Leaving a part of the root of the tooth can also cause problems and prevent healing so this must be avoided

26. Diastema • Spaces between the teeth that can lead to food becoming packed and forced down between gum and tooth causing damage and pain • Diastema should be carefully flushed under sedation to remove packed food and allow the gum to heal. They are often packed with a dental plug so that food is excluded • Some diastema require widening so that food is not forced into a v shaped space (valve diastema) – widening to a U shape can allow food to be removed by the tongue without causing a problem • Diastema widening needs to be done with care as there is potential to damage the live tissues of the tooth • Diastema treatment is painful for the horse and deep sedation is usually required

27. Excessive Transverse Ridges • Enamel ridges are a normal part of the grinding surface of cheek teeth • In some cases one or two teeth may have prominent ridges which may drive food into the spaces between the opposite teeth causing periodontal food packing and gum disease (similar to situation with diastema) • In these cases it may be appropriate to reduce the enamel ridge (with a power rasp) to avoid or treat this problem

28. Dental ‘Modifications’ Bit seating and Wolf Tooth Removal – Modern Viewpoint

29. Bit seating • Popular in disciplines such as dressage and polo • A notch for the bit at the front of the cheek teeth is unnecessary as the bit should sit on the lower bars of the mouth • There may be rationale in some horses for rounding of the first upper and lower cheek teeth to prevent a soft tissue fold becoming trapped between the tooth and bit • This is only usually required where a lot of bit strain is used or a double bridle • Excessive bit seating is potentially harmful as the live tissues are close to the surface at the front of these teeth (59)

30. Wolf Tooth Removal • Historically popular although there is little evidence of any benefit in normally erupted, normally placed wolf teeth • Unerupted (blind), loose, or displaced wolf teeth may be sensitive if contacted by the bit • Wolf tooth removal should be done with sedation and local anaesthesia to avoid unnecessary pain • Legally only a vet or qualified EDT under continuous supervision of a vet can remove wolf teeth. This is because of the need for pain control and rare but potentially dramatic complications of wolf tooth removal! • If done correctly there is no harm in removing these • Young horses may have lost erupted wolf teeth by the age of 3 because the eruption of the adult first upper cheek tooth can cause the root to be resorbed and the wolf tooth may drop out all by itself!

31. ANY QUESTIONS… Or are you all asleep?

32. FREE stuff from Vets, Well I Never! Did you know? • Most vets don’t charge for a basic oral examination to see if horse needs sharp points removing at annual vaccination (or at other times when we are seeing your horse) • Good equine vets will give an honest opinion as to whether any work needs to be done or not • But please let us know in advance (if you can) if you want teeth checking when we are doing vaccs (one of the reasons vets are always late!) • We may not be more expensive than most dentists (certainly qualified ones!) and we only charge an extra £10 for sedation if required (unless the horse needs bucketloads!) • You only need to get together 4 people to have any type of work done by us to benefit from a free yard visit (however we try to avoid knowingly depriving other vets of their routine work so all clients must ring to register with us BEFORE the visit)