Equine Dentistry Flashcards
How are equine teeth numbered?
triadan system with quadrants for numbering
- 100-400 permanent
- 500-800 deciduous
What are canine and wolf teeth?
CANINE = ‘04, mostly present in males
WOLF = ‘05, small tooth in front of premolars
How many incisors, canine, wolf teeth, and cheek teeth do horses have?
I = 3 per side, deciduous and permanent, 01-03
C = 0-1 per side, 04
W = 0-1 per side, 05
CH = 6 per side, 3 premolars (D & P), 3 molars (P), 06-11
Permanent vs deciduous teeth:
What kind of teeth do horses have?
hypsodont - long crown with continuous eruption
- crown shortens over time
What is the difference between the apex and crown of teeth?
APEX - area of the tooth root (innermost) that begins to form at ~6 y/o
CROWN - more outer portion of the tooth embedded in the alveolus (reserved) and exposed (1-2 cm)
What is anisognathia?
upper cheek teeth are set wider apart than the lower teeth
- contact surface of cheek teeth set at 10-15 degrees
What is the arcade? Table? Occlusal surface?
row of cheek teeth
total occlusal surface
area between two arcades (biting surface)
What are the outer and inner surfaces of the incisors?
OUTER - labial surface toward the lips
INNER - lingual surface toward the tonge of mandibular arcade; palatal surface toward the palate of the maxillary arcade
What are the outer and inner surfaces of the molars?
OUTER - buccal surface toward the cheek (vestibular)
INNER - lingual surface of the mandibular arcade; palatal surface of the maxillary arcade
What is the alveolar bone of teeth? How does it appear on radiographs?
compact bone that lines the alveolus
opaque lines —> lamina dura dentes
What is the periodontal ligament? How does it appear on radiographs?
sheet of tendon-like tissue that attaches cementum to alveolar bone to help reduce stress
dark space - radiolucent
Alveolar bone vs. periodontal ligament, radiograph:
What is the table angle? What are 3 causes of variability? How is it approached when floating?
angle of the occlusal surface
- anatomic differences between individuals
- front to back - back = steep, front = flat
- upper to lower arcade
don’t change artificially —> alters grinding surface
What is the cusp of the tooth?
occlusal eminence toward the occlusal surface of the tooth essential for grinding
What are cinguli? What happens when they’re sharp?
vertical ridges on the buccal surface of upper cheek teeth (2 per tooth)
responsible for soft tissue injury due to sharp enamel points
What are the 4 dental tissues?
- CEMENTUM - outer layer that attaches to the periodontal ligament
- ENAMEL - laminated sheets under the cementum (hardest tissue in the body)
- DENTIN - bulk of tooth under enamel with tubular ultrastructure
- PULP - blood and nerve supply to the tooth (inner surface of the tooth)
What produced the cementum? What causes wear?
subgingival cementoblasts throughout the life of the tooth
occlusion - wear highest on occlusal surface
What are the 2 functions of the cementum? How does it differ in deciduous teeth and permanent teeth?
- root formation
- periodontal attachment
white at the beginning and can stain with age
What are the 3 major properties of enamel?
- hardest substance in the body, but brittle
- 98% mineral
- when damaged, it cannot be repaired
What are the 2 portions of enamel?
- EXTERNAL - on the outside of tooth
- INTERNAL - surrounds infundibula
What are infundibula?
invaginations of enamel in the center of the tooth
- aka cup
How do the infundibula compare in incisors, maxillary cheek teeth, and mandibular cheek teeth?
single (cup)
multiple
none
Maxillary cheek tooth, infundibula:
multiple
- black = external enamel
- brown = central enamel
Mandibular cheek tooth, infundibula:
none
- black = external enamel
What provides the bulk of the tooth material? What produces it?
dentin
odontoblasts and pulp as the tooth erupts
What is the difference between primary and secondary dentin?
PRIMARY - forms before tooth eruption
SECONDARY - forms after tooth eruption and fills into the receding pulp chamber and is commonly stained dark from food pigment
What makes up the pulp? How does it compare in immature and mature teeth?
nerves, arteries, veins, lymph vessels
- IMMATURE = larger apex (inner)
- MATURE = smaller due to increased secondary dentin used for strength of the tooth
What causes attrition in horse teeth?
reserved crown erupts continuously, but the dentin, enamel, and cementum wear at different rates resulting in irregular occlusal surfaces
How do cheek teeth communicate with paranasal sinuses? What is the frontomaxillary aperture?
- rostral maxillary sinus = roots of 8, 9, 10
- caudal maxillary sinus = roots of 10, 11
communication between the conchofrontal sinus and the caudal maxillary sinus
Equine dental eruption:
When do incisors and premolars shed? How does this look?
- INCISORS = 2.5/3.5/4.5 yrs
- PREMOLARS = 2.5/3/4 yrs
caps formed by deciduous teeth on top of permanent ones
When do canines and wolf teeth erupt?
4-5 years in males
6 months
How does the incisor angle change with age?
becomes more acute with age
How is shape of incisors used to age horses?
- OVAL = 5-9 yrs
- TRIANGLE = 10-15 years
- SQUARE = 16-20 yrs
When do cups disappear and dental stars appear in the incisors?
6/7/8 yrs
5/6/7-8 yrs
When does the mark (enamel ring) disappear in the incisors?
- 12-15 yrs
- 14-17 yrs
- 16-19 yrs
How does the shape of corner incisors change as the horse ages?
- <9 y/o = shorter than width
- 9-10 = square
- > 10 = taller than width
When does the incisor hook appear?
at 7 y/o and 11-13 y/o
What is Galvayne’s groove? How is it used for aging horses?
longitudinal depression on the labial surface of the 3rd incisor, often stained dark
- 10 y/o = start at gingiva
- 15 y/o = halfway down
- 20 y/o = all the way down
- 25 y/o = halfway gone
- 30 y/o = gone
How do cheek teeth rest at rest? What are the 4 phases of the chewing cycle?
not in contact
- opening stroke
- closing stroke = first arcade in contact
- power stroke = grinding phase
- reset phase
How do sharp enamel points cause pathology?
injury to the cheek or tongue
What is shear?
abnormally steep angle of the meeting of upper and lower molars
affects lingual surface of the lower arcade and buccal surface of the upper arcade
What are hooks? What causes it?
long, sharp points that grow on the upper arcade rostral surface (06) and lower arcade caudal surface (11)
What is occurring in this picture?
hooks
- upper = rostral
- lower = caudal
What are ramps?
when the lower arcade begins overgrowing the upper arcade
- most common in the molars > premolars
What is happening in this picture?
ramp
premolars are becoming longer on the lower arcade
What are steps?
loss of a tooth results in the overgrowth of the corresponding tooth on the other arcade and prevents normal attrition
What is occuring in this picture?
steps
What are waves?
multiple teeth begin overgrowing forming a wave
- common in horses 12 years and older that have not had adequate dental care
What are exaggerated transverse ridges? What are 2 common occurances?
growth of the transverse ridges, making them more prominent than the rest of the ridging in the arcade
- young horses
- newly erupted teeth
What is periodontal disease most commonly associated with in horses?
malocclusion causes the formation of a pocket between teeth, where food commonly gets stuck
How does the origin of neoplastic diseases of teeth affect prognosis?
dental origin = no treatment option
juvenile ossifying fibroma = good prognosis with amputation (mandibulectomy)
What is equine odontoclastic tooth resportion and hypercementosis (EOTRH)? How is it treated?
painful disease of unknown etiology common in older horses (>15), starting at the third incisor —> resorption soft tissue proliferation at gingiva, hyperplasia of cementum
extraction of affected teeth
