aging horses by teeth

describe the standard system

categorizes teeth based on their type and location, incisors, canines, premolars, molars

describe the cheek teeth system

highlights function and location, premolars, molars

describe the triadan system

numerical system that divides the mouth into four quadrants: right maxillary, left maxillary, left mandibular, right mandibular

hypsodont teeth

continually erupting, slowly erupt over most of life, long crown (body), little root

hypsodont animals

horses, cows, deer

brachydont teeth

permanent teeth fully erupt before maturity, normally survive for life of animal

brachydont animals

dog and cat

what is cementum and where is it found

bone-like tissue that covers tooth root (comes off when floated)

what does floating mean

leveling the teeth

what is enamel and where is it found

coating of the crown, gives it hardness, protecting underneath, found in complex folds or ridges on the occlusal

what is dentin and where is it found

makes up bulk of tooth, surrounds pulp cavity, less mineralized than enamel but harder than bone

what is the pulp cavity of an equine incisor tooth?

soft tissue where the blood and nerve supplies of tooth come through tooth. incisor can have single pulp, cheek teeth complex compartmentalization of pulp cavities, 5 compartments

how does the pulp cavity relate to the dental star

dental star is visible mark that appears on the occlusal surface of tooth as pulp cavity gets filled with dentin due to wear and aging

why can we generally age younger horses (<5 yrs) more accurately?

when under 5 yrs, we can use eruptions as a guide and it is very consistent and predictable whereas over 5 yrs you use shape and wear of occlusal teeth which does happen consistently and is more of an educated guess. wide ranges of wear and shape exist

deciduous teeth

baby teeth, smooth no ridges, distinct neck, round

permanent teeth

adult teeth, grooved, less white, not distinct neck, more square in shape

describe canine teeth, where are they?

between upper and lower corner incisors and the first cheek teeth, called the bridle path

when do canine teeth erupt

typically erupt around 4-5 yrs of age

do females have canines?

typically no, but if they do, they are to a much smaller scale. Canines are testosterone driven teeth.

true or false: The canines, molars, and wolf teeth are not preceded by deciduous teeth.

true, only incisors and premolars are preceded by deciduous teeth

The permanent cheek teeth all have deciduous caps that fall off.

false, don’t have caps and aren’t precede by deciduous teeth

Molars begin to erupt at 8 years of age

false, begin to erupt around 6 yrs

All the permanent incisors are erupted and in wear for the first time at 3 ½ years.

false, typically in wear at 5 yrs

Galvayne’s groove is on the lower I3 teeth (303/403).

no, UCI, upper corner incisor

dental star

appears when tooth is worn to the pulp space; pulp space filled in with dentin. appears on labial (lip) side of tooth, rostral to enamel spot

enamel spot

appears after the cup has worn down to the bottom

cup (infundibulum)

physical indentions/ depression you can see in tooth

full mouthed meaning

all permanent incisors erupted and in wear (by 5 yrs)

smooth mouthed meaning

they have no cups left on their teeth, at least 11 yrs

what are caps, which teeth have them?

caps refer to retained baby teeth specifically deciduous premolars, that haven’t shed naturally as permanent teeth erupt.

what problems can caps cause?

uneven tooth growth, pain, difficulty eating or biting

what are wolf teeth? why remove them?

vestigial teeth, premolar 1, typically get removed because they can cause interference and irritation with the bridle/bit

what does in wear mean

two permanent teeth erupt fully from gemlike and are in wear/ are touching. erupt > 6 months> in wear. in wear is at least 5 yr

permanent dental formula. explain and include why there is a variable number of teeth in adult horses

2(I 3/3 C (0-1)/(0-1) P (3-4)/(3-4) M 3/3) = 36-44 total

Incisors-canines(varies, male horse has one or some mares)-premolar (varies due to wolf tooth)-molar. variation is due to the variability of presence of first premolars (wolf teeth) in males and females and variability of canines in females

on what tooth/teeth and surface is Galvayne’s groove potentially visible?

Groove on lateral (labial) surface of upper I3: UCI (upper corner incisor)

how is Galvayne’s groove useful in determining age of horse

10yrs- groove appears

15 yrs- groove ½ down

20 yrs- groove all the way down (reaches occlusal surface)

25 yrs- absent from upper ½

30 yrs- grooves disappears

who was Dr. Galvayne?

a well known horse tamer and author who created a “perfect” system for horse aging by looking at their teeth

how is UCI and upper central incisors used to “ball park” horses into age category?

through shape and wear

5-9 yrs: wider than tall

10-14 yrs: UCI was about as wide as tall, square

15-20 yrs: UCI was taller than wide

Rule of 8’s

1-8days: I1 erupts

4-8 weeks: I2 erupts

6-8 months: I3 erupts

occlusal surface

touching, grinding surfaces

buccal surface

surface against cheek

lingual surface

surface against tongue

labial surface

surface against lip

shapes in relation to age

young-oval transversely

9-10 yrs- round

16-17 yrs- triangular

20yrs- oval rostrocaudally

impacted wolf tooth

lack of eruption

over bite

parrot mouth

under bite

monkey mouth

examining for aging steps

1. Look at incisor profile

2. determine number of deciduous and/or permanent incisors

3. shape of upper i3. Look for galvaynes upper i3

4. examine occlusal surface of lower incisors (cups)

aging

Rule of 8”: if under 2 ½

2 ½ to 5 yrs: i1 2 ½ yrs i2 3 ½ yrs i3 4 ½ yrs in wear at 5 years canines 4-5 yrs

Over 5: shape of UCI- wider vs taller: 5-9 square: 10-14 taller vs wider: 15-20

Lower: i1 cup gone 6 yrs i2 cup gone 7 yrs(hook on upper i3) i3 cup 8 yrs

Upper: i1 cup gone 9 yrs i2 cup gone 10 yrs i3 cup gone:11 yrs (smooth mouthed) by 11 yrs

Age this horse (within 6 months), and state 3 specific reasons why you chose that age

it has its I1 permanent teeth which puts it at least at 2 1/2 , it can be seen that the horses I2 are starting to come in so it is a little under 3 ½ but since the i1 are in use, 6 months can be added. This horse is most likely 3 yrs

Age this mare (within 1 year), and state 3 specific reasons why you chose that age

It has all of its permanent teeth and they are in wear so at least 5 years, it also has the canine teeth, so at least 4-5 yrs, it also is missing cups on I1 so it is at least 6 years. My guess is 6 years

Age this foal and state 3 specific reasons why you chose that age range.

over 4 weeks because the I1 has erupted so it is at least over 8 days and the I2 is beginning to erupt so that puts it in the 4-8 week range and these are deciduous teeth

stage permanent

I1: 2 ½ I2: 3 ½ I3: 4 ½

stage cup gone

I1: 6 yr I2: 7 yr I3: 8 yr

stage dental star

I1: 8 yr I2: 9 yr I3: 10 yr

stage cup gone upper

I1 9 yr I2 10 yr I3 11 yr

stage enamel spot gone

I1 12 yr I2 13 yr I3 15 yr