export_chapter 7 aging Flashcards
What was old theory of force for tooth eruption in horses?
What is thought now?
- root lengthening
- PDL remodeling
At what age to equine incisor teeth stop growing?
When do they stop erupting?
Between what ages is the size of horse incisors constant?
- age 17
- never
- between 6 and 17
What is rate of occlusal wear of equine incisors?
- 2.5 mm /year
Where is the dental star found?
- between labial edge of incisor and the cup
What is the “mark” on equine incisors?
How does it change with time?
- when the bottom of the infundibulum which is filled with cementum comes into occlusion making a cementum core surrounded by enamel
- young horses oval, become smaller, rounder and move caudally, turns into enamel spot, then disappears
How do incisor teeth change shape with time?
- oval mesiodistal, trapezoid, triangular, oval labiolingual
What are three categories of incisor shapes and corresponding age?
5-9, wider than tall
9-10 square
>10 taller than wide
What is Galvayne’s groove and is it accurate?
- Groove in labrial surface that appears around age 10 and supposed to be gone by 30
- No, more than 50% of horses do not have groove between 10 and 30
What are most accurate ways to age horses by teeth?
- eruption and dental stars
What color are dental stars and what does the color vary with?
- yellow to brown
- diet (brown on grass/fodder, yellow on other foods)
Why does dental star have a white dot?
Few tubules (tertiary dentin)
What forms dentin tubules?
- retreating odontoblast (leaving only cytoplasmic process behind)
Where are primary, secondary and tertiary dentin located?
Primary right next to enamel
Secondary central
tertitary - only between tip of pulp chamber and occlusal surface
What is difference structurally between primary and secondary dentin?
- peritubular (intratubular) dentin
What is structure of dentin in dental stars?
Where is the peritubular dentin?
- central core of tertiary dentin (very few tubules)
- broad ring of secondary dentin
- neither
