Lecture 1: Dental Anatomy and Nomenclature

brachydont

• in dogs, cats, primates, and man

• having short crowns, well-developed roots, and only narrow canals in the roots

• short teeth

hypsodont

• in horses, cows, and other herbivores

• high crowns that erupt throughout life providing extra material for grinding food particulates down

animals have

incisors, canines, premolars, and molars

what is the cusp?

a pronounced point on the occlusal or most coronal portion of a tooth

what is 1?

pulp

what is 2?

cementum

what is 3?

cusp

what is 4?

enamel

what is 5?

dentin

what is 6?

cementoenamel junction (neck)

what is 7?

gingiva

what is 8?

periodontal ligament

what is 9?

alveolar bone

what is 10?

apex

enamel

• covers the tooth crown

• hardest substance in body

• formed by ameloblasts in root bud

• amelogenesis stops prior to tooth eruption

• effective barrier to heat/cold/sweet sensitivities and bacterial entrance to the tooth

true or false: enamel is incapable of repair after eruption.

true

dentin

• makes up bulk of tooth

• comprised of dentinal tubules that communicate between pulp and dentin, dentin/enamel, and dentin/cementum junctions

• primary, secondary, and tertiary

what do dentinal tubules contain?

odontoblasts that produce dentin throughout the life of the tooth when the tubule is exposed

what are these?

dentinal tubules

odontoblast processes extend into the dentinal tubules along with nerve endings which cause

sensitivity within the dentin

when enamel and dentin is gradually lost as the result of a local insult, what happens?

existing odontoblasts or odontoblast-like cells produce tertiary dentin to protect pulp

what is this showing?

tertiary (reparative) dentin

cementum

• hard tissue forming the surface of the root

• periodontal ligament and gingiva attach here

• produced throughout life increasing the width with age

• cementoblasts produce cementum at apex of root

what does chronic irritation do to cementum?

causes hypercementosis and locks the tooth into the alveolar socket

loss of cementum prevents

reattachment of the periodontal ligament

periodontal ligament

• fibrous connective tissue which fills space between cementum of the tooth root and alveolar bone

• composed of fibers → collagen bundles in various shapes and orientations

functions of the periodontal ligament

• shock absorption

• transmits occlusal forces

• attaches tooth to bone and cementum

• supplies nutrients

• provides tactile and proprioceptive information

the periodontal ligament is composed of

sharpey fibers

what is this?

sharpey fibers in periodontal ligament

pulp

• soft tissue connective tissue encased in root canal containing nerves, fibroblasts, collagen fibers, blood, and odontoblasts, which produce dentin throughout the life of the tooth

• as animals age, the pulp chamber/root canal narrows

odontoblasts lining the pulp chamber and root canal produce

secondary dentin, causing the pulp to become narrower as the animal ages

what is 1?

crown (coronal)

what is 2?

neck

what is 3?

cementum

what is 4?

root (apical)

what is 5?

enamel

what is 6?

dentin

what is 7?

pulp chamber

what is 8?

furcation

what is 9?

periodontal ligament space

what is 10?

interradicular bone

what is 11?

root canal

what is 12?

alveolar margin

4 components of periodontium

• gingiva

• cementum

• periodontal ligament

• alveolar bone

the structures of the periodontium are affected by and lost from

periodontal disease

gingival sulcus

the normal, physiological space between the free gingiva and the tooth surface

normal sulcus depth

• dogs → less than 3mm

• cats → less than 1mm

what is 1?

gingival sulcus

what is 2?

free gingiva

what is 1?

alveolar mucosa

what is 2?

mucogingival junction

what is 3?

free gingival margin

what is 4?

attached gingiva

what is 5?

gingival sulcus

what is 1?

distal

what is 2?

mesial

what is 3?

lingual

what is 4?

labial

apical

toward the apex of the root

coronal

toward the tip of the crown

subgingival

area or structure apical to the gingival margin

supragingival

area or structure coronal to the gingival margin

proximal

mesial or distal surfaces of a tooth in close contact with an adjacent tooth

interproximal

space between adjacent teeth

occlusal

surface of a tooth that faces the tooth of the opposing arcade

vestibular

refers to the surface of the tooth facing the vestibule or lips; aka buccal and labial

lingual/palatal

• lingual = the surface of a mandibular tooth facing the tongue

• palatal = the surface of a maxillary tooth facing the palate

mesial

the interproximal surface of a tooth that face rostrally or towards the midline of the dental arch

distal

the interproximal surface of a tooth that faces caudally or away from the midline of the dental arch

rostral

refers to a structure closer to, or a direction toward the tip of the nares

caudal

refers to a structure closer to, or a direction toward the tail

canine deciduous teeth formula

2 x (I 3/3, C 1/1, PM 3/3) = 28

canine permanent dentition formula

2 x (I 3/3, C 1/1, PM 4/4, M 2/3) = 42

which canine maxillary teeth have 1 root?

101-105 and 201-205

which canine maxillary teeth have 2 roots?

106, 107, 206, 207

which canine maxillary teeth have 3 roots?

108-110, 208-210

which canine mandibular teeth have 1 root?

301-305, 311, 401-405, 411

which canine mandibular teeth have 2 roots?

306-310, 406-410

309 and 409 have how many roots compared to 109 and 209?

309 and 409 = 2 roots, 109 and 209 = 3 roots

canine deciduous teeth eruption

• incisors → 4-6 weeks

• canines → 3-5 weeks

• premolars → 5-6 weeks

canine permanent teeth eruption

• incisors → 3-35 months

• canines → 5-7 months

• premolars → 4-6 months

• molars → 5-7 months

normal occlusion for dogs

4th maxillary premolar superimposes 1st mandibular molar

what are these showing?

normal occlusion for dog

kittens are missing

05 and 06

true or false: kittens have molars.

false

in permanent feline teeth, what are they missing in the mandible?

no 05 and 06

permanent feline dental formula

2 x (I 3/3, C 1/1, PM 3/2, M 1/1) = 30

which feline maxillary teeth have 1 root?

101-104, 106, 201-204, 206

which feline maxillary teeth have 2 roots?

107, 109, 207, 209

which feline maxillary teeth have 3 roots?

108 and 208

which feline mandibular teeth have 1 root?

301-304, 401-404

which feline mandibular teeth have 2 roots?

307-309, 407-409

what is 1?

zygomatic arch

what is 2?

frontal bone

what is 3?

nasal bones

what is 4?

infraorbital foramen

what is 5?

upper and lower canine teeth

what is 6?

upper and lower incisors

feline deciduous tooth eruption

• incisors → 3-4 weeks

• canines → 3-4 weeks

• premolars → 5-6 weeks

feline permanent tooth eruption

• incisors → 3-4 months

• canines → 4-5 months

• premolars → 4-6 months

• molars → 5-7 months