Oral Cavity-Teeth

Question 1

What are the two dental arcades of the oral cavity?

Answer 1

Maxillary (upper) and mandibular (lower)

Question 2

What is a heterodont?

Answer 2

An animal with differences in tooth shape along the rows (I, C, PM and M)

Question 3

What is a diphyodont?

Answer 3

An animal with two successive sets of teeth, deciduous (milk) and permanent (adult)

Question 4

What is a diastema?

Answer 4

A gap between the teeth

Question 5

Describe the two regions of a tooth.

Answer 5

The crown, the visible portion, and the root, the region below the gum line

Question 6

What is the borderline between the crown and the root?

Answer 6

Cementoenamel junction (CEJ)

Question 7

How is the tooth anchored into the root?

Answer 7

By a socket of bone called the alveolus

Question 8

What lines the alveoli? Describe it.

Answer 8

Lamina dura, a thin shell of dense bone

Question 9

What is the pulp cavity? What does it contain?

Answer 9

The central space of the tooth, containing pulp soft tissue with nerves, blood vessels and lymphatic vessels

Question 10

What is the connective tissue called?

Answer 10

Periodontium

Question 11

Which four structures make up the periodontium?

Answer 11

Gingiva, cementum, alveolar bone and the periodontal ligament

Question 12

How does periodontium attach the root to the bone?

Answer 12

Via periodontal ligaments

Question 13

Describe the gingiva.

Answer 13

The gums, oral mucosa that covers the tooth

Question 14

Describe the two types of gingiva.

Answer 14

Free gingiva forms a collar around the tooth and is looser, whereas attached gingiva is keratinised and firmly attached to tooth and bone.

Question 15

Describe the junction between visible tooth and the free gingiva.

Answer 15

The gingival crevice or sulcus. The cells in the epithelium of the gum adhere to the tooth enamel via a basement membrane

Question 16

Describe brachydont teeth

Answer 16

-Smaller and low crowned with a constricted neck at the gum line
-Suitable for a soft diet, such as dogs, cats, ferrets and pigs.
-The root is embedded in the jaw bone.
-Only the crown is encased inn enamel
-Only the root is encased in cementum
Acellular, so cannot regenerate-except C in pigs

Question 17

Describe hypsodont teeth

Answer 17

-Larger crown
-Suitable for wear and tear via feeding on tough, fibrous diets
-All pernament teeth in horses, cheek teeth in ruminants, pig canines and lagomorphs
-Radicular or aradicular
-Enamel extends past the gum line and stops at the root

Question 18

What are radicular vs aradicular hypsodont teeth?

Answer 18

-Radicular teeth have a closed root, eventually forming a true root which slows growth, eventually stopping (horses)
-Aradicular teeth have an open root, so teeth continuously grow throught life (rabbits)

Question 19

What is enamel? What is its function? Which cells secrete enamel forming proteins?

Answer 19

The hardest substance in the body, forming a tough outer layer to the teeth
-Formed by ameloblasts

Question 20

What is dentin? What is its function? Which cells form dentin?

Answer 20

Forms the bulk of the tooth, and is a hard substance
-Its function is to support the enamel, and absorb pressure from eating. Also transfers impulses from enamel to pulp
-Formed by odontoblasts via dentinogenesis

Question 21

What is cementum? What is its function?

Answer 21

-Thin, bonelike connective tissue covering the outer surface of the root. Fills the infundibula of hypsodont teeth
-It attaches the tooth to the alveolar bone by insertion of periodontal ligament fibres

Question 22

Describe incisors

Answer 22

Adapted for grasping, pinching nipping and scratching

Question 23

Describe canines

Answer 23

Used as weapons for tearing flesh during hunting and fighting

Question 24

Describe premolars

Answer 24

Rostral cheek teeth with deciduous precursors

Question 25

Describe molars

Answer 25

Flattened and triangular with jagged edges, function like serrated-edged blades. No deciduous precursors

Question 26

Describe the vestibular surface of the tooth.

Answer 26

Surface facing vestibule or lips

Question 27

Describe the lingual surface of the tooth.

Answer 27

Surface of the mandibular teeth facing the tongue or median plane of the mouth

Question 28

Describe the palatal surface of the tooth

Answer 28

Lingual surface of the maxillary teeth

Question 29

What is the coronal region?

Answer 29

Towards the occlusal surface (top

Question 30

What is the apical region?

Answer 30

Towards the root

Question 31

What is the mesial surface?

Answer 31

Surface of the incisor teeth towards the median plane of the mouth, rostral surface of the canine, pre molar and molar teeth

Question 32

What is the distal surface?

Answer 32

Surface of the incisors away from the median plane of the mouth caudal surface of the canine, pre molar and molar teeth

Question 33

Give the dental formula for pigs. How many teeth do they have? How do they differ from other species?

Answer 33

I C PM M U 3 1 4 3 L 3 1 4 3 -44 teeth (full set) -Born with needle teeth, including deciduous incisors and canines (3+3+1+1=8) -Canines (tusks) are aradicular hypsodonts, so continuously erupt

Question 34

Give the dental formula for dogs. How many teeth do they have? How do they differ from other species?

Answer 34

I C PM M U 3 1 4 2 L 3 1 4 3 -42 teeth -Upper PM 4 and lower M1 are carnassial-biggest pair of shearing teeth

Question 35

Give the roots of each dog tooth

Answer 35

-All incisors have a single root -Root of the canine is larger than the crown -PMs and Ms mostly have 2 roots except: -Both PM1s and lower M3 have 1 root -Upper PM4 and both upper Ms have 3 roots

Question 36

Give the dental formula of ruminants. How many teeth do they have? How do they differ from other species?

Answer 36

I C PM M U 0 0 3 3 L 4 0 3 3 -32 teeth -Heavily cornified dental pad instead of upper incisors or canines -Canines assimilated to incisors -Is and Cs are brachydont, PMs and Ms are hypsodont -Large diastema

Question 37

Describe the microanatomy of the dental pad

Answer 37

Thick stratum corneum and well developed papillae of connective tissue

Question 38

Give the dental formula for horses

Answer 38

I C PM M U 3 1 3 or 4 3 L 3 1 3 3 3 40-42 teeth

Question 39

Describe horse incisors. How are they different in young horses?

Answer 39

-High crowned with a single root -In young horses, they are curved (convex on labial aspect, concave on lingual aspect)

Question 40

Describe horse canines

Answer 40

-In mares they are small and may not erupt -Deciduous canines are often absent

Question 41

Describe the difference between maxillary and mandibular cheek teeth in horses

Answer 41

-Maxillary cheek teeth have less pronounced infoldings, but two enamel rings called infundibulum -Mandibular cheek teeth have more pronounced infoldings/invaginations

Question 42

What are the wolf teeth in horses?

Answer 42

P1 teeth, they are vestigial, so often lacking

Question 43

How does the occlusal surface of hypsodont teeth differ to that of brachyodont teeth?

Answer 43

All dentalhard tisues are exposed, whereas only the enamel is eposed in brachydont teeth

Question 44

Give the number of roots of different horse teeth

Answer 44

-All Is have 1 root -PM2 to PM4 and M1 to M3 of the upper jaw have 3 roots, and 2 in the lower jaw

Question 45

What is infundibulum? Why do they look dark? What are they filled with? Does it connect with the pulp cavity?

Answer 45

-A cup or funnel shaped invagination of enamel from the occlusal surface of the equine incisor and maxillary cheek teeth -Look dark because food gets packed inside and turns black as it decays -Partially filled with cement, leaving a small cavity -Does not connect with the pulp cavity

Question 46

What is secondary dentin? What does it form, after how long?

Answer 46

-Forms after eruption as the tooth develops with age -Forms dental stars after about 8 years