Oral Cavity-Teeth Flashcards
What are the two dental arcades of the oral cavity?
Maxillary (upper) and mandibular (lower)
What is a heterodont?
An animal with differences in tooth shape along the rows (I, C, PM and M)
What is a diphyodont?
An animal with two successive sets of teeth, deciduous (milk) and permanent (adult)
What is a diastema?
A gap between the teeth
Describe the two regions of a tooth.
The crown, the visible portion, and the root, the region below the gum line
What is the borderline between the crown and the root?
Cementoenamel junction (CEJ)
How is the tooth anchored into the root?
By a socket of bone called the alveolus
What lines the alveoli? Describe it.
Lamina dura, a thin shell of dense bone
What is the pulp cavity? What does it contain?
The central space of the tooth, containing pulp soft tissue with nerves, blood vessels and lymphatic vessels
What is the connective tissue called?
Periodontium
Which four structures make up the periodontium?
Gingiva, cementum, alveolar bone and the periodontal ligament
How does periodontium attach the root to the bone?
Via periodontal ligaments
Describe the gingiva.
The gums, oral mucosa that covers the tooth
Describe the two types of gingiva.
Free gingiva forms a collar around the tooth and is looser, whereas attached gingiva is keratinised and firmly attached to tooth and bone.
Describe the junction between visible tooth and the free gingiva.
The gingival crevice or sulcus. The cells in the epithelium of the gum adhere to the tooth enamel via a basement membrane
Describe brachydont teeth
-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
Describe hypsodont teeth
-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
What are radicular vs aradicular hypsodont teeth?
-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)
What is enamel? What is its function? Which cells secrete enamel forming proteins?
The hardest substance in the body, forming a tough outer layer to the teeth
-Formed by ameloblasts
What is dentin? What is its function? Which cells form dentin?
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
What is cementum? What is its function?
-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
Describe incisors
Adapted for grasping, pinching nipping and scratching
Describe canines
Used as weapons for tearing flesh during hunting and fighting
Describe premolars
Rostral cheek teeth with deciduous precursors
Describe molars
Flattened and triangular with jagged edges, function like serrated-edged blades. No deciduous precursors
Describe the vestibular surface of the tooth.
Surface facing vestibule or lips
Describe the lingual surface of the tooth.
Surface of the mandibular teeth facing the tongue or median plane of the mouth
Describe the palatal surface of the tooth
Lingual surface of the maxillary teeth
What is the coronal region?
Towards the occlusal surface (top
What is the apical region?
Towards the root
What is the mesial surface?
Surface of the incisor teeth towards the median plane of the mouth, rostral surface of the canine, pre molar and molar teeth
What is the distal surface?
Surface of the incisors away from the median plane of the mouth caudal surface of the canine, pre molar and molar teeth
Give the dental formula for pigs. How many teeth do they have? How do they differ from other species?
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
Give the dental formula for dogs. How many teeth do they have? How do they differ from other species?
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
Give the roots of each dog tooth
-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
Give the dental formula of ruminants. How many teeth do they have? How do they differ from other species?
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
Describe the microanatomy of the dental pad
Thick stratum corneum and well developed papillae of connective tissue
Give the dental formula for horses
I C PM M
U 3 1 3 or 4 3
L 3 1 3 3 3
40-42 teeth
Describe horse incisors. How are they different in young horses?
-High crowned with a single root
-In young horses, they are curved (convex on labial aspect, concave on lingual aspect)
Describe horse canines
-In mares they are small and may not erupt
-Deciduous canines are often absent
Describe the difference between maxillary and mandibular cheek teeth in horses
-Maxillary cheek teeth have less pronounced infoldings, but two enamel rings called infundibulum
-Mandibular cheek teeth have more pronounced infoldings/invaginations
What are the wolf teeth in horses?
P1 teeth, they are vestigial, so often lacking
How does the occlusal surface of hypsodont teeth differ to that of brachyodont teeth?
All dentalhard tisues are exposed, whereas only the enamel is eposed in brachydont teeth
Give the number of roots of different horse teeth
-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
What is infundibulum? Why do they look dark? What are they filled with? Does it connect with the pulp cavity?
-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
What is secondary dentin? What does it form, after how long?
-Forms after eruption as the tooth develops with age
-Forms dental stars after about 8 years
