Oral Cavity Anatomy - Teeth Flashcards
What is the teeth anatomy arranged into?
Two dental arcades
What are the two dental arcades associated with?
one is associated with the mandible and the other is associated with the incisive and maxillary bones
Meaning of heterodont?
They have different types of teeth
What types of teeth are there? (heterodont)
I, C, PM, M
(incisors, canines, pre-molars and molars)
Mammals are…
diphyodont
Meaning of diphyodont?
two types of teeth
What are the two types of teeth that ‘diphyodonts’ have?
permanent and deciduous (I, C, PM only)
For the teeth anatomy, what do we see in farm animals?
Diastema in farm animals AND RABBITS
What equine, what is the diastema known as?
interdental space
Diastema?
nothing is wrong, there is just a gap
What anchors the tooth?
the root, it is anchored in a socket of bone called alveolar bone/alveolus
What is the basic anatomy of the dental unit?
Crown, neck and then the root
What is the neck of the tooth?
it is found between the crown and the root and is a constricted region just below the ginigival line
What is the lamina dura also known as?
cribriform plate
What is the lamina dura?
it is the thin shell of dense bone lining the alveoli
What do teeth consist of?
Enamel, Dentine, Cementum and Pulp
What is the pulp cavity?
The central space of the tooth containing pulp-soft tissue with nerves, vessels, lymphatics
What is the periodontium?
The connective tissue that attaches root to the bone
What are the four defined structures that the periodontal tissues include?
Gingiva, cementum, alveolar bone and the periodontal ligament
What does the periodontal ligament do?
attaches the tooth to the bone
acts like a shock absorber
What is the periodontal ligament?
interconnected interwoven bundle of fibres, anchored to the cementum and bone
Name the two types of teeth:
Brachydont
Hypsodont
Describe the Brachydont tooth:
smaller and low crowned
it has a constricted neck at the gum line
It has a true root
What type of feeding is the brachydont suitable for?
feeding on soft diet; dogs, cats, ferrets and pig etc.
Describe the hypsodont tooth:
larger crown that can resist wear and tear
It has an open root or closed root
meaning of aradicular or radicular?
aradicular - open root
radicular - closed roots
type of feeding that hypsodont is suitable for and which animals have this type of tooth?
can resist the wear and tear of feeding on tough and fibrous diet as in ungulates; horse all permanent teeth (except canines) , ruminant cheek teeth, lagomorphs, tusks of pig (canine teeth)
What type of teeth do rabbits, guinea pigs, chinchillas and degus have?
They have aradicular hypsodont teeth
What is the hardest and most mineralised substance in the body?
Enamel
Is enamel cellular/acellular?
acellular
Because enamel is acellular, what does this mean?
it cannot regenerate
What is the exception to enamel’s inability to regenerate?
swine canine teeth
describe the innervation/vascularisation of enamel:
no nerve or blood supply
For a brachydont, explain the enamel cover:
enamel covers the external surface of the crown
For a hypsodont, explain the enamel cover:
Covers the entire body of the tooth, but not the root
what does folding of the enamel create?
peripheral and infundibular enamel
What produces enamel?
ameloblasts
Histologically, what is enamel composed of?
long, slender rods
What is Dentin?
it forms the bulk of the tooth, it is hard, substance-like bone
what does dentin surround?
the pulp cavity
where does secondary dentin form?
forms at the periphery of exposed pulp cavity
How does dentin respond to trauma?
reparative or tertiary dentine is formed
What are odontoblasts?
the cells that continuously deposit the dentine
Where are odontoblasts found?
next to the pulp cavity
When are odontoblasts active?
they remain active throughout life
Describe the structure of the cementum?
it is the least hard of all, thin bonelike layer
what attaches the cementum to a bone and which bone is it attached to?
attached to the alveolar bone by the periodontal ligament
Describe the coverage of the cementum on a brachydont:
covers the root only
Describe where cementum is found on hypsodont teeth:
fills the infundibula of hypsodont teeth and covers the entire tooth
Why is equine cementum unique?
because it is vascular and innervated - and deposition continues throughout the life of the tooth
What is the gingiva/gums?
the name for the oral mucosa that covers the tooth
which one (of the four) of the periodontal tissues is normally seen in the mouth?
the gingiva/gums
where is the cementoenamel junction found?
borderline between the crown and root(s)
what is the CEJ?
The cementoenamel junction
what types of gingiva are there?
attached and free gingiva
What are attached gingiva attached to?
firmly attached to the underlying periosteum of the alveolar bone
where are free gingiva found?
adopted to the tooth surface
what is the gingival crevice also known as?
the sulcus
at what point in the mouth do the cells in the epithelium of the gum adhere to the tooth enamel?
at the gingival crevice
what forms a tight seal?
the adherence of the gingiva to the tooth
what are incisors adapted for?
for grasping, pinching, scratching and nipping
uses of canines?
‘weapons’ –> tearing flesh during hunting and fighting
what do premolars have that molars do not?
they have deciduous precursors
which premolars have deciduous precursors?
rostral cheek teeth
description of molars?
flattened and triangular with jagged edges
function of molars?
like serrated-edged blades
what teeth in particular are used for shearing and grinding?
upper P4 & lower M1
what is the vestibular surface of the tooth?
the surface of the tooth that is facing the vestibule/lips
(labial - incisors+canine
buccal - molars+premolars)
palatal?
refers to the lingual surface of the maxillary teeth
what is the lingual surface of the maxillary or mandibular tooth?
the surface facing the tongue
what collective name refers to the surfaces of the tooth face next to another tooth in the same row(?)
interproximal
What is the occlusal surface of the tooth?
the portion of the tooth that comes in contact or faces the opposite tooth (PM or M)
Meaning of the mesial surface?
surfaces of the incisor teeth that are toward the middle or median plane of the mouth
- rostral surface of the canine, premolar and molar teeth
Distal surface meaning?
surface of the incisor teeth that are AWAY FROM the middle or median plane of the mouth
- caudal surfaces of the canine, premolar and molar teeth
meaning of coronal?
the term relating toward the occlusal surface (crown of the tooth)
how many teeth do pigs have?
44 permanent teeth
meaning of apical?
towards the apex (root) of the tooth
what teeth are pigs born with?
needle teeth
which ones are the needle teeth?
the deciduous I3 and the canines
which tusk is larger?
lower one
describe the growth of the canines:
continuously grow
which teeth are the canine of a pig?
the tusk
what is the upper arcade of a pig?
I - 3 C - 1 P - 4 M - 3
What is the lower arcade of the pig?
same
what is found on the occlusal surface of the molars?
numerous tubercles
how many teeth do dogs have? what teeth are they missing?
42
the upper M3
Which teeth are the longest teeth in dogs?
canines
which are the carnassial teeth?
they are the biggest pair of shearing teeth
Upper PM4 & lower M1
upper and lower arcade of a dog?
I - 3 C - 1 P - 4 M - 2 (upper arcade)
3 1 4 3 (lower arcade)
in dogs, how does eruption time differ?
it differs between breeds
describe the root situation for the incisors of dogs?
all incisors have a single root
size of the root of the canine?
root of canine is large, it is larger than the crown
which teeth in dogs have two roots? What is the exception?
PMs and Ms
HOWEVER
PM1s have a SINGLE root
Upper PM4 + two upper M1, M2 have THREE roots
Lower M3 has SINGLE root
Describe ruminant teeth:
dental pad, NO upper incisors or canines
in ruminants, what are canines assimilated to?
incisors
the incisors and canines in ruminants are what type of tooth?
brachydont
the premolars and molars in ruminants are what type of tooth?
hypsodont
size of the diastema in ruminants?
large
describe the dental pad of ruminants:
thick stratum corneum (II) and well developed papillae of connective tissue
what is the stratum corneum?
the outermost layer of the epidermis
What happens to a horses hypsodont teeth?
they undergo continuous wear and slowly erupt
describe a horses’ incisors:
high crowns with single root
describe the incisors in a younger horse:
they are curved
(convex on their labial aspect - concave on their lingual aspect)
describe a horses canine, in a mare:
often small and may not erupt
in a made, deciduous canines are often…
absent
in horses, describe the development of roots?
delayed
and they have closed roots
describe the large cheek teeth in a horse:
have a rough occlusal surface that acts as a grinding surface for fibrous feeds
which ones are the ‘wolf teeth’ in horses?
P1 - they are vestigial and often lacking
which teeth form a continuous surface in horses?
the premolars and the molars
PM2-PM4 and M1-M3 –> how many roots in upper and lower jaw?
3 roots in upper jaw and 2 roots in lower jaw
what separates the molars from the sinus in a horse? what does this result in?
a thin plate of alveolar bone - infection may easily spread to the sinus from tooth or alveolar abscesses
RMS?
rostral maxillary sinus
describe the cheek teeth on the maxillary arcade in a horse:
they have 2 infundibulae, which are deep infoldings of enamel filled with cementum in the center of the teeth
describe the mandibular cheek teeth in a horse:
same pattern of infoldings’invaginations as cheek teeth on the maxillary arcade BUT NO infundibulum
which teeth have complicated folding of enamel in horses?
the incisors and maxillary cheek teeth
what causes the appearance of the occlusal surface to change in horses?
as teeth continually erupt and wear down
tissues wear at…
varying rates
what is an infundibulum?
a cup/funnel shaped invagination of enamel
what does secondary dentin form in a horse?
it forms dental stars on worn surface of tooth
what does wear of a horses tooth result in?
causes the cup to get smaller and eventually disappear from all lower incisors, leaving the enamel spot in its place
what is infundibulum called colloquially (in teeth)?
a cup
what does infundibulum look like, and why?
looks like a dark mark, because food gets packed inside and turns black as it decays
what is infundibulum partly filled with and what does this result in?
partly filled with cement, leaving a small cavity
what does the infundibulum not connect with?
the pulp cavity
when secondary dentin is formed in the infundibulum, what does it overly?
pulp horn (dark brown D2)
How many roots do maxillary cheek teeth have? What are these roots?
3
2 buccal and 1 palatial
how many infundibulae do maxillary cheek teeth have? What are these called?
they have two: a mesial and distal infundibulum
how many roots do the madibular cheek teeth have and what are they?
has 2 roots, they are rostral and caudal roots
mandibular cheek teeth have no infundibulae, hence?
much narrower bucco-lingually
how many pulp horns do equine cheek teeth have?
either 5 or 6 pulp horns each
in which direction do pulp horn run?
run towards chewing surface
what order do rabbits belong to?
order of lagomorpha
why do rabbits belong to lagomorpha?
because of two small second incisors behind the maxillary incisors
in rabbits, what are the two small second incisors also known as?
peg teeth or Rudimentary incisor
how many incisor pairs do rabbits have?
three pairs of incisors: two upper and one lower
what shape do rabbits incisors have?
chisel shaped
describe the enamel distribution around the incisor of a rabbit:
it is not distributed uniformly around the tooth, the enamel is thicker on the vestibular aspect and thinner on the lingual aspect
what type of teeth are the cheek teeth and both incisors of a rabbit?
aradicular hypsodont
both incisors and cheek teeth in a rabbit are aradicular hypsodont, what does this mean?
meaning that teeth have long anatomic crown, erupt continuously and remain open rooted - they are elodont
meaning of elodont?
continuously growing, ‘open rooted’
a type of tooth that increases in its height or length on the pulpal axis throughout life
what teeth do rabbits not have?
canine
rabbits have a typical herbivore occlusion, describe it:
horizontal occlusal surface with transverse enamel folds for shredding and grinding tough fibrous food
do rabbit have diastema?
yes
What artery is the terminal branch of the external carotid artery?
maxillary artery
describe the blood supply for the upper teeth:
supplied by the infraorbital artery
the infraorbital artery is a branch of which blood vessel?
maxillary artery
describe the blood supply for the lower teeth:
lower teeth are supplied by inferior alveolar artery (IAA)
Where does the inferior alveolar artery enter the mandible?
through the mandibular foramen into mandibular canal
IAA?
inferior alveolar artery
which nerve is cranial nerve 5? (CN V)
trigeminal nerve
what does the trigeminal nerve supply?
it supplies the sensory innervation of the teeth through its maxillary and mandibular divisions
describe the innervation of the upper incisor teeth:
innervated by infraorbital nerves (maxillary nerve)
where does the infraorbital nerve run?
runs in the infraorbital canal
describe the innervation of the mandibular teeth:
mandibular teeth are supplied by inferior alveolar nerves (mandibular nerve)
where does the inferior alveolar nerve (mandibular nerve) run?
runs in the mandibular canal
which nerve is the maxillary nerve?
infraorbital nerve
which nerve is the mandibular nerve?
the inferior alveolar nerve
which teeth don’t have baby teeth?
molar
diphyodont?
just means that there are baby teeth which develop into adult teeth
