GUMES Oral Bio Flashcards
1
Q
which layer of the teeth does not contain collagen
A
enamel
2
Q
what is the enamel
A
the hard mineralised coating of the crown that is brittle but resistant to abrasion
3
Q
is enamel vascular
A
no it is not
4
Q
what changes can enamel go through
A
it is unable to regenerate but it can undergo mineralisation changes
5
Q
what does translucent mean
A
allows light to pass through
6
Q
what is amelogenesis
A
enamel development
7
Q
what is the enamel developed from
A
the ectoderm
8
Q
which cells form enamel
A
ameloblasts
9
Q
what are the stages of enamel formation
A
secretory and maturation stage
10
Q
how many ameloblasts form a single rod
A
four
11
Q
what is the rate of amelogenesis
A
4 microns per day
12
Q
when do primary epithelial bands appear
A
at 6 weeks of pregnancy
13
Q
what does the primary epithelial band divide into
A
dental lamina and vestibular lamina
14
Q
what does the dental lamina form
A
the enamel
15
Q
what are the enamel prisms
A
tightly packed masses of hydroxyapatite crystals
16
Q
how is the enamel rod arranged to the amelocemental junction
A
perpendicular
17
Q
how thick is enamel
A
2.5mm
18
Q
where is enamel the thickest
A
cusps and incisal edge
19
Q
where is enamel the thinnest
A
the cervical margin
20
Q
how does the enamel of deciduous teeth compare to the enamel of permanent teeth
A
it is thinner
21
Q
what percentage of weight of enamel is hydroxyapatite
A
95%
22
Q
what percentage of volume of enamel is hydroxyapatite
A
90%
23
Q
what percentage of enamel is water weight
A
4%
24
Q
what percentage of enamel is water by volume
A
5-10%
25
what percentage of enamel is organic matrix by weight
1%
26
what percentage of enamel is organic matric by volume
1-2%
27
what is dentine
calcified tissue that surrounds pulp
28
what does dentine do
provide support for enamel as it is not as brittle
29
why is dentine permeable
due to the presence of tubules
30
are there cells in dentine
no, only the cell processes that extend from the pulp
31
is dentine vascular
no
32
how much of organic matric is ground substance in dentine
10%
33
how much of organic matrix is type one collagen in dentine
90%
34
how much of dentine by weight is hydroxyapatite
70%
35
how much of dentine by volume is hydroxyapatite
50%
36
how much of dentine by weight is water
10%
37
how much of dentine by volume is water
20%
38
how much of dentine by weight is organic matrix
20%
39
how much of dentine by volume is organic matrix
30%
40
what forms the walll of each dentinal tubule
intratubular dentine
41
describe the shape of dentinal tubules
s
42
what is found within dentinal tubules
odontoblast processes
nerve terminals
dendritic cells
extra cellulular fluid from the pulp
43
what is the pulp made up of
odontoblasts fibroblasts and defence cells
44
describe the pulp
centre of the tooth that is innervated, vascular and containing lymphatics
45
where is pulp contained
within the pulp chamber
46
what is dentine formed from
the dental papilla
47
what is pulp formed from
the dental papilla
48
if pulp is exposed and there are senses like cold, hot or pressure, are they generated as seperate senses
no it is all generated as pain
49
what are the four primary functions of pulp
- form dentine
- provide nutritents and moisturise the surrounding tissues
- protective role through reparative dentine
- sensory role as it transmits sensivity
50
what is cementum
calcified substance covering the root dentine
51
what forms cementum
cementocytes
52
where are cementocytes found
in lacunae
53
is cementum vascular
no
54
where does cementum receives its nutrition from
the periodontal ligament
55
what does cementum contain
collagen matrix
56
is cementum regenerated
continuously
57
which form of cementum is formed first
acellular
58
which form of cementum is formed later
cellular
59
where is cellular cementum found
apical root and furcation regions
60
which type of cementum contains extrinsic fibres
acellular
61
how are the extrinsic fibres orientated
perpendicularly
62
what produces the extrinsic fibres
periodontal ligament fibroblasts
63
what are sharpey's fibres
terminal ends of principle fibres that attach tooth to the alveolar bone
64
which cementum has sharpeys fibres
cellular
65
how do the intrinsic fibres of cementum lie
parallel to the surface
66
does cellular cementum attach tooth to the bone
no
67
what is the periodontal ligament
fibrous connective tissue that joints the cementum to the alveolar bone
68
how thick is the PDL
0.2mm
69
what are the features of PDL
cellular
vascular
innervated
70
what does the organic matrix of periodontal ligament contain
proteoglycans
glycoproteins
GAGs
71
what are the cells of the periodontal ligament
fibroblasts
cementoblasts
osteoclasts
cementoclasts
epithelial cells
defence cells
72
what is present in the PDL to register pain and pressure
nerve endings
73
what do the mechanoreceptors in the PDL do
allow the jaw to relax when biting down on hard objects
74
what do nociceptors in the PDL do
respond to potentially damaging stimuli by causing perception of pain
75
what are the two PDL fibres
true periodontal ligament and gingival ligament
76
function of true PDL
adhere tooth to bone
77
where is gingival PDL
above the alveolar crest which is the portiono f alveolar bone extending beyond the periphery of the socket
78
describe the gland types in salivary glands
compound tubuloacinar
79
when is the bicarbonate concentration of saliva high
at high flow rate
80
what are the ions found in saliva
fluoride
calcium
phosphate
thiocyanate
bicarbonate
81
how does bicarbonate enter the saliva
partially from the blood carbon dioxide and through action of carbonic anhydrase
82
what is the buffering capacity of saliva
6.7
83
how many ml of saliva is in the mouth at any one time
1.1ml over an area of 200 cm squared, making it 50-100 micrometres thick
84
what is clearance
the rate at which substances are removed from the mouth
85
how do plaque microorganisms generate acid
metabolising fermentable carbohydrates
86
can alternative sweeteners be metabolised by plaque bacteria
no
87
what are the types of sweeteners
bulk caloric
low caloric
non caloric
88
what is xerostomia
this is when salivay flow rate falls below 50% of normal levels
89
what can cause xerostomia
sjogrens syndrome
salivary stones blocking ducts
side effect to drugs
90
what can saliva substitutes be based on
mucin or cellulose
91
what does pressure on the PDL lead to
saliva secretion from the ipsilateral galnds
92
what is the primary secretion of salivary glands produced by
acinar
93
what is the secondary secretion of salivary glands produced by
ducts
94
at what angle to enamel rods deposite to the ameloblast
right angles
95
what is sulcular fluid
the crevicular fluid, the fluid from the epithelium lining the gingival crevice
96
what is the sulcus
the gingival crevice
97
which cells are found in the pulp
proteoglycans
odontoblasts
fibroblasts
lymphocytes
98
what are the functions of the periodontium
retain the tooth in socket
resist masticatory loads
defensive barrier, protect tissues against threats from the oral environment
99
what are the periodontal fibres
- alveolar crest
- horizontal
- interadicular
- oblique
- trans septal group
- apical
100
where are interadicular fibres found
bifurcation region
101
where is transeptal found
horizontally above the alveolar crest fibres
102
functions of oral fluids
- cleansing
- mucosal protection
- buffering
- antimicrobial
103
what is the main buffering system in saliva
the carbonic acid, bicarbonate system is the most important buffer in stimulated saliva due to its higher concentration
104
when are phosphates important buffers
at rest
105
when does the main buffering action of proteins occur
at pH lower than 5
