Teeth

Question 1

Teeth are grossly divided into:

Answer 1

root and crown

Question 2

Portion of tooth embedded in bone
called:

Answer 2

tooth root

Question 3

Portion of tooth embedded in part of jaw called
___

Answer 3

alveolar ridge

Question 4

Portion of tooth embedded in tooth socket called
___

Answer 4

alveolus

Question 5

Portion of tooth that projects into
oral cavity—

Answer 5

crown

Question 6

Tooth is Protected by layer of highly
mineralized ____, covers crown

Answer 6

enamel (E),

Question 7

___ is a hard, translucent
substance, containing < 1% organic
material & 96-98% hydroxyapatite

Answer 7

Enamel

Question 8

Enamel is Secreted by tall, ______ of
enamel organ

Answer 8

columnar ameloblasts

Question 9

Ameloblasts degenerate when ____, after which the enamel cannot be
replaced by new synthesis

Answer 9

the tooth
erupts

Question 10

Apical, secretory end of ameloblast forms
_____
(microtubules & secretory vesicles)

Answer 10

single, large process, Tome’s process

Question 11

Enamel mineralization is _____,
resulting in highly calcified enamel rods
or prisms—roughly hexagonal, ~4-8m in
diameter

Answer 11

non-uniform

Question 12

Enamel mineralization is non-uniform,
resulting in highly calcified ____—roughly hexagonal, ~4-8m in
diameter

Answer 12

enamel rods
or prisms

Question 13

Enamel rods extend from ameloblasts at
enamel surface to ____
junction

Answer 13

dentino-enamel junction

Question 14

Bulk of tooth composed of less
mineralized ___

Answer 14

dentine

Question 15

(Dentine) Secreted by odontoblasts of dental
papilla as _____

Answer 15

non-mineralized pre-dentine

Question 16

T/F: Matrix vacuoles (Ca2+ and PO4-) play a
key role in mineralization of dentine
matrix [like odontoblasts].

Answer 16

True

Question 17

Dentine contains ____ collagen and ___

Answer 17

Type I collagen and GAGs

Question 18

Dentine arranged in ____—
hollow, parallel tubes radiating from
pulp cavity

Answer 18

dentine tubules

Question 19

Dentine arranged in dentine tubules—
hollow, parallel tubes radiating from
____

Answer 19

pulp cavity

Question 20

Dentine arranged in dentine tubules—
hollow, parallel tubes radiating from
pulp cavity—
Contain long, rod-like cytoplasmic
processes of odontoblasts (aka _____)

Answer 20

Tome’s
fibers

Question 21

___ contains
support structures—e.g., sensory
nerves & blood vessels

Answer 21

Central pulp cavity

Question 22

Dentine innervated by ___

Answer 22

myelinated
nerves

Question 23

____ is mesodermal in
origin; resembles primitive
mesenchyme

Answer 23

Dental pulp

Question 24

Dental Pulp: Richly supplied by capillaries from
arterioles running with ____

Answer 24

periodontal
ligament

Question 25

Tooth root is covered by a thin layer of ___

Answer 25

cementum

Question 26

Tooth root covered by cementun secreted by cementoblasts which mature into ____

Answer 26

cementocytes

Question 27

Cementocytes that lie against the surface of the periodontal ligament probably produce new cementum by ____

Answer 27

appositional growth.

Question 28

Region of tooth between root & crown is ___

Answer 28

neck of tooth

Question 29

Neck of tooth is Protected by masticatory oral mucosa called ____ ; covers upper portion of alveolar ridge

Answer 29

gingiva (= gums);

Question 30

Gingiva sometimes divided into

Answer 30

attached and free gingiva

Question 31

gingiva covering upper alveolar bone

Answer 31

attached gingiva

Question 32

gingiva forming cuff~neck of tooth

Answer 32

free gingiva

Question 33

Space between free gingiva & crown called ___

Answer 33

gingival sulcus or crevice

Question 34

Gingival sulcus Lined by ______—very thin, only 2-3 cells thick, easily breached by bacteria => periodontal disease, gingivitis

Answer 34

crevicular epithelium

Question 35

Tissues that surround & support tooth collectively referred to as ____— include epithelium, cementum, periodontal ligament & alveolar bone

Answer 35

periodontium

Question 36

periodontium includes: (4)

Answer 36

epithelium, cementum, periodontal ligament & alveolar bone

Question 37

Cementum layer anchored to bone of alveolus with ____

Answer 37

fibers of periodontal ligament or membrane

Question 38

Cementum layer anchored to bone of alveolus with fibers of periodontal ligament or membrane—composed of dense, collageous fibers, called ____

Answer 38

Sharpey’s fibers

Question 39

Run at oblique angle, support tooth in socket * Allows slight movement of tooth during mastication

Answer 39

sharpeys fibers

Question 40

May see occasional clusters of epithelial cells within ____t—vestigial epithelial rests (of Malassez)

Answer 40

periodontal ligament

Question 41

(cap stage) Tooth formed between opposing layers of epithelial cells— ____ of enamel organ & ____ of dental papilla

Answer 41

ameloblasts ; odontoblasts

Question 42

enamel is of ____ origin

Answer 42

ectodermal

Question 43

Dentine, cementum, pulp, & periodontal ligament are ___ origin

Answer 43

mesodermal

Question 44

(cap stage) 6th week of fetal development, a horseshoe-shaped epithelial ridge arises from ____

Answer 44

oral epithelium

Question 45

(cap stage) ~6th week of fetal development, a horseshoe-shaped epithelial ridge arises from oral epithelium * Forms ____ in position of future jaws

Answer 45

dental lamina

Question 46

(cap stage) In each quadrant, lamina develops several globular, ectodermal swellings (one for each deciduous tooth) => Superficial half forms ___ ; deep half forms ____

Answer 46

enamel organs ; dental papilla

Question 47

(early bell stage) Cells of epithelial tooth bud develop into the ___

Answer 47

enamel organ

Question 48

(early bell stage) cells of epithelial tooth bud develop into the enamel organ. Become a bell-shaped structure with a core of loosely arranged stellate cells & peripheral layer of cuboidal/low columnar epithelium (external & internal enamel epithelium). Meet at ____

Answer 48

cervical loop.

Question 49

(early bell stage) Internal enamel epithelium differentiates into layer of ameloblasts & 2-3 cell thick _____

Answer 49

stratum intermedium

Question 50

(early bell stage) Mesenchyme condense to form _______. Row of odontoblasts develop at junction with ameloblasts.

Answer 50

dental papillae

Question 51

(early bell stage) Permanent tooth arises from side- growth of ___

Answer 51

dental lamina.

Question 52

Enamel organ initially____-shaped (cap stage)

Answer 52

cup-shaped

Question 53

Cells of enamel organ progressively differentiate, become ____, with extracellular matrix of GAG’s

Answer 53

stellate reticulum

Question 54

enamel later form bell-shaped structure in ___ stage

Answer 54

bell stage

Question 55

(bell stage) Cells lining outer, convex surface of enamel organ become ____

Answer 55

external enamel epithelium

Question 56

(bell stage) Cells lining concave surface of enamel organ form____, differentiate into tall, columnar ameloblasts (A)

Answer 56

internal enamel epithelium

Question 57

(bell stage) Cells lining concave surface of enamel organ form internal enamel epithelium, differentiate into _____

Answer 57

tall, columnar ameloblasts (A)

Question 58

—enamel formation

Answer 58

Amelogenesis

Question 59

(odontogenesis) Deep to developing enamel organs is primitive mesenchyme; develops into ___

Answer 59

dental papilla

Question 60

(odontogenesis) Cells lining convex surface of dental papilla develop into ___

Answer 60

odontoblasts

Question 61

—dentine formation

Answer 61

Dentinogenesis

Question 62

(late bell stage) Development of ameloblasts induces differentiation of _____, but calcification of dentine induces deposition of enamel

Answer 62

odontoblasts

Question 63

(late bell stage) Development of ameloblasts induces differentiation of odontoblasts, but calcification of dentine induces ___

Answer 63

deposition of enamel

Question 64

(late bell stage) Tooth formation initiated by deposition of organic _____ by odontoblasts on surface of dental papilla—later calcified into dentine

Answer 64

pre- dentine

Question 65

____ secondarily induces enamel production by ameloblasts

Answer 65

Calcification of dentine matrix

Question 66

Odontoblasts have odontoblast processes, embedded in dentine matrix—form ___

Answer 66

dentine tubules

Question 67

(odontogenesis) Enamel forms in mineralized columns of ____, separated by less mineralized interprismatic material

Answer 67

enamel rods

Question 68

(odontogenesis) Enamel forms in mineralized columns of enamel rods, separated by _____

Answer 68

less mineralized interprismatic material

Question 69

Subsequent to deposit of dentine & enamel, dental lamina ____

Answer 69

fragments & atrophies

Question 70

At time of tooth eruption, enamel organ & ameloblasts ___

Answer 70

degenerate

Question 71

Overlying mucosa ___ as tooth erupts, exposing crown

Answer 71

separates

Question 72

Dental papilla shrinks, becomes ___, surrounded by dentine

Answer 72

dental pulp

Question 73

(late bell stage) Dental papillae enclosed by dentine to become ___

Answer 73

pulp cavity

Question 74

(late bell stage) ____- a proliferation of epithelial cells located at the cervical loop of the enamel organ. Hertwig epithelial root sheath initiates the formation of dentine in the root by causingthe differentiation of odontoblasts from the dental papilla.

Answer 74

Hertwig’s root sheath

Question 75

The root sheath eventually disintegrates with the ___, but residual pieces that do not completely disappear are seen as epithelial cell rests

Answer 75

periodontal ligament

Question 76

After tooth formation is complete, small amounts of ____continue to be produced, may eventually obliterate pulp cavity

Answer 76

2’ dentine

Question 77

Overall shape of enamel organ determines 3-D shape of ___

Answer 77

tooth crown

Question 78

Outer rim of enamel organ known as ____

Answer 78

epithelial sheath of Hertwig (= Hertwig’s root sheath, HERS)

Question 79

Outer rim of enamel organ known as epithelial sheath of Hertwig determines ____

Answer 79

cross-sectional outline of tooth

Question 80

Surrounding mesenchyme forms dental follicle (DF) => ___

Answer 80

periodontal ligament

Question 81

___ of permanent teeth develop as buds from dental lamina & “deciduous” enamel organ

Answer 81

Enamel organs

Question 82

In case of ____, dental lamina proliferates caudally to form enamel organs of 2’ dentition

Answer 82

molars

Question 83

In humans, tooth development begins ~___ week of fetal development

Answer 83

6th week of fetal development

Question 84

In humans, tooth development begins ~6th week of fetal development—but tooth eruption does not occur until ___ after birth

Answer 84

6- 30 months

Question 85

premolars usually have ___ roots

Answer 85

2

Question 86

molars usually have ___ roots

Answer 86

2-4 roots

Question 87

Between 6-12 years of age, deciduous teeth replaced by ___

Answer 87

permanent dentition

Question 88

____, administered during development of permanent dentition incorporated into enamel => yellow discoloration of teeth

Answer 88

Tetracycline

Question 89

Orthodontia accomplished by osteoblast & osteoclast activity in ___

Answer 89

alveolus

Question 90

___—results when weak acids in food & drink erode calcified enamel, augmented by bacterial action

Answer 90

Dental caries

Question 91

____helps harden enamel & kills bacteria

Answer 91

Fluoride

Question 92

Caries may extend into dentine or pulp cavity, produce abscesses or death of tooth =>

Answer 92

root canal

Question 93

___—caused by accumulation of calcified food & bacterial debris (plaque) in gingival sulcus => widening of gingival sulcus, possible inflammation & destruction of periodontal ligament

Answer 93

Periodontal disease

Question 94

inflammation of gums—

Answer 94

gingivitis

Question 95

Inflammation of periodontal ligament—

Answer 95

periodontitis