Odontogenesis

Question 1

Tooth (4)

Answer 1

 Enamel
 Dentin
 Cementum
 Pulp

Question 2

Periodontium (4)

Answer 2

 Gingiva
 Periodontal Ligament
 Cementum
 Alveolar Bone Proper

Question 3

stages of tooth development (6)

Answer 3

 Initiation 
 Bud Stage 
 Cap Stage 
 Bell Stage 
 Apposition 
 Maturation

Question 4

Initiation

Answer 4

Cellular Induction

Question 5

Bud Stage

Answer 5

Cellular Proliferation

Question 6

Cap Stage

Answer 6

Proliferation, Differentiation

and Morphogenesis

Question 7

Bell Stage

Answer 7

Proliferation, Differentiation

and Morphogenesis

Question 8

Apposition

Answer 8

Induction and Proliferation

Question 9

Maturation

Answer 9

Maturation

Question 10

Epithelium (ectoderm) plays an “instructional” role
during the — — stage of tooth formation.
At this early stage, the fate of the neural crest cells
(mesenchyme) has yet to be fully determined.
Epithelium specifies the “dental nature”of
the —, and the mesenchyme, in turn,
specifies the (2)

Answer 10

pre-tooth bud
mesenchyme
tooth type (incisor vs. molar) and nature of the product produced by the epithelium (i.e., enamel matrix).

Question 11

Tooth Development (Induction Stage – 6th to 7th weeks) includes (3)

Answer 11

► Oral Ectoderm
► Neural Crest Cells
► Dental Lamina

Question 12

Ectoderm invaginates into
the mesenchyme, and is now
called the

Answer 12

dental lamina

Question 13

The lamina is separated
from the surrounding
mesenchyme by a

Answer 13

basement membrane

Question 14

Proliferating oral ectoderm making the transition into

Answer 14

dental lamina

Question 15

OEE
cell type
function

Answer 15

cuboidal

protective barrier

Question 16

IEE
cell type
function

Answer 16

cuboidal cells

differentiate into ameloblasts

Question 17

stellate reticulum
cell type
function

Answer 17

star shaped cells forming network inside enamel organ

supportive function in enamel production

Question 18

stratum intermedium
cell type
function

Answer 18

compressed layer of flat cuboidal cells

supportive function in enamel production

Question 19

dental sac
cell type
function

Answer 19

collagen fibers around enamel organ

differentiated into cementum, PDL, and bone

Question 20

dental papilla
cell type
function

Answer 20

cells nearest IEE have basement membrane separation

outer cells differentiate into odontoblasts, whereas inner cells differentiate into pulp tissue

Question 21

Cervical Loop

Answer 21

Junction of the outer

& inner enamel epithelia

Question 22

Cervical Loop is the site of

Answer 22

cemento-enamel
junction (CEJ) in the adult
tooth (a.k.a., cervix)

Question 23

Hertwig’s Epithelial Root Sheath

Answer 23

Fusion and apical
extension of the
outer and inner
enamel epithelia

Question 24

Hertwig’s Epithelial Root Sheath determines the

Answer 24

outline of
the root dentin and the
number of roots a tooth
will have.  It is removed
before the cementum is
laid down

Question 25

Enamel formation stops at the

Answer 25

termination of the enamel organ

Question 26

Dentin formation continues, and pushes the tooth

Answer 26

occlusally

Question 27

The epithelial diaphragm is the

Answer 27

modification of Hertwig’s Sheath creating “septa” that divide the pupal tissue and create mutiple roots.

Question 28

Root length is not complete until

Answer 28

1 to 4 years after the tooth has emerged into the oral cavity. The pulp chamber narrows, and the apical opening constricts.

Question 29

first formed dentin

Answer 29

Mantle Dentin

Question 30

Mantle Dentin thickness

Answer 30

thin, 30-50 um

Question 31

Mantle Dentin contains both

Answer 31

type 1 and 3 collagen

Question 32

Mantle Dentin collagen fibers are oriented

Answer 32

perpendicular to the DEJ

Question 33

Actively secreting

ameloblasts are

Answer 33

tall

columnar cells

Question 34

Inactive (a.k.a. reduced)

ameloblasts are

Answer 34

short
columnar or elongated
cuboidal cells

Question 35

At the final stage of mineralization,
the reduced ameloblasts with the
remaining cells of the outer enamel 
epithelium, stellate reticulum, and
stratum intermedium form a
membrane on the surface of the
enamel.  This is termed the

Answer 35

primary cuticle (a.k.a. Nasmyth’s membrane).

Question 36

Anodontia:

Answer 36

Refers to the total lack of tooth

development.

Question 37

Hypodontia:

Answer 37

Denotes the lack of development

of one or more teeth.

Question 38

Oligodontia:

Answer 38

Indicates the lack of formation of
six or more teeth (a subdivision
of hypodontia).

Question 39

Hyperdontia:

Answer 39

The development of an increased
number of teeth (the additional
teeth are termed supernumerary).

Question 40

Supernumerary Teeth:

Answer 40

Defect that
originates during I nitiation Stage that
results in development of one or more extra
teeth.

Question 41

Mesodens:

Answer 41

The most common manifestation of

supernumerary tooth formation.

Question 42

Odontoma:

Answer 42

originates during the I nitiation Stage
and results in multiple small fragments of tooth
structure consisting of dentin, enamel,
cementum or any combination.

Question 43

Complex Odontoma:

Answer 43

Comprised of a conglomerate
mass of enamel and dentin that bears no anatomic
resemblance to a tooth.

Question 44

Compound Odontoma:

Answer 44

Comprised of multiple,

small tooth-like structures.

Question 45

Taurodontism:

Answer 45

An enlargement of the body and pulp
chamber of multirooted teeth with apical displacement
of the bifurcation, i.e., an exceptionally long root trunk
with very short roots

Question 46

Dilaceration:

Answer 46

defined as an abnormal angulation

or bend in the root.

Question 47

Gemination:

Answer 47

Defect that originates during Cap
Stage of development that results in large single-
rooted tooth with one pulp cavity and exhibits
“twinning”in crown area.

Question 48

gemination vs fusion

Answer 48

Gemination: Tooth count is normal when
the double tooth is counted as one.

Fusion: Refers to a double tooth in which
the tooth count reveals a missing tooth
when the double tooth is counted as one.

Question 49

Concrescence:

Answer 49

Defect occurring during Apposition
and M aturation stages that results in union of root
structure of two or more teeth by cementum.

Question 50

Tubercle Formation:

Answer 50

Defect occurring during Cap
Stage of development that results in an extra cusp
due to effects on enamel organ

Question 51

Dentigerous Cyst (a.k.a. Follicular Cyst):

Answer 51

Originates
by separation of the dental follicle (dental sac) from
the crown of an unerupted tooth. The cyst is attached
at the CEJ. This cyst type comprises 20% of all jaw
cysts.

Question 52

Odontogenic Keratocyst (OKC) arises from

Answer 52

the cells rests of the dental lamina (also called rests of serres)

Question 53

Odontogenic Keratocyst (OKC) constituted –% of all odontogenic cysts

Answer 53

3-11%

Question 54

Odontogenic Keratocyst (OKC): 60% of all cases are diagnosed in patients between the ages of —

Answer 54

10-14 years

Question 55

Odontogenic Keratocyst (OKC): 65% of cases are located in the

Answer 55

mandible

Question 56

Odontogenic Keratocyst (OKC) are — cysts

Answer 56

expanding

Question 57

Odontogenic Keratocyst (OKC) are located in the posterior mandible often present as

Answer 57

multi ocular lesions

Question 58

Odontogenic Keratocyst (OKC): — — is the treatment of choice, however there is a recurrence rate of approximately –%

Answer 58

surgical removal

30

Question 59

Odontogenic Keratocyst

Answer 59

Cyst wall consists of a 6-8 cell layer of stratified
squamous epithelium with parakeratosis at the
luminal surface. The lumen is often filled with
keratin. The presence of inflammation will generally
cause epithelial proliferation and pallisading of the
basal cell layer.

Question 60

Ameloblastoma:

Answer 60

The most common neoplastic lesion
arising from odontogenic epithelium. Considered a
slow growing, locally invasive tumor. Lesions have a
multilocular or “soap bubble”appearance on
radiographs. These tumors are radio-resistant.