NBDE ANATOMICAL SCIENCES: Tooth Components Flashcards Preview

NBDE PART 1 BIOCHEM/PHYSIOLOGY > NBDE ANATOMICAL SCIENCES: Tooth Components > Flashcards

Flashcards in NBDE ANATOMICAL SCIENCES: Tooth Components Deck (293):
1

A 17 year old man falls down and chips the incisal edge of his maxillary central incisor, reducing the length of the crown. The dentist informs him that the tooth may erupt a little to compensate for the loss. Which structure will be deposited in the apex of the tooth when the tooth continues to erupt?

cementum

2

the bone-like mineralized tissue in our oral cavity is

cementum

3

the primary function of cementum is to

attach Sharpey's fibers

4

compared to dentin, cementum is:
1. softer or harder than dentin
2. is it softer or harder than bone?
3. color is lighter or darker than dentin

1. it is softer than dentin (because it is less calcified than dentin)
2. it is harder than bone
3. it is lighter yellow than dentin

5

cementum is formed by ___ of the ___

cementoblasts from the PDL

6

Dentin is formed by ___ of the ___

odontoblasts of the pulp

7

cementum develops from the dental ___

follicle aka dental sac

8

does cementum more closely resemble bone or dentin?

Bone

9

unlike bone, cementum does not have _ or _.

no haversian system or blood vessels. it is avascular

10

1. is bone vascular
2. is cementum vascular

1. bone is vascular
2. cementum is avascular

11

mature cementum is by composition:
1. __% mineralized inorganic material (hydroxyapatite)
2. __% organic material

1. 45-50% mineralized inorganic material
2. 50% organic material = mostly collagen and noncollagenous matrix protein

12

the organic portion of cementum is primarily composed of

collagen and proteins

13

does cementum have any nerve innervation or vascularity?

neither

14

cementum is thickest where in the root

at the apex, thinnest at the CEJ at cervix of the tooth

15

cementum/dentin/enamel is important in orthodontics

cementum

16

cementum is more resistant to __ than alveolar bone, permitting orthodontic movement of teeth without root resoption.

resorption

17

there are two types of cementum that are functionally different. T/F

False! there are two types of cementum that functionally are NO DIFFERENT

18

Acellular cementum is aka

primary cementum

19

cellular cementum is aka

secondary cementum

20

the first layers of cementum deposited at the DCJ and contains no embedded cementocytes is which kind of cementum

acellular (think no cells)

21

the last layers of cementum deposited over the acellular cementum

cellular

22

1. cellular cementum is located in the _ third of the root
2. acellular is located _

1. cellular is in apical third
2. acellular is in the coronal 2/3 of the root.

makes sense bc tooth forms from cusp towards root. and remember near the root you will have more cells.

23

which forms at a faster rate - acellular or cellular

cellular
to remember think of the size of root it is smaller in the bottom so less area to cover

24

why is cellular cementum the thickest

to compensate for occlusal/insical wear and passive eruption of the tooth

25

composition of bone is _% inorganic, _% organic, _% water

50% inorganic, 25% collagen, 25% water

26

intertubular dentin is formed in peripheral parts of the mineralized dentin inside the walls of dentin tubules. T/F

False
peritubular is inside the tubules. intertubular is outside

27

T/F Peritubular dentin is highly mineralized and it also contains little collagen.

True

28

___ dentin is formed by odontoblasts thru predentin meineralization bw the tubules

intertubular

29

which dentin has a dense collagen matrix

intertubular dentin

30

1. intertubular dentin (bw tubules) has a dense collagen matrix. How about peritubular dentin?

it contains very little collagen

31

_ dentin is formed in peripheral parts of the mineralized dentin inside the walls of dentin tubules

peritubular dentin

32

the first dentin formed is

mantle dentin

33

mantle dentin is the outermost/inner most layer of primary dentin

outermost

34

is mantle dentin more/less mineralized than other layers of primary dentin (circumpulpal)

slightly less

35

name the 2 types of primary dentin

circumpulpal and mantle dentin

36

the layer of dentin around outer pulpal wall is called

circumpulpal dentin

37

is primary or secondary dentin more mineralized

primary > secondary

38

which type of dentin is formed after completion of the apical foramen?

secondary

39

which forms faster primary or secondary dentin

primary

40

primary dentin and cellular cementum form __ than secondary dentin and acellular cementum

faster

41

__ dentin outlines the pulp chamber and constitutes the main part of the dentin mass

primary

42

which dentin is formed as a result of injury

tertiary/reparative/reactionary dentin

43

tertiary/reparative/reactionary dentin has an ___pattern of tubules

irregular

44

each dentinal tubule contains the cytoplasmic cell process of an odontoblast called

Tome's fiber

45

___secrete the organic components of the dentin matrix

odontoblasts

46

odontoblasts secrete the organic components of the dentin matrix which is made of which type of collagen

type 1

47

___ are a group of empty tubules due to the death of odontoblasts whose processes formerly filled the tubules

dead tracts

48

these tracts have been attributed to the aging process of dentinal tissue

dead tracts

49

dead tracts may also be caused by

caries, erosion, cavity preparation or odontoblastic crowding

50

the cell free zone of the pulp is aka

zone of Weil

51

the innermost tissue of the tooth is: Pulp/dentin/enamel/cementum

pulp

52

1. the pulp is formed from central cells of the dental
2. cementum and PDL is formed from the dental

1. papilla
2. follicle aka dental sac

53

__ pulp is located in the pulp chamber and forms pulp horns

coronal

54

_ pulp is located in the pulp canals (root portion of tooth)

radicular

55

the apical foramen allows the pulp to communicate with the

PDL

56

accessory canals form when __ encounters a __ during root formation.

Hertwig's epithelial root sheath
blood vessel

57

when Hertwig's epithelial root sheath encounters a blood vessel, the root structure forms around the vessel, forming the __

accessory canal

58

the peripheral aspect of dental pulp is referred to as the ___ zone. It differentiates into a layer of dentin-forming odontoblasts

odontogenic

59

immediately subjacent to the odontoblast layer is the __zone

cell-free zone (of Weil)

60

the cell free zone of Weil contains numerous bundles of

reticular fibers aka (Korff's fibers)

61

reticular fibers aka (Korff's fibers) pass from the central pulp region, across the cell-free zone and between the odontoblasts, with their distal ends incorporatied into the

dentin matrix

62

are there capillaries/nerves in the cell free zone?

yes

63

right under the cell free zone is the __ zone, containing numerous fibroblasts (the predominant cell type of pulp)

cell-rich zone

64

are odontoblasts capable of cell division

no

65

since odontoblasts are incapable of cell division, any dental procedure that relies on the ___ after destruction of odontoblasts

formation of new dentin - differentiation of new odontoblasts from these multipotential cells of the pulp

66

what cells can you find in pulp

odontoblasts, plasma cells, lymphocytes, eosinophils (POLE)

67

name the layers of the pulp

odontogenic zone (odontoblasts) = periphery, cell free zone of weil (reticular fibers, capillaries and nerves), cell-rich zone (fibroblasts)

68

medial to the cell-rich zone is the deep pulp cavity that contains

subodontoblastic plexus of Raschkow

69

All of the following are stages of amelogenesis except one:

presecretory
secretory
transitional
morphogenic
maturation
post-maturation

morphogenic

70

amelogenesis occurs during which stage in tooth development

appositional

71

enamel matrix is produced by _ cells

ameloblast

72

Ameloblasts are columnar cells that differentiate during the _ stage in the crown area

bell stage

73

the enamel matrix is secreted from each ameloblast from its ___

Tomes' process

74

Tomes' process is the secretory surface of the ameloblast that faces the

DEJ

75

Enamel matrix is firs formed in the __ portion of the future crown near the _

incisal/occlusal
DEJ

76

___ is produced in a rhythmic fashion

enamel

77

the odontoblasts begin dentin formation (dentinogenesis) __ enamel formation by ameloblasts

immediately before

78

dentinogenesis begins with the odontoblasts layind down a dentin matrix aka ___, moving from the __ towards the__

predentin
from DEJ toward the pulp.

79

the most recently formed dentin layer is always adjacent to the

pulpal surface

80

predentin/dentin matrix is a mesenchymal product consisting of __

non mineralized collagen fibers

81

these odontoblasts are induced by the newly formed ameloblasts to produce predentin in layers moving ___ DEJ

away from the

82

where does calcification of a tooth begin

DEJ

83

the morphology of the DEJ is determined at _ stage

bell

84

the oldest enamel in a fully erupted molar is located

at the DEJ underlying a cusp

85

in order for ameloblasts to form enamel, cells from the __ must be present

stratum intermedium

86

pulpal involvement of a carious lesion in a young child is much more likely bc

pulp chamber is larger in primary teeth compared to permanent teeth

87

dental pulp is CT so it has everything other CT does such as

tissue fluid, intercellular substance, cells, lymphatics, vascular system nerves, fibers

88

cells found in the pulp

fibroblast (most numerous), odontoblasts (only the cell bodies in the pulp), undifferentiated mesenchymal cells, lymphocytes, plasma cells and eosinophils

89

how many nerves enter anterior teeth

one

90

how many nerves enter posterior teeth (premolars and molars)

several large nerves

91

t/f a young premolar may have as many as 700 myelinated and 2000 unmyelinated axons entering the apex

true

92

the only 2 types of nerve fibers in the pulp are

afferent sensory fibers and autonomic sympathetic nerve fibers

93

are parasympathetic nerve fibers in the pulp

no

94

the sympthatetic nerve fibers that extend from neurons have their cell bodies in the _ ganglion in the skull

superior cervical ganglion

95

sympathetic nerve fibers are myelinated/unmyelinated and travel with __

unmyelinated
BV's

96

the sympathetic nerve fibers innervate the smooth muscle cels of the arterioles and therefore regulate the

blood flow in the capillary network

97

afferent (sensory) fibers arise from the maxillary and mandibular branches of _ CN

CNV

98

Afferent Sensory fibers are predominantly myelinated/unmyelinated

myelinated

99

1. myelinated nerve fibers of the pulp are__
2. unmyelinated nerve fibers are

1. afferent sensory nerve fibers
2. sympathetic (ANS) nerve fibers

100

The afferent sensory fibers terminate in the central pulp where some will send out individual fibers that form the ___ just under the odontoblast layer

subodontoblastic plexus of Raschkow

101

in addition to being the formative organ of dentin, the pulp has what 3 other functions

nutritive - keeps the organic components of surrounding mineralized tissue supplied w/moisture and nutrients
sensory-extremes in temp, pressure, or trauma to dentin or pulp perceived as pain
protective- formation of reparative or tertiary dentin (by odontoblasts)

102

pulp capping is more successful in young teeth because:
1. apical foramen in young pulp is__
2. young pulp contains __ cells (odontoblasts)
3. young pulp is very __
4. young pulp has fewer
5. young pulp has more tissue__
6. young pulp lacks __

1. large
2. more
3. vascular
4. fibrous elements
5. fluid
6. collateral circulation

103

main function of cementum

attach sharpey's fibers

104

cementum is composed of mineralized fibrous matrix and what cells

cementocytes

105

sharpey's fibers are the terminal portions of the principal fibers of the PDL and are each inserted into the bone and outer surface of cementum at _ degrees

90

106

other functions of cementum

compensates for the loss of tooth surface due to occlusal wear by deposition of cementum throughout life
protects the root surface from resorption during vertical eruption and tooth movement

107

enamel vs cementum
1. __ has collagen fibers
2. __ has cellular components in the mature tissue

1. cementum
2. cementum

108

uncalcified (immature) cementum in the peripheral layer of developing cementum laid down by cementoblasts during cementogenesis

cementoid

109

when the cementoid reaches __ the cementoid surrounding the cementocytes become calcified or matured and is then considered cementum

its full thickness

110

what are cementocytes

they are cementoblasts trapped by the cemntum they produce

111

an irritating or painful response to cold, hot, or pressure stimuli is usually caused by sensitivity to which tissue:
dentin/pulp/enamel/cementum

dentin

112

name the dental hard tissues

enamel, dentin, cementum, bone

113

what is the embryological origin of enamel

enamel organ

114

what is the embryological origin of dentin

dental papilla

115

what is the embryological origin of cementum

dental sac (follicle)

116

what is the embryological origin of alveolar bone

mesoderm

117

what type of tissue is enamel

epithelial

118

what type of tissue is dentin

CT

119

what type of tissue is cementum

CT

120

what type of tissue is alveolar bone

CT

121

the only dental hard tissue that is epithelial is __. all other are __

enamel
CT

122

what are the incremental lines in enamel called

lines of Retzius

123

what are the incremental lines in dentin called

imbrication lines of von Ebner

124

what are the incremental lines in cementum called

arrest and reversal lines

125

what are the incremental lines in alveolar bone called

arrest and reversal lines

126

Enamel:
1. the formative cells of are the
2. the resorptive cells are

1. ameloblast
2. odontoclast

127

Dentin
1. the formative cells of are the
2. the resorptive cells are

1 odontoblast
2. odontoclast

128

dentin, enamel, and alveolar bone all have the same resorptive cells called

odontoclast
(note only cementum is different)

129

Cementum
1. the formative cells of are the
2. the resorptive cells are

1. cementoblast
2. cementoclast

130

Alveolar bone
1. the formative cells of are the
2. the resorptive cells are

1. osteoblast
2. osteoclast

131

tissue formation after eruption occurs in all the dental hard tissues except

enamel

132

what is the only vascular dental HARD tissue

alveolar bone

133

is enamel, dentin, or cementum vascular

no

134

what dental hard tissues are innervated

alveolar bone and dentin

135

dentin has vascularity/innervation?

only innervated, not vascular

136

give the percent inorganic content of all the hard tissues

E: 96
D: 70
C: 65
AB: 60

137

give the percent organic content of all the hard tissues

E: 1
D: 20
C: 23
D: 25

138

As dental pulp ages the number of cells __ and the number of collagen fibers__

decrease
increase

139

as pulp ages: what 3 things decreases

intracellular substance, water, and cells: major decrease in the # of undifferentiated mesenchymal cells. =size of pulp cavity due to the addition of secondary or tertiary dentin

140

as pulp ages: what 2 things increases

number of collagen fibers and calcifications w/in the pulp called denticles or pulp stones

141

as pulp ages it becomes more fibrotic leading to less _ capacity of pulp

regenerative

142

the ONLY type of NERVE ENDING found in the pulp is

FREE NERVE ENDING = specific receptor for pain

143

the pain receptors (free nerve endings) are located in the

plexus of Raschkow

144

regardless of the source of stimulation of free nerve endings in the plexus of Raschkow the only response is

pain

145

the pulp contains both myelinated and unmyelinated nerve fibers. which is more abundant

myelinated

146

myelinated nerve fibers are

sensory or afferent neurons axons that are located in the dentinal tubules in dentin

147

the unmyelinated fibers are __

sympathetic and associated with BVs

148

are proprioceptors found in the pulp (respond to stimuli regarding movement)

no

149

nodular calcified bodies having an organic matrix and occur frequently in relation to the coronal pulp

pulp stones

150

there are 2 types of pulp stones that can be free within the pulp or attached to the dentinal wall. name them

true and false

151

___ pulp stones are composed predominantly of dentin and have dentinal tubules. they may have an outer layer of predentin ad are often located adjacent to odontoblast cells

true

152

false pulp stones are composed of concentric layers of calcified material with no ___

tubular structures

153

__ pulp stones are surrounded on all sides by pulpal tissue and are not attached to the dentinal wall

free

154

_pulp stones are surrounded by reactionary or secondary dentin

embedded

155

which of the following has the least amount of collagen:
bone, dentin, enamel, cementum

enamel

156

the hardest calcified tissue in the human body

enamel

157

the tissue richest in calcium

enamel

158

does enamel have cells

none

159

enamel = (germ layer)?

ectodermal

160

enamel's organic matrix is mainly protein, which is rich in which amino acid

proline

161

the morphologic unit of enamel

enamel rod/prism

162

most enamel rods extend the width of enamel from DEJ to the outer surface. T/F

true

163

the specific shape of the enamel rod is dictated by the __ of the ameloblast

Tomes' process

164

in most cases, enamel is _ shaped in the longitudinal section

cylindrical (4micrometers)

165

the oldest enamel in fully erupted tooth is located at the

DEJ underlying a cusp or cingulum

166

when do ameloblasts lose their functional ability

when the crown of the tooth has completed = therefore no power or regeneration

167

does enamel have power of metabolism

no

168

can enamel combat bacterial invasion

no

169

does enamel have a nerve supply?

no

170

enamel is a _ thermal insulator

good

171

topical application of fluorides in dental caries prevention reduces the

acid solubility of enamel

172

__ is the loss of teeth structure by mechanical forces from opposing teeth

Attrition

173

all of the following are changes in enamel except one:
a. attrition
b. discoloration
c. flattening of groove and fissures
d. modifications in the surface layer
e. increased permeability

increased permeability

aging enamel will be less permeable

174

enamel is a nonvital tissue t/f

true

175

enamel is capable of regeneration t/f

false

176

with increasing age, enamel will become ___ which is linked to the apparent ___(reduction/increase) in incidence of caries

discolored, reduce in permeability, modification in the surface layer

DECREASE

177

teeth darken with age. T/f

true

178

dentin becomes __ with age (thicker or thinner)

thicker

179

enamel becomes _ permeable with age (more/less)

less

180

young enamel behaves as a semipermeable membrane permitting water and small substances thru pores bw the crystals. with age the pores will __ as the crystals acquire more ions and as the surface increases in size

diminish

181

as you get older, there is a ___ (increase/decrease) in fluoride content in the surface of enamel

increase

182

T/F enamel tufts and lamellae may be likened to geologic faults and have no clinical significance.

true

183

the striae of Retzius often extend from the DEJ to the outer surface of enamel where they end in shallow furrows known as

perikymata

184

fan shaped HYPOcalcified structures of enamel rods that project from the DEJ into the enamel. they are found in the INNER 1/3 of enamel and represent areas of less mineralization.

enamel tufts

185

___are an anomaly of crystallization and seem to have no clinical importance

enamel tufts and enamel lamellae

186

___ represent short dentinal tubules near the DEJ that result from odontoblasts that crossed the BM before it mineralized into the DEJ. the dentinal tubules became trapped during apposition of the enamel matrix and enamel became mineralized around them.

enamel spindles

187

enamel spindles may serve as

pain receptors

188

__ are partially calcified vertical defects in the enamel resembling cracks or fractures that travers the entire length of the crown from the surface to the DEJ. they are narrower and longer than enamel tufts

enamel lamellae

189

over the cusps of teeth the enamel rods appear twisted around each other in complex arrangement

gnarled enamel

190

as tooth erupts it is covered by a _ consisting of debris from the enamel organ that is lost rapidly

pellicle

191

_ optical phenomenon produced by changes in direction bw adjacent groups of enamel rods.

Hunter-Schreger bands

192

Hunter-Schreger bands are seen most clearly in _ ground sections viewed by reflected light and are found in the __ of the enamel

longitudinal

inner 2/3 of the enamel

193

the incremental (or imbrication) lines of vonEbner in dentin are similar to the growth rings/incremental ___ in enamel

lines of Retzius

194

__ are dark bands seen in dentin.

contour lines of Owen

195

contour lines of Owen represent a

disturbance in body metabolism that affects the odontoblasts by altering their formation efforts

196

Tomes' granular layer is most often found

in peripheral portion of the dentin beneath the root's cementum adjacent to the DCJ.

197

enamel formation begins at the future cusp and spreads down the cusp slope. As the ameloblasts retreat in incremental steps, the ameloblasts create an artifact in the enamel called the

lines of Retzius

198

one line of Retzius is accentuated and is more obvious than the others. it is called the

neonatal line (marks division bw enamel formed before birth and the enamel formed after birth)

199

neonatal line is found in which deciduous teeth

all of them

200

neonatal line is found in which permanent teeth

in the larger cusps of the permanent 1st molars

201

the organic phase of dentin is about 90% collagen, mainly type __ with small amounts of type _ and _

type I majority
type III and IV minority

202

_ makes up the bulk of the tooth

dentin

203

dentin extends

almost the entire length of the tooth

204

Calcium hydroxyapatite formula

Ca10(PO4)6(OH)2

205

are fluoride and carbonate minerals present in dentin

yes

206

unlike enamel which is acellular dentin has a

cellular component that is retained after its formation by odontoblasts

207

dentin and pulp are both formed by

dental papilla

208

pulp tissue is very loose/dense

loose and vascular

209

is pulp tissue calcified

no

210

is dentin vascular

no

211

the main cell type in dentin is the

odontoblast

212

the odontoblast is derived from

ectomesenchyme

213

dentin is more flexible than enamel = (__ modulus of elasticity)

lower

214

dentin's compressive strength is much ___ than its tensile strength

higher

215

dentin is _ mineralized than cementum or bone

more

216

morphologically and chemically dentin has many characteristics in common with _

bone

217

orthodontic movement of teeth ALWAYS causes remodeling of the alveolar bone to accommodate movement of the teeth. T/f

true

218

the new alveolar bone deposited during ortho treatment is

intramembranous

219

the bone-forming cells that secrete the collagen and minerals needed to lay down new bone

osteoblasts (from mesenchyme)

220

osteoblasts that have been trapped in the osteoid produced by other surrounding osteoblasts are called

osteocytes

221

osteocytes/osteoblasts maintain bones, play a role in controlling extracellular concentration of calcium and phosphate and are directly stimulated by calcitonin and inhibited by PTH

osteocytes

222

osteoclasts are derived from

stem cells in bone marrow- the same ones that produce monocytes and macrophages

223

osteoclasts are bone_ cells

resorbing

224

the alternate loosening and tightening of a deciduous tooth before it is lost is caused by alternate _ and _ of cementum and bone

resorption and apposition

225

the alternate loosening and tightening of a deciduous tooth before it is lost is caused by alternate resorption by __ and ___ and appostion by __ and __

resorption: osteoclasts and cementoclast

appostion: cementoblast and osteoblast

226

during active tooth eruption, there is __ of bone on all surfaces of the alveolar crest and on all walls of the bony socket

apposition

227

permanent teeth move _ and _ when erupting

occlusally and facially

228

apical abscesses of which teeth have a marked tendency to produce cervical spread of infection most rapidly

mandibular 2nd and 3rd molars

229

certain anatomical features determine to a large extent the actual direction that infection may take. the attachment of muscles may determine the route that the infection will take, channeling the infection into certain tissues. t/f

true

230

a lesion in submandibular skin region most commonly affects which teeth

mandibular 2nd and 3rd molars if roots are inferior to the mylohyoid

231

a lesion in the sublingual region most commonly affects which teeth

mandibular 1st and 2nd molar if lingual root is SHORT and SUPERIOR to the mylohyoid

232

a lesion in submental skin region most commonly affects which teeth

mandibular incisors if the root is long and inferior to mentalis

233

a lesion in buccal skin surface region most commonly affects which teeth

maxillary molars if buccal roots are superior to buccinator

234

a perforation into max sinus region most commonly affects which teeth

maxillary molars if buccal roots are long

235

a lesion in the palate region most commonly affects which teeth

maxillary lateral inscisors, premolars (lingual root), maxillary molars (palatal root)

236

a lesion of nasolabial skin region most commonly affects which teeth

maxillary canine if root is long and superior to levator anguili oris

237

penetration of nasal floor region most commonly affects which teeth

max central incisor

238

lesion of maxillary vestibule region most commonly affects which teeth

max CI and LI
max canine (if root is short and inferior to levator anguili oris)
max premolars
max molars (if buccal roots are short and inferior to buccinators)

239

a lesion in mandibular vestibule region most commonly affects which teeth

md incisors (if roots are short and superior to mentalis)
md canines and premolars (if roots are short and superior to depressors), mandibular 1st and 2nd molars (if roots are short and superior to buccinators)

240

the bone directly lining the socket (inner aspect of the alveolar bone) is referred to as

bundle bone

241

the alveolar __ Is the bone of the jaws that contain the alveoli (sockets) for the teeth

process

242

the alveolar process contains an outer (buccal and lingual) ___

cortical plate

243

the alveolar process contains a central __

spongiosa

244

the alveolar process contains a bone lining called

alveolar bone

245

the cortical plate and alveolar bone meet at the

alveolar crest (usually 2mm below the CEJ)

246

alveolar bone is aka

cribiform plate

247

in x rays the alveolar bone is referred to as

lamina dura bc increase radiopacity

248

the bone directly lining the socket (inner aspect of alveolar bone) is referred to as

bundle bone

249

PDL fibers attach to _bone

bundle

250

the cortical plate consists of layers of _ bone

lamellar

251

cortical plate is thinner/thicker in maxilla, and thickest on the __

thinner in maxilla
thickest in the buccal aspect of MD PM's and molars

252

trabecular bone is absent in which region

anterior teeth. here the cortical plate and alveolar bone are fused together.

253

a newly erupted tooth has a membranous covering derived from what structure

oral epithelium

254

Nasmyth's membrane = the seconadary enamel cuticle, is the thin membrane covering __

newly erupted teeth

255

Nasmyth's membrane = the seconadary enamel cuticle is a remnant of the _ and is ectodermally derived

reduced enamel epithelium

256

Nasmyth's membrane = the seconadary enamel cuticle is produced what cells

ameloblasts after it produces the enamel rods

257

Nasmyth's membrane = the seconadary enamel cuticle has an inner clear and structureless and outer cellular layers that are abraded by

mastication

258

the seconadary enamel cuticle is seen microscopically as an amorphous material bw the

attachment epithelium and the tooth

259

the Nasmyth's membrane = the seconadary enamel cuticle is replaced by an ORGANIC deposit called

pellicle (from salivary PROTEINS)

260

it is the __ that is invaded by bacteria to form bacterial plaque that if not removed will cause dental caries and perio disease

pellicle

261

the __ enamel cuticle is the organic matrix responsible for binding the epithelium to the tooth during development

primary

262

Gaburnaculal canal

small canal located bw the PERMANENT tooth germ and the APEX of the deciduous tooth containing remnants of dental lamina and CT

263

after ameloblasts are finished w both enamel apposition and maturation they become part of the __

reduced enamel epithelium (along w other portions of the compressed enamel organ)

264

the __ fuses with the oral mucosa creating a canal to allow the enamel cusp tip to erupt thru the oral mucosa into the oral cavity.

reduced enamel epithelium

265

ameloblasts are lost forever t/f

true

266

dentin is considered a living tissue t/f

true

267

dentin is considered a living tissue because of odontoblastic cell processes known as

Tome's fiber

268

the Tome's fibers are

odontoblast processes that occupy the dentinal tubules. one per odontoblast

269

one theory of dentin sensitivity is that Tome's fibers are

receptors and transmit an impulse to pulpal nerves

270

the preferred theory of dentin sensitivity is that

fluid movement w/in the tubules, in response to stimulus, triggers the pulp nerves

271

the odontoblasts begin dentin formation (dentinogenesis) ___ before __

immediately before enamel formation by ameloblasts

272

dentinogenesis begins w/ odontoblasts laying down___ moving which way

dentin matrix aka predentin
move away from DEJ toward the pulp

273

the most recently formed layer of dentin is always adjacent to the

pulp surface

274

predentin or dentin matrix is _ origin w/non mineralized collagen fibers

mesenchyme

275

Tomes' fiber vs Tomes' process?

Tomes' process = ameloblast
Tomes' fiber = odontoblast

276

the cell body of the odontoblast lies in the

pulp cavity

277

the dentin tubules are _ shaped in the crown due to

S shaped (curvature) due to overcrowding of odontoblasts.

278

the curvature of the dentin tubules (S-shape) decreases in _ dentin

root

279

T/F tertiary dentin is produced only by those cells DIRECTLY affected by the stimulus

true

280

__ dentin is produced in reaction to various stimuli, such as attrition, caries, or restorative dentin procedure

teritary

281

unlike primary or secondary dentin that forms along the entire pulp-dentin border, tertiary dentin is produced only by those cells

directly affected by the stimulus

282

reactionary dentin is deposited by __ odontoblast

pre-existing

283

reparative dentin is deposited by__ odontoblst-like cells

newly differentiated

284

__ dentin is the dentin formed in a tooth BEFORE THE COMPLETION of the apical foramen

primary

285

primary dentin is characterized by a _ pattern of tubules

regular

286

__ dentin is the dentin formed in a tooth AFTER THE COMPLETION of the apical foramen

secondary

287

secondary dentin is formed at a __ rate than primary dentin and is _ mineralized

slower, less

288

the junction of primary and secondary dentin is characterized by a

sharp change in direction of dentinal tubules

289

when dentin is damaged, by injury/caries/ odontoblastic processes will

die or retract = leaving empty dentinal tubule called dead tracts - dark areas in ground sections of tooth

290

with time the dead tracts become completely filled w calcified material called

sclerotic dentin

291

when sclerotic dentin fills the dead tracts (dark), it is called ___ and appears _ in ground sections of the tooth

blind tracts
white

292

the adaptive advantage of blind tracts over dead tracts is

the dentinal tubules have been sealed off to prevent bacteria from entering the pulp.

293

clinically sclerotic dentin appears

dark, smooth, shiny