shedding of deciduous teeth

Question 1

two generations of the human dentition

Answer 1

deciduous (primary) dentition
permanent (secondary) dentition

Question 2

The physiologic process resulting in the elimination of the deciduous dentition

Answer 2

shedding or exfoliation

Question 3

The shedding of deciduous teeth is the result of progressive?

Answer 3

resorption of the roots of teeth and their supporting tissue, the periodontal ligament.

Question 4

resorption of the roots of the deciduous incisors and canines begins on their _____ surfaces

Answer 4

lingual

Question 5

The cells responsible for the removal of dental hard tissue are identical to osteoclasts,

Answer 5

odontoclast

Question 5

The cells responsible for the removal of dental hard tissue are identical to osteoclasts,

Answer 5

odontoclast

Question 6

they are readily identifiable as large, multinucleated cells occupying resorption bays on the surface of a dental hard tissue.

Answer 6

odontoclast

Question 7

They are smaller than osteoclast, contain fewer nuclei, and produce smaller resorption lacunae.

Answer 7

odontoclast

Question 8

Their cytoplasm is vacuolated, and the surface of the cell adjacent to the resorbing hard tissue forms a ‘ruffled’ border

Answer 8

odontoclast

Question 9

an extensive folding of the cell membrane into a series of invaginations 2 - 3um deep, with mineral crytallines within the depth of the invagination

Answer 9

ruffled border

Question 10

peripheral to the ruffled border which it is devoid of organelled but rich in contractile proteins actin and myosin.

Answer 10

clean zone

Question 11

it represents the attachment apparatus of the odontoclast

Answer 11

clear zone

Question 12

odontoclast is characterized by?

Answer 12

high content of mitochondria and many vacuoles

Question 13

T OR F: Deciduous teeth may be retained for a long time beyond their usual shedding schedule.
Such teeth are usually without permanent successors, or their successors are impacted.

Answer 13

TRUE

Question 14

T OR F: If the permanent lateral incisor is missing, the deciduous tooth is often resorbed under
the pressure of the erupting permanent canine.

Answer 14

TRUE

Question 15

what chemical activity occurs within the vacuoles of the odontoclast?

Answer 15

acid phosphate activity

Question 16

T or F: odontoclast are able to resorb all the dental hard tissues, including enamel

Answer 16

TRUE

Question 17

The monocyte, circulating in the blood, originally gives rise to all the different tissue ____ including the osteoclast

Answer 17

macropahges

Question 18

odontoclast is derived from?

Answer 18

tartrate-resistant acid phosphatase (TRAP) - positive circulating monocytes

Question 19

these cells were involved in
the differentiation, migration and activation of odontoclast and cementoblast like cells during resorption of deciduous teeth.

Answer 19

HLADR positive cells

Question 20

The periodontal ligament cells in teeth undergoing
shedding express the tumor necrosis factor named?

Answer 20

RANKL
Receptor Activator of Nuclear factor Kappa B Ligand

Question 21

this expression is linked to odontoclast formation and activation of shedding process

Answer 21

RANKL expression

Question 22

odontoclast differentiation is promoted by _ and is inhibited by _

Answer 22

RANKL , OPG

Question 23

a decoy receptor that prevents RANKL from binding to RANK

Answer 23

OPG - osteoprotegrin

Question 24

most commonly found on surfaces of the roots in relation to the advancing permanent tooth.

Answer 24

odontoclast

Question 25

T or F: single-rooted teeth are usually shed before root resorption is complete and in molars, the roots are usually completely resorbed and the crown is also partially resorbed, before exfoliation.

Answer 25

True

Question 26

the odontoblast layer is replaced by _____ which resorb both primary and secondary dentin

Answer 26

odontoclast

Question 27

give at least 3 similariries of odontoclast and osteoclast

Answer 27

* Large multinucleated giant cell of variable shape * Occupy resorption bays or lacunae * Show ruffled border and clear zone peripheral to it * Cytoplasm adjacent to ruffled border shows high amounts of mitochondria and vacuoles * Acid phosphate activity within vacuoles * Process of resorption similar * Similar origin: from TRAP 1 circulating monocytes * Odontoclast differentiation promoted by RANKL and inhibited by OPG

Question 28

give 3 dissimilarities of odontoclast and osteoclast

Answer 28

* Smaller and contain fewer nuclei * Produce smaller resorption bays * Resorb dental hard tissues: dentin, cementum and enamel * Seen, therefore on surfaces of dentin, cementum and enamel which are to be resorbed * Seen also in pulp chamber and root canal of resorbing deciduous teeth

Question 29

___ is achieved by cells resembling cementoblasts that lay down a dense collagenous matrix in which spotty mineralization occurs

Answer 29

repair

Question 30

may be the cause for pathological root resorption

Answer 30

pressure excerted by tumors and cysts

Question 31

Unlike osteoblasts, ____ covering the root are not responsive to hormones and cytokines.

Answer 31

cementoblasts

Question 32

odontoclast attaches to the hard-tissue surface peripherally through the___

Answer 32

clear zone

Question 33

The membrane of the ruffled border acts as a proton pump, adding ___ to the extracellular environment and acidifying it so that mineral dissolution occurs.

Answer 33

hydrogen ions

Question 34

It is a common clinical observation that when a successional tooth germ is missing, shedding of the deciduous tooth is ___.

Answer 34

delayed

Question 35

As resorption of the roots initiated by pressure of the underlying tooth occurs, there is a progressive loss of surface area for attachment of the ___

Answer 35

periodontal ligament fiber bundles.

Question 36

_is involved with apoptotic cell death where shrinkage of cell can be phagocytozed by the neighboring cells

Answer 36

PDL

Question 37

Apoptotic cell death is a normal feature of ___ and is programed so that cells die at specific times to permit orderly development.

Answer 37

EMBRYOGENESIS

Question 38

shedding is a programmed developmental event influenced by __

Answer 38

local factors

Question 39

The occurrence of apoptotic cell death in the resorbing periodontal ligament, in monozygotic twins the eruption pattern is largely how many %?

Answer 39

(80%)

Question 40

sometimes the roots of the deciduous teeth arent in the path of erupting permentent teeth and may escape resorption. they remain embedded in the jaw and are most frequently found in permanent premolars esp in lower second premoilar. They are cased in heavy laters of cellular celemtum

Answer 40

remnants of deciduous teeth

Question 41

the remnants of deciduous teeth are frequently found in__

Answer 41

lower second premolar

Question 42

the reason why there are remnents of deciduous teeth in molar

Answer 42

the roots of the lower second deciduous molar are strongly curved or divergent. The mesiodistal diameter of the second premolars is much smaller than the greatest distance between the roots of the deciduous molar

Question 43

Deciduous teeth are retained for a long time beyond their usual shedding schedule. most often the upper lateral incisor

Answer 43

retained deciduous teeth

Question 44

teeth without permanent successors

Answer 44

retained deciduous teeth

Question 45

which tooth are affected in retained deciduous teeth

Answer 45

most frequent: upper lateral incisor less frequent: second permanent premolar rarely: lower central incisor

Question 46

Eruption of the tooth ceases and becomes ankylosed to the bone of the jaw

Answer 46

submerged deciduous teeth

Question 47

They prevent the eruption of their permanent successors?

Answer 47

submerged deciduous teeth

Question 48

What are the factors that affect resorption/shedding?

Answer 48

Pressure, Masticatory Stress, Genetic Factors.

Question 49

This leads to trauma to the ligament and initiates resorption?

Answer 49

Masticatory Stress.

Question 50

Mechanism of Shedding?

Answer 50

1. Resorption of primary tooth continues 2. Root length decreases 3. Surface area for attachment of PDL decreases 4.Shedding/ExfoliationMasticatory Stress.

Question 51

Resorption of the roots of deciduous molars often first begins on what of their surface?

Answer 51

inner surface