lecture 4/5 developing dentition

from _________gm at 28 weeks to about _______________ by birth the fetus underfoes rapid growth

1000

3000

evidence of development of the human tooth can be observed as early as ______________ of embryonic life

6 week

head size is nearly ____________ of total body mass at birth

50%

_______________- reduce risks during delivery, improving chances for both mother and infant

adaptation strategies

the fetal head growth but maintains flexibility due to __________________ allowing shape distortion during deliver

fontanelles

what tooth erupts first in primary dentition

mandibular central incisors

what tooth erupts last in primary dentition

maxillary second molar

eruption pattern and months of maxillary and mandibular primary teeth (earliest to latest)

mandibular central incisor (8 month)

maxillary central incisor (10 month)

maxillary lateral incisor (11 month)

mandibular lateral incisor (13 month)

maxillary and mandibular first molar (16 month)

maxillary canine (19 month)

mandibular canine (20 month)

mandibular second molar (27 month)

maxillary second molar (29 month)

primary teeth eruption starts about __________. the sequence is

6 months

central incisors, first molar, canines, second molar

permanent teeth begins around age __________ sequence is

6

molars, incisors, canines

eruption of primary teeth between

6 month and 2 years

by what age the occlusion of 20 primary teeth is established

age 3

preeruptive phase

period during which the tooth root initiates it formation and begins to move toward the surface

eruptive phase (prefunctional)

consists of that period of development of the tooth root through gingival emergence

tooth root is usually 1/2 or 2/3 of its final length

eruptive phase (functional)

after the tooth has erupted into the oral cavity and contacts its antagonist

natal teeth

present at birth

neonatal teeth

teeth present at birth or within the first month after birth

primate spaces

developmental spaces between primary teeth

generalized spacing of the primary teeth is a requirement for _______________ of the ______________________

proper alignment of the permanent incisors

in the maxillary arch the primate space is located between

lateral incisors and canines

in the mandibular arch the space if between

canines and first molars

primary teeth tend to have __________ crowns and ___________ enamel compared to permanent teeth

shorter

thinner

primary pulp chamber size is ____________ relative to the crown

larger

maxillary central incisors ____________ diameter of the crown is greater than the cervicoincisal

mesiodistal

maxillary central incisor rooth is what shape

cone shaped

maxillary lateral incisor outline is similar to central but ______________ is smaller

crown

maxillary canine is more contrict at the _________ region than incisors. the incisal and distal surfaces are more _____________

cervical

convex

mandibular central incisor is __________ than maxillary central

smaller

mandibular lateral incisor outline is similar to central incisor but somewhat _______ in all dimensions except ________________-

larger

labiolingually

primary teeth differences from permanent teeth

crowns are wider mesiodistally

usually lighter in color

primary teeth have a _____________, ______________ proximal contact area

broad and flat

mixed dentition period between ages ___ and __________. this period provides gradual lose of primary teeth and eruption of permanent ones , starting with ____________-

6 and 12

molars

function of permanent incisors

cutting food

function of permanent canines and premolars

tearing and grinding

function of permanent molars

crushing and chewing food

most used notation system in us

universal numbering system

numbers teeth from 1-32 starting from maxillary right third molar

what are the 3 notation systems

FDI world dental federation notation

palmer notation system

universal numbering system

what notation is common in orthodontics

palmer notation system

uses symbols to represent teeth in quadrants

primary dentition notation

starts with A from maxillary right second molar and ends with t at mandibular right

developmental stages of teeth

initiation (bud stage)

proliferation (cap stage)

histodifferentiation and morpho differentiation (bell stage )

Intiation/bud stage begins as early as the _____________ week of embryonic life. cells in the oral epithelium form ______________ leading to formation of primary teeth

6th week

dental lamina

proliferation (cap stage) _____________ creates a cap structure. the enamel organ begins to take a cap like shape, signaling the differentiation and proliferation of cells that will eventually form _____________, _______ and ______________ of the tooth

cell proliferation

enamel

dentin

pulp tissues

histodifferentiation and morphodifferentiation (bell stage) the enamel organ assumes a bell form. cells differentiate into ______ and ____________ crucial for tooth structure

odontoblasts

ameloblasts

lack of initiation stage can result to

missing teeth

excessive proliferation can lead to

supernumerary teeth

disturbance in differentiation can lead to

abnormal dentin/enamel structures

deficiency if proliferation of cells can lead to

affect number of teeth , may result in epithelial rests

fusion

union of 2 independently developing teeth

germination

bifid crown on a single tooth

primary teeth show 2 crowns and 2 pulp chambers connected to a single root and pulp canal

ameloblast failing to differentiate properly results in

amelogenesis imperfecta

odontoblast failing to differentiate properly results in

dentinofenesis imperfecta

disturbances and aberrations in ___________ result in abnormal forms and sizes of teeth

morphodifferentiation

any systemic disturbance or local trauma that injures the ameloblasts during enamel formation can cause an interruption or arrest in matrix apposition resulting in

enamel hypoplasia

dental fluorosis is a pathological condition characterized by ________________ of the enamel due to excessive exposure to fluoride during enamel _________________________

hypo mineralization

mineralization

green teeth is a result of

hyperbilirubinemia during early development of primary teeth