Midterm Exam Flashcards
separates dentin from enamel
dentinoenamel junction
What exits the apical foramen?
nerves
where anatomic crown meets anatomical root
cementoenamel junction
where cementum and dentin meet
cementodentinal junction
no blood supply, no nerves
avascular
What is the final job of ameloblasts?
to form nasmyth’s membrane
What does nasmyth’s membrane do?
protects enamel
imperfect enamel formation
- little holes in teeth, discolored
amelogenesis imperfecta
What is the result of too much fluoride ingested?
- modeled, white coloration
fluorosis
What happens in children that get lots of fevers and/or infections?
enamel damage
hard tissue loss from tooth-to-tooth movement
- grinding, bruxism
attrition
chemical means tooth decay
- acid reflex, bulimia, soda
erosion
wearing away tooth surface by mechanical means
- brushing teeth too hard
abrasions
combination of abrasion of CEJ and grinding
Abfraction
what do dentin and pulp develop from
dental papilla
What is softer than enamel but still as hard as bone?
Dentin
genetic condition with imperfect genetic formation, dentin can’t support house
dentinogenisis imperfecta
Babies teeth are affected because of mother taking tetracycline, grey colored
tetracycline staining
secreted layers of enamel, dentin, and cementum matrix
apposition
mineralization completes
maturation
inner enamel epithelial cells elongate and differentiate into pre-ameloblasts
Bell stage
What begin to lay down hydroxyapatite crystals and mineralization begins?
dentin and enamel
process of enamel matrix formation known as the apposition stage of tooth development
amelogenesis
what is the hardest tissue of the body
enamel
what can only be removed by rotary cutting instruments
enamel
what is 96% mineralized
enamel
what forms from ameloblasts and is avascular
enamel
what develops from the enamel organ
enamel matrix
outer layer of epithelial cells
ectoderm
what form from the inner enamel epithelium
ameloblasts
how many ameloblasts join together to form the enamel rod
3 to 4
a column of enamel that runs perpendicular to the CEJ and extends to the surface of the tooth
enamel rods
what is the stage when ameloblasts excrete the enamel matrix
mineralization stage
during what stage do crystals grow and begin to calcify
maturation stage
incremental growth lines seen in sections of enamel described as brown in color
lines of retzuis
horizontal lines seen on the labial surface of anterior teeth
imbrication lines
When does root development occur
after crown of tooth is formed
what is root development formed from
cervical loop
what is responsible for the shape of the roots
hertwigs epithelial root sheath
what has genetic control and determines the shape of tooth
the dental papilla
what is 70% mineralized
dentin
what is softer than enamel
dentin
what is formed from odontoblasts
dentin
what is yellow- white in color
dentin
what makes up the bulk of the tooth and is present on both the crown and root
dentin
what secrete the matrix at the dentoenamel junction and the cells move toward the pulp
odontoblasts
dentin that is formed before the apical foramen is complete in the root
primary or regular dentin
formed after the completion of the apical foramen and continues to form throughout the life of the apical tooth
secondary dentin
formed as a result of localized injury to exposed dentin; can form quickly
tertiary (reparative, reactive) dentin
dentinal tubules are fully calcified associated with chronic injury
sclerotic dentin
incremental lines (growth rings) in dentin similar to the lines of retzius in enamel
imbrication lines of von Ebner
what develops from the mesoderm tissue of the dental papilla
the pulp
where is the pulp chamber
in the crown
where is the pulp canal
in the root
what is blood vessels, lymphatic vessels, nerves, fibroblasts and collagen fibers and cells of connective tissue
the pulp
what is soft - not calcified or mineralized
pulp
last portion of tooth to form after the crown erupts
apical foramen
small calcified circular areas found in the pulp chambers of older persons
pulp stones
what function of dental pulp is dentin producing cells (odontoblasts)
formative
what function of dental pulp is the nerve ending relay sense of pain so we feel it
sensory
what function of dental pulp can pass from heart to tooth in 6 seconds
nutritive
what function of dental pulp lays reparative dentin
defensive or protective
what is the dull yellow external layer of tooth root
cementum
what is very thin especially at the cervical line
cementum
what is 50-65% mineralized
cementum
what is hard as bone but softer than enamel
cementum
what develops from dental sac
cementum
what is produced by cementoblasts
cementum
What is odontogenesis?
tooth development
when does odontogenesis begin
6 weeks in utero
what is the longest growth period of all organs
odontogenesis
What are the stages of tooth development in order?
Initiation stage
Bud stage
Cap stage
Bell stage
Apposition stage
Maturation stage
When is the initiation stage?
6-7 weeks
What week is the bud stage?
8th week
When is the cap stage?
9-10 weeks
What are the three MAIN stages of tooth development?
Bud, Cap, and Bell stages
What is the primitive mouth (stomodeum) lined by?
ectoderm
What gives rise to the oral epithelium?
ectoderm
Consists of two horseshoe-shaped bands of tissue which will become the two arches/jaw
oral epithelium
What migrates to area to influence ectomesenchyme tissue?
neural crest cells
What are the oral epithelium and ectomesenchyme separated by?
basement membrane
What grows at end of the 7th week?
oral epithelium
Oral epithelium grows deeper into ectomesenchyme to produce what?
dental lamina
What starts at the midline and spreads posteriorly to the molar area?
Dental lamina
Absence of single or multiple teeth
anodontia
extra tooth or teeth
supernumerary teeth
What stage is extensive growth of the dental lamina into tooth germ penetrating into ectomesenchyme?
Bud stage
How many buds will be present for primary and permanent dentitions?
Primary - 20 buds
Permanent - 32 buds
In areas where teeth don’t develop the dental lamina remains thickened and becomes what?
oral mucosa
What stage is when proliferation of growth of cells continues?
Cap stage
What leads to the formation of a cap shape attached to the dental lamina?
Cap stage
predominant process during cap stage is what?
morphogenesis
A depression results in the deepest part of each tooth bud of dental lamina and forms a cap or what?
enamel organ
During cap stage, inner mass of ectomesenchyme now becomes what?
dental papilla
During cap stage, remaining ectomesenchyme surrounding the outside becomes what?
the dental sac
At the end of the cap stage, what three embryological structures are now considered to be tooth germs?
- the enamel organ
- dental papilla
- dental sac
What will give rise to the four tissues that make up a tooth?
tooth germ
What are the four tissues that make up a tooth?
- enamel
- dentin
- cementum
- pulp
“tooth without tooth”
dental papilla
Formation of tooth bud in cap shape with deep central depression
enamel organ
what is the future dental tissue produced from the enamel organ?
enamel
Condensed mass of ectomesenchyme within the concavity of the enamel organ
dental papilla
what is the future dental tissue produced from dental papilla?
dentin and pulp
condensed mass of ectomesenchyme surrounding the enamel organ
dental sac
what future dental tissue is produced from the dental sac?
“PAC” the sac
PDL
Alveolar bone
Cementum
tooth germ tries to divide
- tooth count is normal
germination
union of two adjacent tooth germs
- one less tooth count
fusion
extra cusp
tubercle
What stage is the continuation of proliferation, differentiation, and morphogenesis?
Bell stage
What are the four developing tissues of the enamel organ?
- outer enamel epithelium
- stellate reticulum
- stratum intermedium
- inner enamel epithelium
Where are cubodial cells?
outer enamel epithelium
What is a protective barrier for enamel organ during enamel production?
outer enamel epithelium
more outer star-shaped cells in many layers forming a network
stellate reticulum
What supports production of enamel matrix?
- stellate reticulum
- stratum intermedium
compressed layer of flat to cubodial cells
stratum intermedium
what is the innermost layer?
inner enamel epithelium
What are tall columnar cells?
inner enamel epithelium
What will differentiate into enamel secreting cells (ameloblasts)?
Inner enamel epithelium
What are secreting cells?
ameloblasts
What are the two developing tissues of the dental papilla?
- outer and inner cells of the dental papilla
What are nearest to inner enamel epithelium?
outer cells of dental papilla
Where does the basement membrane exist between?
between the inner enamel epithelium and the outer cells
What will differentiate into odontoblasts that form dentin matrix?
Outer cells of dental papilla
- inner cell mass
- will differentiate into pulp tissue
inner cells of dental papilla
What stage is when enamel, dentin, and cementum secrete in successive layers initially as a matrix
Apposition stage
What stage is when dental tissues fully mineralize?
maturation
What is the order of odontogenesis?
- ectoderm
- dental lamina
- enamel organ
- inner enamel epithelium
- ameloblasts
- enamel
What numbers are the maxillary incisors?
7-10
What numbers are the mandibular incisors?
23-26
What years do the maxillary central incisors (#8-9) usually erupt?
years 7-8
What years do the maxillary lateral incisors (#7 and #10) usually erupt?
years 8-9
What years do the mandibular central incisors (#24-25) usually erupt?
years 6-7
What years do the mandibular lateral incisors (#23 and #26) usually erupt?
Years 7-8
What are the functions of the incisors?
Cut food
Articulate speech
Support lips
Guide mandible during movement
How many lobes do incisors develop from?
4 lobes
What are mamelons?
Round bumps on incisal edges
What is diastema?
space between teeth, typically between central incisors
What are diastema’s a result from?
frenum attachment
What years do all incisors typically erupt by?
6-9 years
What are developmental lobes?
little pockets for growth centers
Small maxillary incisors
Peg-lateral
What teeth are symmetrical?
Mandibular central incisors
What is it called when you twist a tooth?
Distolingual twist
Where are the facial and lingual heights of contour for canines located?
Cervical third
Where is the contact of the maxillary lateral incisors located?
Middle-third
What is the largest CEJ curvature of all teeth?
Mesial of the maxillary central incisors
Where are the mesial and distal marginal ridges of incisors located?
The mesial and distal borders of the lingual surface
What teeth have wider and longer crowns?
Maxillary central incisors (#8-9)
What teeth numbers have the smallest root-to-crown ratio?
8 and #9
What teeth have smaller crowns - narrowest tooth mesiodistally?
Mandibular central incisors (#24-25)
What teeth have one pulp horn?
Maxillary lateral incisors
What’s another name for the facial surfaces of anterior teeth?
Labial
What’s another name for the lingual surface of maxillary teeth?
Palatal surface
Surface closer to midline
Mesial
Surface away from from midline
Distal
Imaginary junction line where two surfaces meet
Line angle
Elevation or peak on the occlusal surfaces of posterior teeth and the incisal edge of canines
Cusp
Greatest bulge on facial and lingual crown surfaces
Height of contour
(Crest of curvature)
Continuous space around each contact area
Embrasure spaces
What are the last teeth to be lost from dental disease?
Canines
What are the longest teeth in a permanent dentition?
Canines
What are the numbers of the maxillary canines?
6 and #11
What are the numbers of the mandibular canines?
22 and #27
What years do maxillary canines erupt between?
years 11-12
What years are maxillary canines root completion?
Years 13-15
What years do mandibular canines erupt between?
Years 9-10
What year are mandibular canines root completion?
Year 13
What are the functions of the canines?
Support lips
Cut, pierce, and shear food
Protection mechanism
What are the lobes of the canines?
3 facial lobes
1 lingual lobe
How many cusps on the incisal edge of canines?
One cusp
What teeth have the largest cingulum of all anterior teeth and is centered over the midroot axis?
Maxillary canines
What angle do mandibular lateral incisors have?
Rounded distal angle
What heights of contour for the canines are located in the cervical third?
Facial and lingual
Where are the maxillary canines mesial contacts located?
The incisal/middle junction
Where are the maxillary canines distal contacts located?
Toward the middle third
Where are the mandibular canines mesial and distal contacts located?
The incisal third
What are the facial surface ridges of the canines?
Mesial cusp ridge
Labial ridge
Distal cusp ridge
What are the lingual surface ridges of canines?
Mesial marginal ridge
Lingual ridge
Distal marginal ridge
What ridges are shorter than distal cusp ridges on canines?
Mesial cusp ridges
What are mesial and distal cusp ridges also known as?
Cusp slopes or cusp arms
What are the specific longest teeth?
Maxillary canines #6 and #11
What surfaces of canines appear to be smooth?
Lingual surfaces
What tooth roots bend distally at apex?
Maxillary canines
What teeth have more prominent distal root depression?
Mandibular canines
How many pulp horns do canines have?
One pulp horn
When do the maxillary first premolars erupt?
10-11 years
When do the maxillary second premolars erupt?
10-12 years
When do the mandibular first premolars erupt?
10-12 years
When do the mandibular second premolars erupt?
11-12 years
What are the functions of the premolars?
- Masticate food
- Maintain vertical dimension of the face
- Assist canines in cutting food
- Support corners of the mouth to keep from sagging
What are the developmental lobes for canines?
3 facial lobes
1 lingual lobe
What teeth often times form from two lingual lobes, resulting in two lingual cusps?
Mandibular second premolars
What do the lingual cusps form from on anterior teeth?
Cingulum
What is the facial height of contour for all premolars?
Cervical third
Where is the lingual height of contour for all premolars?
Middle third
Where are mesial contacts for all premolars located?
occlusal middle junction
Where are the distal contacts of premolars located?
NOT mand. first premolars
Middle third
Where are the distal contacts for the mandibular first premolars located?
Occlusal third
Where are crowns wider at for premolars?
Faciolingually
What cusp ridges do premolars have?
Mesial and distal cusp ridges
What merge together to make the occlusal table for premolars?
Cusp ridges of the buccal and lingual cusps
What form transverse ridges for premolars?
Two triangular ridges
Central grooves run ______ across the occlusal surface EXCEPT mandibular 1st premolars.
Mesiodistally
Fossas contain pits in the center making them suseptible to what?
Decay
What teeth have longer mesial cusp ridges and more prominent buccal ridges?
Maxillary 1st premolars (#5 and #12)
What teeth are most often extracted for orthodontic purposes?
Premolars
Where does the central developmental groove run on premolars?
From mesial to distal pit
What premolars are smaller?
Maxillary 2nd premolars
(#4 and #13)
What premolars buccal cusp tip is more obtuse?
(120 degree angle)
Maxillary 2nd premolars
What teeth have a more symmetrical occlusal outline?
Maxillary 2nd premolars
What teeth do the crowns tilt lingually?
Mandibular premolars
What teeth’s lingual cusp is relatively shorter than buccal?
Mandibular 1st premolars
What teeth’s mesial marginal ridge is more horizontal?
Mandibular 2nd premolars
What premolars have a bifurcated root?
Maxillary 1st premolars
What teeth bend distally in the apical third?
Premolars
What teeth have two canals even if it has a single root?
Maxillary 1st premolars
How many pulp horns do premolars have?
Most have 2
Mand. 2nd may have 3
