embryology

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what are the three components of the peridontium
- cementum
- alveolar bone
- periodontal ligament
what are the had and soft tissues that support the teeth?

periodontium
what does the cementum come from?

mesoderm
the cementum covers the entire _____

root (similar to enamel covering the crown)
what are the two attachments for the PDL?
- cementum
- alveolar bone
t/f the cementum is vascular

false-avascular and has no innervations it gets it from the periodontal ligament
where does the cementum get its nutritional supply from?

periodontal ligament
how mineralized is the cementum?

65%
how mineralized is the enamel?

96%
how mineralized is the dentin?

70%
what induces the cells of the dental sac to differentiate into cementoblasts?

newly formed dentin
are there ameloblasts present on the root?

no-enamel is not formed here that is why cementum is laid on top of dentin instead
cells of the dental sac ______ into cementoblasts

differentiate
what is the cementum matrix called?

cementoid
what are cementoblasts that get caught in the matrix called?

cementocytes
what are the ends of the periodontal ligament fibers that have embedded themselves into the cementum

sharpey's fibers
where do the cementum and enamel meet?

cementoenamel junction
what are the three types of cementoenamel junctions?
- overlap
- meet
- gap
with overlap the _____ overlaps the _____. why?
- cementum overlaps the enamel
- because the enamel was formed first
with the overlap what can the cementum be confused with? why

calculus because it is rough
t/f when the cementum meets in the middle it has no problems

true
what is it called when there is a space between the cementum and the enamel leaving the dentin exposed? what can this cause?
- gap
- hypersensitivity
what are reversal lines

after cementum resorption, you can tell where the resorption stopped and started laying down new cementum
what lines are shown when the cementum was once broken down and then it rebuilt itself?

reversal lines
what lines are just like retzius lines with enamel and lines of von ebner with dentin?

arrest lines (laid cyclically)
what are the two types of cementum
- acellular
- cellular
which type of cementum is the first to get laid down and has no cementocytes.

acellular cementum
why doesn't acellular cementum have cemetocytes

laid slowly, cells don't get stuck
what is the last cementum to get laid down and it has cementoblasts

cellular cementum
why does cellular cementum have cementoblasts

laid quicker
the cementoblasts that don't get stuck go where?

migrate to the periphery of the cellular cementum and wait until they need to make more cementum
what are three clinical considerations with cementum?
- cementicle
- cemental spurs
- hypercementosis
what is it called when the cementoblasts start to lay cementoid around cellular debris in the PDL

cementicles
t/f a cementicle starts attached to the tooth

false-is floatin around in the PDL but can become attached to the tooth
what is it called when the cementum is laid down more excessively at the CEJ

cemental spurs
what is a cemental spur similar to?

enamel pearl
t/f the cemental spur starts out floating in the PDL and becomes attached to the tooth

false-starts connected to the tooth
what is excessive production of cementum that results from occlusal trauma

hypercementosis
what directly surrounds and supports the teeth?

alveolar bone
what does the alveolar bone start out as?

dental sac
what is the alveolar bone formed from?

mesoderm
how mineralized is the alveolar bone?

60%
the alveolar bone has _____ _____ that embed in the bone to anchor the teeth

sharpey fibers
what is the bone beneath the alveolar bone that forms the body of the mandible and maxilla?

basal bone
what does basal bone form?

body of the mandible and maxilla
what is the term for the individual tooth socket?

alveolus
what is an alveolus

individual tooth socket
what is the compact bone that lines the alveolus

alveolar bone proper
what is the alveolar bone proper called on a radiograph?

lamina dura
what is the most cervical rim of bone that should be 1-2 mm apical to the CEJ

alveolar crest
where should the alveolar crest be from the CEJ?

1-2 mm apical of the CEJ
what is the compact bone that makes the facial and lingual walls of the bone?

cortical bone
what is cancellous bone that fills the space between compact bone?

trabecular bone (lacelike)
what is the bone between the roots

interradicular septum
where is the interradicular septum located?

bone between the roots
what is the bone between each tooth?

interdental septum
where is the interdental septum located?

bone between each tooth
what type of xray can you see the interdental septum and the interradicular septum?

periapical
what happens with the alveolar bone during orthodontic movement?

the osteoclasts on the compressed side break down the bone and osteoblasts rebuild bone on the opposite side
during orthodontic movement it puts pressure on the tooth, the ______ on the compressed side breaks down the bone and the ______ rebuild the bone on the opposite side
- osteoclast
- osetoblast
if teeth are moved too quickly with ortho what can it cause?

root resorption
why must ortho treatment go slowly?

to prevent root resorption and because only the matrix is laid down and it needs to mineralize to prevent teeth movement
what stimulates the bone growth or bone breakdown with ortho movement?

ligaments
when the _____ _____ doesn't have constant stimulation of chewing and speaking what happens?
- alveolar bone
- it will start to resorb (USE IT OR LOSE IT!)
what is a great way for edentulous patients to give the alveolar bone stimulation to prevent resorption

implants
what is the implant made out of?

titanium
t/f with periodontal disease the body sends out osteoclasts to break down the bone

true
why does the body break down the bone around teeth with periodontal disease?

because the body doesn't want the infection to become systemic, it would rather lose the tooth than die
what is a bone graft?

it is the matrix (bone bait) placed to give the osteoblasts a place to lay down osteoid.
when is a bone graft typically done?

after extractions in prep for an implant
why isn't an implant painful to place?

no nerves in the bone
what does the PDL start out as?

dental sac
what does the PDL form from?

mesoderm
the PDL is ____ connective tissue that attaches the _____ to the ____
- fibrous
- tooth to the bone
on a radiograph how does the PDL appear and what is it referred to as?
- appears radiolucent
- it is called the periodontal space
how do you know how hard to bite?

because of the PDL it transmits occlusal forces
t/f the periodontal ligament transmits occlusal forces

true
t/f the PDL is avascular

false
what does the PDL give nutritional support to?

alveolus, cementum and pulp
onces the vessels of the PDL enter through the apical foramen what does it give nutrition to?

the pulp
what kind of nerves does the PDL have?

afferent sensory nerves
what are six cells that live in the PDL?
- fibroblasts
- osteoblasts/clasts
- cementoblasts/clasts
- epithelial rests of malassez
where are osteoblasts/clasts located within the PDL?

along the periphery of cementum
what are epithelial rests of malassez

started out ash HERS but got last (can become cystic)
the PDL is made up of lots of ____ with many different names.

fibers
what are two clinical considerations of the PDL?
- occlusal trauma
- periodontal disease
what is occlusal trauma and what happens to the PDL?
- clenching and grinding
- PDL widens to withstand forces
t/f occlusal trauma can be seen radiographically

true
what happens to the PDL with periodontal disease?

fibers get disorganized and lose their attachment because of the resorption of the bone and cementum

Author

sweetpea281

50895

Card Set

embryology

Description

periodontium

Updated

2010-11-21T19:17:20Z

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