Periodontum Flashcards
Periodontal tissues of the tooth consist of
- Cementum
- Periodontal ligament connect tooth to BAP
- Bony alveolar processes
- Gingiva facing tooth
Tissues form ________ that binds teeth to bony sockets.
Gomphosis
Unique fibrous joint from ectomesenchyme of dental sac/follicle
The periodontium is a type of ______.
Fibrous joint
Why is the periodontal pocket important?
Gateway for biofilm bacteria to enter root system
Periodontal Pocket Severity
1-2 mm : GOOD
Inflammation response will open pocket further.
What is cementum made of?
Similar to bone
Primary and Secondary Cementum
ORGANIC material: 23%
Hydroxyapatite: 65%
Water: 12%
What is in the ___% organic material in cementum?
23%
Collagen 1,3,12(PDL), little of 6,5,14
Proteins:
Bone Sialoprotein
Osteopontin
Osteocalcin
Osteonectin
Dentin Matrix Protein 1
Dentin Sialoprotein
BOOODDS
Cementum is thicker ________. It is an intermediate between _______.
Apically
Dentin and bone tissue
Cementum is vascular. True or false?
FALSE
Vascular
What does the cementum cover?
Root of teeth
It is formed in two stages what are they?
The first stage is pre-functional or primary where the Dentin is covered. This occurs during root formation.
The second stage is functional or secondary, where it is formed when teeth are erupted and in occlusion.
What are the 3 function of cementum?
- Cover root dentin (and tubules)
- Site of attachment for periodontal fibers (teeth to bone)
- Compensate for changes in surrounding bone.
Primary cementum is acellular/cellular. It has __________ and covers________.
acellular
one or more layers covers entire root surface
Secondary cementum is acellular/cellular. It is involved with __________ and covers _________.
cellular
tooth movement, repair, readjustment to changes in bone
covers apical third of root and interradicular surfaces
Fibrillar cementum
Abundance Collagen I
Afibrillar cementum
without well defined Collagen Type 1
Extrinsic fiber cementum
Extrinsic collagen fibers from periodontal ligament
Intrinsic Fiber Cementum
Intrinsic collagen fibers made by cementoblasts
What does Cementum look and feel like?
Pale yellow, darker than enamel
Grainy compared with harder, smooth enamel
Primary cementum has _______ at the surface.
Junction with dentin is called _______.
Collagen fibers ___________ to _______ junction.
cementoblasts
Tomes Granular Layer
Perpendicular to cementodentine
What is another name for extrinsic fibers and what collagen is it made of?
Sharpey’s Fibers
Collagen Type I
_________ generate the matrix for primary cementum.
How does it do so?
Cementoblasts
They synthesize collagen fibers which intermingle with collagen fibers of dentin with the cementoid (organic) becoming mineralized.
Striations of cementum in histology
Horizontal : PDL fibers
Parallel: Layering of cementum
Secondary cementum covers the ____ of the root and is present in the _______ for teeth with ___ roots.
apical 1/3
interradicular region more than 1
Teeth with 1 root do or do NOT have secondary cementum/
DO NOT (only some)
In cellular intrinsic fiber collagen, _______ in lacunae are surrounded.
_________ is a ________ matrix deposited by cementocytes and is _________. How does it become mineralized?
cementocytes ( remember this makes in collagen)
Cementoid, collagen, unmineralized
Trapping cementoblasts
What is the difference between cementoblasts(CB) and cementocytes (CC)
CB come from the ectomesenchyme and are on the surface of cementum
CC are in lacunae have have processes in canaliculi projecting towards PDL which vascularized. They transport nutrients to cell body.
CEMENTOCYTES LOOK LIKE OCTOPUS`
Cementocytes look like _______. How do we know where the PDL is based on cementocytes
octopus
Tentacles face PDL towards tooth surface
The CEJ is made of ______ cementum and has 3 forms.
Primary
- Cementum overlapping dentin - TIGHT SEAL
- Gap between dentin and enamel - BAD
- Cementum and enamel head butt against each other like mountains
Hertwing’s epithelial root sheath is located at the ________________.
junction of the inner and outer enamel epithelium
________ of Hertwing’s epithelial root sheath induces what?
Fragmentation as ameloblasts die off. Only dentin and cementoblasts is found near this apical portion where the root sheath is for this reason
predentin induces differentiation of cementoblasts AS WELL AS ameloblasts and odontoblasts
Where are cementoblasts cells originating from?
Dental follicle or sac of ectomesenchymal cells (neural crest origin)
Rooth Sheath Cells
HERs cells either ________ or ___________.
die or migrate away from the dentin toward the dental sac as cementum is laid down
Some become trapped in developing cementum and become the epithelial CELL OF MALASSEZ found in the PDL
What do Malassez look like?
Clusters or long strands along cementum
What is a cementicle?
Mineralized acellular cementum spheres at cemental root or in PDL.
ONLY acellular cementum formed later in life.
Increases with AGE and can be in/on cementum layer or free in PDL
Hypercementosis
Too much cementum
Can result from occlusal trauma due to excessive occlusal forces
Alveolar bone (___________) is supported by ____________ which is surrounded by a ________.
lamina dura (socket where teeth reside)
spongy bone
cortical plate (buccal and lingual)
The cortical plate is in contact with the tooth. True or False
FALSE! It is the outer portion of the mandible and maxila that we can feel
Alveolar bone is also known as ______-.
Bundle Bone
The PDL will stick into the ________ and _______ via _______.
Cementum or Lamina Dura of alveolar bone via Sharpey’s fibers.
PDL is high vascularized and innervated. True or false?
TRUE
PDL does what for cementocytes?
Provide nutrients
What are Volkmann’s Canals?
Hole in the alveolar bone with a neurovascular unit coming into the PDL
Ectomesenchyme gives rise to _______.
Fibroblasts
Cementoblasts
Osteoblasts
Osetoclasts
Cementoclasts
Fred Cries Over Organic Chemistry
Fibers, amorphous ground substance
Collagen bunles (Type 1 and 3- elastic fibers)
Osteoblasts will break down ______ cementum if something is wrong with tooth.
Secondary
Describe the development of the PDL.
What does it happen concurrently with?
Root System Development
HERs is disrupted and cementoblasts form from ectomesenchymal cells of dental sac.
Collagen forms from dental sac cells.
OsteoBLASTS develop and form alveolar bone.
Fiber Groups in PDL
Embedded in cementum of root and lamina dura of alveolar both : Sharpey’s
Fibers: Collagen I and III
Elastic Microfibril
What will the PDL remodel in response to?
Use/Manipulation
Metabolic - Low Vitamin C causes impaired collagen production
Aging
Fiber TYPES in Periodontal Ligament
Which one is found most often?
Alveolar Crest
Horizontal
Oblique - MOST
Apical
Interradicular
AlOHAI
Additional Fiber Types
Dentogingival
Dentoperiosteal : Tooth to outer crest of alveolar bone
Alveolargingival: Alveolar bone to gingiva
Transseptal ligament: Adjacent teeth to one another over alveolar crest
Periodontal Ligament Vascularization
BV form _______________ located in the _______________
single vascularized mesh in the middle of the periodontal space
Like a BASKET
Nerves run from _______ to _______margin
apical to gingival
4 Nerve Endings
Free :Nociceptors and Mechanoreceptors
Ruffini Endings: Mechanoreceptors
Coiled Ending: unknown
Encapsulated : Unknown
