Periodontium Flashcards
What is the periodontium made up of?
Cementum
Alveolar bone
Periodontal ligament
What is the periodontium?
Tissues that invest & support the tooth
What is cementum?
Mineralized cementoid covering root dentin
Characteristics of cementum
- Avascular, non-innervated tissue
- Covers & protects root dentin
- Anchors PDL fibers to tooth root
- Mineralized CT
- Softer than root dentin
Physical/Chemical characteristics of cemetum
Has Type 1 Collagen and amphorous ground substances (AGS)
What types of cells are found within the cementum?
Cementoblasts
Cementocytes
What are cementocytes?
- Cell body situated in lacunae
- Cell processes in canaliculi radiate out ONLY toward the PDL
Cementum Types
Acellular extrinsic fiber cementum
Cellular intrinsic fiber cementum
Acellular extrinsic fiber cementum (AEFC)
-Primary cementum
- No cementocytes
- Covers cervical 2/3 of root
- Forms slowly during tooth eruption
- Plays major role in tooth attachment
Cellular intrinsic fiber cementum (CIFC)
-Secondary cementum
- Contains cementocytes
- Covers apical 1/3 of root
- Forms rapidly
- Plays minor role in tooth attachment
Fiber Collagen 1 Types
What is intrinsic fiber?
- Produced by cementoblasts
- Run parallel to the root surface
Fiber Collagen 1 Types
What is extrinsic fiber?
- Produced by fibroblasts
- Sharpey’s fibers of PDL
- Run at right angles to root surface
What are the 3 patterns of the Cementoenamel junction?
- Cementum overlaps enamel ~60%
- Cementum meets enamel ~30%
- Gap between cementum and enamel ~10%
***these can occur developmentally or post-eruptive
What can occur from exposed root dentin
Dentin hypersensitivity
Clinical significance of cementum
Orthodontic tooth movement
- Cementum more resistant to resorption than alveolar bone
- Application of proper forces can move teeth through bone
What is hypercementosis?
- Abnormal thickening of cellular cementum
- Tooth may become ankylosed
Alveolar Process?
Portions of the maxilla and mandible that support the roots of the teeth
Chemical composition of the Alveolar Process?
Alveolar bone contains more mineral than cementum
What are the components of the alveolar process?
Alveolar bone proper
Cortical plate
- Inner plate: lingual/palatal surface
- Outer plate: buccal & labial surface
Central spongiosa (trabecular bone)
Components of Alveolar Process:
What is the Alveolar bone proper?
- Also called: bundle bone, lamina dura and cribiform plate
- Specialized type of compact bone because the ends of the PDL fiber bundles insert into it
- Appears more radiopaque than the adjacent supporting bone
- NO periosteum present
- Remodeling rate may be high due to constant adaptation to tooth mvmts.
Components of Alveolar Process:
What is the cortical plate?
- Composed of the inner and outer plates
- Covered WITH a periosteum
- Alveolar crest: junction of cortical plate and alveolar bone proper
Components of Alveolar Process:
What is the Central spongiosa?
- Trabecular (spongy/cancellous) bone supporting alveolar bone proper & cortical plate
- Marrow is red in young & yellow in old aged
Describe both of the Bony Septa in the alveolar process
Interdental septum
- located between roots of adjacent single-rooted or multi-rooted teeth
Interradicular septum
- located between roots of a single multirooted tooth
What is an edentulous jaw?
A jaw with only basal bone
Lost alveolar process
