Flashcards in The Periodontium I Deck (89):
Define the periodontium
The tissues that invest and support the tooth
What are the 3 principle components of the periodontium?
1. Alveolar Process
3. Periodontal LIgament
What is a Gomphosis?
Fibrous peg-in-socket joint
The periodontium develops during a series of complex interactions of ________, _____, and _______
3. Dental Follicle
What are the cells involved in the origin of the periodntium?
3. PDL fibroblasts
Where do osteoblasts come from in the periodontium?
Surrounding Mesenchymal tissues
Where do cementoblasts come from in the periodontium?
Where do PDL fibroblasts come from in the periodontium?
Follicle cells/Ectomesenchymal celss
What do Odontoblasts contribute to the periodontium?
Form dentin part of cemento-dental junction, and dental papilla
T/F the periodontium contains 3 out of 4 types of mineralized tissues found in the oral cavity
How does the alveolar process form?
*Mesenchyme direct to bonef, no cartilage intermediate
When does the alveolar process form?
During the 8th week of uterine life
__________ are contained in horseshoe-shaped grooves of the mandible and maxilla
What develops around tooth germs that eventually forms the sockets?
Alveolar Processes develop substantially during _______, under the influence of ______
1. Tooth eruption
2. Dental follicle
T/F Alveolar processes are remodeled throughout life
What is an anodontic individual?
People whose alveolara process development is impaired
What kind of bone is alveolar bone proper?
*Cribiform plate, lamina dura
Supporting alveolar bone is what type of bone?
Both compact and trabecular
What is the compact component of supporting alveolar bone?
What is the trabecular portion of supporting alveolar bone?
What are the 3 main descriptors associated with Alveolar bone proper?
1. Cribiform plate
2. Lamina dura
3. Bundle bone
T/F Cribiform plate has volkmann's canals running through it
What is the lamina dura?
Radiographic term for alveolar bone proper: area of PDL attachment
What is bundle bone?
Histological term for alveolar bone proper: Sharpey's fibers (PDL) embedded in bone
T/F There is an inner and outer aspect ot alveolar bone proper
*inner is towar the PDL
Describe the remodeling rate of the inner alveolar bone proper
May be high due to constant adaptation to tooth movements
Because of its higher rate of remodeling, inner alveolar bone proper primarily consits of ______ bonne but _______ is also present
1. Woven bone
2. Lamellar bone
Describe the texture of the surface of inner alveolar bone proper as it changes with age
Smooth surface in young individuals, but becomes rougher with age
Describe the outer alveolar bone proper
-Continuous with supporting alveolar bone
What are the 3 main parts of supporting alveolar bone?
1. Cortical plate
2. Alveolar crest
3. Central spongiosa
What are the two parts to the cortical plate?
1. INNER: Lingual and palatal surface
2. OUTER: Labial and buccal surface
Describe the alveolar crest
-Junction of cortical plate and alveolar bone proper
-Thinner in maxilla
-Thickest in premolar and molar region of mandible
What are the 2 components associated with the central spongiosa?
1. Trabecular (spongy/cancellous) bone supporting alveolar bone proper and cortical plate
2. Marrow: red (hemeopoietic) in young, yellow in aged
Spongiosa is more prevalent in the ________ than in the __________
The spongiosa is often absent or diminished in what part of both jaws?
The anterior region
What are the 4 functions of Alveolar bone?
1. Protection and structure of the socket for the tooth to rest in
2. Attachment of sharpey's fibers of the PDL which are embedded in bone
3. Support of tooth roots, especially facial/lingual
4. Distribution of loading from the tooth and PDL to the surrounding bone
The Bone septa is divided into what two parts?
1. Interradicular septum
2. Interalveolar septum
What is the interradicular septum?
Bony septum between roots of a single tooth
What is the interalveolar septum?
Bony septum between adjacent teeth
Periodontal ligament development occurs concamitant with _______ and _______ development
2. Alveolar process
The periodontal ligament develops after ______, and starts of as ________
1. Detachment / fragmentation of HERS
2. Unorganized, fibrillar short connective tissue
What develops from the dental follicle and differentiate into fibroblasts which produce and organize collagen fibers, and are generally oriented in an oblique manner?
Ectomesenchyme cells that form PDL
PDL fiber orientation changes with ______
PDL fibers form from the CEJ in what direction?
The PDL fiber orientation changes with eruption. What is that change based on?
The relative positions of the tooth and alveolar crest
T/F Remodeling of the PDL occurs throughout life
Developing cells of the PDL may also prevent _________, preventing _______
What is the width of the PDL?
Between .15mm to .38mm
*decreases with age
The PDL is composed of what type of cells?
2. Mesenchymal cells
3. Epithelial cells and macrophages
*Osteoblasts, osteoclasts and cementoblasts are also associated with the ligament on the adjacent mineralized surfaces
Primarily the PDL is ________, supported by a ________
1. Collagen fibers
2. Non-collagenous protein matrix
What types of collagen are in the PDL?
Type I, III, XII
Describe the arrangement of Collagen in the PDL
Arranged in fibers, which in turn are grouped into bundles
*Individual fibers can be remodeled while the overall bundle is not changed, making a very dynamic environment
The main elastic fiber of the PDL is _______
*NOT mature elastin
Oxytalan is distributed extensively throughout the _____ and are largely associated with _______
Describe the orientation of Elastic fibers in the PDL
Fibers run vertically from cementum to the tooth apex, terminating in the neurovascular complex
T/F Elastic fibers (Oxytalan) Possible regulate vascular responses of the PDL
*Stretching these fibers increases exfiltration into the PDL
Describe the ground substance of the PDL
-Similar to other connective tissues
-Increased hydrostatic pressure, possibly means greater ability to absorb loads
T/F the PDL is well vascularized
What supplies the PDL with blood?
Superio/inferior alveolar arteries
In the vasculature of the PDL, arterioles penetrate the ________
*called penetrating arteries
Where do you typically see more Penetrating arterioles?
Posterior teeth have more of them generally and they are more prevalent in the mandible as opposed to the maxilla
In the vasculature of the PDL, arteries occupy loose connective tissue 'bays' in the PDL, called ______
*Tucked into the principle fiber bundles
What is the arrangement of blood vessels in the PDL critical for?
How do nerves arrive to innervate the PDL?
Both apically and through the cribiform plate
Nerves innervating the PDL run _______
Axially in relation to the tooth
Generally the concentration of nerve endings is greatest in the _______. With the exception of ________
1. Tooth apex
2. Upper Incisors
*Greater nerve density, especially in the coronal, labial part of PDL
T/F PDL has sympathetic innervation of the vasculature
What are the 4 types of nerve endings of PDL innervation?
1. Free nerve endings
2. Ruffini's Corpuscles
3. Coiled nerve endings
4. Spindle nerve endings
Describe the Free nerve endings of PDL innervation
-Nociceptive and mechanoreceptive
-These reach the cementum and each innervates a region of the root
-Some are associated with schwann cells
Describe the Ruffini's corpuscles in PDL innervation
-Bulbous dendritic endings
-Associated with schwann cells, and are associated with collagen fibers
-Slow adapting mechanoreceptive fibers
-Can be simple or compound
Describe Coiled nerve endings in PDL innervation
-Around mid-region of the PDL
Descdribe Spindle nerve endings in PDL innervation
-Surrounded by a fibrous capsule
-Found apically and are relatively rare
Name the 5 main histological groups of PDL fibers
1. Alveolar Crest group
2. Horizontal group
3. Oblique group
4. Apical group
5. Interradicular group
*based on orientation
Describe the alveolar crest group
Attach just at the CEJ and run 'outward' to attach into the alveolar socket rim
Describe the horizontal group
Run from cementum at a right angle to the tooth into the alveolar socket
Describe the Oblique group
-Run at an oblique angle from the cementum most of the way down the root
Describe the apical group
From the root apex to the underlying tissue
Describe the interradicular group
Only on multi-root teeth, they attach to the interradicular septum
The 5 types of PDL fibers terminate in _________ or ________ and are attached to these structures via ________ which are embedded in ______
2. Alveolar Bone
3. Sharpey's fibers
4. Collagen fibers
T/F The gingival ligament is part of the PDL proper
*But they are intamitely associated with the periodontium
T/F Gingival ligament is composed of collagen fibers which pass through oral lamina propria
What does the gingival ligament do for the teeth?
Gives the tooth a connection to surrounding soft tissues and neighboring teeth (attachment of gingival margin)
Name the 5 main bundles that make up the gingival ligament
1. Dentogingival group
2. Alveologingival group
3. Circular group
4. Dentoperiosteal group
5. Transseptal Fibers
Describe the dentogingival group
-Run from cervical cementum to lamina propria of the free attached gingivae
Describe the alveologingival group
-Run from the alveolar crest (bone) to the lamina propria of free/attached gingivae
Describe the Circular group
-Circular band around the neck of the tooth
-Attaches to other fibers and the free gingiva
Describe the dentoperiosteal group
-Run apically from cementum to the periosteum of the outer cortical plate