9 Periodontium Flashcards
T/F: Primary cementum contains cells.
False. As primary cementum is secreted, the cementoblasts retreat toward the location of the future PDL. They are out of the way when mineralization of the cementum occurs.
T/F: Primary cementum is deposited as the tooth is erupting into the mouth.
True. Primary cementum is the first-deposited. It is initiated soon after that root dentin begins to be laid down and occurs simultaneously with the elongation of the root and eruption into the oral cavity (ie simultaneous with the pre-functional stage of eruption).
Identify location where primary cementum is most abundant.
Top: No, this is enamel.
Middle: Yes, primary cementum is more abundant in the cervical part of the tooth, reflecting the fact that it’s laid down first, and that cementogenesis proceeds from the CEJ to the root apex.
Bottom: No, this is the lcoation where secondary cementum is most abundant. Cementogenesis proceeds from the CEJ to the root apex, and primary cementum is secreted before secondary cementum.
Explain the mechanism responsible for the development of a secure attachment between dentin and cementum.
The initial organic matrix of cementum is composed of collagen fibers which intermingle with the adjacent unmineralized dentin amtrix prior to the mineralization of both these tissues.
Identify tissues.
L: acellular cementum
R: dentin/root
Identify tissues.
L: aceullar cementum
M: Tomes’ granular layer = hypomineralized regions in mantle dentin of the root
R: dentin, tubules organized at right angles to CEJ
Identify tissues.
L: Cellular cementum, dark areas are trapped cells called cementocytes, much thicker than previous acellular cementum
R: dentin
Identify.
Sharpey’s fibers.
Identify. Name an analogous structure in the dental pulp.
Cementicle. Pulp stones
Identify.
Alveolar crest.
Identify.
Red: horizontal
Blue: alveolar crest
Identify.
Both are oblique.
Identify.
Interradicular
Which represents cancellous/trabecular bone and which represents the cortical plate?
Orange: cancellous/trabecular
Blue: cortical platecomprised of lamellar and compact haversion system bone
Identify alveolar crest bundles.
Top: alveolar crest fiber bundles
Bottom: oblique fiber bundle
Identify.
- gingiva 2. PDL 3. alveolar bone 4. cementum
Identify
Both are periodontal ligament.
Identify.
- Periodontal ligament 2. Lamina dura 3. Cementum
Identify.
- Periodontal ligament (radiolucent)
- Lamina dura (opaque)
Identify.
- cementum
- periodtondal ligament
- alveolar bone
Identify.
- cementum
- periodontal ligament
- lamina dura
- trabecular bone
- bone marrow
Identify.
- cementum
- principal fiber bundles of PDL
- interstial space (site of larger vessels and nerves)
- alveolar bone
Identify.
- alveolar crest
- horizontal
- oblque
- apical
- interradicular
Most numerous cell type of PDL.
Fibroblast.
Identify.
A: cementicle
B: epithelial rest of Malassez
Identify the most numerous cell type of the periodontal ligament.
fibroblast
Label.
- lamina propria
- acellular cementum
- alveolar bone proper
- interstitial space
Identify.
- Acellular cementum
- cementoblast
- epithelial rest of Malassez
- fibroblast
Identify PDL.
Left.
Which of the following peridontium sites are vascularized?
A. cementum
B. periodontal ligament
C. cribriform plate
D. lamina propria of gingiva
- *B.** It is highly vascular. Larger vessels are located within clear areas called “interstitial spaces.”
- *C.** Vascualr canals are scattered throguhout the cribriform plate (socket wall). The main blood supply to the PDL come by way of these canals.
- *D.** This area is highly vascular.
The osteoclasts found in the PDL, like elsewhere in the body, arise from which of the following sites?
A. Haversian canal
B. periosteum
C. endosteum
D. bone marrow
D. This is where stem cells become osteoclasts and from where they are distributed throughout the body.
Label.
- acellular cementum
- PDL
- alveolar bone
- bone marrow
Which of the following rangse of numbers is the width of the PDL?
A .50 - 1.00 mm
B .20 - .30 mm
C .12 - .33 mm
C
Which of the following terms is used for the ends of the principal fiber bundles embedded in cementum and alveolar bone?
A. Tomes’ fiber
B. Hertwig’s fiber
C. Sharpey’s fiber
D. Korff’s fiber
C; he described them as “fibers that join together the lamellae of bone.” The fibers are not confined to the alveolar process. They exist where ends of tendons or ligaments are embedded in bone.
T/F: Sharpey’s fibers are located in cellular or secondary cementum, but do not exist in aceullar or primary cementum.
False, they are found in both types of cementum.
Which collagen types comprise the principal bundles of the periodontal ligament?
Type I: it’s the most abundant type of collagen; also found in bone, cementum, dentin, and bundle groups of the free ginigiva; provides tensile strength to tissues.
The PDL and pulp tissues have which of the following similar structures?
A. collagen fibrils
B. tissue fluid
C. abundant nerve and blood vessel networks
D. proprioceptive sense
A, B, C in both.
D Proprioceptive sense is found only in PDL’s nerve supply (not pulp).
Which of the following are function sof the PDL?
A. supportive
B. sensory
C. nutritive
D. formative E. resorptive
ALL!
A. Suspenses and supports the tooth by way of its collagen fiber bundles.
B. Abundant nerve supply.
C. Served by vast blood supply.
D. 3 blast cells (fibroblast, cementoblast, and osteoblast)
E. Carried out by osteoclast and odontoclast.
Identify cementicle.
Top: epithelial rest of Malassez (remnants of epithelial cells involved in tooth development). Bottom: Yes, ectopic mineralization in PDL.
Identify osteoclast.
Top: osteoclast
Bottom: epithelial rest of Malassez
Label.
- Fibroblast
- Sharpey’s fibers
- Cementoblast
D. Cementocyte
Label.
- Cementoblast
- Osteoblast
- Cementocyte
The formative function of the PDL is carried-out by which of the following cells?
A. Cemtoblast
B. Macrophage
C. Fibroblast
D. Osteoblast
A. Yes, formed cementum.
B. No, defense cell.
C. Yes, forms ligament’s extracellular substance.
D. Forms alveolar bone.