Flashcards in Periodontium II Deck (37):
What is cementum made of?
Type I collagen fibers within a mineralized matrix.
Cementum has intrinsic cementoblasts and extrinsic fibroblasts.
The matrix is composed of hydroxyapatite.
How long is cementum deposited?
Does cementum have a blood or nerve supply?
No, neither --> avascular.
This makes grafts challenging.
At the cementoenamel junction (CEJ), does the enamel and cementum meet up perfectly?
No, it only meets perfectly in about 30% of the teeth in the mouth.
About 10% of the teeth have no contact btw enamel and cementum
About 60% of teeth have an overlapping contact of enamel and cementum
What are the two types of cementum?
Primary: created during tooth eruption and normal development.
Secondary: in response to damage post development.
Where are the different locations that cementum is found and named for?
1. Radicular cementum
2. Coronal cementum
What different types of cellular cementum are there?
1. Cellular cementum: at the apical 1/3, so formed later in development. Thick!
2. Acellular cementum: at the cervical 1/3, only fibers, formed at beginning of development. Thin!
Does all cementum have collagen fibrils in its matrix?
No, there are two types of cementum based on this:
What are the 3 classifications for where matrix fibers originate?
1. Extrinsic fiber: collagen is deposited somewhere other than cementum...such as fibroblasts at the PDL
2. Intrinsic fiber: Collagen is deposited directly on the cementum by cementoblasts
3. Mixed fiber
What is the resorption lacunae?
The area of cementum resorption in response to trauma.
A pit or concavity found in bones undergoing resorption, frequently containing osteoclasts. Similar lacunae also may be found in eroding surfaces of cementum.
What are Sharpey's fibers?
Matrix of connective tissue consisting of bundles of strong collagenous fibers connecting periosteum to bone. They are part of the outer fibrous layer of periosteum, entering into the outer circumferential and interstitial lamellae of bone tissue.
These are the principal fibers of the PDL. They connect to both the alveolar bone and the cementum.
When does hypercementosis take place?
From local factors: trauma, inflammation, unopposed teeth, root fracture.
From systemic factors: acromegaly, and pituitary gigantism, Paget disease, Vit A deficiency.
Where is the alveolar process?
The jawbone portion that holds the teeth.
What is the spongey bone called?
The smooth, hard bone = Compact bone.
What is the layer of compact bone that forms and lines the tooth socket?
The alveolar bone proper --> can see it as a white line in the radiograph.
This is where the Sharpey's fibers attach.
AKA "Lamina dura" when viewing it on the radiograph. Can see the bundle bone.
AKA "cribriform plate."
Where is the alveolar crest?
The highest portion of bone.
What is the cancellous bone?
The bone in-between the teeth. Cancellous bone is called trabecular bone because of the holed trabeculae.
Aka "spongy bone".
Osteocytes live in the lacunae and everything is irregularly arranged.
What are the main components of alveolar bone?
1. Inorganic matrix: made of Calcium, and Phosphate, mineral salts
2. Organic matrix: made of collagen and proteins (like osteopontin)
3. Cells such as osteoblasts and osteoclasts
How is the compact bone arranged?
Haversian canals contain blood and lymph. Osteons with osteocytes surround the canal.
These osteons are aligned along the lines of stress and can change as the stress on the bone changes.
Does alveolar bone proper exist without teeth?
Alveolar bone proper is tooth dependent. No tooth = loss of compact bone = less blood supply = bone shrinkage.
Where are the mesenchymal cells located in the bone?
In the periosteal layer.
What arteries supplies blood to the teeth and periodontal tissue?
Superior or inferior alveolar artery
What arteries supply the gingiva?
The supraperiosteal blood vessels:
sublingual, mental, bucca, facial, greater palatine, infraorbital, posterior superior alveolar artery (PSA)
What type of nerve receptors are located in the periodontium?
Nociceptors and mechanoreceptors.
Which ganglion houses the trophic centers for the pain, touch, and pressure nerves?
Semilunar ganglion, via the trigeminal nerve.
Which nerves service the maxilla?
1. Infraorbital nerve: labial of incisors
2. PSA: buccal of the posterior teeth
3. Greater Palatine nerve: palatal gingiva
Which nerves service the mandible?
1. Sublingual nerve: lingual of mandible
2. Mental Nerve: Labial up to the canine teeth
3. Buccal nerve: gingiva at the buccal of the molars
Where is the lymphatic drainage?
1. Mandible anterior: submental nodes
2. Palatal gingiva of the maxillary: deep cervical group
3. Buccal gingiva of the maxilla: submandibular nodes
4. Third molars: jugulo digastric group
What two main bony protuberances are there?
1. Exostosis: facial side
2. Torus: on the palate
What is a fenestration?
A window defect in the bone - can see through to the root of the tooth underneath
What is a dehiscence?
Not the same as a fenestration, but is recession of bone --> "lack of marginal bone"
What differentiates periodontitis from gingivitis?
For periodontitis, the inflammation has progressed from just the gingiva and progressive destruction of the periodontal ligament and alveolar bone occurs.
When the bone is destroyed, there is significant attachment loss.
How deep is a healthy sulcus?
0.69 - 1.8 mm (or 2 - 3 mm as measured by a probe in the clinic)
How deep must the sulcus be to be called a "pocket" and have disease?
What is a furcation?
A little space at the natural bifurcation of the tooth. These are graded I - IV.
II--furcal bone loss, not thru and thru.
III--thru and thru; not clinically visible.
IV--thru and thru visible clinically
When assessing a periodontal pocket, bone loss is classified. What is vertical bone loss and horizontal bone loss?
1. Vertical bone loss: intrabony and involves multiple walls (1, 2, or 3 walls).
2. Horizontal bone loss: Suprabony and is only in one direction, parallel to the occlusal plane.