Peridontium Flashcards
What is the periodontium?
The periodontium is the tissue that surrounds and supports the teeth.
What are the components of the periodontium?
The components include the gingiva, cementum, alveolar process, and periodontal ligament (PDL).
What is the primary function of the periodontium?
Its primary function is to support and surround the teeth.
What is the role of cementum in the periodontium?
Cementum attaches the teeth to the alveolar bone by anchoring the periodontal ligament (PDL).
Where is cementum located?
It forms the outermost layer of the root(s) of the tooth.
Is cementum clinically visible in healthy patients?
No, cementum is not clinically visible in healthy patients.
Where is cementum thickest and thinnest?
It is thickest at the tooth’s apex or apices and in interradicular areas of multirooted teeth, and thinnest at the cementoenamel junction (CEJ).
Does cementum have a nerve supply?
No, cementum does not have a nerve supply.
Is cementum vascular or avascular?
Cementum is avascular.
How does cementum receive its nutrition?
It receives nutrition through the surrounding periodontal ligament (PDL).
Can cementum form throughout the life of the tooth?
Yes, cementum can form throughout the life of the tooth, including after eruption.
What is the composition of mature cementum by weight?
Mature cementum consists of 65% inorganic or mineralized material, 23% organic material, and 12% water.
What crystalline material is found in mature cementum?
The crystalline material is mostly calcium hydroxyapatite.
From where does cementum develop?
Cementum develops from the dental sac.
What initiates the formation of cementum on the root dentin?
Cementum formation begins after the disintegration of Hertwig epithelial root sheath (HERS).
What happens when the dental sac cells contact the root dentin?
The contact induces the undifferentiated cells of the dental sac to become cementoblasts.
What do cementoblasts do during cementum formation?
Cementoblasts disperse to cover the root dentin area and undergo cementogenesis, laying down cementoid.
What are cementocytes, and how are they formed?
Cementocytes are cementoblasts that become entrapped by the cementum they produce.
When is cementoid considered mature cementum?
Cementoid becomes mature cementum when it reaches the full thickness needed and undergoes mineralization.
What are the primary components of cementum?
Cementum is composed of a mineralized fibrous matrix and cementocytes.
What are Sharpey fibers, and where are they located?
Sharpey fibers are collagen fibers from the PDL that are partially inserted into the outer surface of the cementum at a 90º angle and also insert into the alveolar process.
What are the three possible transitional interfaces at the CEJ?
Cementum may overlap enamel (<15%), meet enamel end-to-end (52%), or leave a gap between enamel and cementum, exposing dentin (33%).
What can result from a gap at the CEJ?
A gap can expose dentin, potentially leading to dentinal hypersensitivity.
Can these transitional interfaces vary in an individual’s oral cavity?
Yes, all three patterns can be present within the same individual, and variations can occur even around a single tooth.