Periodontium Flashcards
What is the periodontium and what are its functions
Tissues surrounding and supporting the teeth
Retains tooth in socket
Resists masticatory loads
Defensive barrier, protecting tissues against threats from the oral environment
What is the junctional epithelium
The physical barrier separating the body tissues from the oral environment
What are the different periodontal tissues
Cementum
Gingiva
Alveolar bone
PDL
Describe cementum
Covers root dentine Very similar in structure to bone Provides attachment for some periodontal fibres Two types - cellular and acellular Laid down by cementocytes
Describe acellular cementum
No cells within
Usually adjacent to dentine
First formed (primary cementum)
Describe cellular cementum
Contains cementocytes
Later formed (secondary cementum)
Found in apical part of root and in furcation regions
What is the function of alveolar bone
Supports the teeth
Provides attachment for PDL fibres (Sharpey’s fibres)
What is the alternative classification of cementum
Acellular extrinsic fibre cementum
Cellular intrinsic fibre cementum
Describe acellular extrinsic fibre cementum
Contains collagen fibres from PDL (Sharpey’s fibres)
Present on cervical 2/3 of roots
Anchors periodontal fibres
Describe cellular intrinsic fibre cementum
No Sharpey’s fibres
Intrinsic collagen fibres parallel to the surface
No role in tooth attachment
May represent a transitional form
What is periodontal ligament
A connective tissue containing cells, ECM, fibres, nerves and blood vessels
What is the function of periodontal ligament
Attaches tooth to jaw
Transmits biting forces to alveolar bone
What cells are found in the PDL
Fibroblasts Cementoblasts Osteoclasts and cementoclasts Epithelial cells - cells rests of Malassez Defence cells
Which nerves are found in the PDL
Sensory: Mechanoreceptors - Ab and As fibres Proprioception for chewing control Nociceptors - As and C fibres for protective reflexes Autonomic (sympathetic): Blood vessel control - vasoconstriction
What is the periodontium blood supply
PDL and alveolar bone from the inferior and superior alveolar arteries
Gingivae from the lingual and palatine arteries
What are the different types of periodontal fibres
True periodontal ligament
Gingival ligament
Collagen - types I and III
Oxytalan fibres
What is true periodontal ligament
Fibres connecting tooth to bone at or apical to the alveolar crest
What are gingival ligament
Fibres mainly above the alveolar crest including free gingival fibres
What is the function of collagen fibres in the PDL
Supports teeth for load bearing
What are the different PDL principal fibre groups and which types of fibres are found in each
Alveolo-dental ligament: Alveolar crest Horizontal Oblique Apical Interradicular - multi-rooted teeth Interdental ligament: Transseptal fibres
What are the different types of gingival fibres
Dento-gingival
Alveoli-gingival
Dento-periosteal
Circular
What is the interdental col
Depression in the gingiva that connects a facial and lingual papilla
