Anatomy of Periodontium Flashcards
What are the structures making up the periodontium
Gingiva
Cementum
Alveolar bone
Periodontal ligament
Functions of the periodontium
Tooth attachment to bone and support/protection by withstanding occlusal forces
Providing mechano-sensory feedback
To provide nourishment to surrounding structures
Clinical presentation of gums
Coral pink
Stippling (dots/ridges on the gums), if initially have but now dont have the gums are swollen
Attached gingiva pink, can see blood vessels, directly attached to bone
Base of sulcus should be at CEJ, FGM should be above CEJ
Discharge of pus = infection of gum/root canal/vestibule
Filled interdental papilla with no black triangles (but may be due to ortho treatment)
Where is the junctional epithelium?
At the base of the sulcus, just above the border between free gingiva and attached gingiva
What is free gingiva?
Unattached gingiva, from the FGM to base of sulcus
FGM (in healthy pts) is located on enamel surface, 1.5-2mm coronal to CEJ
Lower border of the free gingiva is the gingival sulcus, a shallow groove surrounding an erupted tooth
What is interdental papilla/col?
Not keratinized, periodontitis starts from interdental papillae
Shape is determined by the contact relationships between the teeth, width of proximal surfaces of the teeth and the course of the CEJ
Anterior is pyramidal, molars are more flattened
What is attached gingiva?
Masticatory parakeratinized mucosa
Firm, coral pink
Coronal border may be free gingival groove in 30-40% of adults
Apical border is mucogingival junction, stable throughout life
Stippling seen in 40% of adults
No submucosa, lamina propria directly attached to underlying alveolar bone
Widest bands of KG: incisors, lingual of mandibular molars
Narrowest bands of KG; premolars, lingual of mandibular incisors
Is KG/AG band important?
Not necessary for maintenance of a healthy periodontium, but preferable
Significance of thin vs thick periodontal phenotypes?
Thin has thinner bone and delicate/friable soft tissues. So reacts readily with gingival recession
Thick has thicker bone and dense and fibrotic soft tissues. So relatively resistant to acute trauma and reacts with pocket or intrabony defect formation
Different types of gingival epithelium
Oral epithelium: faces oral cavity
Sulcular epithelium: faces tooth, not in contact
Junctional epithelium: contacts tooth and gingiva
Function of sulcular epithelium
Thin non-keratinized or parakeratinized stratified squamous epithelium that acts as a semi-permeable membrane through which injurious bacterial products pass into the gingiva
Junctional epithelium deets
Non keratinized SS epithelial collar surrounding the teeth and extends from CEJ to bottom of sulcus
Extends for up to 2mm, length depends on stage of eruption, physiological migration with age, response to inflammation
3-4 cell layers thick, increases to 10-20 layers with age
15-30 cells thick at base, tapers to single cell apically
Functions of junction epithelium
Attaches to tooth via hemidesmosomes, acting as a site for signal transduction (for regulation of gene expression, cell proliferation and differentiation)
Barrier with rapid turnover, continually self renewing structure
Gingival crevicular fluid seeps into sulcus from gingival CT through sulcular epithelium, increasing in amount during inflammation to flush bacteria and by products out. Also contains plasma proteins that may improve adhesion of epithelium to tooth, possesses antimicrobial properties and antibody activity to defend gingiva.
What is gingival connective tissue?
AKA lamina propria
Collagen fibers (mainly type 1), fibroblasts, vessels and nerves embedded in an amorphous ground substance (matrix)
Also has fibroblasts, mast cells, macrophages and inflammatory cells (PMN leukocytes, lymphocytes, plasma cells)
Layers of CT
Papillary layer - finger like extensions in the depressions delineated by rete ridges
Reticular layer - located beneath rete ridges, towards bone
