Anatomical Characteristics of the Periodontium
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This handout is provided by the CLR.
Periodontium consists of the gingiva, PDL, cementum and alveolar bone
The attachment apparatus consists of the PDL, cementum, alveolar and
supporting bone
Three types of oral mucosa: 1. Masticatory
2. Lining
3. Specialized
Masticatory mucosa is divided into the free, attached and IDP gingiva/col
o The outer surface is stratified squamous epithelium
 Flattened epithelial cells on a basement membrane
 Layers adhere to one another, bottom layer adheres to
basement membrane for structural integrity
o Well suited for abrasion
Free gingiva is separated from attached gingiva by the free gingival
groove
The mucogingival junction seperates the alveolar mucosa and the
attached gingiva
Papillae can be tall or blunter and are pyramidal in shape in the anterior,
well more broad in the posterior
Nonkeratinized tissue in the interproximal space is the col
Location and size of the papillae is dependant on the shape, contour,
location, position and contact points of the teeth
Oral epithelium is the outer epithelium
o Function is to protect teeth
o Typically keratinized
o Parakeratinized stratified squamous epithelium
o Rete pegs (epithelial ridges) are extensions into the underlying
connective tissue
o Connective tissue projections (papillae) are connective tissue
projections into the epithelium
Kertatinized tissue has no nucleus in the top layer
Parakeratinized has nuclei in the top layer
Nonkeratinized has no keratin
Sulcular epithelium is an extension of the oral epithelium
o Usually nonkeratinized or parakeratinized
o Extends from gingival margin to the JE
Junctional epithelium is permeable
o Downgrowth of squamous epithelium of the gingiva
o Attached to enamel by epithelial attachment
 Basal lamina and hemidesmosomes
 Hemidesmosomes=JE to tooth
 Desmosomes=tight cell to cell junctions
o Nonkeratinized stratified squamous epithelium
o Functional unit that involves the attachment of the gingiva to the
tooth surface (dentogingival unit)
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This handout is provided by the CLR.
Dentogingival unit= epithelial attachment of the JE and the
gingival connective tissue attachment
 Length of the dentogival unit= biologic width
 2.04 mm
 if invaded=chronic inflammation
 must measure before putting on crown
Alveolar mucosa is compressible, and movable
o Has a submucosa between the lamina propria and the underlying
tissue
o Nonkeratinized
o No epithelial ridges are present
o Darker red than the gingiva
Lamina propria is the connective tissue beneath the gingiva
o Papillary layer
 Appears stippled due to rete pegs and connective tissue
projections
 Layer immediately beneath the epithelium
o Reticular layer
 Connective tissue composed of collagen
 Collagen fibers bundles known as gingival ligament
 Main cells are fibrobalsts
 Outside of alveolar bone
 Contains nerve and blood supply
Gingival fiber groups
o Principal
 Dentogingival- cementum into free and attached gingiva
 Alveologingival-periosteum into attached gingiva
 Dentoperiosteal- cementum to alveolar crest
 Circular-encircle entire tooth coronal to alveolar crest
 Transseptal- span the interdental space
PDL Fiber Groups
o Alveolar crest- cementum and insert into crest
o Horizontal- form cementum and inserts at right angles into bone
o Oblique- slant towards the apex of the tooth, apical to horizontal
fibers in mid-third of tooth
o Apical- originate at cementum on the apex and insert into bone
o Interradicular- from crest of interradicular septum into cementum in
the furcation area
Abnormalities in the PDL consist of rests of Malassez and cementicles
Sharpeys fibers attach the fiber bundles of the PDL to the tooth surface
(cementum), brush like fibers
Cementum anchors the teeth, maintains occlusal relationships and is a
seal for the dentinal tubules (contain nerves)
Alveolar process is the extension of bone form the body of mandible and
maxilla
o Periosteum= connective tissue that covers the outer surface of the
alveolar process
 Has blood vessels and nerves that enter bone
o Two parts: alveolar bone proper and supporting bone
 Bone proper=cribiform plate
 Compact bone with perforations to permit passages
from bone to PDL that line the tooth socket
 Directly lines tooth socket
 Supporting bone
 Made of compact bone that makes facial and lingual
cortical plates
 Made of cancellous bone that surrounds the alveoli
between the alveolar bone proper
o Marrow and blood supply
o Lamina dura= walks of the tooth socket as viewed in a radiograph
(3mm apical to the CEJ)
o Alveoli=tooth sockets
 Bone lining sockets contain sharpeys fibers
 Terminal ends of principle PDL
 Bone where these terminate=bundle bone
o Dehiscence= resorbed area of bone on facial surface of a root
o Fenestration= opening or window in bone covering the facial
surface of a root
o Buttressing bone=at margin of bone where it thickens in response
to increased functional demand (repair process including bone
resorption and deposition
Color
Size
Shape
Health
Light pink, coral
Normal, not enlarged
Scalloped, knife-edge
Unhealthy
Red or bluish-red
Enlarged or swollen
Rolled, rounded, bulbous
Texture
Consistency
Stippled, matte
Firm, resilient
Rounded, shiny
Spongy, edematous, boggy
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This handout is provided by the CLR.
Color of the gingiva depends on the amount of vascularity, keratinization,
thickness, melanocytes, amount of saliva
Blood supply to the gingiva is primarily through the vessels of the
periosteum, PDL and alveolar bone
Lymphatic drainage is primarily through the submandibular nodes
Nerve supply comes form the trigeminal (5th cranial nerve)
o Maxilla= maxillary nerve
 ASA, MSA and PSA- incisors and canines, premolars and
molars
 GP- palatal gingiva
o Mandible= mandibular nerve
 Inferior alveolar nerve- facial gingiva
 Mental/mandibular nerve- innervates incisors, canines and
premolars
 Gingival branches of the buccal nerve- buccal mucosa and
molars
 Lingual nerve- lingual gingiva and the tongue
This handout is provided by the CLR.