Lecture 2 Flashcards
Healthy Periodontium
histology
the study of the microscopic structures of tissue
taking a closer look at the microscopic anatomy of the periodontium will give us a better understanding of
how the periodontium functions in health
changes that occur to the periodontium during the disease process
microscopic anatomy of a tissue
cells: smallest structural unit of living matter
tissue: group of interconnected cells
4 types: epithelial, connective, muscle, nerve
tissues of the periodontium
gingiva
periodontal ligament
cementum
alveolar bone
extracellular matrix consists of
ground substance: gel-like substance surrounding tissue cells, nerves, blood vessels
fibers: collagen, elastin and reticular fibers
the extracellular matrix provides
a framework giving connective tissue its strength to withstand mechanical forces
the gingiva in health
stippled/attached gingiva tightly anchored to teeth and underlying bone
the gingiva consists of both
epithelial tissue
connective tissue
epithelial tissue
outer surface of skin
lines body cavities such as mouth, stomach, intestines
does not contain blood vessels
what is made of stratified squamous epithelium
skin and oral mucosa
stratified squamous epithelium is made of what cells
flat cells arranged in several layers
gingival epithelium consists of
oral epithelium
sulcular epithelium
junctional epithelium
oral epithelium
outer gingival epithelium
covers free and attached gingiva
gingival margin to MGJ
only part of the periodontium clinically visible
protective function so typically keratinized/parakeratinized
joins CT in a wavy interface via rete pegs
sulcular epithelium
faces the tooth surface without contact
lines gingival sulcus (1-3mm)
gingival margin to the coronal edge of JE
thin (3 layers), non-keratinized (softer more flexible)
in health: smooth interface with CT
permeable to bacterial products and gingival crevicular fluid from CT
junctional epithelium
forms base of sulcus and attaches the gingiva to the tooth surface
in health slightly coronal to CEJ
non-keratinized stratified squamous epithelium
smooth interface with CT in health
barrier between biofilm and CT
basal lamina
thin layer of extracellular matrix providing attachment of epithelial cells to adjacent structures
OE to connective tissue
SE to CT
JE to CT and tooth surface: internal basal lamina (tooth), external basal lamina (CT)
gingival connective tissue
more extracellular matrix with less cells
cells include: fibroblasts, mast, immune cells (macrophages, neutrophils, lymphocytes)
blood vessels and nerve supply
mostly collagen fibers (60%) produced by fibroblasts
gingival connective tissue fibers
classification based on their orientations, insertion points, connecting structures
circular: encircle tooth
dentogingival: cementum into gingiva
dentoperiosteal: cementum into periosteum
alveologingival: periosteum into gingiva
transeptal: IP between adjacent teeth
the attachment apparatus
periodontal ligament
cementum
alveolar process
functions of the PDL
supportive: anchors tooth in socket
sensory: nerve fibers transmit tactile, pressure and pain sensations
transports nutrients
tissue development and maintenance
periodontal ligament
rich nerve and blood supply
thin sheet of fibrous connective tissue
components of the PDL
cellular element: fibroblasts, osteoblasts/osteoclasts, cementoblasts/cementoclasts
extracellular matrix: collagenous fibers: largest component of the PDL
sharpey fibers
terminal portions of the principal fibers embedded in cementum and bone
cementum
mineralized layer of connective tissue
no blood or nerve supply
components of cementum
cells (cementoblasts/fibroblasts)
extracellular ground substance (collagen fibers, mineralized portion)
calcium + phosphate (hydroxyapatite crystals)
types of cementum
acellular (primary): forms before tooth eruption, coronal + middle 1/3 of root, no production during life of tooth, no living cells)
cellular (secondary): apical 1/3 of root + furcations, less calcified, contains cementoblasts/fibroblasts, deposited throughout life of tooth and increase in thickness with age
alveolar process is composed of
mineralized connective tissue
external cortical plates
alveolar bone proper: inner socket wall
cancellous/trabecular/bone
alveolar process functions
protection: for the roots of teeth
remodels: in response to mechanical forces or inflammation
components of the alveolar process
cells: osteoblasts (synthesize), osteoclasts (resorb)
extracellular matrix: collagen fibers, gel matrix (rigid B/C of hydroxyapatite)
has blood vessels and nerve innervation
blood supply to the periodontium how and via what arteries
transport oxygen and nutrients/remove carbon dioxide and waste products
via major alveolar arteries: superior alveolar arteries (max), inferior alveolar arteries (mand)
branch arteries function
supply blood to the teeth and periodontium
branch arteries
intraseptal artery: enters socket
supraperiosteal blood vessels: free gingiva
subepithelial plexus: in CT beneath free and attached gingiva
PDL vessels: PDL
dentogingival plexus: network of blood vessels in CT beneath gingival sulcus
a fine network of vessels supplies blood to
the gingiva, gingival connective tissue and periodontal ligament
the rich blood supply to the gingiva accounts for
the dramatic color changes that are seen in gingivitis
