Periodontal Tissues in Health

Question 1

What is periodontium

Answer 1

The supporting apparatus of the tooth consisting of; alveolar bone, periodontal ligament, cementum and gingiva

Question 2

Anatomy of gingiva

Answer 2

alveolar mucosa 
muco-ginigval junction
attached gingiva
free gingival groove 
free gingiva 
gingival margin

Question 3

Gingival clinical appearance in health

Answer 3

pink, stippled, knife edge margin, scalloped profile

Question 4

Gingival function

Answer 4

Attachment of oral mucous membranes to dentinal hard tissue (alveolar mucosa to teeth) and protects underlying periodontal tissues from invasion of bacteria present in oral cavity

Question 5

Describe junctional epithelium

Answer 5

Attaches gingiva to enamel tooth surface by hemidesmosomes and internal basal lamina, terminating apically at cemento-enamel junction in health
High turnover of cells
Permeable epithelium
Stratified epithelium with cells running with long axis parallel to enamel surface

Question 6

Describe sulcular epithelium

Answer 6

lines gingival crevice, not attached to tooth surface
SSNK
0.5-2mm deep

Question 7

Describe oral gingival epithelium

Answer 7

SSK
masticatory mucosa
rete pegs interdigitating with dermal papilla of underlying connective tissue

Question 8

Describe gingival connective tissue

Answer 8

composed of collagen fibres embedded in extracellular matrix; GAGs bind large amounts of water and therefore resist compressive forces; fibroblasts, nerve cells, blood vessels are all present

Question 9

Fibroblasts

Answer 9

Major cell type in periodontal connective tissues – both in gingiva and periodontal ligament

Secrete all components of the extracellular matrix including collagen fibres

Are responsible for degradation of the matrix through secretion of MMPs

Question 10

Sharpey fibres

Answer 10

The ends of the periodontal ligament fibres which are embedded in alveolar bone and cementum

Question 11

Alveolar bone proper

Answer 11

Thin lamella of bone surrounding the root of the tooth and provides attachment for sharpeys fibres; sometimes called bundle bone and appears as lamina dura on radiograph (thin white line) and is perforated due to ingress of vessels/nerves

Question 12

Cancellous bone

Answer 12

surrounds the alveolar bone proper and provides support for the socket; spongey bone consisting of widely spaced concentric or transverse lamella enclosing the marrow spaces

Question 13

Cortical plates

Answer 13

facial and lingual plates made up of compact bone

Question 14

Cells responsible for bone deposition

Answer 14

osteoblasts/osteoprogenitor cells

Question 15

Cells responsible for bone resorption

Answer 15

osteoclasts; multi-nucleated cells residing in how ships lacunae

Question 16

Cementum

Answer 16

Calcified mesenchymal tissue that covers entire root surface
It is avascular and not innervated
Formed slowly throughout life
Thicker at root apices
Resistant to resorption

Question 17

Acellular cementum

Answer 17

forms a thin surface layer which is often confined to cervical portions of the root. It doesn’t contain cementocytes but does have cementoblasts present on its surface.

Question 18

Cellular cementum

Answer 18

contains cementocytes in lacunae which communicate through canaliculi

Question 19

Hypercementosis

Answer 19

excessive deposition of non-neoplastic cementum over normal root cementum, which alters root morphology. This cementum may be either hypocellular or cellular in nature