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Flashcards in periodontal tissues (OB2) Deck (23):

tooth support tissues

-periodontium (peri -around in latin, odous = tooth in greek)
->comprises periodontal ligament, alveolar bone, gingiva (gum) including junctional epithelium
-cementum (some include as part of the periodontium)


components of periodontium

-periodontal ligament
-alveolar bone
-gingiva (gum) including junctional epithelium


periodontal ligament (PDL)

-ligament that attaches around the tooth and attaches tooth to bone/soft tissue
->dense fibrous connective tissue
->occupies periodontal space between tooth and alveolar bone (~0.2mm wide)
->fibres (principally collagen/strong structural protein, collagen fibres run OBLIQUELY in PDL)
->ground substance
->nerves (stimulated by abscess
->blood vessels
-PDL = complicated structure in very small space


functions of PDL (periodontal ligament)

-occupies space between tooth and bone
-attachment = tooth-bone
->suspensory system
->shock absorber
->to withstand masticatory/chewing forces (500-700N... 1,500N)
->highly innervated
->sesnitive to mechanical touch
->stimuli of nerves = sensation and pain


alveolar bone

-surrounds tooth/ bone that tooth sits in
-rest of jaw bone = basal bone
-alveolus = 'sac'/ 'little cavity'/bony socket that the tooth sits in
->if tooth is extracted, alveolar bone disappears over time due to reshaping (this creates problems for dentures as the denture sits on top of basal bone therefore implants hold the dentures in place as the alveolar bone has disappeared)


different zones of jaw bone

-trabecular bone = spongy/cancellous bone, basal bone = trabecular bone
-cortical bone (dense outer surface of bone that forms a protective layer around the internal cavity), alveolar bone = cortical bone (very dense, thin and porous/full of holes)
-lamina dura (bone of tooth socket, bundle bone, cribiform plate, bundles of fibres into ligament, full of holes/is porous, looks dense in x-ray)


inner layer of jaw bone

trabecular bone


outer layer of jaw bone

cortical bone


bone of tooth socket

lamina dura


methods of applying local anaesthesia

-to upper incisors: pass needle through mucousa until it touches the surface of the cortical bone (outer part of jaw bone) and diffuses through holes as cortical bone is very porous (into lining mucosa)
-to lower molars: intraligamentary anaesthesia, injected into the periodontal ligament (putting needle between tooth and bone into ligament, anaesthesia flows out of holes)
->into lining mucosa (flexible therefore can be pain free if done properly in some areas)
->into a masticatory mucosa (tightly bound down therefore painful!)


gingiva (gum)

-tissue around tooth covering bone
-a type of oral mucosa (masticatory mucosa)


function of oral mucosa

-protection (lines the mouth):
->mechanical protection (eg. protection from sharp foods)
->bacterial protection
->chemical protection (eg. against acids)
->acts as a barrier to protect against dehydration
-sensation (richly innervated/filled with nerves)
-secretion (contains salivary glands and prevents dry mouth)
-thermal regulation (important in dogs - panting)


2 tissues that make up oral mucosa

-epithelium (barrier on outside, which attaches to tooth)
-connective tissue (lamina propria, underneath epithelium)


3 types of oral mucosa

-masticatory mucosa (chewing)
-lining mucosa (flexible, is thinner therefore is more flexible)
-specialised mucosa (contains gustatory mucosa which contains receptors for the sensation of taste)


areas of masticatory mucosa

-in areas where mucosa is exposed to areas of mechanical damage
->exists around teeth and onto hard palate
->very unflexible/tough


areas of lining mucosa

-is thinner than masticatory mucosa therefore is more flexible
-present where you want flexibility (inside of lips, underneath the tongue, valves)


areas of gustatory mucosa

-gustatory mucosa contains receptors for the sensation of taste
-present at the back of the tongue/dorsal of tongue


oral mucosa of the periodontium (around the teeth)

-gingival mucosa = masticatory mucosa (relatively thick epithelium, keratinised/tough, pink, firm, stippled)
-alveolar mucosa = lining mucosa (relatively thin epithelium, non-keratinised, red, loose/mobile, smooth)


why is alveolar mucosa darker than gingival mucosa

-gingival mucosa is keratinised, alveolar mucosa is non-keratinised


mucogingival junction

junction between oral mucosa of the periodontium (between alveolar mucosa and gingival mucosa)


types of gingival mucosa

-free gingiva (directly around tooth/enamal)
-attached gingiva (between free gingivi and mucogingival junction), attached to alveolar bone
-free gingival groove (between free and attached gingiva)


dento-gingival junction

-junction between tooth and gingiva (junctional epithelium which can leak)
->gingival sulcus = between enamel and gingiva, space where bacteria can lie/glucose from food can get trapped



part of tooth involved in tooth support