Periodontal Tissues Flashcards
What does periodontium mean? What does periodontal tissues mean?
Peri = around/periphery Dontium = tooth Periodontal Tissues: tissues around the tooth
What are the components of periodontal tissue?
Periodontal tissue comprises
- Peiordontal ligament (PDL) – collagen-containing soft tissue between tooth and bone which attaches tooth to bone, acts like a shock absorber
- Alveolar bone – bone that surrounds the tooth
- Gingiva
Label the diagram
What is the PDL made of?
Where does it sit?
How thick is it?
PDL is made of dense fibrous (collagen based) connective tissue
It occupies periodontal space between tooth and alveolar bone
It is about 0.2mm thick
What does the PDL contain?
PDL contains:
- Cells: mostly fibroblasts (cells that produce collagen and other fibers)
- Fibers: mostly collagen fibers
- Ground substance: gel
- Water
- Nerves: sensory role - receptors that tell us how much force we’re applying and modulates the force we apply
- Blood vessels
What kind of ligament is the PDL called?
What are its functions?
PDL called a suspensory ligament:
- collagen fibers obliquely arranged to support the tooth root within the alveolar bone
- The arrangements are very complicated
Functions:
- Attachment of tooth to bone
-
Support
- Suspensory system collagen ligament arrangement supports the tooth
- Shock absorber – can absorb huge force of 1500N
- Sensory: heavily innervated
What does alveolus mean?
(alveolar bone)
Alveolus = little cavity, or sac
Label the different kinds of bone orally and generally
Orally: alveolar bone and basal bone
Generally: cortical bone and trabecular/spongy/cancellous bone
What is a problem with alveolar bone?
How is this problem overcome?
When tooth is extracted, alveolar bone resorbs, leaving only basal bone
Creates problems when bone resorbs around dentures:
- nothing much to hold it in place – wobbly dentures
We want to try and preserve alveolar bone, which will disappear if we take teeth out
So we take the crown off and leave the root in place to preseve alveolar bone
What kind of bone is the mandible/maxilla made of?
Bulk of mandible/maxilla is basal bone: gives the arch/jaw shape
Alveolar bone is only the bit that supports the tooth
Label the diagram
What are the characteristics of the different bone types and what implications does this have for clinical practice?
Layers of the alveolar bone
- Outer layer: cortical bone
- Thin
- Porous
- Inner bone: trabecular bone
- Spongy
This governs how we anesthetise – close to the cortical bone so anesthesia can diffuse through
What is the name of the socket when the tooth is extracted?
Why is it so called?
What kind of bone is it?
What are clinical implications and the name of the procedure?
The lining of the socket if we take the tooth out = lamina dura
The term lamina dura comes from radiographs – looks whiter/denser in radiographs. But in real life it is quite porous
Cortical bone
- Thin layer of bone
- Porous
- Better described as a cribiform plate (sieve)
Again, this helps with anesthesia. We shove needles down PDL space – intraligamentary anesthesia. Anesthesia travels out of the porosity of the lamina dura
What is mucosa?
Give an example of oral mucosa
Mucosa is the membrane that lines the cavities of the body and the surface of internal organs
An example of oral mucosa is gingiva
What are the layers of tissue oral mucosa is composed of?
Mucosa in the oral cavity comprises of 2 layers of tissue:
- epithelium and
- underlying lamina propria (connective tissue)
What are the types of oral mucosa?
Give examples of each
3 types of oral mucosa:
- Masticatory mucosa (quite tough) e.g. gingival mucosa
- Lining mucosa (flexible and soft) e.g. alveolar mucosa
- Specialized mucosa for taste (particularly on tongue): gustatory mucosa
What are the mucosa types in the periodontium?
Describe the characteristics of each
Oral mucosa of the periodontium comprises gingival mucosa (masticatory mucosa) and alveolar mucosa (lining mucosa)
Gingival mucosa (masticatory mucosa)
- Keratinized
- Thick epithelium
- Firm (attached tightly to the bone)
- Pink
- Stippled
Alveolar mucosa (lining mucosa)
- Non-keratinised
- Thin epithelium
- Loose/mobile
- Red
- Non-stippled
What is the area called where the gingival and alveolar mucosa meet?
The area where gingival and alveolar mucosa meet is called mucogingival junction
Describe the types of gingiva present in the mouth (masticatory mucosa) and the area where they meet
- A little bit of gingiva directly around tooth not attached to the bone: called free gingiva
- Gingival sulcus: groove around the tooth formed by the free gingiva
- Above free gingiva (and below alveolar mucosa), the majority of the gingiva is tightly attached to bone: attached gingiva
- Where the free gingva and attached gingiva meet, there is a depression: free gingival groove
Label the diagram
What is the area called where the gingiva meets the teeth?
Name the kind of epithelium and describe its characteristics
Dentogingival junction:
Junctional epithelium – epithelium at the base of the gingival sulcus
- Porous, weak epithelium allowing for bacteria entry and growth
Label the diagram
Label the diagram
List the functions of oral mucosa
Function of oral mucosa:
- Protection
- Mechanical
- Bacterial
- Chemical (acidity)
- Sensation
- Highly innervated
- Sense of taste/texture is our last check before food goes down the hatch
- Secretion
- Salivary glands
- Prevents tissue underneath from being dehydrated
- Thermal regulation
Describe the distribution of the different types of oral mucosa in the mouth
Mucosa distribution
- Masticatory mucosa: on gingivae around teeth and hard palate
- Lining mucosa: inside of lips, underside of tongue, floor of mouth, soft palate behind hard palate, cheeks,
- Gustatory mucosa: dorsum of tongue
