Lecture 1- Anatomy of Periodontium Flashcards
what are the 3 zones of the oral mucosa
- the gingiva and covering of the hard palate - masticatory mucosa
- dorsum of the tongue- specialized mucosa
- oral mucous membrane lining remainder of oral cavity
what makes up the tissues of the periodontium
- gingiva
- cementum
- PDL
- alveolar bone
what does the masticatory mucosa cover
alveolar bone and tooth root coronal to the CEJ
what is masticatory mucosa divided into
marginal gingiva
- attached gingiva
- interdental areas
what is the marginal gingiva
free or unattached, cufflike tissue surrounding the teeth on facial , lingual, and interproximal surfaces
what is the gingival margin
- most coronal portion of the gingiva
- scalloped outline of teeth
what is the gingival sulcus
-space formed by tooth and sulcular epithelium and the coronal end of the JE
what sulcular measurements are WNL of gingival health
2-3mm
where is the free gingival groove
divides free gingiva from attached gingiva
what percentage of patients have free gingival groove
50%
what part of the gingiva does the interdental gingiva belong to
free gingiva
where is the interdental papilla
the interdental space
how is the interdental papilla attached to the tooth
by the JE and CT fibers
what is the gingival col
valley like depression of the interproximal contact areas
- connects lingual and buccal interdental papilla
when is the gingival col absent
when the teeth are not in contact
what is nonkeratinized epithelium susceptible to
inflammation and disease progression
what is attached gingiva attached to and by what
attached to alveolar bone and cementum by CT fibers and epithelial attachment
what are attached gingiva fibers demarcated by
-apically by the MGJ
- coronally by the base of the gingival sulcus
what is the width of the attached gingiva
varies from 1-9 mm
where is the widest aspect of attached gingiva and narrowest
maxillary central incisors and narrowest in premolar facial areas
how do you measure attached gingiva
subtract width of gingival from periodontal pocket
describe alveolar mucosa
- movable tissue, loosely attached to underlying alveolar bone
- thin, nonkeratinized epithelium
- separate from attached gingiva at the MGJ
- darker shade of red than gingiva due to blood supply
what is the MGJ and where is it found
visible line where the pink keratinized gingiva meets the more vascular alveolar mucosa
- found on maxillary facial and mandibular facial and lingual areas
describe gingiva microscopically
- stratified squamous epithelium and CT
- epithelium is mostly cellular in nature
- CT is less cellular and mostly composed of collagen fibers and ground substance
what is the function of the gingival epithelium
- physical barrier to infection
- protection of deep strucures
- participate actively in responding to infection in signlaing host response
- allows a selective interchange with oral environment
epithelium covering the free gingiva may be differentiated into the following:
- the oral/outer epithelium
- the sulcular epithelium
- the junctional epithelium
describe the sulcular epithelium
lines gingival sulcus, thin, non keratinized
what epithelium changes the most in the presence of bacteria
junctional epithelium
describe junctional epithelium
nonkeratinized epithelium surrounding and attaching to the tooth on one side and the gingival CT on the other side
where is junctional epithelium located
base of the sulcus/pocket
JE is more permeable to_____
cells and fluid
what does JE serve as a route of passage of
fluid and cells from the CT into the sulcus for bacteria/bacterial products from sulcus to CT
JE easily penetrated by ____ especially when _____
periodontal probe; gingiva is inflammed
what is the length of the JE
0.25-1.35mm
describe the color of the gingiva- attached/marginal
- generally coral pink
- produced by vascular supply and thickness/degree of keratinization
- presence of pigment containing cells
- lighter color in blond individuals with fair complexion than in dark complexioned dark haired individuals
describe the color of the alveolar mucosa
red
- smooth
- shiny
- epithelium is thinner and nonkeratinized
- blood vessels are more numerous
what is melanin responsible for
normal pigmentation of the skin, gingiva and remainer of the oral mucous membrane
melanin pigmentation in the oral cavity is prominent in______
black individuals
what does pigmentation in black individuals appear as
diffuse, deep-purplish discoloration or as irregularly shaped brown and light brown patches
size of the gingiva corresponds with:
the number of cellular/intercellular elements and vascular supply
what does the change in size of gingiva indicate
gingival disease
what does the contour of gingiva vary depending on
the shape of the teeth and alignment
what is gingival biotype
thickness of tissue
what is the shape of interdental gingiva governed by
contour of proximal tooth surfaces, location and shape of embrasures
interdental papilla can appear ____ or ____ depending on location
pyramidal; flattened
describe the consistency of gingiva and why
- firm and resilient except the free margin
- collagen fibers determine firmness of attached gingiva
- gingival fibers contribute to firmness of gingival margin
describe the surface texture of gingiva
- attached gingiva is stippled
- marginal gingiva is not stippled
where is stippling less prominent
on lingual than facial surfaces
how is stippling best viewed
drying the tissue
what are the ways to describe the quality of color of gingica
red, bright red, pink, cyanotic
what are the ways to describe the quality of contour
bulbous
- flattened
- punched out
- cratered
what are the ways to describe the quality of consistency
firm
- spongy
what are the ways to describe the quality of surface textrue
smooth
- shiny
- eroded
- stippling
describe cementum
-calcified connective tissue covering the roots of the teeth
what is the least mineralized of the calcified tissues of the tooth
cementum
what are the 2 types of cementum
acellular (primary) and cellular ( secondary) consisting of a caclified interfibrillar matrix and collagen fibrils
what is the function of the cementum
to attach fibers of the PDL to the tooth to seal the tubules of the root dentin
what is in cementum
no blood, lymph vessels of innervation noted
where is cementum deposited and during what stages of life
continuously deposited in the apical area of the root throughout life
describe acellular cementum
- first cementum formed
- covers approximately cervical third or half of the root
- does not contain cells
- formed before the tooth reaches the occlusal plane
describe cellular cementum
- formed after tooth reaches occlusal plane
- less calcified
- deposited throughout life of tooth
- deposited at intervals producing arrest lines
what is hypercementosis and where is it found
local abnormal thickening of parts of the cementum typically found in the apical region
what is hypercementosis a result of
- chronic inflammation of the tooth
- no opposing tooth
- additional eruption
- tooth becoming fused to surrounding alveolar bone proper
what are the 3 relationships involving and cementum that may exist at the CEJ
- space between the enamel and cementum with the dentin exposed occurs in 10% of cases
- end to end relationship of enamel and cementum occurs in 30% of cases
- cementum overlapping the enamel occurs in 60% of cases
what is the PDL
- fibrous connective tissue surrounding and attaching roots of teeth to bone
where is the PDL located
in periodontal space between the cementum and bone
what is PDL composed of
connective tissue cells and intracellular substance
what are sharpeys fibers
the fibers inserted into the cementum on one side and bone on the other
what are the 4 functions of the PDL and describe each
- supportive: anchors tooth to bone. sharpeys fibers
- formative: helps maintain biologic activity of bone and cementum
- nutritive: supplies nutrients and removes waste products via blood and lymph vessels
- sensory: capable of transmitting tactile pressure and pain sensations
how is PDL width seen
only in radiographs
what does PDL width depend on
age, stage of eruption, function of tooth and angle of film
what are the PDL fiber groups
gingival fiber groups and principal fibers
where are gingival fiber groups located
around the cervical are within the gingival tissue
what are the gingival fiber groups
- dentogingival fibers (free gingival)
- alveologingival fibers (attached gingival)
- circumferential fibers (circular)
- dentoperiosteal fibers (alveolar crest)
- transseptal fibers
where are principal fiber groups
surround the root
what are the principal fiber groups
- apical fibers
- oblique fibers
- horizontal fibers
- alveolar crest fibers
- interradicular fibers
where are the dentogingival fibers
from the cementum in the cervical region into the free gingiva to give support to the gingiva
where are the alveologingival fibers
from the alveolar crest into the free and attached gingival to provide support
where are the circumferential fibers
continuous around the neck of the tooth to help maintain the tooth in positionw
where are the dentoperiosteal fibers
from the cervical cementum over the alveolar crest to blend with fibers of the periosteum of the bone
where are the transseptal fibers
from the cervical area of one tooth across to an adjacent tooth on the mesial or distal only to provide resistance to separation of teeth
where ar apical fibers
from the root apex to adjacent surrounding bone to resist vertical forces
where are oblique fibers
from the root above the apical fibers obloquely towards the occlusal to resist vertical and enexpected strong forces
where are horizontal fibers
from the cementum in the middle of each root to adjacent alveolar bone to resist tipping of the tooth
where are the alveolar crest fibers
from the alveolar crest to the cementum just below the CEJ to resist intrusive forces
where are interradicular fibers
from cementum between the roots of multirooted teeth to the adjacent bone to resist vertical and lateral forces
what is alveolar bone and what is it made of
- bone that forms and supports the alveoli (tooth sockets)
- consists of alveolar bone proper and supporting bone
contour of the alveolar bone follows contour of the _____
CEJ and arrangement of the dentition
shape of the alveolar crest is generally ______
parallel to the CEJ of adjacent teeth’ approximately 1.5mm-2mm apical to the CEJ
cortical plates are thicker in the _____
mandible
what does the alveolar bone surround
thin layer of bone that surrounds the root and gives attachment to the PDL
what is alveolar bone proper called in radiographic images
lamina dura or cribiform plate
what is the supportive alveolar bone
portion of alveolar process that surrounds the alveolar bone proper and gives support to the sockets
what are the types of supportive alveolar bone
- compact (cortical)
- cancellous or trabecular (spongy) bone