dentinogingival junction
TRANSCRIPT
The gingival sulcus
is an area of potential space between
a tooth and the surrounding gingival
tissue.
It is lined by two entities:
-Apically by the gingival fibers of
connective tissue attachment .
_Coronally by free gingival margin .
The gingival sulcus
Under normal conditions the depth
of the sulcus is variable.45% of all
measured sulci are below 0.5 mm
,the average sulcus is 1.8mm
the shallower sulcus is the more
likely that the gingival margin is
not inflamed
THE SULCULAR EPITHELIUM
Its stratified squamousepithelium ,non keratinized .Para keratinized that iscontinuous with the oralepithelium and lines thelateral surface of the sulcus .
Its lacks epithelial ridges soforms a smooth contact withlamina properia
THE SULCULAR EPITHELIUM
Apically it overlaps the
coronal border of the
junctional epithelium
this epithelium shares many
of the characteristics of oral
epithelium including good
resistance to mechanical
forces and relative
impermeability to fluid and
cells
the junctional epithelium
Its the stratified non keratinizingepithelium that surround the tooth likea collar .
its attached by one broad surface tothe tooth and by the other to thegingival connective tissue
The junctional epithelium has twobasal lamina:
oOne that faces the tooth (internal basallamina )
oThe other faces connective tissue(external basal lamina)
the junctional epithelium
The desquamative sheddingsurface of the junctional epitheliumis located at its coronal end whichalso forms the bottom of thegingival sulcus
The junctional epithelium is morepermeable than oral or sulcularepithelium It serves as theperferential route for the passage ofbacterial products from the sulcus into connective tissue into the sulcus
THE JUNCTION EPITHELIUMTHE SULCULAR EPITHELIUM
1. It is epithelium that surroundthe tooth like a collar .
2. It is more permeable than oral orsulcular epithelium It serves asthe perferential route for thepassage of bacterial productsfrom the sulcus in to connectivetissue and fluid and cells from C.Tinto the sulcus
1. It is continuous with the oralepithelium and lines the lateralsurface of the sulcus .
2. It characterized by goodresistance to mechanical forcesand relative impermeability tofluid and cells
Development of the junctioanal epithelium
As the erupting tooth approaches the
overlying epithelium, the external
cells of the reduced enamel
epithelium proliferate, causing the
epithelial covering of the enamel to
thicken.
Development of the junctioanal epithelium
Proliferation of the externel cells
of the reduced enamel epithelium
begins around the cusp tips and
slowly progresses toward the
cervix of the tooth
Development of the junctioanal epithelium
proliferating cells eventually displace
any remaining reduced ameloblasts, thus
replacing the relatively inert reduced
enamel epithelium with an epithelial
collar of cells with a high turnover
rate. This collar of cells with a high
turnover rate is the early junctional
epithelium.
Eventually, the entire reduced enamel
epithelium will become replaced by
junctional epithelium.
Development of the junctioanal epithelium
After accomplishing of amelogenesis(protective stage) the ameloblast secreteor leave structure less material on enamelsurface primary enamel cuticle .
The enamel organ becomes reduced inthickness (reduced enamel epithelium )and function as aprotection againstcontact with connective tissue ,to inhibitcementum deposition or enamelresorption
The reduced enamel epi theliumconsists of two layers
1-the reduced ameloblast
2-remnant of the dental organ
Development of the junctioanal epithelium
The ameloblast develop hemidesmosomesto attach the reduced enamel epithelium tothe surface of the enamel at the time oferuption the reduced enamel epitheliumsecrete desmolytic enzymes causingdegenerating of the of the c.t presentbetween it and the oral mucosa (desmolyticstage of amelo blasts )
The outer layer of the reduced enamelepithelium and the cells of the oralepithelium proliferate into the degeneratedc.t. to form amass of cells over the eruptingtooth the epithelial plug.
Development of the junctioanal epitheliumCell death in th middle portion of plug cause formation of epithelial lined canalthrough which tooth will erupt with out hemorrhage
Once the tip of the crown appear in the oral cavity reduced enamel epithelium willbe called primary attached epithelium
And the the shallow groove present between the tooth and the gingiva is calledGINGIVAL SULCUS
The cells of primary attached epithelium (PAE) originate from reduced enamelepithelium and attached to tooth by primary enamel cuticle
When primary attachment epithelium is replaced by oral epithelium its calledsecondary attached epithelium that attaches by secondary enamel cuticle.
Secondary enamel cuticlePrimary enamel cuticle
1. Binds secondary attachedepithelium to the enamel surface
2. It is formed finally when the teeth erupt
1. Binds primary attached epitheliumto the enamel surface
2. It is formed initially at theprotective stage
Secondary attached epi.Primary attached epi.
1. It is Primary attachmentepithelium replaced by oralepithelium
2. attached by secondary enamelcuticle
1. originate from reduced enamel epithelium
2. attached to tooth by primary enamel cuticle
Shift of the dento gingival junction
The dentogingival junction is an anatomicaland functional interface between the gingivaand the tooth structure.
Dento gingival junction is the region wherethe tooth is attached to gingival and is formas soon as the tooth erupts in the oral cavity.
It provides attachment of the gingiva to theenamel surface via hemidesmosomes
with time the position of the gingiva of thesurface change
Shift of the dento gingival junction
Components
1. Epithelial component is derived fromreduced dental (enamel) epitheliumand oral epithelium.
2. The connective tissue component isderived from the lamina propria of theoral mucosa.
The attachment of the functionalepithelium to the tooth is reinforced withthe gingival fibers, which brace the gingivalagainst the tooth surface.
Shift of the dento gingival junction
almost entire enamel is covered byepithelium when the tip of the enamelfirst emerge through the mucous
membrane of the oral cavity .
the eruption of teeth continuous until itreach the plan of occlusion.
the firmness strength of the dentinogingival junction beacause of connectivetissue attachment of epithelium toenamel is not week as the crowncontinuous on to the oral cavity
the attachment separate from the enamelsurface gradually
Shift of the dento gingival junction
when the tip of the enamel first emerge through the mucous membrane of
the oral cavity . one third to one fourth of enamel is still covered by the gingiva
The actual movement of teeth towards occlusal plane called acitveeruption
The separation of primary attached epithelium from the enamel
surface called passive eruption
THE SHIFT OF DENTINO GINGIVAL JUNCTION INVOLVE
First stage
Occur in the primary teeth till one year
before shedding in the permanent teeth
20_30.
the bottom of the sulcus present on
the enamel and the apical end of the
AE on the cement enamel junction.
Clinical crown is less than anatomical
crown.
THE SHIFT OF DENTINO GINGIVAL JUNCTION INVOLVE
Second stage
Occur till age of the 40 or even later.
The bottom of the sulcus still present
on the enamel and the apical end of the
AE on cementum.
the clinical crown is less than
anatomical crown.
THE SHIFT OF DENTINO GINGIVAL JUNCTION INVOLVE
Third stage
It is unhealthy condition.
The bottom of the sulcus present at the
CEJ and the apical end at cementum.
The clinical crown equal to the
anatomical crown.
THE SHIFT OF DENTINO GINGIVAL JUNCTION INVOLVE
Fourth stage
It is unhealthy condition.
From 60 years later .
The bottom of the sulcucs and apical
end on the cementum.
The clinical crown is longer than
anatomical crown
•As the original sulculardepth increase and apicalmigration of the junctionalepithelium simultaneouslytack place.
•pathosis has occurred to havetrue periodontal pocketaprobing measurment of 4mm must be clinicallyevidence.
The periodontal pocket
It results in:1. A bluish-red vertical zone from
the gingival margin to thealveolar mucosa.
2. Gingival bleeding.3. Suppuration & tooth mobility4. And diastema formation.
symptoms such as localizedpain or pain "deep in the bone"are suggestive of the presenceof periodontal pockets