Perio, 9/27/11

Front 1

What is the gingival connective tissue made up of?

Back 1

Gingival fibers, ground substance, and cells - neural and vascular elements.

Front 2

What is the main component of gingival CT?

Back 2

Principal fibers - dense, collagenous matrix containing collagen fibers running in recognized fiber groups.
Dense gingival CT = lamina propria or gingival corium.
Has 2 layers:
-papillary layer - finger like projections
-reticular layer

Assorted cells (8%)
Fibers (65%)
GS: water, glycoproteins, etc.
Blood vessels and nerves

Front 3

What happens to the gingival CT at the junction with the lining mucosa?

Back 3

Lamina propria becomes continuous with the much looser CT of alveolar submucosa. This is delineated by the MG junction.

Front 4

Cells of the CT..

Back 4

Fibroblasts (65%)
Inflammatory cells (2-10%)- depends on what stage of disease process.

Fibroblasts are interwoven in the collagen fibers, repairing them if needed, or contributing to their breakdown.

Front 5

What do fibroblasts produce?

Back 5

Produce collagen, elastin, oxytalin, glycoproteins, GAGs that make up ground substance.

Also make matrixmetalloproteinases (MMPs) - and inhibitors of Metalloproteinases (TIMPS)..in some cases these are good and others will cause tissue breakdown.

TIMPs are natural inhibitors They are balanced off by MMPs.

Front 6

Name the important MMPs

Back 6

1. Gelatinase - MMP2, 9 : denatures collagens
2. Collagenases - MMP1, 8: collagen 1, II, III, VII, VIII, X
3. Stromelysins-MMP 3, 10, 11: fibronectin, laminin, collagen IV
4. Matrilysin, MMP 7: fibronectin, laminin, collagen IV

(cont)

Front 7

Inflammatory cells

Back 7

make up 3% of tissue volume
all function to protect surrounding microbial invasion..

Esp when gingival sulcus gets exposed to bacteria, yousee more white blood cells work their way inot the CT.

Front 8

5 principal groups of gingival fibers

Back 8

1. DG fibers - attach to cementum and travel horizontally and then coronally and terminate in free gingival margins.
2. Dentoperiosteal fibers - attach to cementum and run HORIZONTALLY, then
APICALLY and merge with the periosteum that covers the bone.
3. Alveolar gingiva -“fan” out CORONALLY into the lamina propria from the
periosteum at the alveolar crest.
4. transeptal - last fibers to be destroyed during perio disease (1 mm) are interdental fibers that go from the MESIAL aspect of the tooth
to the DISTAL aspect of the adjacent tooth and inserts into the cementum of both teeth.
5. circular: DO NOT ATTACH INTO CEMENTUM in any way! They are
present in the free gingival margin area an wrap around the tooth circumferentially.

Front 9

6 secondary gingival fibers

Back 9

1. Periosteogingival
2. Interpapillary
3. Transgingival
4. Intercircular
5. Intergingival
6. Semicircular

Front 10

What happens if you are able to see the root on the patient/

Back 10

Periodontum is definitely lost, and you should never be able tos ee ths in clinical health.

Front 11

When we look at the attachment apparatus, there are 3 junctions that we look at..

Back 11

1.
Gomphosis Joint, via PDL, cementum and alveolar
bone (bundle bone, cribriform plate, inner cortical
plate)
2.
Dentinocementum Junction (DCJ)
• Involves the Hyalin/Hyaline Layer of
Hopewell-Smith
• “Cements" the Cementum to the Mantle Dentin

3.
Cementoenamel Junction (CEJ)
• Butt joint between cementum and
enamel
• Overlap of cementum onto enamel
• Gap between cementum and
enamel

Front 12

What is cementum

Back 12

The dentin of the roots of the teeth is covered
by a thin (50-200μm) of calcified tissue called
cementum.

function of the cementum is to
provide anchorage of the tooth to its alveolus and its done by Sharpey's fibers.
This is accomplished by the collagen fiber
bundles of the periodontal ligament, whose
terminations (Sharpey’s Fibers) become firmly
embedded in cementum during the process of
cementogenesis.
• Cementum is essential for normal anchorage of
the tooth. By serving as the attachment for
Sharpey's fibers on the tooth side, it mediates
the attachment of the tooth to the gingival
connective tissue, as well as to the periodontal
ligament and, hence, the alveolar bone.

Front 13

Is cementum vascular or avascular?

Back 13

Its avascular. Its sort of like bone.

Front 14

Why do we care about cementum?

Back 14

It becomes contaminated irreversibly when exposed. It lost following disease process and associated with periodontal treatment. Regeneration of it is very hard to acheive.
In root planing, we strip the infected cementum away.

Front 15

Describe important components of cementum

Back 15

Main difference from bone is that its avascular and therefore, doesn't regenerate on a predictable basis.
-No osteons, etc.
-Not a reservoir of minerals unlike bone.

Front 16

Function of cementum

Back 16

Attachment/Support [via Acellular
Cementum plus the Hyaline Layer]
• Adaptation/Protection (during tooth
movement and wearing) [via
Cellular
Cementum]
• Not considered to be a reservoir of minerals
(therefore, more static than bone)

assist
in maintaining occlusal relationships.
• This process serves to maintain the width
of the PDL space at the apex of the tooth.
• Cemental deposition in the apical portion of
the root compensates to some degree for
the slow tooth eruption that takes place
throughout one’s lifetime.

Front 17

Attrition?

Back 17

wearing down of occlusal surfaces due to
diet or habitual behavior. However, as the occlusal surfaces
wear, the tooth is continually erupting as a result.

Front 18

Active eruption?

Back 18

ACTIVE ERUPTION and is
proportional to the wear of the occlusal surface. This eruptive
process is accomplished by continual deposition of cellular
cementum at the apical ends of the roots, which pushed the tooth up.

Front 19

Supraeruption?

Back 19

If functional anatgonist of tooth is lost, the tooth will start to drift lower and may grow into the space thats left.
-its not clinically predictable.

Front 20

Cementum composition of minerals..

Back 20

61% minerals
27% oragnic
12% water..

Dentin is 70% inorganic and enamel is 95% inorganic.

Front 21

What types of collgen are in cementum?

Back 21

Type 1 and Type III collagen

Front 22

Does cementum turnover?

Back 22

No, its pretty static. Resorption doesn't occur under physiologic conditions. It only occurs due to inflammation and due to orthodontic tooth movement.

Front 23

1. Location classification of cementum
2. Cellular classification
3. Fibrillar classification

Back 23

1. –Radicular cementum: The cementum that is
found on the root surface. The thickness of radicular
cementum increases with age. It is thicker apically than
cervically. Thickness may range from 0.05 to 0.6 mm.
–Coronal cementum: The cementum that
forms on the enamel covering the crown.

2. Cellular cementum: Cementum containing
cementocytes in lacunae within the cementum
matrix. As cellular cementum is formed and
calcifies, cementoblasts become trapped within the
matrix; thus, the origin of cementocytes. Surrounds
the apical aspect of the root.
– Acellular cementum: Cementum without any
cells in its matrix. After a tooth erupts into the
dental arch there is no longer any formation of
acellular cementum. Surrounds the coronal aspect

3. Fibrillar cementum: Cementum with a
matrix that contains well-defined fibrils of
type I collagen.
–Afibrillar cementum: Cementum that
has a matrix devoid of detectable type I
collagen fibrils. Instead, the matrix tends to
have a fine, granular consistency.

Front 24

What kinds of fiber support tooth?

Back 24

ONly the sharpey's fibers. Not the intrinsic fibers...

During the initial formation of cementum,
cementoblasts lay down collagen randomly.
Following this calcification occurs, and the
trapped random fibers are called INTRINSIC
FIBERS.
–The second kind of collagen fibers in
cementum are SHARPEY’s FIBERS. These are
extensions of the periodontal ligament into
cementum and are formed by fibroblasts

Front 25

Name all the major cell types found in cementum..

Back 25

-Cementoblasts
-cementocytes
-Periodontal ligament fibroblasts
-Odontoclasts (cementoclasts)

Front 26

Cementoblast

Back 26

-produces matrix and eventually gets trapped within the matrix (cementocyte).
-orginiates from dental follicle (ectomesenchyme).
-produce intrinsic collagen . these are oriented with long axis parallel to tooth surface so there's no mechanical support.

Front 27

Periodontal fibroblasts

Back 27

-migrate from the PDL and produce collagen fibers that become mineralized and are incorporated into cementum.
-PDL fibroblasts contribute to cementogenesis and are considered cementum cells.

Front 28

Relationship between cementum and enamel at CEJ..

Back 28

-30%: butt joint - neither overlaps
-60-65% - cementum overlaps
-5-10% - gap junction. dentin is exposed and there may be root sensitivity problems.

cementum overlaps enamel, there's never a case where enamel overlaps cementum.

Front 29

What are enamel pearls?

Back 29

Localized masses of enamel that develop over the root surface near the CEJ.
-can't get attachment into enamel. Generally find these in the furcation areas. Enamel pearl can't be removed by scaling and it has to be ground away to restore the normal contour of the tooth.

Front 30

Enamel projections?

Back 30

Enamel organ continues to produce enamel over root dentin and this additional enamel takes the shape of enamel spurs that project into furcuation of multirooted teeth.
-may favor onset of periodontal leasions.

Front 31

Hypercementosis

Back 31

-abnormally larg cellular cementum deposits on apical third or more teeth.

Front 32

Cementicles

Back 32

small, spherical particles of cementum that may lie free in PDL next to cementum surface. Can also be attached to cementum surface or incorporated into cemenutum layer.

May mimic calculus and serve as promoters of periodontal disease.

Front 33

Ankylosis

Back 33

Fusion of bone directly with dentin and cementum and is considered undesirable, and results in progressive resorption of tooth structure due to ongoing osteoclastic activity.

Ankylosis is how dental implants actually work through osseointegration. Positioning if implant is paramount.

Front 34

Periodontal ligament

Back 34

fibrous CT structure with neural and vascular components that joints cementum covering the root to alveolar bone.
-PDL is highly cellular and important for health of masticatory apparatus.

Front 35

When is a ligament NOT a ligament?

Back 35

PDL is actually not a ligament. Ligaments are avascular and dense CT and has little capacity for healing

PDL doesnt have any of these characteristics but it is a natural shock absorber. Presence of vasculature allows collagen networks to be well protected and provides neurosensory protection against the overload.

Front 36

What does PDL contain?

Back 36

-extracellular fibers
the extracellular fibers (composed
primarily of collagens and associated
molecules) that connect cementum with
alveolar bone
2) the cells responsible for normal
maintenance (ex. fibroblasts,
neurovascular elements) of the PDL and
also for regeneration of periodontal
tissues (ex. undifferentiated precursor/
progenitor cells)

Front 37

Functions of PDL

Back 37

Supportive: mediated
primarily by the principal fibers of
the periodontal ligament that
form a strong fibrous union
between the root cementum and
the bone.

– Nutritive: well-vascularized, with the major blood
supply originating from the dental arteries that enter the
ligament through the fundus of the alveoli. Major
anastomoses exist between blood vessels in the adjacent
marrow spaces and the gingiva
– Sensory - periodontal
surgical wounds, especially the healing of bone grafts. Just because tooth has root canal doesnt mean its going to be pain free. myelinated dental nerves that perforate
the fundus of the alveoli rapidly lose their myelinated
sheath as they branch to supply both the pulp and
periodontal ligament. The periodontal ligament is richly
supplied with nerve endings that are primarily receptors
for pain and pressure.
– Formative providing cells that are able to
form as well as resorb all the tissues that make up the
attachment apparatus, i.e. bone, cementum and the
periodontal ligament

Front 38

Name the 5 principal fibers of the PDL + functions

Back 38

• Alveolar Crest Fibers: run from the root to the
osseous crest of bone. retain root in socket, resist later forces, protect deeper pal
• Horizontal Fibers: run HORIZONTALLY from bone
to root. restrict lateral forces
• Oblique Fibers: radiate from the apex of the tooth. resist axial forces
root to bone. (make up majority of fibers)
• Apical Fibers: radiate from the apex of the tooth root
to bone. prevent tooth tipping, resist luxation, protect blood, lymph and nerve supply
• Interradicular Fibers: run from cementum in the biand
tri-furcations, splaying APICALLY towards furcal
bone. aid in resisting tipping + torquing. resist lunation.

Front 39

Besides collagen, what other fiber type is found in PDL?

Back 39

Immature Elastic Fibers (Oxytalin & Elaunin molecules)
• Found in the PDL
• Extensive distribution within the PDL
• Run in an apico-coronal direction within the PDL
• Form a 3-D branching meshwork that surrounds
the root
• Most likely function to regulate vascular flow in
response to tooth function [again, viscoelastic

Front 40

Describe the ground substance of PDL

Back 40

Proteoglycans/Glycosaminoglycans are
important in absorbing water (due to their
high density of (-) charges)
• Dermatan Sulfate is the main PG/GAG
• Water (~70% of the mass of the ground
substance in PDL) [again, viscoelastic shock

Front 41

Cell types of PDL

Back 41

1. fibroblasts are majority
2. cementoblasts for cellular cementum
3. osteoblasts
4. odontoclasts, osteoclasts
5. undifferentiated ectomensenchymal cells that gives rise to fibroblasts, cementoblasts, and osteoblasts (kwown as pluripotential cells).
6. Rests of Mallasez - remnants of HERS. Usually found in apical portion of PDL..no known function. sometimes these cells can be turned on and start to proliferate and form lateral periodontal root cysts.

Front 42

Vascular supply of PDL

Back 42

-rich network that runs throughout and communicates with vessels in the bone, traveling through gingiva. All connected through vasculature.
In disease, it allows for easy migration in sites where they are not usually found.

Front 43

Innervation of PDL

Back 43

neural elements are high and quite innervated. myelinated apically and unmyelinated coronally. mastication is controlled by these nerve fibers.

Front 44

Describe hypo and hyperfunction of PDL

Back 44

-avg width is 0.2 mm but under occlusal surfaces can start to stretch. With will increases in hyperfunction and when its hypofunction the PDL can shrink.

Front 45

What happens if you lose PDL?

Back 45

Ankylosis and fusion will occur and the tooth will be difficult to extract.

Front 46

Describe guided tissue regenration

Back 46

Using biologically compatible barriers the therapists promotes ingrowth of cells into damaged sites where a new PDL is needed. PDL contains precursos cells for production of entire attachment apparatus (cementum, PDL, and bone).

Front 47

Alveolar process

Back 47

Part of the bone thats involved in the support of the tooth.

Front 48

Alveolar bone

Back 48

part of jawbones circumscribing and forming the tooth sockets.
-part of jawbones to which teeth are attachmed. same overall physical and chemical structure as bone.

Front 49

Function of alveolar process

Back 49

-protection and support to teeth.
-reservoir of minerals

Front 50

3 parts of the alveolar process

Back 50

1. cribiform plate - next to cortical bone and has Sharpey fibers attachments.
2. (2) SUPPORTING PLATE: which is
located between the outer plates and the
cribriform plate; is composed of
CANCELLOUS BONE and has trabeculae
and marrow. In children, the marrow is
hemopoitic (forms blood cells). In adults,the
marrow is fatty and converts to a fibrous
state during inflammation (during
periodontitis).
– (3) OUTER PLATES: (there are 2; one
FACIAL and 1 LINGUAL) is also composed of
cortical bone and is covered with
periosteum. These are continuous with the
body of the maxilla and mandible.

Front 51

Periosteum

Back 51

-has outer fibrous lyaer and inner cambium layer - with osteblasts and osteoclasts.

3 functions
-attaches gingiva and mucosa to bone
-provides innervation, lymp drainage and blood supply
-participates in healing of periodontal wounds

Front 52

Alveolar process vs. alveolar bone

Back 52

process: jawbone that contains the teeth. this rests on basal bone.
-process development is based on tooth eruption and its maintaenance on tooth. when teeth don't develop, alveolar process fails to form. if all teeth are extracted, alveolar process will shrink and it gets down to basal bone.

Bone- only the inner lining of the socket. Composed of a thin plate of cotrical bone with numerous performation (cribiform plate) that allows passage of blodo vessels between bone marrow and periodontal ligament.

Front 53

Alveolar crest

Interdental septum

How does this change for each tooth?

Back 53

Position of the interdental bone. Point at which cribiform and outer plates fuse. It should be 1-2 mm below CEJ.

Interdental septum - amoutn of bone in between the 2 teeth. has cribiform, outer, and supporting plates. Shape of bone changes as we go around the tooth also, and overlying gingiva follows the same shape too.

thickness that surrounds tooth varies too. outer buccal plane is thinner esp around canines is very thin. On lingual, its a little thicker except on mandible where it can get pretty thin. Towards the molars it thickens out. You follow the profile of the osseuous crest and should be a 1-2 mm away. If teeth are tilted or rotated, the bone can also change.

Front 54

What type of bone has the best type to heal?

Back 54

Cancellous bone, not cortical bone.

Front 55

Lamina dura

Back 55

Thin white line that mimics where the outline of the bone on the roots of the teeth. You can't see this clinically, only radiographically. Dense structures like teeth appear light and non mineralized tissues dark.