Periodontium & Gingiva

Question 1

What is the Periodontium?

Answer 1

Periodontium describes those tissues that surround, attach and support the teeth. These include Gingiva, Periodontal ligament, Cementum and Alveolar bone.

Question 2

What are the functions of the Periodontium?

Answer 2

1. Attach the teeth to alveolar sockets.
2. Resist and resolve the forces generated by mastication, speech and deglutition.
3. Adjust for structural changes associated with wear and aging through continuous remodeling and regeneration.
4. Defend against the noxious external influences that are present in the oral cavity.

Question 3

What are the types of Oral Mucosa?

Answer 3

The oral mucosa is divided into three types:
•masticatory mucosa (covers gingiva & hard palate),
•specialized mucosa (on dorsum of tongue),
•lining mucosa (covers rest of the oral cavity)

Question 4

What is Alveolar Mucosa?

Answer 4

Alveolar mucosa is part of the lining mucosa,that extends from the gingiva to the vestibule and floor of the mouth.

Question 5

What is the morphology of healthy gingiva?

Answer 5

Healthy gingiva is coral pink, firm, tightly bound to tooth,
•Size: Knife-edged gingival margins and interdentally fills the interproximal embrasure.
•Contour: scalloped outline on the facial and lingual surfaces, interdentally follow the contour of proximal tooth surfaces.
•Texture: Stippling on attached
gingiva and central portion of
Interdental papilla, due to the rete pegs papillary layer of connective tissue projects into elevations.

Question 6

What are the types / components of the gingiva?

Answer 6

The gingiva consists of free gingiva, attached gingiva, and interdental gingiva.

Question 7

What is the Junctional Epithelium (JE)?

Answer 7

The connection between gingiva and tooth is mediated by special kind of epithelium called junctional epithelium.
Extends apically from base of sulcus to the CEJ.

Question 8

What is the Dentogingival Junction?

Answer 8

The Dentogingival Junction is where the gingiva attaches to the tooth, consisting of junctional epithelium, sulcular epithelium, and connective tissue attachment.

Question 9

What is the biologic width?

Answer 9

-The measurement of soft tissue attached to the tooth coronal to the alveolar bone.
-Histological width is 2.04 mm.
-BW is the distance from the base of the sulcus to the crest of the alveolar bone.

Question 10

What is Gingival Crevicular Fluid (GCF)?

Answer 10

GCF is an inflammatory exudate that seeps into gingival crevices or periodontal pockets around teeth with inflamed gingiva.

Question 11

What factors increase GCF flow?

Answer 11

•Mastication, brushing and any other gingival stimulation.
•Inflammation
•Pregnancy
•Plaque antigens

Question 12

What are rete pegs?

Answer 12

Rete pegs are finger-like projections of the epithelium that extend into the underlying connective tissue. Rete pegs enhance the structural integrity of the gingiva by increasing the surface area for attachment.

Question 13

What are the microscopic features of gingiva?

Answer 13

90% cells are keratinized, rest are melonocytes, Langerhans and non-specific cells.
Gingival oral epithelium made up of four layers: basal, spinous, granular, and cornified layers.

Question 14

What is the free / marginal gingiva?

Answer 14

Free gingiva is the unattached or movable portion of the gingiva.

Question 15

What is attached gingiva?

Answer 15

Attached gingiva is the non-moveable part of gingiva that extends from marginal groove to the mucogingival junction.

Width of Attached gingiva varies from 1-9 mm. Narrowest is on buccal aspect of mandibular first bicuspids while widest in the maxillary anterior zone.

Question 16

What are the functions of GCF?

Answer 16

•GCF cleanses materials from the sulcus,
•exert antibody activity in defense of gingiva,
•posseses antibacterial properties, •contains plasma proteins that improve adhesion of epithelium to the tooth.

Question 17

Why is biologic width important in restorative dentistry?

Answer 17

It is important from the restorative point of view because it’s violation leads to complications like gingival enlargement, alveolar bone loss and improper fit of the restoration.

Question 18

What are the main components of connective tissue (CT)?

Answer 18

CT consists of collagen fibers (60%), fibroblasts (5%), and vessels, nerves, and matrix (35%).

Question 19

What cells are present in connective tissue?

Answer 19

Fibroblasts (65%), mast cells, neutrophils, lymphocytes, plasma cells & undifferentiated mesenchymal cells.

Question 20

What are the connective tissue fibers produced by?

Answer 20

-Fibers in CT are produced by fibroblasts.
-Collagen fibers predominant in CT.
-Smallest unit Tropocollagen → Protofibrils → Collagen fibrils → Collagen fibers.
-Cementoblasts and osteoblasts also produce collagen.

Question 21

What are dentogingival fibers?

Answer 21

Extend from cementum into the gingiva over the alveolar margin.

Question 22

What are alveolar crest fibers?

Answer 22

Arise from the alveolar crest and run coronally into the gingiva.

Question 23

What are circular fibers?

Answer 23

Circular fibers encircle the tooth.

Question 24

What are transseptal fibers?

Answer 24

Transseptal fibers connect adjacent teeth. (Run from tooth to tooth coronally to alveolar septum).

Question 25

What are methods of collecting GCF?

Answer 25

Absorbing paper strips, twisted threads, micro-pipettes, and intracrevicular washings.

Question 26

What is gingiva?

Answer 26

Part of the oral mucous membrane that surrounds the teeth and covers the coronal portion of the alveolar process. It consists of dense collagenous connective tissue and keratinized epithelium.

Question 27

What is COL ?

Answer 27

COL – A valley-like depression in the interdental area, absent in cases of diastema and gingival recession.

Question 28

What is the mucogingival junction?

Answer 28

The gingiva / boundary separating the gingiva from alveolar mucosa.

Question 29

What is free gingival groove?

Answer 29

A linear depression in the external surface of the gingiva, which roughly corresponds to the bottom of the clinical sulcus.

Question 30

What are the characteristics of junctional epithelium?

Answer 30

•JE is very thin, doesn't show resistance against probing. •Cells larger and loosely attach with each other. •Attachment with tooth is via hemidesmosomes. •In adults 40 cells long, 10-20 cells wide. •Turn over rate is 4-6 days. •Relatively permeable.

Question 31

What is lamina lucida?

Answer 31

A lucent zone immediately beneath the basal epithelial cells.

Question 32

What is lamina densa?

Answer 32

Electron dense zone immediately beneath the lamina lucida. Achoring fibers project into the connective tissue from lamina densa.

Question 33

What are hemidesmosomes?

Answer 33

Electron-dense areas - attach the epithelium to the underlying basement membrane. Seen at regular intervals along the cell membrane.

Question 34

What are desmosomes?

Answer 34

Dark-stained structures between adjacent epithelial cells. Actually 2 hemidesmosomes facing each other.

Question 35

What are the functions of junctional epithelium?

Answer 35

•Forms an epithelial barrier against plaque bacteria as JE is firmly attached to the tooth. •Allows the access of GCF, inflammatory cells and components of the immunological host defense to the gingival margin. •JE cells have a rapid turnover rate, which contributes to the host-parasite equilibrium and rapid repair of damaged tissue.

Question 36

What are the types of gingival connective tissue fibers?

Answer 36

CT fibers specially Type I forms the bulk of the lamina propria and provide tensile strength to gingival tissue. Others are type IV. • Reticulin Fibers: Present adjacent to the basement membrane, epithelium-CT interface & endothelium-CT interface. • Oxytalan Fibers: Long thin fibers, present along long axis of tooth. •Elastic Fibers: Present along blood vessels, abundant in alveolar mucosa.

Question 37

What is the role of junctional epithelium in gingivitis?

Answer 37

The JE becomes densely infiltrated with neutrophils and it may begin to show development of rete pegs in the early lesion of gingivitis.

Question 38

Where does the junctional epithelium around implants originate from?

Answer 38

The JE around implants always originates from epithelial cells of the oral mucosa as opposed to the JE which originates from the reduced enamel epithelium.

Question 39

What structures pass from CT into crevice?

Answer 39

Gingival exudate, PMN Leucocytes, immunoglobulin, and complement

Question 40

Which structures pass from crevice to corium?

Answer 40

Carbon particles, bacterial products

Question 41

Does junctional epithelium exhibit tissue defense mechanism?

Answer 41

Yes

Question 42

Can Microorganisms pass through the junctional epithelium?

Answer 42

No, microorganisms cannot pass through the JE.

Question 43

How junctional epithelium develops?

Answer 43

•Formation of reduced enamel epithelium (REE). •Union of REE and oral epithelium during eruption. •As the tooth erupts, REE is converted into JE. •Ameloblasts are replaced with squamous epithelium.

Question 44

Why is junctional epithelium important?

Answer 44

JE is important because of its anatomical location. It is the site of host-bacterial interaction in initiation of periodontal disease.

Question 45

What makes junctional epithelium an important structural component of periodontal defense mechanism?

Answer 45

There is constant presence of bacteria and their products in the gingival sulcus which makes this an important structural component of periodontal defense mechanism.

Question 46

What is regarded as hallmark in the development of periodontitis?

Answer 46

The conversion of the JE to pocket epithelium is regarded as hallmark in the development of periodontitis.

Question 47

What is the site of host-bacterial interaction in initiation of periodontal disease?

Answer 47

Junctional epithelium is the site of host-bacterial interaction in initiation of periodontal disease.

Question 48

Which fibers are predominant in connective tissue?

Answer 48

Collagen fibers

Question 49

What are the gingival fibers?

Answer 49

Dentogingival Fibers Alveolar crest Fibers Circular Fibers Transeptal Fibers

Question 50

Explain connective tissue matrix.

Answer 50

Produced by fibroblasts mainly, rest by mast cells & components of Blood. •CT cells are embedded into matrix. •Transportation of water, electrolytes, nutrients, metabolities etc, to and from individual CT cell occurs within matrix.

Question 51

What are the constituents of connective tissue matrix?

Answer 51

Proteinpolysacchride macromolecules 1. Proteoglycan, Glycosamineglycogen (GAG), predominant component is polysaccharide. • GAG are large, flexible, chain formed, negatively charged molecules, each of which occupy a rather large space. 2. Glycoprotein, predominant component is protein.

Question 52

What are the functions of macromolecules in connective matrix?

Answer 52

•Regulate diffusion & fluid movement. •Resists towards deformation. •Gives resilience to gingiva i.e. can be suppressed and regain their original shape.

Question 53

What is the gingival blood supply?

Answer 53

Blood supply is derived from 3 sources: 1. Supraperiosteal vessels 2. Periodontal ligament vessels 3. Alveolar vessels Form capillary loops within CT papillae.

Question 54

What is the gingival lymph drainage?

Answer 54

Lymph drainage into regional lymph nodes, from mandibular gingiva into cervical, submandibular & sub mental nodes; from maxillary gingiva into deep cervical lymph nodes.

Question 55

What is the gingival nerve supply?

Answer 55

Nerve supply is from branches of trigeminal nerve.

Question 56

What is the amount of GCF collected?

Answer 56

The amount of GCF collected is extremely small i.e 0.5 to 2.4 ul/day.

Question 57

What are the layers of gingival oral epithelium?

Answer 57

Made up of four layers: 1. Basal Layer consists of cuboidal cells, are in contact with basement membrane, separated by hemidesmosomes. 2. Spinous Layer consists of polygonal cells separated by desmosomes. 3. Granular Layer consists of flattened cells and usually contain keratohyalin granules. 4. Cornified Layer consists of flat cornified cells.

Question 58

What is the width of attached gingiva?

Answer 58

Width of Attached gingiva, varies from 1-9 mm. Narrowest is on buccal aspect of mandibular first bicuspids while widest in the maxillary anterior zone.

Question 59

What are the characteristics of alveolar mucosa?

Answer 59

•The epithelium of the alveolar mucosa is thin, non-keratinized and lack of rete pegs. •It is loosely bound to the underlying periosteum of the alveolar bone and offers less resistance to inflammation.