Anatomy of the Normal Periodontium and Gingiva

Question 1

What is the free gingival groove/marginal groove?

Answer 1

It is a shallow linear depression that separates free/marginal gingiva from attached gingiva.
Roughly corresponds to the gingival sulcus (wall lined by free gingiva)
Approximately 1-1.5 mm from gingival margin

Question 2

What is the attached gingiva?

Answer 2

It is tightly attached to the periosteum of underlying alveolar bone.
Lingual aspect on maxilla continues with palatal mucosa and on mandible continues with lingual alveolar mucosa.

Question 3

Mucogingival junction

Answer 3

separates attached gingiva from alveolar mucosa.

Histologically = transition from keratinzed to non keratinzed mucosa.

Question 4

Gingival Zenith

Answer 4

Is the apical portion of the free gingiva.

Question 5

What is the width of attached gingiva?

Answer 5

Distance from free gingival/marginal groove to the mucogingival junction.

Question 6

What is the width of keratinized gingiva?

Answer 6

Distance from margin of free gingiva to the mucogingival junction. FREE GINGIVA + ATTACHED GINGIVA!
Widest in the Mx incisors
Thinnest width on the mandibular lingual incisors

Question 7

What is a Col?

Answer 7

A col is a valley like depression that separates facial and lingual papilla. Pyramidal in shape in the anteriors.
Internally non-keratinized stratified squamous epithelium.

Question 8

Interdental Papilla

Answer 8

Keratinized mucosa

Lateral borders are free gingiva, while the central portion is attached gingiva.

Question 9

What determines the shape of interdental papilla?

Answer 9

The shape is dependent upon the tooth and embrasure morphology. If there is a diastema, there will be no interdental papilla because there is no proximal contact.

Question 10

Can recession change the shape the interdental papilla and col?

Answer 10

Yes

Question 11

What is the interdental groove?

Answer 11

It is a vertical groove within the facial surface o the interdental papilla. The groove is parallel to the long axis of adjacent teeth.

Question 12

What is lamina propria?

Answer 12

The lamina propria is a thin layer of loose areolar connective tissue, which lies beneath the epithelium and together with the epithelium and basement membrane constitutes the mucosa.

Question 13

The gingival epithelium forms a mechanical, chemical, water, and microbial barrier, name some cells that are involved with the gingival epithelium. Proliferation of these cells occurs in the stratum basale.

Answer 13

Keratinocytes - morphological and biochemical changes occur in these cells as they move from the stratum basale to the stratum corneum (result is keratinization).
Non-keratinocytes - Langerhan cells, Merkel cells, and Melanocytes.

Question 14

Different areas of epithelium are located throughout the mouth, name them.

Answer 14

Orthokeratinized epithelium - no nuclei on cell surface
Parakeratinized epithelium - partially nucleated pyknotic nuclei.
Non-keratinized - many nuclei.

Question 15

What are key characteristics involved in the differentiation of keratinocytes?

Answer 15

Increased tonofilaments , Progressive loss of nuclei (pyknotic nuclei in parakeratinized epithelium and viable nuclei in non-keratinized ).
Keratinosomes or Odland bodies in uppermost layers of STRATUM SPINOSUM, they are modified lysosomes containing acid phophatases that help dissolve organell membranes.

Question 16

What are tonofilaments and what are they embedded in?

Answer 16

(A structural cytoplasmic protein, of a class known as intermediate filaments, bundles of which together form a tonofibril; a tonofilament is made up of a variable number of related proteins, keratins, and is found in all epithelial cells, but is particularly well developed in the epidermis). 
They are embedded in FILAGGRIN!!!

Question 17

What are melanocytes and where are they located? Are they keratinized?

Answer 17

They produce the protein melanin.
They are non-keratinized cells.
Found in basale and spinous layers of epitheilum.

Question 18

Where is melanin pigmentation most prominent?

Answer 18

Gingiva and hard palate.

Question 19

What are Langerhan cells and where are they located? Are they keratinized?

Answer 19

They are dendritic cells involved in Antigen presentation. They are found in all layers of epithelium excluding the CORNEUM.
Non-keratinized cells.

Question 20

What are Merkel cells? Are they keratinized?

Answer 20

These cells are involved in tactile perception, transmits mechanical stimuli.

Question 21

WHat is the basal lamina and what two layers is it composed of?

Answer 21

It is an acellular layer between the epithelium and underlying connective tissue.
Composed of the basal lamina (epithelial cells) and lamina reticularis (CT cells).

Question 22

WHat twol layers make up the lamina propria? What is the lamina propria?

Answer 22

Papillary layer and the reticular layer.
is a thin layer of loose areolar connective tissue, which lies beneath the epithelium and together with the epithelium and basement membrane constitutes the mucosa.

Question 23

What type of collagen are gingival fibers composed of, and what is their function?

Answer 23

Type I Collagen
It helps hold the free/marginal gingiva against the tooth and prevent its deflection due to masticatory forces. It also connects the free/marginal gingival to cementum and attached gingiva.

Question 24

What is oral epithelium? What type(s) of keratinization does it consist of ?

Answer 24

Oral epithelium is the outer surface of marginal gingiva and attached gingiva.
It is composed of orthokeratinized and parakeratinized epithelium.

Question 25

What is sulcular epithelium? Is it keratinized?

Answer 25

The sulcular epithelium is that epithelium which lines the gingival sulcus. It is apically bounded by the junctional epithelium and meets the epithelium of the oral cavity at the height of the free gingival margin. The sulcular epithelium is nonkeratinized.

Question 26

How many layers are involved with the junctional epithelium, and what is the typical length of the JE?

Answer 26

There are typically 3-4 layers early in life, but with age there can be 10 to 20 layers.
The length varies from 0.25 to 1.35 mm

Question 27

How many basal lamina(e) does the junctional epithelium have?

Answer 27

Cells of the JE immediately adjacent to the tooth are attached to the tooth surface via HEMIDESMOSOMES and the INTERNAL BASAL LAMINA.

Cells of JE adjacent to the lamina propria is attached via the external basal lamina.

Question 28

Cells of the Junctional epithelium immediately adjacent to the tooth are attached to the tooth surface via what two structures?

Answer 28

1. Hemidesmosomes

2. Internal basal lamina

Question 29

Cells of the JE adjacent to the lamina propria is attached by what structure?

Answer 29

External basal lamina

Question 30

What two things make up the Dentogingival unti?

Answer 30

JE + gingival fibers

Question 31

What is the clincical significance of the internal basal lamina?

Answer 31

Maintains tooth attachment during active and passive eruption
Barrier to microbial invasion
Allows access of gingival fluid, inflammatory cells

Question 32

What is the JE?

Answer 32

a nonkeratinized stratified squamous epithelium, lies immediately apical to the sulcular epithelium, which lines the gingival sulcus from the base to the free gingival margin, where it interfaces with the epithelium of the oral cavity.

Question 33

The JE has cells that are similar to immune cells, elaborate on the cells function.

Answer 33

The JE has special endocytic cells that are similar to macrophages and neutrophils. They can resist perio disease progression, and help with perio healing.

Question 34

What is Burton’s line?

Answer 34

Exogenous pigmentation of the gingiva seen in patient’s with lead poisoning.

Question 35

What is active eruption?

Answer 35

It is movement of the tooth towards the occlusal plane.

Question 36

What is passive eruption?

Answer 36

It is exposure of the teeth by apical migration of the gingiva.
Teeth are not moving, but gingiva is actually receeding away from the occlusal plane.