gingiva and perio ligament

Question 1

what are the three parts of the oral mucosa?

Answer 1

Masticatory. M [gingiva, hard palate]

Specialized. M [ dorsum of tongue]

Lining. M [ rest of mucosa]

The connective tissue can be differentiated as lamina propria and sub mucosa. The lamina propria is the CT layer immediately below the epithelium.

Question 2

what is the definition of gingiva and what are the three parts?

Answer 2

That part of the mucosa that covers the alveolar process and cervical portions of the teeth.

3 PARTS:
FREE gingiva
ATTACHED gingiva
INTERDENTAL gingiva (Papilla)

Question 3

what is free gingiva (marginal)?

Answer 3

Unattached or terminal portion of the gingiva. Pink surface, firm and dull.

• SULCUS:1 mm in width. Surrounds tooth in a collar like fashion to form a small ditch – Depth: 0.5 – 2.0 mm

Question 4

what is attached gingiva?

Answer 4

Firm, resilient,, TIGHTLY bound to the underlying bone.

Surface: orange peel [stippled] like appearance.

Question 5

what are the buccal and lingual aspects like of attached gingiva?

Answer 5

Buccal aspect: extends to the ALVEOLAR mucosa demarcated by the MUCO-GINGVAL JUNCTION

Lingual Aspect: blends with the floor of the mouth.

Alveolar mucosa and ventral surface of the tongue and floor of the mouth aren’t keratinized because they don’t have to withstand that trauma.
Red appearance because the alveolar mucosa has so many blood vessels. Because there is no keratin in this you can see the blood vessels and the appearance is red. The gingiva below it, is keratinized so ou can’t see it very well. There are still blood vessels but you can’t see them.
Alveolar mucosa is loosely attached to the bone.

Question 6

what is the width of attached gingiva and what are the putative functions?

Answer 6

Width: depends on location – widest relative to Max.Incisors and narrowest near Premolars. Av.width: 1.5 – 4 mm

PUTATIVE FUNCTIONS:

Withstand trauma from brushing / mastication

Act as a buffer to dissipate frena/muscle pull resulting in a more stable gingival margin

Putative means they’re not 100% sure, but this is what they think.

Question 7

Alveolar mucosa is what? what is the border?

Answer 7

NON Keratinzed & loosely attached

MUCO GINGIVAL JUNCTION

The position of the M.G.Junction remains stationary throughout life. So any changes in width occurs in a coronal direction.

Question 8

what is the interdental gingival (papilla)?

Answer 8

Occupies space between teeth

Buccal and lingual papilla

Pyramidal in shape. A little flat in the posterior teeth

Question 9

what is the COL?

Answer 9

Valley like depression.
Conforms to the shape of contacts surface.
No contact – No col!
Non keratinized.
Quite vulnerable to infections. 

Susceptible to infections because it is non-keratinized and so it is susceptible more to trauma. Also because it is a concave depression, particles of food or debris can get trapped in there more easily to attract bacteria.

Question 10

what is the histology of the oral epithelium?

Answer 10

Epithelium: Oral, Sulcular, Junctional.

The Oral epithelium is Keratinized, joined to the underlying C.T by the BASAL LAMINA.

Question 11

what is the sulcular epithelium ?

Answer 11

Narrow band of cells

stratified, squamous
non-keratinized epithelium (Has the POTENTIAL to KERATINIZE!)

Relatively impermeable to fluid and cells.

In the sulcular epithelium there are neutrophils. It makes it’s way into the sulcus to engulf the bacteria because it senses the production of materials by the bacteria.

Question 12

how is the junctional epithelium different from the oral epithelium?

Answer 12

Diff.between J.E and Oral.E
Much narrower band of cells.
Larger cell size.
Wider inter cellular space.
Less number of desmosomes.
Absence of rete pegs.
Rapid turnover rate.
Attached to the tooth.

Approximately 1mm in length. The only part of the epithelium attached to the tooth surface.
Junctional epithelium has a turnover of about 8-9 days.
Hemidesmosomes attach the junctional epithelium to the tooth.

Question 13

what is the epithelium-C.T. interface?

Answer 13

Follows a wavy course
Portions of CT project into the epithelium – rete pegs.
The projections are separated by ridges in the epithelium.
These projections and ridges are reflected on the surface as STIPPLES.

When there’s an infection there is edema and the stippled appearance disappears.

Certain genetic factors inherent in the C.T. determine the nature or specificity of the epithelium.

Question 14

what is the predominant components in the connective tissue?

Answer 14

predominant components:
 fibers [see next slide]
 Collagen, reticular, oxytalen, elastic
 cells
 Vessels, nerves
 matrix

The labial frenum is connective tissue. It can separate the middle teeth which is a diastama, or it can be quite long and things might get caught in there more often causing infections.

Question 15

what are the 3 groups of gingival fibers?

Answer 15

There are 3 groups within which gingival fibers are arranged:
Dento gingival group - there are 3 types of fibers within this group:
*fibers that extend towards the crest of the gingiva
*fibers that extend laterally to the outer surface of the gingiva
*fibers that extend outward, past the height of the alveolar crest, and then downward along the cortex of the A.Bone

Circular/circumferential group – unique - they exist entirely within the gingiva and do not contact the tooth

Trans septal group - span the I.P (interproximal) tissue between adjacent teeth, into which they are embedded

Question 16

LOOK AT THE DIAGRAM OF THE DIFFERENT TYPES OF FIBERS IN THE NOTES!!!!!!!

Answer 16

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Question 17

What is a periodontal membrane/ligament?

Answer 17

Def: Soft CT surrounding the roots, joining the cementum to the alveolar bone

Most impt.element:
Principal group of fibers

Question 18

what are the principles group fibers ?

Answer 18

Alveolar crest
Horizontal
OBLIQUE
Apical 
Inter-radicular

Question 19

do periodontal fibers stretch from bone to cementum in a line?

Answer 19

Periodontal fibers do not stretch cable-like from cementum to bone, but form a meshwork of interconnected fibers.

Question 20

what is the oblique group of principle fibers like?

Answer 20

Largest group [2/3 of fibers are oblique (80%) ]

Runs in a coronal direction (CEM –> AB)

Bears the brunt of vertical masticatory forces preventing these forces from driving tooth into the socket.

Question 21

what are the different principle fibers like?

Answer 21

Horizontal - maintain tooth in upright position
Apical – wraps around cementum at the apex

Interradicular – (only in multi-rooted teeth)

Alveolar Crest – attaches cementum just below CEJ to the bone.

Question 22

what are the cells found in the P.L? what does the P.L develop from?

Answer 22

Fibroblasts
Cementoblasts
Osteoblasts and clasts
Epithelial rest cells of Malassez
In addition there are Nerves and Blood Vessels

The PL develops from the Dental follicle:

Formation complete during root development and tooth eruption

The PL develops from the Dental follicle:

Formation complete during root development and tooth eruption

Question 23

what are the physical and formative functions of the P.L?

Answer 23

Physical:
acts as a shock absorber (to a certain extent!)

Formative:
 cells in the P.L are involved in the formation and resorbtion of cementum / bone / C.T,
During Phys.tooth movement
In the Repair process after injury
In response to occlusal forces

Question 24

what are the nutritional and sensory functions?

Answer 24

Nutritional and Sensory

supplies nutrients to cem/B/Ging by way of BV

proprio – receptor cells in the P.L detect and localize external forces on individual teeth.

Question 25

what is the blood supply of the PL?

Answer 25

Blood supply. The PL has a rich blood supply that originates primarily from the dental arteries that enter through the apical foramen and from blood vessels in the adjacent bone marrow spaces.
Anastomoses between these vascular supplies are numerous throughout the ligament. The ligament vessels also communicate with the supra periosteal vessels that supply the adjacent gingiva.