TMJ & Oral Mucosa

Question 1

Describe the condyle process

Answer 1

1. Wider mesiodistally than anteroposteriorly
2. Rounded posteriorly, concave anteromedially (pterygoid fovea, where inf. head of lat. pterygoid attach)
3. The superior anterior aspect (articular surface) is slightly convex
   * The condyle and the articular tubercle are covered by fibrous C.T

Question 2

The articular disc is attached to …….

The …… muscle is attached to the disc

Answer 2

the articular tubercle (eminence) & laterally to the condyle head
* Superior head of the lateral pterygoid is inserted into the disc

Question 3

Describe the condyle movement during the following

1. retrusive movement
2. protrusive movement
3. lateral movment
4. lateral protrusive movement

Answer 3

1. both condyles move backward & upward into the mandibular fossa
2. both condyles move downward and forward on the eminence
3. working side: mere rotation. non working side: forward, downward & medially
4. working side: rotation & forward/downward. non working side: forward, downward & medially

Question 4

All teeth are inclined to a certain degree. T/F??

Answer 4

true

Question 5

All teeth are facially inclined except …..

Answer 5

• Mand. second premolar (straightest tooth in relation to the occlusal plane)
• Mand. molars (lingual tilt)

Question 6

The tooth with the greatest facial tilt is ……..

Answer 6

Max. central incisor

* followed by Max. lateral incisor, and Mand. incisors

Question 7

The tooth with the greatest mesial tilt is …..

Answer 7

the Max. canine

Question 8

All teeth have some degree of mesial tilt, except ……

Answer 8

Max. central, and Mand. incisors (which are distally tilted)

* The premolars are not tilted

Question 9

Define:

1. Curve of Spee

2. Curve of Wilson

Answer 9

1. Anterior posterior relation of teeth view from lateral aspect (Convex for Max., concave for Mand.)
2. The tilting of the Max. teeth facially and the Mand. teeth lingually gives a convex Max. profile & a concave Mand. profile when view from the front

Question 10

All Mand. roots are tilted ……. & the posterior Mand. are angled ……..

Answer 10

distally

facially

Question 11

All Max. roots are tilted ….. & all posterior roots are inclined …….. except …..

Answer 11

distally

lingually, except the DB root of the Max. first molar (buccal tilt)

Question 12

Posselet envelop defines ……

Answer 12

the borderline (extent) movement of the mandible.

Question 13

In most of the population, IC (centric occlusion) is about ……. anterior to the RC (centric relation)

Answer 13

1. 25 mm
   * From IC to RC, the mandible moves downward & posteriorly
   * See p. 749

Question 14

The mandible is capable of two opening movement while in the retruded position, …… & …….

Answer 14

1. Pure rotational: the first 20 mm separation, then the ligament become taut
2. Translational movement: after relaxation of the ligament, the condyle moves down the articular eminence. This movement occur in regular mouth opening

Question 15

The line that connects the maximum opening to the protruded contact position is ……..

Answer 15

protrusive opening path

Question 16

Freeway space is …….

Answer 16

the distance from IC to RP (resting position). It is about 3 mm
* The mandible is in postural position

Question 17

The oral mucosa is composed of ……

The oral mucosa is two types:

Answer 17

surface epithelium & lamina propria

• Beneath the mucosa comes the submucosa
  1. Keratinized: not present normally except the masticatory mucosa or irritation
  2. Non keratinized

Question 18

Non Keratinized mucosa lacks……..

It is composed of ….. & …….

Answer 18

stratum granulosum & stratum corneum

• Composed only of
  1. Stratum basale
  2. Stratum spinosum (large area, since the other two are not present)

Question 19

Basement membrane (lamina) is located between ......... & ........
It is composed of two layers:

Answer 19

the epithelium & lamina propria

• Two layers:
  1. Lamina lucida: Beneath the epithelium
  2. Lamina densa: Beneath lucida. Connects the above layers to lamina propria

Question 20

The basal cell layer is ……..

Answer 20

a single layer of nucleated cuboidal cells resting on the basement lamina
* It is the mitotic layer

Question 21

The spinosum cell layer (prickle layer) is …..

Answer 21

composed of nucleated polyhydral cells, larger in non keratinized epithelium. Towards the surface, the cells flatten
* The term prickle cell is caused by fixative, due to pulling of the cell membrane from adjacent cells, while the desmosomal attachment remains intact

Question 22

Stratum granulosum is ……..

Answer 22

a layer of flattened cells, contain “keratohyaline”

Question 23

Stratum lucidum appears in …….

Answer 23

thick skin (soles) and not in the oral mucosa

Question 24

Stratum corneum is composed of ……

Answer 24

cells that have lost their nuclei & filled with keratin

Question 25

There is no keratinization potential in mucosa that abuts .......

Answer 25

against a hard surface (not subject to irritation) | * example is sulcular epithelium

Question 26

Lamina propria is ......... Its extensions in the mucosa is called ...... LP rests on ........

Answer 26

dense CT papillae * In turn, epithelium has rete pegs extension into the propria * Submucosa

Question 27

Vermilion border is .....

Answer 27

transition zone between the mucous membrane & the skin of the lip * Non keratinized, with long papillae close to surface (giving red color) and few sebaceous glands * Note that: the skin of lip is keratinized, short papillae with sebaceous & sweat glands & hair

Question 28

In the masticatory epithelium, submucosa is ....., and the lamina propria is .... The exception is ......

Answer 28

indistinguishable (thin or absent) fused to periosteum hard palate (has definite submucosa, except for the raphe)

Question 29

What is the difference between orthokeratinized & parakeratinized mucosa?

Answer 29

1. ortho: have true keratin (like skin epithelium) | 2. para: keratinized cells retain their nuclei

Question 30

Masticatory mucosa is immovable because ....

Answer 30

lamina propria (distinguishable or not) is firmly attached by fibrous bands to the periosteum

Question 31

The submucosa in the palate has ...... anteriorly & ....... posteriorly

Answer 31

adipose tissue | adipose tissue & glands posteriorly

Question 32

Junctional epithelium is ....

Answer 32

non kertinized epithelium which lies at the base of the gingival sulcus, and is attached to the surface of the tooth with hemidesmosomes at the CEJ level * Roughly 1 mm in width * Lacks rete ridges, that is why susceptible to break down by bacteria

Question 33

Lining mucosa covering muscles are fixed to .....

Answer 33

epimysium or fascia of respective muscles

Question 34

Non masticatory mucosa covers .....

Answer 34

soft palate, ventral surface of tongue, floor of the mouth, cheek, lip, some of the free gingiva, and the alveolar mucosa

Question 35

What are the differences between attached gingiva (ag) & alveolar mucosa (am)?

Answer 35

1. ag: stippled & firm. am: thin & loosely attached 2. ag: no separate submucosa. am: submucosa is well defined 3. ag: immovable. am: movable 4. ag: no glands. am: full of glands 5. ag: epi thick and keratinized. am: thin & non keratinized 6. ag: high epi ridges. am: low epi ridges