10.

Question 1

What functions does the masseter muscle have? (3)

Answer 1

• elevation of the mandible
• chewing
• protruding

Question 2

What functions does the temporalis muscle have? (2)

Answer 2

• mandible elevation

- mandible follows the direction of the portion of fibers contracting

Question 3

What functions does the pyergoideus medialis muscle have? (3)

Answer 3

• elevation
• protrusion
• mediotrusion

Question 4

What are the two divisions of the pyergoideus lateralis?

Answer 4

• inferior

- superior

Question 5

Function of the inferior lateral pterygoid?

Answer 5

• lateral movements
• lowering of mandible
• protrusion

Question 6

Function of the superior lateral pterygoid?

Answer 6

• articular stability of TMJ

- activates when forcing the ICP position

Question 7

Function of the digastricus?

Answer 7

• depression of the mandible
• opening
• swallowing

Question 8

What muscles are involved with protrusion? (2)

Answer 8

Lateral pterygoid assisted with medial pterygoid

Question 9

What muscles are involved with retraction? (4)

Answer 9

• posterior fibers of temporalis
• deep part of masseter
• geniohyoid
• digastric

Question 10

What muscles are involved with elevation? (3)

Answer 10

• temporalis
• masseter
• medial pterygoid

Question 11

What muscles are involved with depression? (3)

Answer 11

• digastric
• geniohyoid
• mylohyoid

Question 12

How much are teeth separated during mouth opening without condyles moving from the fossae?

Answer 12

20-25mm

Question 13

What occurs when the mouth opens wider than 20-25mm? (3)

Answer 13

• Ligaments are fully extended
• Condyles move downward and forward out of the
  fossae
• It is called the second arc of opening

Question 14

What is a predisposing factor?

Answer 14

Increase the risk of appearance of the disorder

Question 15

What is a precipitating factor?

Answer 15

They activate the process

Question 16

What is a perpetuating factor?

Answer 16

They prolong the situation

Question 17

What are the five principal etiological factors in the apparition of TMD?

Answer 17

• Occlusal condition
• Trauma over structures of the masticatory system
• stress
• deep pain input
• parafunctional activities

Question 18

What is the optimum occlusion?

Answer 18

MI & condyles are in their most superoanterior position resting over the posterior slopes of the articular eminences with the discs properly inserted

Question 19

What is a prematurity? (2)

Answer 19

• happen at MI/CR

- avoids ICP in a retruded position

Question 20

What is an interference? (3)

Answer 20

• undesirable contact during eccentric movements

Question 21

What is the ideal articulation for a dentate patient?

Answer 21

Mutually protected articulation

Question 22

What is the worst intereference?

Answer 22

on the NWS

Question 23

Define protrusion (2)

Answer 23

• Mandible moves forward the ICP

- predominant protrusive contact is between the anterior teeth

Question 24

What is a static occlusal factor?

Answer 24

predisposing occlusal factor

Question 25

What can affect the occlusal condition? (5)

Answer 25

- Static occlusal factors - Orthopedical instability of the jaw - Acute changes in the occlusion - chronic changes in the occlusion - types of occlusal interferences

Question 26

What are the static occlusal factors?

Answer 26

``` – Musculoskeletal anterior open bite – Displacement (deviation) from CR to MI of more tan 2mm – Absence of anterior guidance: interferences. – Overjet greater than 4mm – 5 teeth or more missing. ```

Question 27

How does orthopedical instability of the jaw affect occlusal condition? (3)

Answer 27

– Dynamic oclusal factors, like the prematurities, forces a sliding to reach the InterCuspalPosition. – Overexertion of the external pterygoid and intracapsular disorder of the TMJ, specially when subject to higher forces (ex: Bruxism) – Discrepancies of 2 to 3mm are one of the principal factors involved in a TMD

Question 28

How does acute changes in the occlusion (interferences) affect occlusal condition? (2)

Answer 28

- Increase the muscular tone and it´s hyperactivity that can lead to symptoms of the elevator muscles due to aprotective co-contraction – Muscles develop a new way of avoiding the interferences – The patient generally adapts to the new situation. – If it becomes a chronical occlusal situation associated to the stress factor, a parafunctional activity can appear – Sleep bruxism is more associated to the stress and sleep alterations than with the apparition of acute interferences

Question 29

How do chronic changes in the occlusion affect occlusal condition ? (4)

Answer 29

``` – Occlusal interferences due to the migration of teeth adjacent/antagonist to an edentulous ridge – The apparition of a small interference, mantained over the time, can also be converted into a chronical one. – In those cases, there is a failure of the proprioceptive defensive system that was used to avoid the interference – In those situations, the mandible does not try to avoid the interferences, but unconsciously grinds the area creating the subsequent wear ```

Question 30

Adaptation of chronical changes in the occlusion?

Answer 30

``` The musculatory system tend to adapt to avoid the nocive contacts (adaptative reflex). More frequent when not associated to stress ```

Question 31

TMD of chronical changes in the occlusion?

Answer 31

A parafunction is developed by the patient for an increase of emotional factors (stress), that leads to the typical muscular hyperactivity associated to bruxism

Question 32

What are the types of occlusal interferences? (3)

Answer 32

Prematurites causing more than 2mm discrepancies -– The factor that is mostly associated to TMD, it creates an overloading of both pterygoid muscles or one of them – Pain during the palpation and functional manipulation of the inferior external pterygoid muscle

Question 33

Make cards for slide 23-24

Answer 33

go

Question 34

What are the different types of trauma over the masticatory system?

Answer 34

- Macro trauma | - Microtrauma

Question 35

What is defined macrotrauma of the masticatory system? (3)

Answer 35

- intense and sudden force - Intracapsular disorders - Elongation of the ligaments and disc displacement

Question 36

What is an example of macrotrauma of the masticatory system? (2)

Answer 36

– Accident, practicing sports, a fight, etc... – Iatrogenic trauma: intubation during general anesthesia, complex tooth extraction,...

Question 37

What is defined as microtrauma of the masticatory system? (3)

Answer 37

- Small repetitive forces over the same structures during a long period of time. - Ex; grinding teeth, bruxism - If associated to orthopedical instability in the IPC; high risk of elongation of the ligaments