Quiz 1

Question 1

Ligaments Supporting the Tempromandibular Joint and the Mandible

Answer 1

Limit mandibular movement.
Protect the musculature, especially during extreme movement.
They are non-elastic, non.contractile, and do not have innervation.

Question 2

Stylomandibular Ligament

Answer 2

Limits excessive protrusive movements of mandible.

Question 3

Sphenomandibular Ligament

Answer 3

Limits protrusive movement and lateral mandibular movement to either side.

Question 4

Limitations of Movement with Tempromandibular Ligament

Answer 4

The position of the TMD is designed to limit pure hinge axis rotational movement of the mandible
Full length of TMD occurs at no more than 15-20 mm of the opening as measured between the incisal edge of the maxillary and mandibular incisors.

Question 5

The Temporomandibular or Articular Disk

Answer 5

Fibrous connective tissue.
Interface between the mandible and temporal bone.
Pliable in texture.
Bi-concave in shape.
Collateral ligament attach it to condyle in a medial and lateral position.
No innervations or vascularizations.

Question 6

Maximum Intercuspation

Answer 6

AKA centric occlusion (CO), which is now obsolete term.
MI describes an occlusal relationship or tooth position.
Commonly referred to as habitual occlusion or habitual centric, because the patient can achieve this position by habit.
Teeth are contacting in position that patient finds most comfortable.
Easily achievable, but not always reproducible.

Question 7

Features of the temporomandibular or articular disc

Answer 7

● Consists of fibrous CT (“NOT HYALINE CT”)
● Interfaces between the mandible and the temporal bone
● Somewhat pliable in texture
● Bi-concave in shape
● Collateral ligaments attach it to the condyle in a medial and lateral position
● No innervation
● No vascularization

Question 8

Terminology Describing Tooth Position: Maximum Intercuspation

Answer 8

● AKA centric occlusion (CO) -obsolete term, intercuspal position
● Commonly referred to as habitual occlusion or habitual centric, because the patient can achieve this position by “habit” (subconsciously)
● Maximum intercuspation describes an occlusal relationship or tooth position
○ # teeth needed to achieve maximum intercuspation varies w/ ea. pt; most likely posterior teeth
● The teeth are contacting in a position that the patient finds most comfortable
● It is easily achievable, but not always reproducible by the patient

Question 9

Clinical conditions regarding the slide from centric relation to maximum intercuspation

Answer 9

● Only 15% of the population have no centric relation to maximum intercuspation discrepancy meaning they have no slide
● For patients with a slide (remaining 85%), after the first occlusal contact in centric relation is obtained (this is usually on two or more posterior teeth), the patient continues to close and slides on inclines of posterior teeth (“You don’t slide on the inclines of anterior teeth”)
● The maxillary and mandibular teeth will come together more completely in the maximum intercuspation position
● The condyles must move out of their most ideal position (out of fossa) when the teeth come fully together and this position is anterior, superior and slightly lateral to the maximum intercuspation position

Question 10

Canine Protected Articulation

Answer 10

○ Implies that only the canines are touching during the complete extent of lateral movement
○ Considered the ideal occlusal scheme

Question 11

Group Function Occlusion

Answer 11

○ Entails that one or more of the posterior teeth, in combination with some of the anterior teeth are in some degree of contact during the complete extent of lateral movement
○ Considered secondary occlusal scheme or the most practical approach
○ Commonly exhibited in older patients (more common than canine protected articulation)

Question 12

Summary of characteristics of an ideal occlusion

Answer 12

● Centric relation and maximum intercuspation occur simultaneously (no slide)
● All teeth contact simultaneously
● All occlusal forces on posterior teeth are directed down the long axis of the teeth
● Posterior tooth contacts dominate over anterior tooth contacts
● All eccentric movements are guided by the anterior teeth
● No crossover contacts on posterior teeth should be seen!!

Question 13

Correct Alignment of the Articular Disc

Answer 13

● Proper alignment of the articular disc is slightly anterior and the thinnest, and most articulated portion is in the middle section

Question 14

Actions of the Masseter

Answer 14

● Elevate the mandible in a superior direction to eventually contact the maxillary teeth → closes mandible
○ This is considered normal functional activity
● Causes clenching of the teeth
○ This is considered parafunctional activity
● Aids in protrusive movements
○ The masseter is not primary muscle to produce protrusive movement
● Minimally aids in lateral movement
○ The masseter is a very minor player to produce lateral movement

Question 15

Actions of the Medial Pterygoid

Answer 15

● A minor player in clenching of the teeth
○ This is considered parafunctional activity
● Normal functional activity
○ Elevates mandible in superior direction to eventually contact maxillary teeth → closes mandible
○ aids in with protrusive movement (NOT the primary m.)
○ primary muscle of mastication that produces mediotrusive movement

Question 16

Functions of Lateral Pterygoid - Inferior Head-

Answer 16

● Normal functional activity:
○ It is active during opening movements of the mandible (“Not active during closing, you would never say it is very active during closing”)
○ It is the primary muscle of mastication involved with protrusive movements
○ It is the primary muscle of mastication that produces lateral movements
● Parafunctional activity:
○ It is the most frequent muscle of mastication to exhibit a spasm as a result of some type of occlusal dysfunction
● This muscle of mastication is so deep in placement, that it cannot be palpated by the clinician

Question 17

Suprahyoid Accessory Muscles

Answer 17

● Collective action or function of the suprahyoid accessory muscles of mastication:
○ Elevate hyoid bone
○ Elevate the base of the tongue
○ Depress the mandible when hyoid bone is fixed
○ Assist in stabilizing the cranium and the mandible during normal mandibular movements
○ Important for control over the pharynx and esophagus during swallowing and speaking activities

Question 18

Normal Jaw Opening Movement - Early

Answer 18

● The inferior head of the lateral pterygoid contracts
○ This is in a controlled, slow and consistent manner
● The condyle will move more anteriorly
○ It actually progresses down the slope of the articular eminence at the beginning of the posterior border of the eminence
● The articular disc will move with condyle
○ This is as a result of the superior head of the lateral pterygoid muscle minimally contracting
○ The condyle interfaces with the thin midsection of the articular disc
● The superior retrodiscal tissues undergo a slight tautness
○ As an attachment to the posterior section of the articular disc and a counterbalance to the superior head of the lateral pterygoid muscle