Occlusion

Question 1

What is the main movement of the temporalis muscle?

Answer 1

Retracts the mandible

Question 2

What is the main movement of the lateral pterygoid muscle?

Answer 2

Protrudes the mandible

Question 3

What is the main movement of the medial pterygoid?

Answer 3

Elevates the mandible and causes lateral movements

Question 4

What is the main movement of the masseter?

Answer 4

Elevates the mandible

Question 5

Where does the temporalis originate and insert?

Answer 5

From the temporal fossa and condenses into a tendon which inserts into the coronoid process of the mandible

Question 6

Where does the lateral pterygoid originate and insert?

Answer 6

Has 2 heads
Superior head originates from the greater wing of sphenoid
Inferior head originates from the lateral pterygoid plate of the sphenoid
The 2 heads converge into a tendon which attaches at the neck of the mandible

Question 7

Where does the medial pterygoid originate and insert?

Answer 7

2 heads, deep and superficial
Superficial head originates from the maxillary tuberosity and the pyramidal process of palatine bone
Deep head originates from the medial aspect of the lateral pterygoid plate of the sphenoid bone
Both heads attach to the ramus of mandible near angle of the mandible

Question 8

Where does the masseter originate and insert?

Answer 8

Superficial part originates from the maxillary process of the zygomatic bone
Deep part originates from the zygomatic arch of the temporal bone
Both parts attach to the ramus of the mandible

Question 9

How does the condyle move on protrusion?
Tooth contacts?

Answer 9

Moves forwards and downwards on articular eminence
No posterior tooth contacts
Eventually no tooth contacts

Question 10

What is the retruded axis position?
How is the retruded contact position related to this?

Answer 10

Most superior anterior position of the condylar head in the fossa
Terminal hinge axis
RCP is the first tooth contact when the mandible is in retruded axis position

Question 11

What is lateral translation also known as?

Answer 11

Bennet Movement

Question 12

What is the Bennet Angle?

Answer 12

The path of the non-working condyle in the horizontal plane during lateral excursion
Angle formed by the sagittal plane and the path of the mandibular condyle during lateral movement when viewed in a horizontal plane

Question 13

What are functional cusps?

Answer 13

Cusps that occlude with the opposing teeth in the intercuspal position
The lingual cusps of the upper posterior teeth and the buccal cusps of the lower posterior teeth

Question 14

What are non-functional cusps?

Answer 14

Cusps that do not occlude with the opposing teeth in the intercuspal position
The buccal cusps of the upper posterior teeth and the lingual cusps of the lower posterior teeth

Question 15

What are the ICP contacts?

Answer 15

The lingual cusp of an upper molar contacts the fossa of a lower molar
The buccal cusp of a lower molar contacts the fossa of an upper molar

Question 16

What is an overbite?

Answer 16

Vertical overlap of the incisors

Question 17

What is an overjet?

Answer 17

Relationship between the upper and lower teeth in a horizontal plane

Question 18

What is a crossbite?

Answer 18

Cross bite is a condition where one or more teeth may be abnormally malpositioned buccal or lingually or labially with reference to opposing teeth
Can be posterior or anterior

Question 19

What is an anterior open bite?

Answer 19

Lack of vertical overlap of anterior teeth when posterior teeth are in full occlusion

Question 20

What is a posterior/lateral open bite?

Answer 20

Failure of contact between the posterior teeth when the teeth are in full occlusion

Question 21

What is Canine Guidance?

Answer 21

Mandible moves to the left (working side)
Contact only between the canines
No posterior tooth contacts (a space)
Known as mutually protected occlusion

Question 22

What is Group Function?

Answer 22

Mandible moves to the left (working side), multiple teeth in contact with the left
Bilateral group function frequently seen in toothwear

Question 23

What are occlusal interferences?

Answer 23

Undesirable tooth contacts that may produce mandibular deviation during closure to ICP or may hinder smooth passage to and from ICP

Question 24

Why should you avoid posterior contacts?

Answer 24

Teeth are designed to absorb heavy forces in the direction of the long axis of the tooth
Most teeth are not designed to absorb significant lateral forces generated by occlusal interferences
Musculature gets a rest as less activity if not undesirable posterior contacts
Occlusal trauma and undesirable tooth movements

Question 25

What is eccentric bruxism?

Answer 25

The parafunctional grinding of teeth
An oral habit consisting of involuntary rhythmic or spasmodic or functional gnashing, grinding or clenching of teeth in other than chewing movements of the mandible which may lead to occlusal trauma

Question 26

What is centric bruxism?

Answer 26

Clenching
The pressing and clamping of the jaws and teeth together
Frequently associated with acute nervous tension or physical effort

Question 27

What are the clinical signs and symptoms of bruxism?

Answer 27

Toothwear
Fractured restorations
Tooth migration
Tooth mobility (often in absence of periodontal disease)
Muscle pain and fatigue
Headache
Earache
Pain and stiffness in the TMJ and surrounding muscles

Question 28

What is occlusal trauma?
Primary?
Secondary?
Fremitus?

Answer 28

Injury resulting in tissue changes within the attachment apparatus, including periodontal ligament, supporting alveolar bone and cementum, as a result of occlusal force
Primary
-Intact periodontium
Secondary
-Reduced periodontium
Fremitus
-Palpable or visible movement of a tooth when subjected to occlusal forces