Occlusion

Question 1

Give the features of the intercuspal position

Answer 1

• the comfortable bite
• best fit for teeth
• also known as centric occlusion
• maximum interdigitation of teeth

Question 2

Give the features of an edge to edge occlusion

Answer 2

• teeth slide forward from intercuspal guiding on palatal surfaces of anterior teeth
• incisal edges of upper and lower incisors touch

Question 3

give the features of mandibular protrusion

Answer 3

• no posterior tooth contacts (only incisors and sometimes canines)
• eventually no tooth contacts
• condyle moves forwards and downwards on articulator eminence

Question 4

Give the features of maximum opening

Answer 4

• no tooth contacts
• mouth wide open
• full translation of condyle over articular eminence

Question 5

Give the features of a retruded axis position

Answer 5

• no tooth contacts
• most superior anterior position of condylar head in fossa
• terminal hinge axis

Question 6

Give the features of a retruded contact position

Answer 6

• first tooth intact when the mandible is in retruded axis position
• ICP is approximately 1mm anterior to RCP in 90%

Question 7

what is the Bennet movement?

Answer 7

lateral translation of the mandible

Question 8

what causes lateral movement of the mandible?

Answer 8

• contraction of one lateral pterygoid muscle
• when one contracts the mandible moves to opposite side

Question 9

what are functional cusps?

Answer 9

cusps that occlude with opposing teeth in the intercuspal position
- lingual cusps of upper posteriors
- buccal cusps of lower posteriors

Question 10

what are non functional cusps?

Answer 10

cusps that do not occlude with opposing teeth in the intercuspal position
- buccal cups of upper posteriors
- lingual cusps of lower posteriors

Question 11

What is the fossa of a tooth?

Answer 11

• depression or concavity on tooth surface
• functional cusp of a tooth contacts fossa of opposing tooth

Question 12

What is an overbite?

Answer 12

vertical overlap of incisors

Question 13

What’s an overjet?

Answer 13

The relationship between the upper and Lower teeth in a horizontal plane

Question 14

What is a cross bite?

Answer 14

A condition where one or more teeth may be abnormally malpositioned buccal or lingually or labially with reference to the opposing teeth

Question 15

what is an anterior open bite?

Answer 15

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

Question 16

what is a posterior open bite?

Answer 16

failure of contact between Posterior teeth when teeth are in full occlusion

Question 17

What is canine guidance (mutually protected occlusion)

Answer 17

When mandible moves to working side:
- only the canines contact
- no posterior tooth contacts leaving a space between them

Question 18

What is group function?

Answer 18

mandible moves to working side
- multiple teeth in contact on working side
- bilateral group function frequently seen in toothwear

Question 19

Name the types of occlusal interference

Answer 19

• working side
• non-working side
• protrusive

Question 20

What is protrusive interference?

Answer 20

• any posterior contact during protrusion

Question 21

What are the 2 types of bruxism?

Answer 21

• eccentric
• centric

Question 22

what is eccentric bruxism?

Answer 22

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

Question 23

what is centric bruxism?

Answer 23

• clenching
• pressing and clamping of jaws and teeth together
• associated with acute nervous tension

Question 24

Give the clinical signs of bruxism

Answer 24

• tooth wear
• fractured restorations
  = tooth migration
• tooth mobility often in absence of Perio disease
• muscle pain and fatigue
• headache
• earache
• pain and stiffness in TMJ and surrounding mucles

Question 25

Name the different types of tooth wear

Answer 25

• multifactorial
• abrasion
• attrition
• erosion
• abfraction