Introduction to occlusion W11

Question 1

What is the definition of occlusion

Answer 1

Contact relationship between maxillary and mandibular teeth when the teeth are in function/parafunction (abnormal movement)
Position/relationship of upper and lower teeth when jaws close/are in function

Question 2

Describe the difference between a static occlusal relationship and a dynamic occlusal relationship

Answer 2

Static: relationship when jaws are closed
Dynamic: relationship during movement

Question 3

What effects occlusal contacts (extraoral and intraoral)

Answer 3

• Skeletal base relationship (condylar head vs slope of articular eminerce, glenoid fossa) - principle and acessory muscles of mastication/jaw movements, TMJ and skeletal relationship
• Development of maxilla and mandible
• Factors affecting development, position and shape of the teeth themselves

Question 4

What does CR stand for

Answer 4

Centric Relation
The most centric or relaxed position of the condyle in a TMJ
- closed jaw but not clenched

Question 5

Describe Centric Occlusion

Answer 5

Occlusal relationship of maxillary teeth with mandibular teeth when the condyles are in centric relationship
- How/position the teeth are meeting in (individual)

Question 6

Describe Retruded Position (RP)

Answer 6

Position of condyle in posterior superior positon during TMJ movements

Question 7

Describe retruded contact positon (RCP)

Answer 7

First contact point of teeth when the condyles are in retruded positon

Question 8

Describe Intercusptal positon (ICP)

Answer 8

Cups to fossa relation of maxillary and mandibular teeth

Question 9

Describe anterior relationship of overjet and overbite

Answer 9

Overjet: horizontal overlap of maxillary teeth over mandibular teeth
Overbite: verticle overlap of maxillary teeth over mandibular teeth

Question 10

Describe angle classification of occlusion for…
* Class 1 malocclusion
* Class 2 malocclusion
* Class 3 malocclusion

Answer 10

• Class 1 malocclusion: molar relationship is normal but teeth are not symmetic in the arch
• Class 2 malocclusion: Retrognathic! Md back or Mx foward
  Divison 1: teeth proclined Mx teeth Divison 2: Mx teeth retruded
• Class 3 malocclusion: Prognathic! Md foward

Question 11

Describe Class 1 normal occlusion

Answer 11

Class 1 normal occlusion: Orthognathic! Mesio-buccal cusp of the Mx 1st molar is aligned with the buccal groove of the Md 1st molar (between cusps) AND Mx canines sit between Md 1st pre-molar and Md canine

Question 12

Constract dental occlusion vs skeletal relationships in terms of class 1,2 & 3

Answer 12

Teeth protruding or retruding
Skeletal involves jaw protruding or retruding

Question 13

What are the three curves/planes of occlusion

Answer 13

• Curve of Wilson
• Curve of Spee
• Curve of Monsoon

Question 14

Describe the curve of Spee

Answer 14

Anteroposterior curvature of the occlusal surfaces - tips of cupids, bicuspids and molars (anteriors-posterior arch)
If the curve was to continue it would make a circle 4 inches in diameter

Question 15

Describe the curve of Wilson

Answer 15

Occlusion is spherical in frontal plane. Joining cusp tips of Md and Mx teeth on opposite side of arches
- enables smooth functioning of lateral excursions without interferences

Question 16

Dynamic occlusion includes…

Answer 16

• Rotation/hinge axis
• Translation
• Lateral movements
• Complex movements

Question 17

Describe dynamic occlusion on rotation/hinge axis

Answer 17

Opening and closing on imaginary horizontal hinge axis through head of the condyles

Question 18

Describe translation

Answer 18

Condyle shifts foward

Question 19

Describe lateral occlusion

Answer 19

Side to side excursions and lateral closing

Question 20

Compare the working and non-working side

Answer 20

During mandibular lateral excursions the side of the mouth to which the mandible has moved towards = working side - usually chewing food, side of the mouth from which the mandible has moved away = non-working side.

Question 21

Explain maximum opening

Answer 21

1st phase: hinge axis opening without moving mandible 20-25mm (HO)
2nd phase: mandible glides out, translation of condyle, further rotation (MO)

Question 22

Differentiate between functional and non-functional cusps

Answer 22

Functional: working cusps on working side (food present)
* Usually palatal cusps of Mx posterior teeth and buccal cusps of Md posterior teeth.

Non-functional: do not occlude with the opposing teeth in centric occlusion.
* Usually buccal cusps of Mx posterior teeeth and lingual cusps of Md posterior teeth.

Question 23

There are two approaches by which to manage a patients dentition to restore proper function long-term and analyse occlusion. What are they?

Answer 23

1. Conformative approach: no change to pre-existing occlusal relationship. ‘simple’
2. Re-organised approach: changing pre-existing occlusal relationship to rehabilitate major discrepancies. ‘complex’

Question 24

How do you check the direct occlusal contact relationships in the patients mouth?

Answer 24

1. Articulating paper: thin rectangular strip or U shaped placed between teeth. Thinner = more accurate.
2. Shimstock: 8um thick, almost gives true occlusion
3. Clinical observation: visually assess dental contacts, taking a mental note

Question 25

Which two ways (forms) can you check occlusion before starting and after finsihing a resoration?

Answer 25

Static assessment - patient taps their teeth together and keeps closed, one colour paper
Dynamic assessment - patient closes sliding side-to-side and back-to-front, different coloured papers

Question 26

In which three areas are articulating paper used

Answer 26

• On restored tooth/teeth and their adjacent neighbours
• Just on mesial neighbour
• On the opposite side that is not numb
  resistance in paper = equilibrium

Question 27

Should you remove all the contact marks the articulating paper has created on the teeth?

Answer 27

No, do not remove all the marks but rather reduce the heavy areas until balance and coincidental timing is achieved.
Areas of high pressure/heavy contact = dark/dense marking