Week 2- Occlusion

Question 1

What are the 3 rules to follow with occlusion?

Answer 1

• To have bilateral and even occlusal contact.
• The disclusion of posterior teeth during canine guidance
• An unobstructed envelope of function.

Question 2

What happens when a tooth interferes with full closure?

Answer 2

• Trigger deflective interferences
• Hypersensitivity
• Abfractions
• Mobility
• Excessive wear or fractures,
• Muscle/TMJ pain.

Question 3

What can posterior teeth deflections create?

Answer 3

May create occlusal avoidance pattern leading to excessive anterior tooth wear

Question 4

What does anterior and canine guidance allow for?

Answer 4

Immediate disclusion of molars and premolars when making lateral or protrusive movements. In doing so, masticatory muscles significantly decrease activity and there is decreased force applied to anterior teeth.

Question 5

How does muscle function differ between when posterior teeth touch vs anterior teeth touch?

Answer 5

• When posterior teeth touch, the muscles can function with full force.
• When only anterior teeth touch, the forces decrease significantly.

Question 6

What happens if a patients posterior teeth don’t disclude during lateral movements?

Answer 6

Posterior teeth grind over each other with full muscular force. It is typical to see these patients with severe signs and symptoms of occlusal disease.

Question 7

What is meant by an unobstructed envelope of function?

Answer 7

Freedom of movement during chewing that swings md forward (protrusively) during the closure movement, returning back into the centric stop.

The correct amount of overjet allows the space for this protrusive movement to occur without interference.

Question 8

What are some interferences to the anterior path of closure?

Answer 8

• Insufficient overjet
• Lingual morphology of the anterior teeth not concave enough

Question 9

What movements are involved in Posselt’s envelope of motion?

Answer 9

• RCP
• Intercuspal Contact position
• Protrusive
• Rotational
• Translational

Question 10

What is the working side and non-working side?

Answer 10

Working side: same side as you slide

Non-working: side not being engaged

Question 11

What is canine guidance?

Answer 11

When you slide your teeth to one side and your canine is the only one that guides your teeth.

Question 12

What is group function?

Answer 12

Contacting more than one tooth when you move your jaw in a sideways motion

Question 13

What will you likely see in patients with group function?

Answer 13

Abfraction, cracks, fractures

Excessive wear on anteriors

Question 14

Why is anterior guidance favourable to group function?

Answer 14

The constant pressure is taken off the posterior teeth, allowing for a more balanced distribution of the force over all our teeth.

Question 15

What happens to posterior teeth if patient has anterior open bite?

Answer 15

Posterior teeth with grind against each other

Question 16

If patient has violation of envelope of function, how can you stop it getting worse?

Answer 16

Occlusal splint

Question 17

What is centric occlusion also known as?

Answer 17

Habitual bite

Bite of convenience

Question 18

What is centric relation?

Answer 18

Relationship of md to mx when the articular disc is in place and the head of the condyle is in its most superior part of the distal facing incline of the glenoid fossa.

Question 19

What is VDO?

Answer 19

Vertical dimension when teeth/substitute materials are in contact in the RCP.

Question 20

What is curve of spee?

Answer 20

When you run line through middle of condyle and occlusal surface of teeth

Question 21

What is a clue to a potential steep curve of spee?

Answer 21

Excessive wear on the occlusal surfaces of molars.

Question 22

Where does curve of Wilson have significance?

Answer 22

In the smooth lateral translation of the condyle

Question 23

What is the greatest problem associated with excessive overbite?

Answer 23

Trauma to gingival tissues on palate

Question 24

Why is it difficult/impossible for patients with overbites to wear mx occlusal splints or partial dentures?

Answer 24

No room for thickness of acrylic without opening posterior occlusion

Question 25

Which bite disorder is the most detrimental to the teeth and TMJ?

Answer 25

Deep overbite

Question 26

What issues can be associated with malocclusion?

Answer 26

• Damage to teeth and gums
• Headaches
• TMJ disorder
• Hearing difficulties and digestive problems

Question 27

What is occlusion?

Answer 27

Itntegrated action of the jaw muscles, TMJ, and teeth.

Question 28

Interpret the following OPG

Answer 28

• Condylar remodelling
• Interference with opposing 17 on 47 causing thickening of PDL space
• Bridge abutment dislodged
• Incisal wear

Question 29

Why does gonial notching occur?

Answer 29

Masseter muscle inserts in this area. When clenching teeth, it is pulled up.

Question 30

Interpret the following OPG

Answer 30

• Gonial notching
• 12-23 incisal wear
• Condylar head remodelling

Question 31

How are anterior guidance and condyles related?

Answer 31

When you go onto protrusion, and you start to get wear of the anterior teeth, the condyle starts to remodel.

Question 32

What is a starting point for evaluating occlusion?

Answer 32

Intraoral evaluation of CR contacts

Diagnostic casts (mount in CR)

Compare CR and MI

Question 33

What is the benefit of duplicated casts coated with project paint?

Answer 33

Paint allows easy visualisation of the areas that have not been reduced.

We can use articulating paper in the pts mouth to see contacts in CR and compare intraoral marks with the stone cast adjustments. Can then adjust the mouth in a manner similar to the stone casts. After adjustment, CR should equal MI.

Question 34

Who are occlusal splints recommended for?

Answer 34

People with bruxism.

Question 35

What are characteristics of a good splint?

Answer 35

• Flat
• Contacting all teeth
• Not too thin, bulky or tight

Question 36

What tray do we use for mx vs md impressions for splint?

Answer 36

• Mx: metal tray
• Md: disposable plastic tray

Question 37

What is the issue with NTI splints?

Answer 37

• Can get overeruption of posterior teeth
• Anterior open bite
• Sore anterior teeth

Question 38

What is normal interarch space?

Answer 38

Interarch space should be 16-20mm but in atrophic mandible it is greater (dentures will be larger and heavier)

Question 39

How should patient with angular cheilitis be managed?

Answer 39

• Remake dentures with increased vertical dimension.
• As temporary measure, prescribe Kenalog with Orabase (corticosteroid)

Question 40

What can an excessively increased VDO lead to?

Answer 40

• Onset of joint and muscle pain
• Tension in functional speech
• Difficulty swallowing
• Impaired chewing
• Pathologic bone resorption
• Abnormal wearing of teeth
• Appearance of elongated face
• Facial expression fatigue

Question 41

What are fovea palatini and their relevance to mx dentures?

Answer 41

2 indentations on each side of midline, formed by coalescence of several mucous gland ducts. They aid in locating the vibrating line and posterior border of denture.

Question 42

When is surgical correction required for palatal tori?

Answer 42

If tori are very large and extend to the vibrating line.

Question 43

What is zygomatic process?

Answer 43

Located opposite to the first molar region. Sometimes denture require relief in this area.

Question 44

When should a lower splint be used rather than an upper?

Answer 44

If pt has 100% overbite, place lower splint rather than upper splint.

Question 45

What is the typical thinning of teeth due to?

Answer 45

Violation of envelope of function

Question 46

What is a common pattern seen when there is violation of envelope of function?

Answer 46

Severe “thinning” of incisal edges, or wear of the palatal surface of the maxillary anterior teeth with wear of the facial of mandibular anterior teeth.

Question 47

What is this caused by?

Answer 47

Violation of envelope of function (ceramic crown wearing opposing teeth)