W2 - Occlusion - Abbott

Question 1

3 Rules of Occlusion

Answer 1

1. Even, bilateral occlusal contact
2. Must be disclusion of posteriors during canine guidance
3. Unobstructed envelope of function

Question 2

Why is canine guidance important (2)

Answer 2

Greatly reduces forces on anterior teeth

• When posterior teeth toch, MoM function with full force
• When only anterior teeth touch, force decreases significantly

Reduces of grinding on posterior teeth

• If pt lacks canine guidance, posteriors will grind with full force on lateral movements → typical to see pts with severe attrition and wear on posteriors when no guidance

Question 3

What is meant by “Envelope of Function” and why must it be unobstructed

Answer 3

Refers to the forward swing of the md while chewing

• Requires correct overjet of anteriors, correct concavity of mx incisors

Interference may cause:

• scraping of anterior teeth
• increased wear
• Thinning of incisal edges
• wear of lingual surface of mx incisors
• wear of labial surface of md incisors
• pt will complain that bite feels “high”

Question 4

What is group function?

Answer 4

More than one tooth is contacting during lateral excursion

• Posteriors are subjected to excess pressure

Question 5

What’s happening here?

Answer 5

Group function resulting in excess wear

• NO canine guidance

Question 6

What happened here?

Answer 6

Violation of envelope of function causing “thinning” appearance

Question 7

Answer 7

Ceramic crown wearing opposing teeth

Question 8

Answer 8

Crown fracture caused by breach of envelope of function

Question 9

Answer 9

Massetter hypertrophy

Question 10

What is Centric Relation?

Answer 10

Retruded Contact Position

• Head of the condyle is in its most superior position in the glenoid fossa

Question 11

What is the greatest problem with excessive overbite?

Answer 11

Gingival stripping of mx palatal mucosa

Also very difficult to wear mx splints or partial dentures bc theres no room

Question 12

What type of malocclusion can missing back teeth lead to?

Answer 12

Class 2 “deep bite”

Question 13

What causes gonial angle notching?

Answer 13

Parafunction - clenching

Masseter is always flexed

Question 14

What causes gonial notching?

Answer 14

Parafunction - clenching

Masseter is always flexed

Question 15

What tool is needed for occlusal equilibration?

Answer 15

Requires articulated study models mounted on a semi adjustable articulator with face bow transfer

Question 16

What caused this?

Answer 16

Clenching with tongue bracing on pre-maxilla day and night

Question 17

What is this and why is it bad

Answer 17

NTI splint

• Leads to overeruption of posterior teeth - pt develops anterior open bite

Question 18

What denture problem can cause angular cheilitis? Solution?

Answer 18

Overclose

• remake dentures with increased VDO

Question 19

What problems can too much VDO cause? (5)

Answer 19

• Joint and muscle pain
• Speech problems
• Difficulty swallowing
• Impaired chewing
• Poor facial aesthetics

Question 20

Answer 20

Canine/Cuspid eminence

• Use as guide for arrangement of mx anterior teeth

Question 21

Answer 21

Zygomatic process (malar bone)

• Located opposite to first molar region
• Often found in mouths that has been edentulous for long time
• May require relie due to soreness from denture pressure