Week 6 - Class IV and V Composites

Question 1

what are the differences between class III prep and class IV

Answer 1

• same principles but incisal angle is missing
• increase the bevel and extend beyond the bevel with the resin for more retention and a better esthetic appearance

Question 2

what might be necessary on a large fracture for extra retention

Answer 2

a labial veneer or full coverage crown

Question 3

describe a class V prep

Answer 3

• axial wall is convex
• mesial and distal walls diverged
• incisal gingival height is 1.5mm
• axial depth 1.0mm

Question 4

what does bevelling do and what bur should you use to do it

Answer 4

• diamonds
• increases surface area
• increases retention
• reduced microleakage

Question 5

where should you bevel on the tooth

Answer 5

ends of enamel rods

Question 6

what does the reduction of microleakage decrease

Answer 6

• reduces margin discoloration
• eliminations white halo effect for better esthetics

Question 7

what do you do for shallow caries or decalcified enamel adjacent to class V caries

Answer 7

basically an extended bevel

Question 8

what do you need to consider when class V restorations extend onto the root surface

Answer 8

• polymerization shrinkage is greater than bond to cementum or dentin
• causes contraction gap

Question 9

what can minimize the contraction gap

Answer 9

retention groove

Question 10

what materials should you consider using in root surface caries and why

Answer 10

RMGI to reduce microleakage
- amalgam

Question 11

what the are non carious cervical lesions

Answer 11

• abrasion
• erosion
• abfraction

Question 12

what is abrasion

Answer 12

• wear from toothbrushing, pen chewing, occlusal wear from grinding

Question 13

what is erosion

Answer 13

• caused by acid
• bullemia
• GERD
• alcoholics
  -extreme diet

Question 14

what is abfraction

Answer 14

• mechanical loss of tooth structure
• loading forces arent where theyre supposed to be
• flexure of tooth and failure of enamel and dentin

Question 15

dentin wears_____ times easier than enamel

Answer 15

25-125

Question 16

bond strength to natural sclerotic dentin is ____ lower than to sound cervical dentin- ______

Answer 16

25-40%; remove with bur

Question 17

what diet can cause erosion

Answer 17

• chewing or sucking on lemons
• frequent soda/energy drink intake

Question 18

where is stress concentrated on the tooth that causes abfraction

Answer 18

cervical area

Question 19

when do you treat non carious cervical lesions

Answer 19

• lesion is deep enough to compromise tooth
• sensitivity
• involved in partial denture design
• defect is approaching pulp
• defect contributes to a periodontal problem

Question 20

what should you try to do with sensitivity in non carious lesionsbefore treating it with restoration

Answer 20

attempt non surgical treatment such as toothpaste and topical fluoride

Question 21

do you need to prep abrasion tooth

Answer 21

not really

Question 22

what should you consider when deciding when to treat sensitivity in class V lesions

Answer 22

• when to restore vs when to leave
• esthetic desire of patient
• lesion greater than 1.0mm depth and progressing
• possible pulp exposure
• structural integrity of tooth is threatened