Week 5- Class III Prep and Restore

Question 1

there are ______ color esthetic zones on a tooth

Answer 1

at least 3

Question 2

when should you choose the shade and why

Answer 2

before placing the rubber dam because dehydrating tooth affects shade

Question 3

how should you choose a shade

Answer 3

take shade from portion of shade guide most similar to thickness of restoration

Question 4

what is the apperance of the shade of the gingival third of the tooth

Answer 4

opaque

Question 5

what is the appearance of the shade of the incisal third of the tooth

Answer 5

translucent

Question 6

what is the appearance of the middle third of the tooth

Answer 6

blend of shades of incisal and gingival

Question 7

avoid margins ending in______

Answer 7

occlusal contact areas

Question 8

when should you mark occlusion

Answer 8

prior to applying the dam

Question 9

in a class III prep where is it acceptable to leave unsupported enamel

Answer 9

on the facial wall of the prep
- incisal contact

Question 10

why is it okay to leave unsupported enamel on the facial wall of the prep

Answer 10

• esthetics improved
• discoloration and deterioration is less visible
• color match is easier
• facial enamel is conserved
• wedge shaped preparation

Question 11

where are caries usually present in class III preps

Answer 11

• usually more lingual than facial
• gingival to contact area

Question 12

how should the class III prep be prepared

Answer 12

perpendicular to long axis

Question 13

what is the inciso gingival length of class III preps on maxillary lateral

Answer 13

1.5mm

Question 14

what is the inciso gingival length of class III preps on maxillary central

Answer 14

2.0mm

Question 15

what is the mesio distal width of class III preps on maxillary lateral

Answer 15

1.0mm

Question 16

what is the mesio distal width of class III prep on maxillary central

Answer 16

1.5mm

Question 17

what contact is broken in class III and what contact is intact

Answer 17

-gingival contact is broken
- incisal contact is intact

Question 18

is retention required in class III prep

Answer 18

not always

Question 19

what are the retentive features in class III preps and what bur should you use

Answer 19

• incisal point
• gingival groove
• placed with 1/2 or 1/4 round bur

Question 20

where should you place the retentive features in class III preps

Answer 20

in dentin

Question 21

when should you avoid placing retention in class III preps

Answer 21

deeper than normal prep to avoid pulp exposure

Question 22

where should you place point and groove retention in deep class III prep

Answer 22

where they would be in an ideal prep

Question 23

how do you bevel in class III prep

Answer 23

• place 1 mm bevel on lingual and facial
• 45-60 degrees
• smooth and even
• flame shaped diamond bur

Question 24

what would you do differently on a class III with root surface caries

Answer 24

same prep but do not bevel in dentin or cementum

Question 25

when would you not bevel and why

Answer 25

if there would be heavy centric contact on margin because enamel wears better than composite and enamel is stronger than composite

Question 26

what should you use for added retention in class III when you dont bevel

Answer 26

dovetail lock

Question 27

when should you approach a class III prep from the facial

Answer 27

- when lingual access may involve only centric contact of tooth - irregular tooth alignment or rotation - extensive caries on the facial - existing defective restoration on the facial

Question 28

is a liner necessary in class III

Answer 28

not really

Question 29

why should you not use eugenol in class III restoration

Answer 29

found in IRM - interferes with polymerization reaction

Question 30

how should a liner be used in a class III if it is necessary

Answer 30

- use CaOH or glass ionomer - avoid liner on enamel - take care to avoid liner in retention points and grooves

Question 31

when are you more likely to need liner in class III and why

Answer 31

in younger patients because larger pulp

Question 32

why should you wedge in class III restoration

Answer 32

- aids in separating the tooth for good contact and control seepage and moisture contamination - minimizes finishing time - required to prevent gingival overhangs and to stop gingival bleeding or moisture seepage

Question 33

is a class III easier to finish incisally or gingivally

Answer 33

incisally

Question 34

how should you use to mylar strip to finish

Answer 34

- tighten mylar strip around restoration and cure - results in smooth finish - eliminates oxygen interference - not necessary to polish this surface if it does not need contouring

Question 35

what are the steps of composite placement in class III

Answer 35

- cover pulpal (axial wall) first get in retentino points and grooves - cure - second layer - cure - third layer - final cure

Question 36

what burs are preferred when finishing class III lingual surfaces

Answer 36

12 bladed finishing burs

Question 37

which is smoother 12 blades or 6 blades

Answer 37

12

Question 38

where should the occlusion be

Answer 38

on the tooth not the restoration

Question 39

how do you avoid flash on gingival

Answer 39

better wedge and clear matrix band placement