Class 3 Prep and Restoration

class 3 is used for

- proximal surfaces

- anterior teeth

- NO incisal edge involvement

- smooth surface caries

where does class 3 prep start?

right below interproximal contact

clinical procedures before doing a class 3 prep

1. anesthesia

2. occlusal assessment

3. shade selection

4. isolation (rubber dam)

5. wedging

purpose of doing shade selection before isolation?

tooth dehydration changes tooth color

purpose of wedging

to avoid damaging adjacent teeth

preferred entry for class 3 preps

lingual entry

advantages of lingual entry (3)

1. enhanced esthetics; the facial enamel is conserved

2. shade matching becomes less critical

3. discoloration of the restoration is less visible

while lingual entry is ideal, ___ is fine when indicated

facial entry

indications for facial entry

1. lesion is positioned facially

2. irregularly aligned teeth, facial access conserves tooth

3. large lesion that extends onto the facial surface

4. replacement of a restoration that originally was placed from the facial approach

principles for preparation outline

1. max tissue preserved

2. no standard shape

3. remove caries + defective restorations

4. no extension

retention for class 3 prep

bevel, prep design, enamel.dedntin bond

in a rare case if additional retention is needed, you can add ___ or ___

wider enamel bevel (increases SA)

retentive features in internal prep dentin walls

matrix application is

applied and stabilized with wedge

matrix application steps

1. contain the adhesive components to the prepared tooth

2. develop axial tooth contours

3. remove restorative material excess

4. minimize the finishing time

# of layers of composite resin depends on

size of cavity

each layer of composite resin should be cured for

at least 20 seconds

you want to fill the prep ___

completely (slight excess)

what reducing finishing time for composite?

good technique in composite resin placement

finishing and polishing materials for convex and flat surfaces

flexible discs and finishing strips

finishing and polishing materials for concave surfaces

oval-shaped finishing burs and polishing points

what can be used to remove excess composite from gingival proximal area/ embrasures?

12 blade (light shaving strokes)

thin and curved shape matches the natural embrasure contours

to prevent over-reduction with a 12 blade

keep a portion of the cutting surface on the external enamel surface as a guide

initial enamel prep bur and entry

330 carbide bur at marginal ridge on the lingual side

once caries are removed, there is no unsupported enamel, and margins are clean, place a

bevel

purpose of beveling enamel

1. to increase surface area which promotes better bonding

2. creates gradual color transition (improved esthetics)

how long do you etch enamel surface for? how long do you rinse?

20 seconds

20 seconds

steps of adhesive application

1. place mylar strip + wooden wedge

2. etch 20 sec

3. rinse 20 sec

4. gently air dry

5. scrub adhesive on enamel and dentin

6. air dry

7. light cure for 20 seconds

where should the first increment of composite be placed?

at the deepest wall aka the facial wall

how long do you light polymerize lingual surface?

20 seconds

once you polish, remove the rubber dam and check/ adjust

occlusion

if you adjust occlusion, you must

redo the polishing steps on the adjusted area

when using a polishing strip in the proximal areas, do not

grind away the proximal contact

only grind below/ gingival to contact area