Week 5- Class III Prep and Restore Flashcards
there are ______ color esthetic zones on a tooth
at least 3
when should you choose the shade and why
before placing the rubber dam because dehydrating tooth affects shade
how should you choose a shade
take shade from portion of shade guide most similar to thickness of restoration
what is the apperance of the shade of the gingival third of the tooth
opaque
what is the appearance of the shade of the incisal third of the tooth
translucent
what is the appearance of the middle third of the tooth
blend of shades of incisal and gingival
avoid margins ending in______
occlusal contact areas
when should you mark occlusion
prior to applying the dam
in a class III prep where is it acceptable to leave unsupported enamel
on the facial wall of the prep
- incisal contact
why is it okay to leave unsupported enamel on the facial wall of the prep
- esthetics improved
- discoloration and deterioration is less visible
- color match is easier
- facial enamel is conserved
- wedge shaped preparation
where are caries usually present in class III preps
- usually more lingual than facial
- gingival to contact area
how should the class III prep be prepared
perpendicular to long axis
what is the inciso gingival length of class III preps on maxillary lateral
1.5mm
what is the inciso gingival length of class III preps on maxillary central
2.0mm
what is the mesio distal width of class III preps on maxillary lateral
1.0mm
what is the mesio distal width of class III prep on maxillary central
1.5mm
what contact is broken in class III and what contact is intact
-gingival contact is broken
- incisal contact is intact
is retention required in class III prep
not always
what are the retentive features in class III preps and what bur should you use
- incisal point
- gingival groove
- placed with 1/2 or 1/4 round bur
where should you place the retentive features in class III preps
in dentin
when should you avoid placing retention in class III preps
deeper than normal prep to avoid pulp exposure
where should you place point and groove retention in deep class III prep
where they would be in an ideal prep
how do you bevel in class III prep
- place 1 mm bevel on lingual and facial
- 45-60 degrees
- smooth and even
- flame shaped diamond bur
what would you do differently on a class III with root surface caries
same prep but do not bevel in dentin or cementum
when would you not bevel and why
if there would be heavy centric contact on margin because enamel wears better than composite and enamel is stronger than composite
what should you use for added retention in class III when you dont bevel
dovetail lock
when should you approach a class III prep from the facial
- 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
is a liner necessary in class III
not really
why should you not use eugenol in class III restoration
found in IRM
- interferes with polymerization reaction
how should a liner be used in a class III if it is necessary
- use CaOH or glass ionomer
- avoid liner on enamel
- take care to avoid liner in retention points and grooves
when are you more likely to need liner in class III and why
in younger patients because larger pulp
why should you wedge in class III restoration
- 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
is a class III easier to finish incisally or gingivally
incisally
how should you use to mylar strip to finish
- 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
what are the steps of composite placement in class III
- cover pulpal (axial wall) first get in retentino points and grooves
- cure
- second layer
- cure
- third layer
- final cure
what burs are preferred when finishing class III lingual surfaces
12 bladed finishing burs
which is smoother 12 blades or 6 blades
12
where should the occlusion be
on the tooth not the restoration
how do you avoid flash on gingival
better wedge and clear matrix band placement
