Class 2 Restorations Flashcards
A Class II amalgam preparation has an open side on the…
interproximal.
What is used to hold the amalgam in the interproximal area during a class II restoration?
matrix band with a tofflemire retainer and a wooden wedge
What are the functions of a good matrix band?
- Has enough rigidity to resist too much deformation by packing forces or wedging, but is slightly burnishable and displacable
- Assists in establishing proper anatomical contour.
- Must prevent excess amalgam from being expressed at the gingival margin as much as possible, so as not to get a gingival overhang that will trap plaque and irritate the gingivae.
- Must be convenient to install.
- Must be easy to remove and allow for removal without breaking a partially set amalgam.
What are the parts of the tofflemire retainer?
What type of tofflemire band do we use in lab?
adult band - box or normal depth gingivally
What are the steps to inserting band into the tofflemire retainer?
- Turn the inner nut counterclockwise until slot vice is about ¼ inch from the guide channels.
- Hold inner nut and turn the outer nut counterclockwise until the pointed end of the spindle is free of the slot in the slot vice.
- Double the band back on itself, forming a loop.
- Insert into the slot vice, and direct it through one of the three guide
channels. Tighten spindle.
Wider Opening in the Loop is Toward the _______ of the Tooth
Occlusal
Slot in Slot Vice is Toward the _______ of the Tooth
Gingival
What are the ways to insert the tofflemire band?
- Retainer on the buccal side; band emerges from one of the side guide channels (most common)
- Retainer on the lingual side; must use a contra-angle retainer
- Band emerges through the middle channel and straight out the end of the retainer; retainer is on the lingual of the tooth
If the band won’t go far enough apically to close the gingival margin in a deep box, use a band that has an…
“apron”
(clinic only)
How do you get ride of the open margin between the band and the tooth?
wooden wedge
When would you use a double wedge (one from lingual and one from buccal)?
in the event of an especially wide interproximal space and a gingivally deep box
When would you use the stacking method to double wedge?
gingival recession and a proximal
box of moderate depth
What are the steps for obtaining a good contact?
*Loosen the band a quarter turn after wedging
*Burnish the band against the proximal surface of the adjacent tooth.
*Scrape with an explorer along the tooth-metal interface at the gingival margin to remove any tissue or debris in this area.
*Pack amalgam hard against the matrix band in the contact area.
Occlusal edge of marginal ridge slightly _________, creating slightly open occlusal embrasure on an amalgam class II restoration.
rounded
What are the additional steps you need for restoring a class II with composite versus amalgam?
Etch (and rinse), Bond Agent placement (gentle dry, light cure), composite placed incrementally, light cure each increment
Why is composite harder to establish contact in a class II restoration than amalgam?
- Composite does not displace the matrix band like amalgam
- Shrinkage occurs as you light cure
- Different type of matrix may help counteract this issue
What are the steps for complete etch?
◦ Place etch on enamel first, followed by dentin
◦ ETCH ENAMEL 20-30 SECONDS
◦ ETCH DENTIN 15-20 SECONDS
◦ Rinse and gently air dry
◦ Typically only done with total-etch and universal bond agents
What are the steps for selective etch?
◦ Etch enamel only
◦ 20-30 seconds
◦ Rinse and air dry
◦ Can only be done with certain bond agents
◦ Universal (what we use in clinic and lab) and Self-etch types
How should you use etch?
Rinse and dry thoroughly.
◦ Be sure to dry on both sides of the matrix band and around the proximating teeth. Check for the whitish etched enamel surface. Re-apply the etchant if there is not clear evidence of etched enamel.
◦ It may be appropriate to re-etch for 10 seconds if the enamel or dentin is contaminated with saliva then wash, dry apply bonding agent, cure and continue.
What is important to not desiccate while etching?
the dentin
- results in collapse of collagen layer and reduced bond strengths
What is the oxygen inhibited layer? (good test question)
The sticky uncured layer left on the surface
- Oxygen in air interferes with polymerization on surface of composite
What does the oxygen inhibited layer do for the next layer?
facilitiates bonding to the next layer added
What is the most important composite layer to make sure is cured when filling a class II composite restoration?
first increment at the gingival wall
What helps you establish interproximal contact on a composite class II restoration?
- Press the matrix band firmly against the marginal ridge of the proximating tooth with the side of a metal condenser while curing the initial increments.
- Palodent Plus shapes this for you
What instrument should you use to form the final anatomy of a class II composite restoration?
plastic instrument
What should you remove before the final cure during a class II composite restoration?
remove the matrix
What are new things to consider with the composite class II restoration?
interproximal contacts
voids
light
polymerization stress
How can voids be created?
- Composite can stick to an instrument and upon pulling back, a void is created
- When injecting the material, lifting the syringe may cause tug back and a void is created
What does finishing and polishing class II composite restorations do?
◦ Removes the oxygen inhibited layer
◦ Establishes anatomy/final shape
◦ Ensures a smooth surface
◦ EXTREMELY IMPORTANT IN COMPOSITE
