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20 Cards in this Set
- Front
- Back
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what are 2 important considerations for amalgam when you use the acorn burnisher? What are 2 factors that contribute to cracking?
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how deep you make the groove in the tooth
how thin the amalgam is relative to tooth structure |
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what happened to amalgam restoration within 24 hours with old amalgam?
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1. corrosion and tarnish quite a bit
2. expanded into hyperocclusion This developed the theory that all old amalgams 24 hours after the restoration had been done, needed to be finished and polished. This was a mandatory thing for old amalgams. |
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Finishing vs. polishing
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finishing: contours need to be perfect. you can reshape amalgam as needed with special contouring instruments.
if you did a good job previously, you don' need to finish polish = putting a high shine or luster on the surface. Smooth surface collects plaque less than a rough surface. |
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What is the order of finshing and polishing?
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Finishing is always doen before polish.
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What can you do to rejuvenate old amalgams?
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use finishing and polishing instruments.
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What are the indications of finishing and polishing?
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1. don't do it since its already good
2. do it because last week's was just okay 3. clean up previously done amalgams before you saw pt. Must do it at least 24 hours after you do this. best time to finish and polish is at later appointments. |
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What are the steps in finishing
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1. check occlusion
2. assess margins - using an explorer 3. check anatomy - 4. assess surface texture 5. carbides for concave surfaces 6. disks for convex |
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Describe the carbides for concave surface
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has 12 blades. The more blades you have, the smoother the surface is. Doesn't cut very well at all, but that's why its meant for finishing.
It will remove just the right amount of amalgam around the confluent edges, and leave a much flatter surface. Remember that this can remove enamel |
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What are soflex disks? (ultra thin finishing disks)
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Used for flat surfaces, or convex surface.
Typically start with course disk. Then medium, fine, superfine. Always go from most rough to most smooth. |
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Describe the polishing cups and points
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Brown - is most rough.
Green - medium Super greenie = very fine polish. Cannot finish with these rubber polishing instruments! Will generate huge amounts of heat. With light touch, with eliminate the rough surface. Greenie = puts a very high polish to amalgam. |
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What was the old fashioned way of polishing?
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Use pumice and tin kits. preppies = finest grit of sand that is mixed with water.
should not use lab grade pumice in the mouth. Add to the prophy brush, for the pumice. The rubber cup is used with the tin oxide. |
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What are 3 things to remember about polishing?
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1. finishing more important than polishing.
2. rubber generates heat 3. too shiny? |
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Common amalgam problems
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1. occlusal preparation
-too shallow pulpal floor (uneven) -too wide bucco-lingually -undermining marginal ridges -crooked preps (not parallel to fissure) |
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What do you line up first, the handpiece or the mirror?
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Line up the handpiece first aong the prop axis, then line up the mirror.
Mirror and your eye can be moved, but handpiece should stay paralell to long axis of tooth. |
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What are some common problems in the proximal prep?
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1. poor cavo surface (90 degrees)
2. not breaking contact 3. damage to adjacent tooth 4. unplaned margins 5. gingival floor not flat 6. caries (wax) left |
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What is unsupported enamel?
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Enamel that doesn't have dentin internal to it. At teh base of enamlel rods. Will break down.
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Does the axial wall need to be a certain height?
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No, theres no rule. We don't want to take away healthy tooth structure.
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Matrix problems
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1. retainer/band upside down
2. retainer not tight/rigid 3. poorly placed 4. gap at gingival trapped dam 5. matrix too low 6. incorrect shape |
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Condensation problems
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1. gaps and voids
2. open proximal contact 3. too weak/ wrong direction 4. stopping too soon |
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Carving problems
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1. too slow/too fast
2. ineffcient instrumentation 3. gingival flash/overhans 4. bulky embrasures, unnatural marginal ridges 5. unrecognizable occlusal anatomy 6. non confluent margins/contours 7. hyper occlusion in MIP 8. excursive interferences 9. rough and scratched surface 10. open/unnatural proximal contact 11. grooves carved too deep |
