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23 Cards in this Set
- Front
- Back
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In terms of stress properties, what is better auto cure or light cure?
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Auto cure which is what the older composites used to use.
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Why do the older composites look so terrible?
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Used large particles and would undergo plucking - filler particles dislodge from the surface and appears granular. Combination of resin wearing and you get losso f anatomical form. Material appeared to be shrinking over time.
Amine discoloration for autocure early composites. Function of the initiators used to initiate the reaction. Get a orangey brown color. |
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What's the single biggest problem of older posterior composites?
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Not being able to get a proximal contact. Open margins and gingival margins were really hard to accomplish.
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Name some other problems of early posterior composites?
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-really bad materials
-confusion and experimentation -unfamiliarity -unknown durability -slow evolution -needed GVB's help! |
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What do we have today with posterior composites?
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-much better materials
-better understanding with problems -better techniques (matrices, etc.) -much more familiarity -15+ years of evidence -still not perfect |
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What may make finishing and polishing easier for posterior composites?
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intentionally mismatching the shade. Good to tell the actual tooth from the restoration.
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What is a dam so important?
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Def worth the time since it makes it much more predictable, less post operative sensitivity, much easier to control with contamination.
-extremely important. bak in the day, place rubber dam napkins were placed under the rubber dam. |
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The pits and fissures..
What does this determine? |
A typical non coalesced fissure's deepest part is dentin.
Aciduric and acidogenic bacteria eats away at the dentin. At the surface of this, the enamel blocks the actual fissure. We don't have an acurate way to diagnose small to medium size pits and fissure caries. When its very large, its visible and explorable. Look for a catch or a stick in most lesions but this is unstickable. 1. determne whether or not to restore 2. how much of occlusal groove should you include in the prep. |
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The fissures include many different types..
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-fully coalesced
-partially coaelsced -non coalesced, non carious -non coalesced, carious -obviously carious challenge is telling the difference between carious and non carious non coalesced pits and fissure. |
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How can you tell between carious and non carious pit and fissures?
3 choices.. |
1. guess - low caries risk, compliant
2. enameloplasty - 3 high tech exploration no explorers since eyeballs are just s accurate. may damge with an explorer |
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why were we better diagnosing pit and fissure caries back then?
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more people had it, and enamel will break down due to lack of fluoridation. bette r guesers back then.
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Air abrasion instruments
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cutting instruments. invented earlier than high speed. became popular when enameloplasties were considered, slow and pretty messy. Pretty big unit so most people aren't using it anymore.
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Fissureotomy bur
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Fine cone shaped bur that came in 3 sizes almost like a fnishing bur that cuts a V shaped preparation. Good for doing a diagnostic enameloplasty.
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Diagnodent
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battery operated tool with visual and auditory read out . Emits a laser with sensors surrounding it. You measure fluorescence over a questionable tooth. You'll get a high number read out and high pitched note if there's caries. Soft dentin fluoresces more than naturally healthy dentin.
Sealants also fluroesce so it can't tell if there's soft dentin below the sealant. Not great for specifitiy for soft dentin but its pretty good. |
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The occlusal prep..
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1. Slot prep - doesn't involve the pits and fissures. Occlusal part of the MO is not important for retention and resistance. Good to do as long as there's no pit and fissure caries.
2. Doesn't need to be extended for prevention like an amalgam does. 3. Deep enough to remove the problem 4. Convergent walls (rentention) not needed. Retention for composite is micromechanical. |
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Step 1
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Identify where the lesion is at the pit and fissure and remove it most minimally invasively as possible.
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Do you need to bevel the occlusal margins?
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No, its already beveled due to the inclines. Cut ends of enamel rods are good for etching for marginal leakage prevention.
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What kind of bur would you use?
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A nice rounded 329 bur.
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Do you need to extend for prevention for class 2 composite?
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May or may not. Need to make a clinical risk assessment. Extension for prevention is based on caries risk, don't need to do it for patients who are at low risk.
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Must you break contact with proximoocclusal preps?
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For high risk of caries, you should but for those with recent low caries risk, you don't need to. Don't need to always break contact, based on your clinical judgement.
Be aware that caries risk can go negative by developing systemic problems. |
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If you break contact..
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-easier to place matrix
-easier to finish -easier to maintain -easier to monitor -probably more predictable! |
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What about unsupported enamel?
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Can leave some unsupported enamel for class 3 anterior but for class 2 its a posterior tooth, and under more stress and strain so you need to always remove it.
-strain from polymerization shrinkage can crack unsupported enamel. |
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Cavo surface?
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On occlusal its less than 90 degrees. Should put a slight bevel on the facial and lingual margins. Want to get a good marginal seal, and a flared wall to expose the cut ends of the enamel walls.
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