Dental Info

  retentive crown preparation for all zirconium crown I was asked this question by a frustrated dental student. She explained that she tried in a zirconium crown and it had no real retention. She asked me why this had happened. I asked her to show me the crown and the model it was made on. Now truth be told, zirconium crowns can have more relief between the prep and the crown than some porcelain fused to metal or full metal crowns, but all types of crowns can have a problem with being non retentive due to a number of circumstances. I explained the following reasons for a poorly retentive crowns to result from our efforts: 1) the degree of taper. In theory crowns can be fabricated on preparations with miniumal taper (3 degrees), but many practitioners are unable to make this sort of preparation without producing undercuts. In their effort to make a preparation without undercuts, it is not uncommon to end up with preparations with greater than a 10 degree taper. These ...

 There are a number of different possible answers to this question. Teeth that are bothered by drinking cold liquids or breathing cold air could be suffering from "cracked tooth syndrome, a loose filling, gingival or occlusal erosion, deep decay, or a pulpitis. If you are experiencing discomfort when dealing with cold liquids or air it's best to see your dentist so he can try to diagnose why. When a patient comes in to a dental office with this complaint , the dentist should  interview them about when they have this symptom. (drinking cold or hot liquids or breathing cold air). Also do  they have intermittent pain on chewing food sometimes (cracked filling or cracked tooth)? In my office, after this brief interview I have my assistant take a periapical and bitewing radiograph and I examine the tooth or teeth in question specifically  looking for signs of a crack in a tooth or filling, decay approaching the pulp and/or dentin erosion. In addition I tap gently on the...