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Finishing the Restoration |
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When reducing excess porcelain, the appropriate diamond is essential. It is possible to crack porcelain, even after the restoration has been bonded, with a diamond that is too coarse. The wonderful characteristic of the Vita Mark II porcelain that allows it to be nonabrasive to the opposite tooth also allows it to be easily carved with a fine-grit diamond. My personal favorite for occlusal reduction is a 1923 F (F is for fine) football-shaped Neodiamond from Microcopy. (While you can purchase direct from Microcopy, I encourage you to form the relationship with your Patterson sales representative that makes you feel good about buying directly from him/her.) The Neodiamond is an inexpensive, "one use" diamond. While I often use this football-shaped diamond more than once, at the first sign of dullness I discard it. One of the most common mistakes leading to frustration in finishing the restoration is using a diamond past its useful life. I make the initial gross occlusal reduction and the finishing of the interproximal areas with the rubber dam in place. Note: be sure to use water spray during gross reduction. A diamond used at high speed against porcelain can cause heat buildup and porcelain cracking. Note: It is also possible to crack the porcelain restoration by having the patient close too hard on the articulating paper in the adjustment process. This porcelain has excellent strength characteristics. However, a sharp opposing cusp under premature excess pressure can crack a bonded porcelain restoration. The interproximal finishing is done with a round end taper 850012 F from Axis (available through Patterson Dental). Because of the vertical nature of the proximal box walls, the infrared camera is not able to process data as accurately as it can on the occlusal. As a result of this situation there may be more discrepancy in the fit in this area, causing the need for extra finishing at the vertical part of the proximal box wall. This is easily done with the taper diamond or a Profin from Dentatus. This essential instrument can be seen here. No clinician providing bonded porcelain restorations of any kind, CEREC or otherwise, can provide consistent, masterfully done restorations without this instrument. If the bottom line has been accurately drawn, there will be little need for finishing this area. However, the Profin is excellent for smoothing the occasional area of residual cement that has been left behind. Once the appropriate occlusion has been established, I smooth any rough areas with the same fine-grit football-shaped diamond as above but now at low speed and without water spray. Caulk Enhance polishing cups used in a slow speed followed by brown rubber points used in a high-speed handpiece at low RPM, give a very acceptable polish. All of the instruments mentioned on this page are available through Patterson Dental. |
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