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False. Dentists must follow clinical protocol for tissue retraction in order to present clear margins. Exposing sub-gingival margins is a primary factor for getting a clear impression, digital or otherwise. Retraction methods include the use of retraction paste, soft-tissue lasers, or retraction cords. Just make sure the cord is not covering the margin before taking the image.
False. For ideal crown prep, each type of restoration demands the use of a certain margin. Feather edge margins on a posterior restoration will lead to thin ceramic margins that might mill inadequately. For ideal results, use heavy chamfer, shoulder, or butt joint margins instead. Anterior restorations should use chamfer or shoulder margins, while onlays should only use butt joint margins. Veneers should only use chamfer margins because correct preparation of the chamfer margins interproximally allows the appropriate bulk of ceramic.
True. Dentists and dental technicians agree: the number one culprit behind poorly fitting restorations and risk of long-term failure is a lack of proper reduction. Without enough reduction for the material presented, the thickness of the final restoration is reduced, compromising its fit and longevity. Thankfully, digital scanners offer the chance to identify any issues with the preparation, such as a lack of reduction. With that, dentists have the chance to fix their error before sending off to the lab or milling chairside, saving themselves from adjustments and remakes in the future and getting their patient in a final restoration faster.
True. While intraoral scanners can be a great teaching tool for dentists and can show you the scan you think you’ve captured, the image on the screen is not always 100 percent reflective of what’s on the file that the lab receives. Capturing a sufficient amount of data with an accurate scanner is the first step to getting your laboratory the information they need.
False. The presence of undercuts on a posterior restoration could lead to insufficient material thickness or support, resulting in a weak restoration.