message board Idiot-Proof Crown Prep? Trying To Come Up With One After a less-than-ideal crown prep, this Townie looks for ways to improve his method mlau Member Since: 11/08/08 Post: 1 of 231 Dear DT, I generally pride myself in above-average work. However, sometimes my preps will look ... embarrassingly horrible. Here's my system: a. Occlusal depth groove with 330 bur. 1.8mm reduction. b. Break contact with 330 bur. c. Use diamond donut bur for gross reduction. d. Use biggest diamond chamfer bur for gross axial reduction. e. Use something like an 856-M to refine prep. I'm thinking of maybe using a round diamond to establish a smooth margin a la DiTolla (maybe a smaller size), going back with a fine diamond to smooth out the margin, finishing up with a white stone on a slow speed for preps. This seems all elementary and 10 years out, it's humbling to look at some of these crappy preps when I pour up my dies. I figure that I can be a *total* idiot sometimes and want to prevent that from driving my labs crazy. ■ 6/5/2019 dr costco Member Since: 07/02/09 Post: 3 of 231 This is one of my bur racks. For the most part, I only use four burs. On a straightforward crown I use the depth bur across occlusal table (2mm) followed by the barrel to homogenize the occlusal. The torpedo bur is next to place functional and nonfunctional cusp bevels, then equigingival axial reduction. I then go into the sulcus with the fine-tapered diamond and " erase " the margin, finalize the taper on the prep and perform rotary gingitage. Pack some cord or Teflon and then round off any sharp edges. The brownie and greenie are for the provisional but can be used to polish the prep as well. Hope this helps. I will have a photo series soon. ■ 6/5/2019 mlau Member Since: 11/08/08 Posts: 4 and 5 of 231 26 Here's some pics of a crappy prep: MARCH 2021 // dentaltown.com DT0321_MB2_Crown_V2.indd 26 2/18/21 10:49 AMhttps://www.dentaltown.com/messageboard/thread.aspx?s=2&f=216&t=329993&g=1 http://www.dentaltown.com