What’s the Best Margin Style for Zirconia? Which Bur? - Discussion and Recommendations

Sep 27, 2026

Uploaded by Liam

A dental discussion focuses on selecting the most effective preparation margin style for posterior zirconia crowns and the bur geometry used. Participants compare knife-edge or feather-edge/area margins against shoulder and chamfer approaches, debating fit, long-term fracture risk, milling feasibility, esthetics, color masking, and ease of impression and lab execution. Key points include the importance of lab technician skill, milling/insertion chipping, conservative tooth structure preservation, and practical considerations for achieving reliable seating and sealing.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Best margin style for zirconia posterior crowns

Knife-edge vs shoulder/chamfer vs chamfer approaches

Evidence, outcomes, and long-term risks

Practical considerations for burs and lab workflow

message board What’s the Best Margin Style for Zirconia? Which Bur? Townies engage in a great discussion of margins and share helpful technique suggestions Hi guys. Buying new burs and want to know if there is any evidence for most effective style of margin for posterior zirconia crowns? I’m not having any problems with fit, leakage or retention. I just want the best long-term results, obviously. Currently I’m using an .856 round something or .847 taper something. ■ 29/11/2018 Any distinct margin works just fine. A knife edge is probably the least appropriate.. ■ 29/11/2018 I do knife edge/area margins with zirconia every day.. ■ 30/11/2018 And these can and do look really nice and tissue really likes them too! As I’m certain Matt knows, look at some of the work many Europeans are doing with knife/feather margins and zirconia. Especially some of the doctors in Italy. Really exceptional work.. ■ 30/11/2018 The caveat … You must use a lab tech that knows what he is doing. It is not just a matter of milling out a crown. My friend Pasquale Venuti and the Tomorrow Tooth FB group docs are huge proponents of this method. ■ 30/11/2018 Although you can do a knife edge prep, with the newer materials you have to start to worry about underlying color. The thinner you make zirconia, the more translucent it becomes. If you need to mask out color, I would recommend a thicker margin. Zirconia needs to be around .7mm to really mask well. ■ 30/11/2018 Shoulder preps are the best ofthe best cause labs can create restorations that flow with the remaining tooth structure with no bulge at or near margin. ■ 3/12/2018 They are also the most destructive preps in the most critical part of the tooth. The bulge that we put in is basically just a CEJ. I spoke with my lab tech last week and he told me he now actually prefers doing feather-edge margins. ■ 3/12/2018 Plus, since zirc’s are milled, a pure shoulder prep is tough to mill. It just doesn’t turn out well. And as Matt indicated, the long-term fracture risk of the tooth itself goes up almost exponentially with a shoulder prep. ■ 3/12/2018 DrBabs Member Since: 19/07/05 Post: 1 of 209 almunk Member Since: 17/12/05 Post: 2 of 209 mattcosta Member Since: 02/07/09 Post: 10 of 209 Timmy G Member Since: 14/04/02 Post: 11 of 209 mattcosta Member Since: 02/07/09 Post: 12 of 209 rgk Member Since: 17/01/02 Post: 16 of 209 exclusivedentallab Member Since: 31/10/06 Post: 18 of 209 mattcosta Member Since: 02/07/09 Post: 19 of 209 Timmy G Member Since: 14/04/02 Post: 20 of 209 [dentaltownuk.com](dentaltownuk.com) \\ APRIL 201935 message board mattcosta Member Since: 02/07/09 Post: 31 of 209 Brett S Member Since: 19/09/13 Post: 39 of 209 mattcosta Member Since: 02/07/09 Post: 31 of 209 Brett S Member Since: 19/09/13 Post: 39 of 209 mattcosta Member Since: 02/07/09 Post: 31 of 209 velogeek Member Since: 04/15/10 Post: 56 of 209 The margin is “arbitrar-intentionally” set by the technician based on soft-tissue profile. ■ 3/12/2018 | I don’t really understand why this is up for debate. A zirconia preparation should have achamfer margin end of story. I’m confident a knife edge will work for most applications with zirconia but why would you do it? We can do a lot of things in dentistry that will “work,” but are not the correct way to do things. But why would we? ■ | 3/12/2018 | | --- | --- | Says who? Knife edge is the oldest crown preparation known to dentistry. I do it because it has a long track record, is the most conservative, and coupled with soft tissue management it results in extremely healthy gingiva. It is also the easiest to prepare and impress. ■ 3/12/2018 Knife edge was designed for metal restorations and it gave them the possibility to be burnished which was great. We don’t burnish zirconia. The amount of tooth structure saved with a conservative chamfer versus a

FAQs

What margin styles are discussed for zirconia posterior crowns?

The discussion compares knife-edge/feather-edge or area margins with shoulder preps and smaller chamfers. Participants argue which designs are most appropriate and why.

Why do contributors emphasize the role of the lab technician?

They stress that outcomes depend on proper lab execution, not just milling a crown. A lab tech who understands the method is described as critical for reliable results.

How does translucency affect margin choice in zirconia?

If a thinner zirconia margin is used, it becomes more translucent, creating color-mask concerns. Thicker margins are suggested when masking underlying color is needed.

Sep 27, 2026

Uploaded by Liam