This is just a quick tip that can speed up your crown prep appointments.
Most crown preps involve teeth that already have large amalgams. Personally, I take out all old restorative materials, clean up the tooth, and do a build-up. I don’t like leaving behind or covering up old amalgam. And, I’m always amazed at how much decay I find hiding under those old amalgams, not to mention the old Dycal “cottage cheese” sludge.
I like an “ideal” crown prep form in terms of retention and resistance form. Remember those terms from dental school? Some of what we learned still applies today.
But, many of us are still doing the steps in the same order as we were taught in dental school. We were taught to first take out all the old amalgam. Clean up any decay or other “schmutz.” Then slap a matrix band on and build-up with composite. THEN start the crown prep. Sure… this works just fine. But, have you ever gotten done with the crown prep and found that there was very little build-up left or sometimes NONE?? Aaaargh! I spent all that time building it up, only to have little to none left after the prep???
Here’s a different approach. Prep the tooth FIRST! That is… do the “rough” crown prep, first. By that, I mean don’t take out the old amalgam. Just prep the tooth as if it was a crown prep on a virgin tooth. Do the occlusal and axial reduction first. Oh… and if you want it to go quickly, try doing it with a “metal cutting” bur like Brasseler’s H34L bur.
Tooth #29 has deep abfraction and large amalgam. Tx plan: Crown
This is the H34-L bur from Brasseler. It's made to cut metal. But, it will go through enamel like butter and works well for the "rough" prep.
When you’re done, you’ll have what I call a “rough” prep. And, you may find that almost all the old amalgam is already gone.
Here is the "rough" prep. Some old amalgam remains.
If there is any old restorative material left, now is the time to remove it and clean up the “schmutz.”
"Rough" prep now with remaining amalgam removed.
Once you’re down to clean dentin, you may find that all you need to do is a little “block out” with composite. The point is that you will likely be able to free-hand a bit of composite for the build-up. And, it won’t take nearly as long as the dental school method.
Once you’ve done your build-up or block-out, you can then use your typical diamonds to refine your crown prep. Presto! Done! Ready for impression!
Composite build-up placed and final prep. Laser troughing for impression.
Final impression (Impregum).
Efficiency while not sacrificing quality… even better… INCREASING quality and lowering stress is the Dental Warrior way!
PS… Some related posts you may find interesting:
- Picasso Lite – It’s time to pull the trigger on a diode laser!
- 3M ESPE’s Disposable Intra-oral Impression Syringe – Product Review
- Optragate for Full Arch Prep & Impression
Copyright protected by Digiprove © 2013 The Dental Warrior® 
http://thedentalwarrior.com/feed
Great minds think alike!
Thanks for checking in, Vic!
Mike, this is one of the best tricks I picked up from you years ago. I was fresh out of school and new to Dentaltown. It is something I’ve passed on to many other dental friends over the years. Between this and using a wheel diamond for my occlusal reduction my crown prep times were really cut down!
Very cool, Nat! It was one of those forehead-smacking moments for me.
Great tip and good luck with the Blog. I will check back often.
So, what’s the deal with the Impregum? I thought you were a hard core H&H/HAIT user.
Hi Brad!
I was a long-time H&H guy. Still use it some. But, recently I visited 3M up in Minnesota and they successfully convinced me to try good ol’ Impregum. Combined with my new Picasso Lite laser (blog coming on that), I get some pretty awesome impressions.
I cant get away from aquasil, when used with their “B4″ surfacant I really cant beat the impressions. But to each their own. Mike u Rock
Very nice pictures !
What camera do you use ?
I use a DSLR. Doesn’t really matter which. You need a macro lens and ring flash. Then you also need a quality front-surface photographic mirror. But for what it’s worth, these photos were taken with a Canon Rebel XSI.
Me Likey!! Great tip Mike!
I can’t believe this post is currently the 3rd most popular!
I have a crazy question! I just started workink for this new dentist and i am not impressed with her work. Im only a dental assistant but I feel I’ve seen enough to know what looks good and what doesnt. Today we had a patient coming in for a post&core and crown. Well, the dentist says she doesnt do post and cores so today she will only do the crown. I asked her what about the post and core. She said the patient can come back and the other dentist there will do it. So we removed the temp filling, put a new cotton pellet in, built the tooth up with a resin composite then took the final impression and sent to the lab. So the patient is coming back in 2 days so the other dentist can place the post and core. We did this on tooth #20 and tooth #15. Im confused…. this just sound backwards! I just need an opinion from someone who is more experienced then me.
Hi Beth,
Of course, it’s impossible for me to really draw any conclusions or render any solid opinion without seeing the case for myself. It sounds like you are in a group / corporate practice (another dentist taking over the case at the next visit?). I’ve never done it as you have described. And, putting a cotton pellet under a build-up is unusual – again as you have described it. But, I can’t be sure what the dentist is planning in the future for the tooth.
You could certainly ask for an explanation from the dentist (privately – not with the patient in the room).
When I had crown procedures in the past, there was some chemical prep prior to gluing the finished crown. I would get a strong acid taste; phosphoric? The dentist I’m seeing now just wipes the “stump” and places the crown. Could this invite decay on the remaining tooth structure? Also, she did not cement the temporary and it came off so often I bought some fixodent. Sorry to bother you with this, but I could find no patient-oriented blog.
I have a similar question to falk burger
I’m not really in a position to comment on treatment by other dentists without having all the information available to me or seeing you in person.
I did a search for “ask the dentist.” There are a number of websites oriented to consumers.
Well , Many years ago I found a trick in operative dentistry journal may be 1975 issue. for crown prep start with a round bur . push it halfway in free gingiva cut the finishing line circumferentialy at an angle of 45 degrees. the shank wont let you go deep. Then cut the remaining of the tooth .If you ask me I,ll tell you what size of bur to use . Dr.Farzin