jpollei said:
And actually prepping a tooth correctly with walls that are reasonably parallel (not teepee'd) never hurts. I've also only lost one with Tempbond in 4 years, and that was cause my prep was a bit dodgy...of course, it was my first one...
My thoughts exactly! As I think back as to how my Full Coverage Crown preps have "evolved" over the years, I've gone from a DEEP chamfer with convergent axial walls in the 10-15 degree range and practically tertiary anatomy on the occlussal surface to where I am today(and have been for the last 4 or 5 years) with a 90 degree 1.5mm wide butt joint, parallel axial walls, and a very smooth occlussal surface. I've always been a rounded edge guy
.
One of the main reasons that I love the 90 degree butt joint, and one of the part time faculty in my residency who I learned a ton from showed me this, is that with a 90 degree butt joint, it's literally a very quick glance 100% yes or no if you got the margin on your impression and it's much easier to identify the margin as your trimming the temp
I also use temp bond (non eugenol version) and rarely have any retention issues(most common reason if I have to recement one is the patient was eating something as sticky as a tootsie roll
, or if the prep is really short vertically)
As for tips on preps, the best thing I can tell anyone, is get a routine and follow it. It doesn't really matter if your a butt jointer, a chamferer, or a feather edge fiend, just make the same steps over and over. For example, my routine is as follows:
#1) occlussal/incisal depth cuts
#2) Gross occussal/incisal reduction
#3) Interproximal reductions
#4) buccal/lingual reduction
#5) Verify adequate reduction of all surfaces
#6) Smooth finish lines/round angles
The burs I use vary depending on anterior/posterior tooth(I've got some really small diameter burs for the mandibular anteriors!
)
Total handpiece running time from start to finish will take me a little under 4 minutes depending on how much chit-chatting I'm doing