Restoration of access opening
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for the individual posts where they are. - ROOTS
From: Marga Ree
Sent: Tuesday, February 01, 2011 2:03 AM
Subject: [roots] Restoration of access opening
When thereZer is a PFM crown, it's always a challenge to
mask the metal when closing the access opening with
composite. This one was easy, because it was an
all-ceramic crown. Thermafil was removed using hedstrom
files and hemostat. Treatment was completed in 2 sessions.
Great case Marga, the RCT and restoration are beautiful.
In other cases that you've posted in roots,
you were sandblasting the pulp chamber.
Are you still doing that?
Do you known some paper that studied this procedure in
endodontics? - Patrick Baltieri
Thanks Marga, I will buy a sandblast device and test in
extracted teeth, to understand how to use it.
- Patrick Baltieri
Thanks Patrick, Yes I always sandblast the pulp floor
after finishing the root canal treatment.
It's very effective to clean up the floor. - Marga
Oper Dent. 2008 Sep-Oct;33(5):556-63.
The effects of tooth preparation cleansing protocols
on the bond strength of self-adhesive resin luting
cement to contaminated dentin. Chaiyabutr Y, Kois JC.
Department of Restorative Dentistry, University of
Washington, Kois Center, Seattle, WA, USA. firstname.lastname@example.org
This in vitro study evaluated the bond strength of a self-adhesive
luting cement after using four different techniques to remove
surface contamination on dentin. Extracted human molars
were flattened to expose the dentin surface and prepared for
full crown preparation. Acrylic temporary crowns were fabricated
and placed using temporary cement. The specimens were stored
at room temperature with 100% relative humidity for seven days.
Following removal of the temporary crowns, the specimens were
randomly divided into four groups, and excess provisional
cement was removed with
(1) a hand instrument (excavator),
(2) prophy with a mixture of flour pumice and water
(3) aluminous oxide abrasion with a particle size of 27 microm
at 40 psi and
(4) aluminous oxide abrasion with a particle size of 50 microm at 40 psi.
The microstructure morphology of the tooth surface was evaluated
and residual materials were detected using SEM and EDS analysis of
randomly selected specimens. The ceramics were treated with 9.5%
hydrofluoric acid-etch and silanized to the prepared dentin prior
to cementing with self-adhesive resin cement (RelyX Unicem, 3M ESPE).
he shear bond strength was determined at a crosshead
speed of 0.5 mm/minute. The results were analyzed with one-way ANOVA,
followed by Tukey's test. Particle abrasion treatment of dentin
with an aluminous oxide particle provided the highest
values of bond strength, while hand instrument excavation was
the lowest (p < 0.05). Aluminous oxide particle size did not
significantly influence the bond strength at 40 psi.
The use of low pressure and small particle abrasion treated
dentin as a mechanical cleansing protocol prior to definitive
cementation increased the bond strength of self-adhesive
resin-luting cement to dentin following eugenol-containing
PMID: 18833862 [PubMed - indexed for MEDLINE]
Excellent work as always Marga. Please can you summarise
what file sequence you used. Thank you for your posting.
- Stephen Day
Thanks Stephen, I used Mtwo files in this case, the usual
sequence: 10/04, 15/05, 20/06, 25/06, 30/05 and finally
35/04. And of course handfiles to obtain patency.
Hi Marga real nice work. can u pl tell what burs did u
use to go through the (probably) zirconia core of the all
ceramic crown thanks - Abhinav Misra
Thanks Abhinav, I use very sharp long diamonds in a high
speed handpiece. - Marga
Hello, Marga! Marvelous case as always! Thaks for sharing!
I have one question: How did you manage to restore so
beautifully the access opening? What was your bonding protocol?
Do you use hidrofluoric acid to etch the porcelain?
I guess I had some questions!:) Thank you again for sharing
this lovely case! - Bojidar
Thanks Bojidar, here is the technique:
1. Clean the internal surfaces with a micro-brush or cotton
pellet containing a solvent such as alcohol.
2. Use air abrasion to clean the cavity and ceramic
3. Acid-etch the ceramic material with 10% hydrofluoric acid
for 1 min (I use porcelain etch by Ultradent)
4. Rinse and dry, the porcelain should have a frosty appearance
5. Acid-etch the dentin with 37% phosphoric acid for 15 s.
This step cleans the porcelain and enhances the silane
6. Thoroughly rinse and dry and then rewet the dentin with a
micro-brush soaked in CHX (CHX has a beneficial effect
on degradation of the hybrid layer).
7. Apply a 4th generation primer to the dentin (I use Clearfil
SA primer ) and gently air-dry
8. Apply a 4th generation adhesive to the dentin ( I use
Clearfil Photobond) Because the Photobond
bonding system is dual cure, you need to mix one drop
of each bottle (universal and catalyst). Gently air-dry
9. Mix 1 drop of Clearfil porcelain activator ( a pre-silane)
with 1 drop of each bottle of Clearfil photobond dual
cure, apply to the ceramic, gently air-dry and light cure
for 15 secs.
10.Bulk-fill with a dual or self-cure composite to within
2 to 3 mm of the cavo-surface margin and light-cure
(I use LuxaCore self-cure).
11. Cover the core material with a hybrid or nanohybrid
light-cure composite can be used as a top layer
12. Contour and adjust the occlusion.
13. Finish and polish the restoration.
It looks time consuming, but it takes approx.
10-15 minutes. - Marga
Marga you simply rock!! Great endo and restaurative skills!!
I read your article from the Dental Clinics of North America
"The Endo-Restorative Interface: Current Concepts" and it
explains that placing a post after endodontic treatment
in a tooth with a crown may improve retention and increase
fracture resistence. Please could you explain why did you
choose not to place a post in the distal canals?
Thanks for share (and care) :)) Kind regards Javier
Thanks Javier! I place posts routinely in crowned teeth
with small roots (premolars and front teeth).
In general, it 's not necessary to place posts in molars,
because of amount of sound tooth structure that is left.
Having said that, I don't think there is a drawback of
placing a fiber post, provided you don't remove additional
tooth structure to accomodate the post. When I am in doubt
about the remaining dentin, I will typically place a post.