Rationale for Low-Modulus Endodontic Posts

Transcription

Continuing Education
Course Number: 124.2
Rationale for Low-Modulus
Endodontic Posts
Authored by Al Heller, DDS
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Recommendations for Fluoride Varnish Use in Caries Management
Rationale for Low-Modulus
Endodontic Posts
These 2 clinicians were merely looking for a post material
that would not predispose root damage, which had been a
serious drawback in their clinical experience with
prefabricated metal posts, and cast posts and cores.
This article discusses the physical properties and
clinical rationale for the use of fiber endodontic posts, and
demonstrates the use of 3 devices that improve the
technique for bonding fiber posts to tooth structure.
LEARNING OBJECTIVES:
After reading this article, the individual will learn:
•
•
The advantages of fiber posts versus metal posts.
Technique for bonding a post utilizing procedures and
devices that enhance and ensure complete treatment
of the post space and preparation.
BACKGROUND
Young’s Modulus of Elasticity (relative stiffness) of fiber
posts is similar to that of dentin. After nearly 2 decades of
worldwide clinical service and observation, it is evident that
this mechanical property alone allows the bonded fiber
post/composite build-up assembly to absorb and dissipate
mastication and traumatic stresses rather than redistribute
the stresses to another part of the tooth.1-4 This appears to
be true whether the fiber post contains carbon, glass,
quartz, zirconia oxide, or a combination of these fiber types,
and regardless of the overall shape (tapered or parallel) of
the fiber post.5-6
Low-modulus fiber post-composite cores dramatically
outperformed the traditional custom cast post in a 4-year
clinical evaluation,7 and few medium- and long-term clinical
studies have been published comparing prefabricated
metal posts to fiber posts. However, research documents
that certain fiber posts offer more than adequate flexural
strength,8-10 fatigue resistance,11-12 and even improved
fracture resistance13-16 in restored teeth. Other studies17-19
demonstrate more favorable fiber post resistance to
microleakage when compared to metal posts. Further,
bonded, tapered, microretentive (smooth to the naked eye)
fiber posts can provide retention to the tooth equal to or
greater than the parallel metal ParaPost.20
All types of post-core restorations can fail clinically, but
clinical observations and the dental literature offer consensus
that failures involving low-modulus post-core buildups are
almost always noncatastrophic and allow retreatment.21-24 In
cases where the post-core does not fail, but the endodontic
treat-ment requires reaccess, studies conclude that fiber posts
can be atraumatically removed in less than 7 minutes.22,25-27
ABOUT THE AUTHORS
Dr. Heller lives and practices in
Uruguay. He is an assistant professor in
the Department of Operative Dentistry,
Postgraduate Course, Postgraduate
School of Dentistry, ABO in Porto
Alegre, Brazil, and is professor of the
Master of Science in Aesthetic Dentistry, Dental-Facial
Aesthetic and Cosmetic Academy in Chile. He lectures
internationally on various aesthetic topics including
bleaching, composites, shade matching, and direct
bonding. Dr. Heller is 2009 winner of the IberoAmerica
Dental Federation Award. He can be reached at
hmstudio@multi.com.uy.
Disclosure: Dr. Heller reports no conflicts of interest.
INTRODUCTION
Fiber reinforced composite posts appear to have attained a
permanent and integral role in the re-engineering of the
endodontically treated tooth. The inherent differences in
clinical behavior between metallic and fiber posts and the
potential benefits to clinician and patient were not well
understood or even apparent when Duret and Reynaud
developed and patented the first generation of fiber posts in
1989 and 1995 (Composipost in 1989; C-Post in 1995).
1
The clinical procedure, however, requires a few minutes more
to remove all of the fibers and cement.28
While the first generation of fiber posts were as
aesthetically unacceptable as their metal predecessors,
since 2001 clinicians have had a wide choice in fiber posts,
translucent or tooth-shaded, and a variety of tapered,
pointed, parallel shapes. From a clinical perspective, all
other mechanical properties being equal, very translucent
posts offer one clinical advantage over the same post in an
opaque version—polymerization energy conductivity.
Manufacturers of fiber posts advocate use of dual-cure
resin cement because of the clinical track record,
expediency, and comparative insolubility. Published data
confirm that translucent fiber posts help to conduct some
light-polymerization energy into the post space.29,30 How
“deep,” how “much” energy, and other factors vary
according to post thickness, post composition, type of
curing light, and curing light output. Regardless, using the
post’s intrinsic fiber-optic bundle to stabilize the post within
a few seconds expedites the restorative technique by
several minutes.
Radiographic visibility is an important clinical attribute,
which is achieved by different means and by various
manufacturers using combinations of different fibers and
radiopacifiying filler particles. The clinician should be aware
that these endodontic post brands offer different levels of
radiopacity as defined by ISO Specification No. 4049.31
By their nature, and in contrast to stainless steel posts
and base metal castings, fiber posts are incapable of
corrosion or galvanic reaction, and they have been proven
biocompatible to the satisfaction of the US Food and Drug
Administration. All of the physical attributes of fiber posts
that have been described were either known and were
intended at the time of invention or have been improved
gradually over the last 15 years. For decades it was
assumed that metal posts would reinforce the
endodontically treated tooth while securing the core and
crown assembly. There is now a body of evidence
suggesting that fiber posts can actually improve the
prognosis of endodontically treated teeth in terms of
fracture resistance32-35 and in clinical cases presenting with
less remaining tooth structure.21,36 The amount of
remaining tooth structure (walls and ferrule structure) may
therefore be less influential to success with fiber posts than
with metallic posts.
CEMENTATION OF FIBER POSTS
The core material of choice for use with fiber posts,
regardless of brand shape, fiber opacity, or any other
consideration, is dual-cure composite. The first alternative
would be light-cure composite, and the least acceptable
option is self-cure (chemical-cure) composite. Research
cited above in references 1 to 32 addresses the mechanical
behavior of fiber posts compared to metallic posts, by
themselves (without surrounding tooth structure) and when
placed in function in teeth. In clinical trials with some
observations as long as 11 years, the most common failure
mode directly related to the fiber post/core (versus
periodontal or endodontic failure, noncompliance, etc) is
decementation. As little as 0%,37-39 1%,40 ~2%,41,42 and
3.5%,43 to as high as 4.3%44 has been reported. While this
level of detachment is no worse than their metal
predecessors, efforts should be made to reduce the
potential for any clinical failures.
Regarding cementation, the interfaces of critical
interest to the clinician are:
1. Post surface to resin cement.
2. Resin cement to bonding adhesive.
3. Bonding adhesive to root dentin.
4. Post to core composite.
Many authors44-57 have studied various means of
enhancing the bond between the surface of the post and
the resin cement, using primers, silane (both factoryapplied and chairside), air-abrasion, etching, and other
methods. Results are contradictory and improvement is
minimal. The most challenging and controversial of these
interfaces is bonding to the dentin in the deep (10 to 14 mm)
post space. In clinical decementation and in vitro testing
(pull-out, push-out, and microtensile) the interface that
usually fails first, albeit at respectable loads, is the bond to
the dentin. Variations in the available bonding/cement
systems’ cavity configuration (C-factor) may contribute to
this. The C-factor has a significant effect on the magnitude
of shrinkage stresses that result from polymerization. The
2
C-factor is defined as the ratio of the bonded surfaces to the
unbonded surfaces of the restoration. The Class I cavity has
the highest C-factor of 5 (ie, 5 bonded:1 unbonded; a Class
2 restoration is 4:2, thus a C-factor of 2). Further, since it is
known that in routine cases of bonding to dentin with flatsurface geometry (such as in vitro studies) current adhesives
and cements work reliably, the reason for cementation
failure of fiber endodontic posts is likely related to clinical
technique. Therefore, the following technique factors should
be considered:
• Cement selection—resin versus glass ionomer
• Self-cure versus dual-cure versus light-cure
• Etch-bonding agent + cement versus self-etch/selfadhesive cement
• Surface treatment of interior dentin
• Interaction with different sealers and obturation
materials (ZOE, noneugenol, new products)
Figure 1.
On the left is a canal
that was filled with
cement, then the post
submerged into the
canal. On the right is
the Dip-N’-Hope
method.
GREAT POST, POOR BONDING
Historically, the luting of a post was merely a small “step” in
the prosthetic process of rebuilding a tooth. It was
accomplished by mixing a powder:liquid luting agent, then
buttering the post with the cement and inserting it into the
canal. This insertion method is still being taught in many
institutions. The technique prevents cement from coating
the bottom one third (or more) of the canal since the
cement on the post is subjected to shear forces upon
insertion and thins as the post is inserted, and ultimately
little if any luting agent is present in the bottom of the canals
(Figure 1). This is easily experienced when placing a
parallel metal post, since one of 2 results typically occurs:
1. The post fully seats with minimal resistance.
2. If cement does reach the apex, the post experiences
hydraulic rebound and begins to “lift” up out of the
canal due to trapped cement and/or air that could
not be vented.
(Note: During certain procedures, some clinicians may use
a Lentulo spiral device to deliver cement alone into the root
canal, but this device cannot be used to deliver etchant to
the bottom of the canal as required for proper bonding of
the post as discussed in this article.)
Figure 2.
Endodontic model
wrapped with polyvinyl
siloxane to hide the
post opening.
Today it is well understood that adhesively bonded
resin cement is the standard protocol for placing a fiber
post. How the post is bonded is as important as which post
is selected.57-59 Bonding an endodontic post is a “blind”
procedure, and certain devices and techniques (discussed
below) may be helpful in achieving optimal results.
In a recent discussion with Dr. Phillip Brown,60 he told
me how he devised a simple experiment for dentists attending a recent continuing education course. An endodontic
model with a post preparation was given to each participant.
The crown of a human molar was sectioned and glued on top
of the model with an occlusal access opening to the endodontic post space. Further, the model was wrapped with a
polyvinyl siloxane (PVS) putty “sleeve” to hide the view of the
canal in the clear model (Figure 2).
3
Participants who acknowledged that they actually do
bond endodontic posts in clinical practice were asked to
deliver etchant into the canal as they normally would. The
dentists were given a choice of 5 popular etchants currently
on the market and an assortment of tips supplied by each
manufacturer. None of the participants asked for special
equipment or devices other than paper points. All dentists
injected their preferred etchant until they felt they had
completely filled the canal, and several participants requested paper points to attempt to further manipulate the
etch to the bottom of the canal. Upon completion, excess
etchant had overfilled the canal and stacked up on the
occlusal surface. At this point, the PVS cover was removed
and the participants were shown how well they had delivered
etchant into the canal (Figure 3). No one successfully
dispensed etchant down the entire canal, including those
who also used paper points (Figure 4).
It is easily observed that upon injecting etchant into the
canal with a standard tip, the etchant tends to block the canal
about halfway down, which creates an air bubble in the apical
portion of the canal. Paper points or instruments cannot
transport etchant farther down the canal since the entrapped air
cannot be vented coronally. The air acts like a balloon and
prevents migration of any etchant to the apical region.
In part 2 of the test, the participants rinsed out the etchant
that they had placed with the PVS cover in place. Considering
the results of the first part of the test, the participants became
determined to fully rinse away the etchant. Several participants
spent almost one full minute attempting to rinse the canal,
which was far more time than they would likely use at
chairside. Using the standard air-water syringe (no one
requested any other device), all participants failed to
completely remove the etchant (Figure 5). Turbulence in the
coronal one third of the canal prevented water from
reaching the bottom and fully removing the etchant.
Research and clinical experience have shown that
restored teeth fail predominantly by debonding of the post.1
However, the weakest link and typical failure location is at
the cement-dentin interface,40 not at the post-cement
interface. Bonding within the root canal presents a clinical
challenge due to poor bonding in the apical portion of the
canal. The higher bond strengths are at the coronal end.
Figure 3.
Etchant failed to reach
the bottom of the canal.
Figure 4.
Paper point failed to
transport etchant to the
apex. The blunt end of
the paper point still
failed to move the
etchant into the air
bubble.
Figure 5.
Canals after rinsing
with standard air/water
syringe. Note residual
etchant still in the
canal.
Potesta, et al61 examined 3 resin cement systems to test
the effect of different etching techniques on bond strength.
UniCore fiber posts (Ultradent Products) were used with all
4
Mega Pascals
Mean maximum bond strengths of all 4 groups at different levels
10
9
8
7
6
5
4
3
2
1
0
PermaFlo DC
(control)
Panavia F 2.0
PermaFlo DC
TriAway/LeurVAc
RelyX Unicem
Groups
Figure 6. Bond strengths at various regions of the post canal. (Figure 6 adapted with permission from: Polo C, Broome J,
Burgess J, and Ramp LC, UAB School of Dentistry, Birmingham, Ala. Effect of cementation technique on pushout strength of
fiber posts. Presented at 2008 IADR meeting in Toronto, Canada.)
3 cements. The cements tested were: (1) PermaFlo DC
(Ultradent Products) resin cement utilizing an etch-andrinse adhesive; the etch and rinse technique utilized a
TriAway irrigation device (Ultradent Products) for the
air/water syringe and a Leur Vacuum adaptor (Ultradent
Products) for the high-volume suction; (2) Panavia, F 2.0
(Kuraray) with self-etching ED Primers; and (3) UniCem (3M
ESPE) as a self-adhesive cement. The results are shown in
Figure 6. Note that for the controls (Panavia F 2.0 and RelyX
UniCem) the bottom three fourths of the canal show
dramatic drops in bond strength. As seen with the PermaFlo
DC/TriAway group, using the TriAway and Leur Vacuum
adaptor produced relatively consistent bond strengths
through the entire length of the canal. Further, the absolute
best bond values for the controls were still less than the
lowest bond value for the PermaFlo DC group.
Figure 7.
A standard etchant tip
is shown on the bottom;
an Endo-Eze extended
length tip is shown
above.
Figure 8.
Air/water syringe
equipped with the
TriAway Adapter with
Leur lock tip (Ultradent
Products).
that reach the bottom of the canal. These are typically about
18 to 20 mm long versus a standard etchant tip which is
about 10 to 12 mm in length. These disposable tips, shown
in Figure 7, are offered by many companies in several
gauges. A 22-gauge tip will fully navigate almost any size
post hole.
2. TriAway air/water adaptor, equipped with a long
cannula tip. This device slides over the air-water syringe
THREE DEVICES FOR MAXIMIZING ENDODONTIC
POST BONDING TECHNIQUE
There are 3 devices that can easily be incorporated into the
bonded post technique that will ensure uniform and
predictable bonding of the post:
1. Long cannula Leur Lock delivery tips for the etchants
5
and supplies an endless amount of water for rinsing. It can
also deliver a stream of air down the canal for drying
adhesive solvents. The TriAway (Figure 8) can be
disinfected and reused. A Stropko Irrigator (SybroEndo) is
another device used in the same manner. The Stropko is
metal and autoclavable.
3. The Leur Vacuum Adapter (Figure 9) fits into any
standard chairside vacuum valve. It is composed of 2
pieces: a standard high-volume suction barrel and a clear
insert with threading to accommodate any Leur Lock tip. This
device will suction fluid out of the root canal, pull high
volumes of air across the canal thus evaporating solvents
from adhesives, and can be used to lightly vacuum excess
moisture out of the canal while leaving it moist for proper
bonding. This device eliminates the laborious and tedious
use of paper points and is fully autoclavable.
The following clinical case describes how these simple
devices can be used to ensure that the canal is properly
treated for bonding a fiber endodontic post.
Figure 9.
Leur Vacuum Adapter
with Leur lock tip
(Ultradent Products).
Figure 10.
Exposure of the
gutta-percha.
CLINICAL TECHNIQUE
A 38-year-old male was referred after completion of endodontic therapy on the maxillary left lateral incisor. The facial
enamel was chipped and approximately one third of the distal
clinical crown was missing. A post-and-core buildup was
initiated with the intent of a full coverage crown in the future.
The temporary restoration was removed and the tooth
opened and prepared for the buildup; the gutta-percha was
exposed for post placement (Figure 10). Based on the size
of the obturated canal, a No. 1 UniCore Fiber Post (Ultradent
Products) was chosen (Figure 11). UniCore Fiber Posts
possess higher flexural and tensile strength than metal
posts while having a modulus similar to dentin, virtually
eliminating the risk of root fractures.15 The post has a tapered root end with a parallel coronal end for maximum
surface area for core bonding. The UniCore drills (Figure 11)
are unique in that they are not end-cutting drills. Rather, the
heat-generating tip plasticizes the gutta-percha, then the
side flutes discharge the debris coronally. With this system,
no other drills are required, eg, no preshaping drill followed
by additional finishing drills. The fact that the drills are not
Figure 11. UniCore post and drill (Ultradent Products).
Figure 12.
Removal of the guttapercha with the
noncutting drill.
end-cutting essentially eliminates the possibility of
perforating even small-rooted teeth. The post hole is
prepared using the drill at full speed with gentle pressure
(Figure 12). Full rpm is maintained while entering and
leaving the tooth to prevent binding on the dentin walls.
The preparation and post space were then rinsed using
6
the TriAway and dried using the Leur Vacuum Adapter
(Figures 8 and 9).
Phosphoric acid was then applied. With proper isolation,
the canal and the super structure can all be etched in one
application. The etchant is delivered to the bottom of the post
canal first using a 22-gauge long delivery tip (Figure 7).
When the canal was filled, the super structure was covered
(Figure 11). After a 15-second dwell time, the TriAway was
used again to accomplish complete rinsing of the etchant
from the apical portion of the canal toward the incisal opening.
Following rinsing of the etchant, the Leur Vac Adaptor,
equipped with a 22-gauge long delivery tip, was used to
lightly vacuum the canal, leaving a moist surface for
application of the bonding agent (Figure 12). Rubber dam
isolation allows application of the adhesive to both the canal
and preparation super structure simultaneously and without
concern for contamination. The adhesive was applied
(Figure 13) using a Navi FX Tip (Ultradent Products) on the
adhesive syringe. This particular tip allows predictable
placement of the adhesive to the apical extent of the canal
while the bristles help scrub the adhesive into the sidewalls,
much like a test tube cleaner. Air drying and light curing
were then accomplished.
PermaFlo DC resin cement, with a new intraoral “goose
neck tip” (Figure 14) was injected directly into the canal
from the apical extent upwards (incisally) to eliminate air
bubbles. The canal was now completely filled with cement
to prevent “joint starvation,” eg, bubbles and voids, between
the post and dentin. The tapered UniCore Post, with its
specially engineered tip, will vent excess cement coronally
upon insertion.
The No. 1 UniCore Post was inserted into the cementfilled canal and the excess was spread over the base of the
post (Figures 15 to 20). Since the UniCore Post conducts
light, a curing light was then directed down through the post
for 40 seconds to polymerize the cement. The clinician can
now proceed directly with the buildup without any loss of
chair time.
Since a crown was not immediately placed, an
aesthetic composite was selected for the final restoration.
Incremental layers of multiopacity nanohybrid were placed
and cured. Note that the post was cut off during adjustment
Figure 13.
Begin injecting etchant
from the apex toward
the coronal opening.
Figure 14.
Clinical application of
etchant, starting at the
bottom of the canal.
Figure 15.
Rinse etchant using the
TriAway syringe
followed by removal of
excess moisture with
the Leur Vacuum
Adapter.
Figure 16.
Removal of excess
moisture with the Leur
Vacuum Adapter.
of the lingual surface and remains as part of the restoration.
Unlike metal posts that require one to 2 mm of core material
coverage, the UniCore Post can be trimmed to be a part of
the buildup since it bonds directly to the composite and has
7
a modulus similar to that of the remaining tooth and buildup.
The post and buildup restoration can be compared to
the original clinical presentation by viewing the preoperative
and postoperative radiographs (Figures 21a and 21b). The
fiber post is best visualized on the postoperative film by first
finding the coronal termination point of the gutta-percha,
then looking for the radiopaque post above it. Note in this
case how well defined the post outline is compared to the
preoperative film. The post can be more difficult to see
when looking in the coronal one third of the canal. Since the
UniCore post has about the same radiopacity as composite,
it may be more difficult to see where the cement and
composite become thicker. Determining the presence of a
good fiber post is no different than visualizing a composite
versus an amalgam—once you know what to look for, it is
relatively easy. Also note that the post has a “clean” fit
against the gutta-percha; that is, the post hole diameter has
not been overprepared such that the post is wider than the
gutta-percha.
Figure 17.
Application of an
adhesive using the
Navi-FX intracanal tip
(Ultradent Products).
Figure 18.
PermaFlo DC
(Ultradent Products)
with an intraoral
“gooseneck” attached
to the static mixing tip
for direct delivery to the
bottom of post holes.
CONCLUSION
Young’s Modulus of Elasticity of fiber posts is similar to that
of dentin. This mechanical property alone allows the bonded
fiber post/composite buildup assembly to absorb and
dissipate mastication and traumatic stresses rather than
redistribute the stresses to another part of the tooth. This
characteristic appears to be true whether the fiber post
contains carbon, glass, quartz, zirconia oxide, or a
combination of these fiber types, and regardless of the
overall shape (tapered or parallel) of the fiber post.
Low-modulus fiber post-composite cores have been
shown to outperform the traditional custom cast post. While
few medium- and long-term clinical studies have been
published comparing prefabricated metal posts to fiber
posts, there exists a plethora of in vitro research
documenting that certain fiber posts offer more than
adequate flexural strength, fatigue resistance, and even
improved fracture resistance in restored teeth. Other studies
demonstrate more favorable resistance to microleakage
compared to metal; bonded, tapered, microretentive fiber
posts can provide retention to the tooth equal to or greater
Figure 19.
Insertion of post into
the cement filled canal.
Figure 20.
Final aesthetic buildup
around the post.
than the parallel metal ParaPost.
Adhesively bonded resin cement is the standard
protocol for placing a fiber post. How the post is bonded is
as important as which post is selected. Even the most
meticulous technique for syringing impression material into
8
a sulcus can periodically lead to the need
to repeat the procedure. Bonding an
endodontic post is a “blind” procedure,
similar to endodontic therapy itself, and
therefore must incorporate similar
endodontic devices and techniques to
achieve the best results. A clinical
technique for achieving successful
bonding of fiber endodontic posts has been
presented.
a
b
Figure 21. Preoperative and postoperative radiographs.
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6.htm. Accessed on February 23, 2010.
35. Salameh Z, Sorrentino R, Papacchini F, et al. Fracture resistance
and failure patterns of endodontically treated mandibular molars
restored using resin composite with or without translucent glass
fiber posts. J Endod. 2006;32:752-755.
36. Dikbas I, Tanalp J, Ozel E, et al. Evaluation of the effect of
different ferrule designs on the fracture resistance of
endodontically treated maxillary central incisors incorporating
fiber posts, composite cores and crown restorations.
J Contemp Dent Pract. 2007;8:62-69.
37. Fazekas A, Menyhárt K, Bódi K, et al. Restoration of root
canal treated teeth using carbon fiber posts [in Hungarian].
Fogorv Sz. 1998;91:163-170.
38. Malferrari S, Baldissara P, Arcidiacono A. Translucent quartz
fibers posts: a 20-months in vivo study. Abstract 2656.
IADR/AADR/CADR 80th General Session. San Diego, Calif.
March 6-9, 2002. http://iadr.confex.com/iadr/2002SanDiego/tech
program/abstract_18989.htm. Accessed on February 23, 2010.
39. Fredriksson M, Astbäck J, Pamenius M, et al. A retrospective
study of 236 patients with teeth restored by carbon fiberreinforced epoxy resin posts. J Prosthet Dent. 1998;80:151-157.
40. Scotti R, Malferrari S, Monaco C. Clinical evaluations of quartz
fiber posts: a 30-month results. Abstract 2657. IADR/AADR/CADR
80th General Session. San Diego, Calif. March 6-9, 2002.
iadr.confex.com/iadr/2002SanDiego/techprogram
/abstract_18943.htm. Accessed on February 23, 2010.
41. Ferrari M, Vichi A, Mannocci F, et al. Retrospective study of
the clinical performance of fiber posts. Am J Dent.
2000;13(Spec No):9B-13B.
42. Ferrari M, Cagidiaco MC, Goracci C, et al. Long-term
retrospective study of the clinical performance of fiber posts.
Am J Dent. 2007;20:287-291.
43. Monticelli F, Grandini S, Goracci C, et al. Clinical behavior
of translucent-fiber posts: a 2-year prospective study.
Int J Prosthodont. 2003;16:593-596.
44. Cagidiaco MC, Radovic I, Simonetti M, et al. Clinical
performance of fiber post restorations in endodontically treated
teeth: 2-year results. Int J Prosthodont. 2007;20:293-298.
45. Mazzitelli C, Ferrari M, Toledano M, et al. Surface roughness
analysis of fiber post conditioning processes. J Dent Res.
2008;87:186-190.
19. Reid LC, Kazemi RB, Meiers JC. Effect of fatigue testing on
core integrity and post microleakage of teeth restored with
different post systems. J Endod. 2003;29:125-131.
20. Borer RE, Britto LR, Haddix JE. Effect of dowel length on the
retention of 2 different prefabricated posts. Quintessence Int.
2007;38:e164-e168.
21. Barjau-Escribano A, Sancho-Bru JL, Forner-Navarro L, et al.
Influence of prefabricated post material on restored teeth: fracture
strength and stress distribution. Oper Dent. 2006;31:47-54.
22. Cormier CJ, Burns DR, Moon P. In vitro comparison of the
fracture resistance and failure mode of fiber, ceramic, and
conventional post systems at various stages of restoration.
J Prosthodont. 2001;10:26-36.
23. King PA, Setchell DJ. An in vitro evaluation of a prototype
CFRC prefabricated post developed for the restoration of
pulpless teeth. J Oral Rehabil. 1990;17:599-609.
24. Pilo R, Cardash HS, Levin E, et al. Effect of core stiffness on
the in vitro fracture of crowned, endodontically treated teeth.
J Prosthet Dent. 2002;88:302-306.
25. Anderson GC, Perdigão J, Hodges JS, et al. Efficiency and
effectiveness of fiber post removal using 3 techniques.
Quintessence Int. 2007;38:663-670.
26. Gesi A, Magnolfi S, Goracci C, et al. Comparison of two
techniques for removing fiber posts. J Endod. 2003;29:580-582.
27. Lindemann M, Yaman P, Dennison JB, et al. Comparison of the
efficiency and effectiveness of various techniques for removal
of fiber posts. J Endod. 2005;31:520-522.
28. Frazer RQ, Kovarik RE, Chance KB, et al. Removal time of
fiber posts versus titanium posts. Am J Dent. 2008;21:175-178.
29. Lassila L, Vallittu P. Photopolymerization of fiber reinforced root
canal post. Abstract 3479. IADR/AADR/CADR 80th General
Session. San Diego, Calif. March 6-9, 2002.
iadr.confex.com/iadr/2002 SanDiego/techprogram/
abstract_17346.htm. Accessed on February 23, 2010.
30. Sawada N, Hikage S, Sakaguchi K. Shape of composite
resins photopolymerized by the translucent post. Abstract
2569. IADR/AADR/CADR 80th General Session. San
Diego, Calif. March 6-9, 2002.iadr.confex.com/iadr/2002
SanDiego/techprogram/abstract_16843.htm. Accessed on
February 23, 2010.
31. Denny D, Heaven T, Broome JC, et al. Radiopacity of luting
cements and endodontic posts. Abstract 0675.
IADR/AADR/CADR 83rd General Session. Baltimore, Md.
March 9-12, 2005. iadr.confex.com/ iadr/2005Balt/techprogram/
32. Salameh Z, Sorrentino R, Ounsi HF, et al. Effect of different allceramic crown system on fracture resistance and failure pattern
of endodontically treated maxillary premolars restored with and
without glass fiber posts. J Endod. 2007;23:848-851.
10
54. Kelsey WP, Latta MA, Kelsey MR. Endodontic post retention
with three surface treatments. Abstract 1863.
IADR/AADR/CADR 83rd General Session. Baltimore, Md.
March 9-12, 2005. iadr.confex.com/iadr/2006Orld/techprogram/
55. Dallari B, Mason PN, Rovatti L, et al. Different surface
pretreatment and composite-to-quartz fiber posts adhesion.
Abstract 0550. IADR Pan European Federation 2006. Dublin,
Ireland. September 13-16, 2006. iadr.confex.com/iadr/pef06/
techprogram/ abstract_83972.htm. Accessed on
February 23, 2010.
56. Radovic I, Monticelli F, Cury AH, et al. Surface treatment
influence on fiber post-resin cement bond strength. Abstract
0245. IADR Pan European Federation 2006. Dublin, Ireland.
September 13-16, 2006. iadr.confex.com/iadr/pef06/techprogram
/abstract_84511.htm. Accessed on February 23, 2010.
57. Cheleux N, Cazalas C, Sharrock P. Influence of silane on bond
strength of fiber post. Abstract 0016. IADR Pan European
Federation 2006. Dublin, Ireland. September 13-16, 2006.
iadr.confex.com/iadr/pef06/techprogram/abstract_84685.htm.
Accessed on February 23, 2010.
58. Polo C, Broome J, Burgess J, et al. Effect of cementation
technique on pushout strength of fiber posts. Abstract 1757.
IADR 86th General Session & Exhibition. Toronto, ON, Canada.
July 1-5, 2008. iadr.confex.com/iadr/2008Toronto/techprogram/
59. Boschian Pest L, Cavalli G, Bertani P, et al. Adhesive postendodontic restorations with fiber posts: push-out tests and
SEM observations. Dent Mater. 2002;18:596-602.
60. Personal communication with Dr. Phillip L. Brown, Draper, Utah.
61. Potesta FL, Broome JC, O’Neal SJ, et al. The effect of etching
technique on the retention of adhesively cemented
prefabricated dowels. J Prosthodont. 2008;17:445-450.
46. Osorio R, Toledano M, Albaladejo A, et al. Influence of
hydrofluoric acid conditioning on silane-treated glass fiber
posts. Abstract 0376. The Joint Meeting of the Continental
European (CED) and Scandinavian (NOF) Divisions of the
IADR. Amsterdam, Netherlands. September 14-17, 2005.
iadr.confex.com/iadr/eur05/techprogram/abstract_68551.htm.
Accessed on February 23, 2010.
47. Aksornmuang J, Nakajima M, Tagami J. Effect of surface
treatments of a glass fiber post on bond strength to dual-cured
resin core material. Abstract 0376. The 32nd Annual Meeting
and Exhibition of the AADR. San Antonio, Tex. March 12-15,
2003. iadr.confex.com/iadr/2003SanAnton/techprogram/
48. Perdigão J, Gomes G, Lee IK. The effect of silane on the bond
strengths of fiber posts. Dent Mater. 2006;22:752-758.
49. Cheleux N, Gregoire G, Sharrock P. Effect of sandblasting on
the mechanical properties of fiber posts. Abstract 0378. Joint
Meeting of the Continental European (CED) and Scandinavian
(NOF) Divisions of the IADR. Amsterdam, Netherlands.
September 14-17, 2005. iadr.confex.com/iadr/eur05/techprogram/
50. Sahafi A, Peutzfeldt A, Asmussen E, et al. Bond strength of
resin cement to dentin and to surface-treated posts of titanium
alloy, glass fiber, and zirconia. J Adhes Dent. 2003;5:153-162.
51. Tavares AU, Cardoso PEC. A microtensile evaluation in fiber
post with different surface treatments. [No abstract number.]
The 21st Annual Meeting of the Brazilian Society for Oral
Research. Sau Paulo, SP, Brazil. September 8-12, 2004.
iadr.confex.com/iadr/brazil04/preliminaryprogram/abstract_5547
7.htm. Accessed on February 23, 2010.
52. Gardner C, Petrie CS, Walker MP, et al. Airborne particle
abrasion and aqueous storage effects on fiber posts. Abstract
2925. IADR/AADR/CADR 83rd General Session. Baltimore,
Md. March 9-12, 2005. iadr.confex.com/iadr/2005Balt/tech
program/abstract_59499.htm. Accessed on February 23, 2010.
53. Egbert G, Broome JC, Ramp LC. Assessing bond of composite
to fiberposts by diametral compression testing. Abstract 1864.
ADEA/AADR/ CADR Meeting & Exhibition. Orlando, Fla. March
8-11, 2006. iadr.confex.com/iadr/2006Orld/techprogram/
11
POST EXAMINATION INFORMATION
2. Which device successfully dispenses etchant down the entire canal?
a. Paper points.
b. TriAway air/water adaptor, equipped with a long cannula tip.
c. Long cannula Leur Lock delivery tips.
d. Paper points and long cannula Leur Lock Delivery tips.
To receive continuing education credit for participation in
this educational activity you must complete the program
post examination and receive a score of 70% or better.
3. Which statement is correct?
a. Young’s Modulus of Elasticity of metal posts is similar to that of dentin.
b. Young’s Modulus of Elasticity of fiber posts is similar to that of dentin.
c. Young’s Modulus of Elasticity of zirconia posts is similar to that of dentin.
d. Young’s Modulus of Elasticity of cast posts is similar to that of dentin.
Traditional Completion Option:
You may fax or mail your answers with payment to Dentistry
Today (see Traditional Completion Information on following
page). All information requested must be provided in order
to process the program for credit. Be sure to complete your
“Payment,” “Personal Certification Information,” “Answers,”
and “Evaluation” forms. Your exam will be graded within 72
hours of receipt. Upon successful completion of the postexam (70% or higher), a letter of completion will be mailed
to the address provided.
4. Which statement is correct?
a. Prefabricated metal posts and fiber posts have the same properties.
b. Prefabricated metal posts improve fracture resistance in restored teeth.
c. Certain metal posts offer more than adequate fatigue resistance in restored
teeth.
d. Certain fiber posts offer more than adequate flexural strength in restored teeth.
5. UniCore Fiber Post was chosen in the clinical case presented because:
a. UniCore Fiber Posts possess an adequate flexural and tensile strength
while having a modulus similar to dentin, virtually eliminating the risk of root
fractures.
b. UniCore Fiber Posts possess an adequate flexural and tensile strength
while having a modulus similar to metal, virtually eliminating the risk of root
fractures.
c. UniCore Fiber Posts possess an adequate flexural and tensile strength while
having a modulus similar to dentin, virtually eliminating the coronal fractures.
d. UniCore Fiber Posts possess an adequate flexural and tensile strength
while having a modulus similar to cast posts, virtually eliminating the risk of
root fractures.
Online Completion Option:
Use this page to review the questions and mark your
answers. Return to dentalcetoday.com and sign in. If you
have not previously purchased the program, select it from
the “Online Courses” listing and complete the online
purchase process. Once purchased the program will be
added to your User History page where a Take Exam link
will be provided directly across from the program title.
Select the Take Exam link, complete all the program
questions and Submit your answers. An immediate grade
report will be provided. Upon receiving a passing grade,
complete the online evaluation form. Upon submitting the
form your Letter Of Completion will be provided
immediately for printing.
6. In the clinical case presented, which statement is correct?
a. The etchant is delivered to the bottom of the post canal first using a 22-gauge
long delivery tip. When the canal was filled, the super structure was covered.
b. The etchant is delivered first to the super structure. When the superstructure
was covered, the canal was filled to the bottom of the post canal using a 22gauge long delivery tip.
c. After a 15-second dwell time, the TriAway was used to accomplish complete
rinsing of the etchant from the incisal opening of the canal toward the apical
portion.
d. After a 15-second dwell time, the TriAway was used to accomplish complete
drying of the etchant from the apical portion of the canal toward the
incisal opening.
a. Following rinsing of the etchant, the Leur Vac Adaptor, equipped with a 22gauge long delivery tip, was used to highly vacuum the canal, leaving a dry
surface for application of the bonding agent.
b. Following rinsing of the etchant, the Leur Vac Adaptor, equipped with a 44gauge long delivery tip, was used to highly vacuum the canal, leaving a
moist surface for application of the bonding agent.
c. Following rinsing of the etchant, the Leur Vac Adaptor, equipped with a 22gauge long delivery tip, was used to lightly vacuum the canal, leaving a dry
surface for application of the bonding agent.
d. Following rinsing of the etchant, the Leur Vac Adaptor, equipped with a 22gauge long delivery tip, was used to lightly vacuum the canal, leaving a
moist surface for application of the bonding agent.
General Program Information:
Online users may log in to dentalcetoday.com any time in
the future to access previously purchased programs and
view or print letters of completion and results.
POST EXAMINATION QUESTIONS
a. PermaFlo DC resin cement was applied using a Navi FX Tip on the
adhesive syringe.
b. PermaFlo DC resin cement was applied using a new intraoral “goose neck
tip” on the adhesive syringe.
c. PermaFlo DC resin cement using a Navi FX Tip was injected directly into
the “goose neck tip” into the canal from the apical extent upwards (incisally)
to eliminate air bubbles.
d. PermaFlo DC resin cement with a new intraoral “goose neck tip” was
injected directly into the canal from the apical extent upwards (incisally) to
eliminate air bubbles.
1. Which procedure is able to fully rinse away the etchant all along the root
canal and the apical region?
a. The standard air-water syringe with the TriAway air/water adaptor, equipped
with a long cannula tip and the Leur Vacuum Adapter.
b. The standard air-water syringe and The Leur Vacuum Adapter.
c. TriAway air/water adaptor, equipped with a long cannula tip and the Leur
Vacuum Adapter.
d. The standard air-water syringe and TriAway air/water adaptor, equipped with
a long cannula tip.
12
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13

Rationale for Low-Modulus Endodontic Posts

Transcription

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