zirconia

Report
Restoration of endodontically
treated tooth
• Amalgam, resin composite, and glass ionomer in
combination with a prefabricated post
• Amalgam had the lowest failure rate,
• Glass ionomer core buildup materials caused the
greatest number of failures
•
R. E. Kovarik, L. C. Breeding, and W. F. Caughman, “Fatigue life of three core materials under simulated chewing conditions,” The Journal of Prosthetic Dentistry, vol. 68, no. 4, pp. 584–590, 1992
• Some studies supported the use of amalgam
dowels in the root canals
•
Tamse compared 49 mesial roots extracted due
to vertical fractures with 52 mesial mandibular
roots without fractures,
• and found that 67.3% of the vertically fractured
roots had an amalgam dowel in the coronal part
(1-2mm) of the root.
• In another study, endodontically treated teeth
not crowned after obturation were lost 6
times more often than teeth crowned after
obturation
•
S. A. Aquilino and D. J. Caplan, “Relationship between crown placement and the survival of endodontically treated teeth,” The Journal of Prosthetic Dentistry, vol. 87, no.
3, pp. 256–263, 2002.
• A 10-year prospective clinical trial, showed
94% survival rate of metal post-and-cores with
a crown
•
G. Heydecke andM. C. Peters, “The restoration of endodontically treated, single-rooted teeth with cast or direct posts and cores: a systematic review,” The Journal of
Prosthetic Dentistry, vol. 87, no. 4, pp. 380–386, 2002.
• Another 17-year controlled prospective study
showed that the type of core restorations
under the crowns had no effect on the survival
rate of 307 endodontically treated teeth
•
W. A. Fokkinga, C. M. Kreulen, E. M. Bronkhorst, and N. H. J. Creugers, “Up to 17-year controlled clinical study on postand- cores and covering crowns,” Journal of
Dentistry, vol. 35, no. 10, pp. 778–786, 2007.
Post-core
• The use of posts does not reinforce
endodontically treated teeth and some
reports even show that teeth which were
restored without a post and core are less
susceptible to fracture than teeth with post
and core
•
A. Smidt and E. Venezia, “Techniques for immediate core buildup of endodontically treated teeth,” Quintessence International, vol. 34, no. 4, pp. 258–268, 2003
Post-core
• Its success relies on the success of the entire
system and vice versa.
• For anterior restorations, consider using a
ceramic or light-colored fiber post made of
quartz, silicone or glass fibers.
Post Shape
• Posts come in three basic shapes: parallel,
tapered, and parallel-tapered
Parallel
• Parallel posts are more retentive than tapered
ones.
• They seem less likely to cause root fractures,
distributing stresses evenly along their length.
• However, parallel posts require removal of
more tooth structure than tapered ones and,
therefore, may not be suitable for roots with
thin walls.
Tapered
• Tapered posts allow for minimal dentin removal
since most roots themselves are tapered.
• The stresses absorbed by these posts are
concentrated in the apex
• Creating a wedging effect and increasing the risk
of vertical root fracture.
• Because of this increased risk when tapered
posts fail, they are more likely to leave the tooth
unrestorable.
Parallel-tapered
• Advantages of both designs with few reported
disadvantages.
• This post has a parallel shaft, tapering at the
apical end.
• This mix achieves retention associated with
parallel sides, while allowing tooth
preservation at the apex.
Length and Diameter
• Post retention improves with increases in post
length, rather than diameter.
• An increase in post length with a minimum
diameter preserves tooth structure and
reduces shear stresses and risk of fracture.
• Diameter is important for strength and
resistance to post fracture
• Sequential use of post twist drills, starting
with narrowest and working up to the desired
post diameter, can be useful in minimizing
tooth loss during post-space preparation.[
The groove is normally located where the root
is bulkiest, usually on its lingual aspect.
Rotational resistance in
an extensively damaged
tooth can be obtained
by preparing a small
groove in the root canal.
This must be in the path
of placement of the post
and core.
Influence of post and cores on light
transmission through all-ceramic
crowns
• Some ceramic systems are semi-translucent
(IPS Empress®, Ivoclar Vivadent)
• Others are semi-opaque (In-Ceram®, Vident,
Brea, CA).
• A traditional metal post (gold or titanium)
results in poor esthetics because of the lack of
light transmission.
• . Metallic posts also create a light blue/gray
appearance at the gingival margin, possibly as
a result of shadows.
Metal post
•
•
•
•
•
•
Esthetic
Corrosion reactions
Taste
Oral burning
Oral pain
Sensitization and other allergic reactions
•
•
•
•
Hayashi Y, Nakamura S. Clinical application of energy
dispersive x-ray microanalysis for nondestructively
confirming dental metal allergens. Oral Surg Oral Med
Oral Pathol 1994; 77: 623-626
Radiopacity
FRC Postec shows reduced
radiopacity
Used in conjunction with
Variolink II provides
additional x-ray identification
Removal
FRC Postec can be removed
with a rotary instrument if
retreatment is required
Zirconia posts
•
•
•
•
•
Meyenberg
Good chemical stability
Mechanical strength
High toughness
Color similar to that of natural teeth
•
•
•
•
Ahmad I. Yttrium–partially stabilized zirconium dioxide
posts: an approach to restoring coronally compromised
nonvital teeth. Int J Periodontics Restor Dent 1998; 18:
454-465.
Zirconia posts
• Nearly impossible to remove
• Removal of zirconia post by ultrasonic causes
temperature rise of the post and on the root
surface
Zirconia post
• Cormier et al: fracture strength of zirconia post varied according to
the different stages of tooth restoration.
• When the post alone was bonded into tooth, fracture strength was
101.5 N;
•
when the post was bonded into tooth with core buildup, fracture
strength was 179.7 N;
•
with post and core buildup as well as full veneer restoration,
fracture strength was 238.8 N
•
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.
• The bond strengths of luting agents to
zirconia posts were measured without
bonding to any tooth structure, and it was
shown that a dual-cured resin cement,Panavia
(Kuraray, Osaka), produced better results than
other cement types
•
Sahmali S, Demirel F, Saygili G. Comparison of in vitro tensile bond strengths of luting cements to metallic and tooth-colored posts. Int J Periodontics Restor Dent 2004; 24: 256-263.
• The reviewed studies suggested that FRC and
zirconia posts might be the preferred clinical
choice for preventing coronal microleakage
•
•
•
Jung SH, Min KS, Chang HS, Park SD, Kwon SN, Bae JM. Microleakage and fracture patterns of teeth restored with different posts under dynamic loading. J Prosthet Dent 2007; 98: 270-276
Reid LC, Kazemi RB, Meiers JC. Effect of fatigue testing on core integrity and post microleakage of teeth restore with different post systems. J Endod 2003; 29: 125-131
Usumez A, Cobankara FK, Ozturk N, Eskitascioglu G, Belli S. Microleakage of endodontically treated teeth with different dowel systems. J Prosthet Dent 2004; 92: 163-169
• zirconia posts showed the highest
radiodensity level, followed by metallic posts,
carbon fiber posts, glass fiber posts, and
carbon fiber post covered with quartz fiber.
• In a study by Dietschi et al.
• It was reported that the carbon fiber post
presented the lowest marginal gap proportion
(7.11%) compared to other post types which
• presented higher degrees of marginal gap
formation:
• titanium post at 11%, zirconia post at 16.5%, and
• stainless steel post at 17.4%
•
Dietschi D, Ardu S, Rossier-Gerber A, Krejci I. Adaptation of adhesive post and cores to dentin after in vitro occlusal loading: evaluation of post material influence. J Adhes Dent 2006; 8: 409-419.
• A) a flame heated endo plugger,
• B) GatesGlidden drills
• C) GPX drills
•
•
•
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sixty-six extracted maxillary central
Removed from CEJ
Ah26
Six teeth were used as positive and negative
control
• other sixty teeth were divided into 3 groups, each
group containing 20 teeth
• apical dye leakage in each group was measured
by astereomicroscope
• Minimal mean dye leakage was related to the
hot plugger group
• Maximum mean leakage was observed in
Gates glidden drill group
• Kwan and Harrington (1981) and Madison and
Zakariasen (1984) found that post space
preparation with Gates Glidden drills
immediately after obturation actually
decreased the amount of apical leakage.
Flame-heated
endo pluggers
•
•
•
•
Fast
Inexpensive
don‘t cause canal shape alterations
Burn potential for the dentist, dental assistant
or the patient
• did not cause any permanent damage to the
• periodontium
Peeso reamers
• Very fast
• Creates parallel walls which provide optimal
retention form for the post
• possiblity of creating root perforation, canal
transportation, overenlargement of the canal
• Only in straight canals
• The gates glidden drills are more conservative
instruments compared with Peeso reamers
drills
GPX
• match standardized endothontic file sizes # 25
#50.
• Slight frictional heat which softens the GP
before removal
• Fast and effective
• The bur does not engage the dentin so canal
shape remains unaltered and the frictional
heat generated is minimal

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