● Effect of ferrule and post placement on
fracture resistance of endodontically
treated teeth after fatigue loading
● F. Zicari, B. Van Meerbeek, R. Scotti , I. Naert
● Journal of dentistry. 2013 Mar 1;41(3):207-15.
UNDER THE ABLE GUIDANCE OF:
PROF(DR.) JAYANTA BHATTACHARYYA(HOD &
PRINCIPAL)
PROF(DR.) SAMIRAN DAS
PROF(DR.) SOUMITRA GHOSH
DR. SAYAN MAJUMDAR
DR. PREETI GOEL
Presented by- Partha Sarathi Adhya. (2nd year PGT)

Introduction
The restoration of endodontically treated
teeth has long been a controversial topic.
Questions and contradictory opinions
remain about clinical procedures and
materials to be used to restore these teeth.
fracture incidence between
nonendodontically treated (14%) versus
endodontically treated (58%) teeth . That is
why restoring endodontically treated teeth
both esthetically and functionally is a
challenge to the prosthodotits.

Endodontically treated tooth characteristics
 Water loss occure (around 10%).
 Change in the collagen cross linkage.
 differences in dentin microhardness or
hardness, elastic modulus and
tensile/compression strengths can be seen
between vital and non-vital dentin.
 Loss of structural integrity associated with
the access preparation results in increased
cuspal deflection during function, which
leads to a higher occurrence of fractures.

Class I: 4 remaining cavity walls
If all the axial walls of the cavity remain and have a thickness greater
than 1 mm, it is not necessary to insert posts.
Classes II and III: 2 or 3 remaining cavity
walls:
Treatment in cases involving the loss of 1
or 2 cavity walls does not necessarily
require the insertion of a post, as the
remaining hard tissue provides enough
surface for the use of other methods, in
particular, for cores using adhesive systems
Post or not??

Class IV: 1 remaining cavity wall
In cases where only 1 cavity wall remains, the core material has little or
no effect on the fracture resistance of the endodontically treated teeth.
If the tooth has to be used as an abutment for fixed or removable
partial dentures, crown preparation will further decrease fracture
resistance.
• For aesthetic reasons, non-metal posts are preferred for treatment of
anterior teeth.
• In posterior teeth, both metal posts and non-metal posts are
acceptable treatment options .

Class V: No remaining cavity wall
In cases of teeth with a high degree of destruction where no cavity wall
remains, the insertion of posts appears necessary to provide for core
material retention. Additionally, the ferrule effect has a great influence
on fracture resistance, especially in decoronated teeth.
Peroz I, Blankenstein F, Lange KP, Naumann M. Restoring endodontically treated teeth with posts
and cores--a review. Quintessence international. 2005 Oct 1;36(9).

Post Length –
 post length should reach two-thirds of the
entire root length.
 A crown-length/post-length ratio of at least 1:1
should be provided.
 Stresses are reduced as post length increases.
Post Diameter
According to Tilk MA, Lommel TJ, Gerstein H (1979):
a. Small teeth such as mandibular incisors: 0.6 to 0.7 mm.
b. Large-diameter roots such as maxillary central incisors and the
palatal root of the
maxillary first molar: 1.0 mm
c. For the remaining teeth: 0.8 to 0.9 mm
 A minimal dentin thickness of 1 mm around the post should be
provided.
 Enlargement of the canal space increases cervical stress.
(Tilk MA, Lommel TJ, Gerstein H. A study of mandibular and maxillary root widths to determine dowel
size. Journal of endodontics. 1979 Mar 1;5(3):79-82.)

Post Material-
The elastic modulus of the post material is
important.
 post that more closely matches the elasticity
of the root is less likely to lead to root
fracture .
 Flexibility may lead to movement of the stiff
crown away from the margin and opening at
the crown margin or fracture of the post.
Parallel & tapered posts
• Parallel metal posts are more retentive than tapered posts .
• Parallel posts induce less stress into the root, because there is less of a
wedging effect.
• Tapered posts, on the other hand, require less dentin removal because
most roots are tapered.

According to type of
Metal.
1. Gold alloy
2. Chrome-Cobaltalloy
3. Nickel-Chromium
alloy
According to material
1. Metallic
i) Titanium
ii) Stainless steel
iii) Brass
2. Non-Metallic*
i) Non-Esthetic
a. Carbon fibre post
ii) Esthetic Post
a. Polyethelene fibre
b. Glass fibre
c. Quartz
d. Ceramic
According to Taper
1. Parallel
2. Tapered
3. Parallel Tapered
Singh SV, Chandra A, Pandit IK. A new classification of post and core. Ind J Rest Dent. 2015;4(3):56-8.
According to fit
1. Active
2. Pasive
According to
fabrication method
1.Pre fabricated
(metallic & non
metallic)
2. Custom made.
According to Vent
1. With Vent
2. Without Vent
Classification of Post

Ferrule-
• 1.A band or ring used to encompass the root or crown of a tooth; 2.
any short tube or bushing for making a tight joint. (GPT-9).
• A 360 metal collar of the crown surrounding the parallel walls of the
dentine extending coronal to the shoulder of the preparation.
(Sorensen JA, Engelman MJ. Ferrule design and fracture resistance of endodontically treated
teeth. The Journal of prosthetic dentistry. 1990 May 1;63(5):529-36.)
1.Promoting hugging action,
2: Preventing the shattering of the
root
3: Reducing the wedging effect of a
tapered dowel,
4: Resisting functional lever forces and
the lateral forces exerted during
dowel insertion.
Extension of dentine, when encircled by a crown, provides a
protective effect by reducing stresses within a tooth.

 Ferrule tooth structure
The ‘ferrule tooth structure’ is the tooth structure that extends 1.5-
2.0 mm in the occlusal direction from the projected ferrule margin,
and will be encircled by the apical 1.5-2.0 mm of the intaglio
surface of the crown or ferrule margin.
The ‘ferrule tooth complex’ is
the complex of tooth structure,
and/or core material and/or
post material that exists within
the volume encircled by the
apical 1.5-2.0 mm of the ferrule
margin.

Different types of Posts-
CARBON FIBRE-REINFORCED EPOXY RESIN POSTS
 This post system was developed in France in 1988 by Duret and
Renaud and first introduced in Europe in the early 1990s.
 An epoxy resin reinforced with unidirectional carbon fibers
parallel to the long axis of the post.
 Exhibit high fatigue strength, high tensile strength and a
modulus of elasticity similar to dentin
GLASS FIBRE-REINFORCED EPOXY RESIN POSTS
 The GFR epoxy resin post is made of glass or silica
fibers (white or translucent).
 Glass fiber posts can be made of different types of
glasses: electrical glass, high-strengthglass, or quartz
fibers, zirconia fibers.

ZIRCONIA POST
 Stabilized zirconia ceramics (zirconium dioxide ZrO2)
have been introduced for the fabrication of posts and
cores (Kwiatkowski S and Geller WA; 1989).
 TZP (tetragonal zirconium polycrystals) with 3 mol%
yttrium oxide (Y2O3) and is called YTZP (yttria-
stabilized tetragonal polycrystalline zirconia .
 Radiopaque, biocompatible, possesses high flexural,
strength and fracture toughness
Commercially available prefabricated metal posts
 Mainly composed of titanium (98-99%),
stainless-steel, Gold –plated.
 Often threaded.
 The Stainless Steel posts are recommended
where extra high shear strength is required.

Article Proper
Aim- Evaluate whether or not fibre-posts adhesively cemented into the root
canal can influence the fracture resistance of endodontically treated teeth when
a ferrule is preserved.
Materials and methods
 Forty extracted upper pre-molars were stored in 0.5%
chloramine in water at 4°C and used within 6 months after
extraction.
• Absence of caries or root
cracks.
• No previous endodontic
treatments.
• Teeth with root length of 15±
1 mm
• Similar mesio-distal and
bucco-lingual dimensions.

 Endodontic treatment
 Teeth were cut at the CEJ (groups a and b) or 2 mm above the CEJ (groups c
and d) using a low speed diamond saw.
 Endodontic treatment was done following a standardized crown-down
technique using the ProTaper system.
 Obturation was done with tapered gutta-percha points using the System-B
continuous wave condensation technique
Specimens were divided in 4 groups of 10 specimens each
(a) NF–NP (no ferrule, no post).
(b) NF–P (no ferrule, fibre-post).
(c) F–NP (2 mm ferrule, no post).
(d) F–P (2 mm ferrule, fibre-post).
A circumferential dentinal wall was preserved with a
minimum thickness of 1 mm.

 Post luting procedures
 After 24-h water storage at 37°C, gutta-percha was removed using no.
2, 3, 4 Gates-Glidden burs up to 5 mm into root canal in NF–P and F–P
groups.
 Double-tapered translucent glass-fibrer posts of 1.6 mm diameter were
cemented.
 In NF–NP and F–NP groups, in which any post was planned to be
placed, gutta-percha was seemingly removed up to 2 mm into the root
canal for retention and filled-up with the composite used for core build-
up.
A standardized core of 5 mm and 6° taper was built with
Optibond FL using core formers .Each layer was polymerized from each
side for 40 s.

Specimens were restored with all ceramic crowns (IPS Empress CAD Mult) &
thickness ranged between 1 and 1.5 mm along the axial walls whereas was
kept of 1.5 mm on the occlusal surface and 2 mm on the cusps.
Mechanical loading
Fatigue loading
• Specimens were embedded in methacrylate resin at 2 mm from the CEJ
to simulate the bone level.
• Fatigue load of 1,200,000 cycles under water irrigation using a
chewing simulator with sliding movement, simulating 5 years of clinical
function. Load was applied at 45° angle at a frequency of 1.6 Hz.

A sinusoidal load of 0–50 N was applied with a stainless-steel ball-shaped
stylus in the centre of the occlusal area of the crown.
Fracture resistance
• After fatigue loading, each specimen was
immediately
subjected to a fracture resistance test using a
universal loading device.
• Each test was performed at a cross-head speed
of 0.5 mm/min and load was applied at 45° using
the same specimen holder.
Failures were classified in:
a. repairable (including adhesive failures and crown fractures) when the
fracture line was above the simulated bone level and
b. not-repairable (including root fracture) when the fracture line was below
the simulated bone level

Statistical analysis
Analysis of variance (two-way ANOVA) with Tukey-HSD for post hoc
comparison was used to analyse the fracture resistance test results. A
significance level of 5% was used.
Results-
The highest fracture resistance was recorded for F–NP (758.52±121.89N),
which was not significantly different from F–P (647.58±132.95N).The
lowest fracture resistance was observed for NF–NP (361.52±151.69 N).
Group Fatigue Failure Fracture strength (N)
Fatigue failures included
Fracture strength (N)
Fatigue failures not included
NF–NP 1 361.5 (151.7) 396.13 (111.4)
NF–P 0 577.0 (104.9) 577.00 (104.9)
F–NP 0 758.5 (121.9) 758.52 (121.9)
F–P 0 647.6 (132.9) 647.58 (132.9)

• Uniform ferrule height of 2 mm led to higher fracture resistance than a
ferrule height varying between 0.5 and 2 mm, in particular when
approximal cavities are not involved. (Tan PL et al)
• The elastic modulous of Fibre posts is in the same range of that of
dentin, are claimed to preserve teeth from catastrophic failures.
• Placing a fibre post did not enhance the fracture resistance of premolars
restored with all ceramic crowns where a ferrule was preserved.
• Heydecke et al, showed that post insertion does not add any beneficial
effect to intact teeth, even in the anterior region where higher tension
stress due to more horizontal forces develops during function.
• Post insertion has also been shown not to improve marginal adaptation,
retention and fracture resistance of adhesive composite restorations on
endodontically treated premolars
Discussion

• Fatigue tests should be performed for a minimum of 10 cycles. A total of
1,200,000 cycles have been performed in this study, which simulate 5 years
of clinical function.
• Fatigue failures are defined as fractures of a material caused by cyclic or
repeated sub-critical loads.
Load was applied at 45°, thus inserting extra-axial forces on the restored
tooth, which are associated with bending moments and unfavourable stress
distribution during function.

• A prevalence of repairable failures was observed in all groups.
• tension develops palatally and compression facially, a typical
fracture pattern extended from the palatal cervical area to the
facial area above the simulated bone level.
Only premolars with a ferrule and restored without a post did not
show not-repairable root fractures.
- This emphasize the importance of a ferrule.

• Endodontically treated teeth with a circumferential ferrule of 2 mm
height and restored without a post may survive fatigue loading as well
as teeth restored with a fibre post. However, in teeth where a ferrule is
not preserved, a post may eventually improve retention of the
restoration.
• Inserting a fibre post seems not to be necessary to improve the
fracture resistance of endodontically treated teeth in which a ferrule is
preserved, whereas is effective in teeth without any ferrule.
• Avoiding extra-removal of sound tooth structure rather than using a
fibre posts does protect endodontically treated teeth against
catastrophic failures, since only endodontically
treated teeth with a 2 mm ferrule and restored without fibre posts did
not show not-repairable root fractures.

Critical analysis-
 Sample selection not motioned properly.
 Number of repairable and non repairable failures are
not mentioned.

● Influence of ferrule preparation with or without glass fiber
post on fracture resistance of endodontically treated teeth
● Alexandra Furtado de LIMA, Aloísio Oro SPAZZIN, Daniel
GALAFASSI, Lourenço CORRER-SOBRINHO
● Journal of Applied Oral Science. 2010 Aug;18(4):360-3.
❏ Aim- was to evaluate the influence of
a 2-mm ferrule preparation and use of
glass fiber post on the fracture
resistance of endodontically treated
teeth restored with composite cores
and crowns .
★ A total of 44 teeth, selected & Crowns were
removed below the CEJ to obtain a root length
of 19 and 17 mm (2 mm was used as ferrule
preparation).

In Groups 1 and 3, the root canal preparations & obturation was
done. 13 and 11 mm of gutta-percha respectively, leaving
approximately 5 mm of canal filling at the apex.
The posts were cemented and the composite
resin cores were standardized using a core-forming
matrix
In Groups 2 and 4, the gutta-percha was
removed (4 and 2 mm, respectively) & core was
being fabricated with core forming matrix .
Specimens were prepared to receive complete
crowns. Specimens were submitted to the fracture
resistance testing using a universal testing machine
1
3
2
4

Group Sample Fracture
Resistance
1 11 573.9
2 11 552.5
3 11 275.3
4 11 258.6
★ The presence of a ferrule preparation was shown to increase the fracture
resistance of endodontically treated teeth with composite core and crown,
irrespective of whether or not a glass fiber post was placed.
★ The use of a glass fiber post associated with a composite core showed no
significant influence on the fracture resistance of endodontically treated
teeth .

● Effect of different ferrule designs on the fracture resistance and
failure pattern of endodontically treated teeth restored with fiber posts
and all ceramic crowns
● Haneef Sherfudhin, Joseph Hobeich, Carlos Augusto Carvalho,
Moustafa N. Aboushelib
● Journal of Applied Oral Science.2011 Jan ,19(1), pp.28-33.
Aim- To evaluate the fracture resistance and failure pattern of
endodontically treated mandibular premolars restored with different
ferrule heights in combination with fiber posts and all-ceramic crowns.
Fifty sound mandibular first premolars were endodontically treated & divided into 5
groups (n=10).
• Group 1- 1-mm circumferential ferrule without post and core.
• Group 2- 1 mm circumferential ferrule with fiber post and resin core.
• Group 3- Non-uniform ferrule height (2 mm buccally and 1 mm lingually) with
fiber post and resin core .
• Group 4- Non-uniform ferrule height (3 mm buccally and 2 mm lingually) with fiber
and resin core post .
• Group 5: received no ferrule preparation with fiber post and resin core.

Other than group 1 , in every other group post space was created & A
translucent glass fiber reinforced composite post was cemented.
Then core build-up was performed using hybrid composite resin restored to
predetermined dimensions.
After cementation of all ceramic crowns all specimens were subjected to cyclic
loading. After completion of cyclic loading, a universal testing machine.
The failure mode recorded for each specimen and classified as either favorable
facture above the cement-enamel junction (repairable) or catastrophic fracture of
the root below cementenamel junction (non repairable).

Group Failure load Favorable
fracture
Catastrophic fracture
Group 1 891.4 7 3
Group 2 1011.5 10 0
Group 3 952.8 10 0
Group 4 909.2 9 1
Group 5 996.7 9 1
 Increasing the ferrule length did not influence the fracture resistance of
endodontically treated teeth restored with glass ceramic crowns.
 Insertion of a fiber post could reduce the percentage of catastrophic failure
of these restorations under function.

• Fracture resistance of three post and core systems in
endodontically treated teeth restored with all-ceramic crowns.
• Tariq Abduljabbar, Haneef Sherfudhin , S.A. AlSaleh , Abdulaziz
A. Al-Helal , Saleh S. Al-Orini.
• King Saud University Journal of Dental Sciences. 2012 Jan
1;3(1):33-8.
Aim-To compare the fracture resistance of endodontically treated teeth prepared
with a 2 mm ferrule restored with a cast post and core, a glass fiber post with a
composite resin core, and a customized zirconia post restored with an all-ceramic
crown .
A total of 40 human extracted mandibular first premolars were
used & divided into four groups.
Group A represented a control group that did not receive any
posts and was filled with core material only;
Group B comprised cast metal posts and cores .
Group C comprised custom milled zirconia posts and cores
Group D comprised glass fiber posts.

• The glass fiber posts (RelyX, Fiber 3 M ESPE) were cementedand the core was
built up with MULTICORE FLOW system .
• Cast posts and cores were fabricated with Duralay. Plastic Para-post
systems were covered with Duralay, and an impression of the canal was
made.
• Duralay buildup of the post and cores was scanned and the presintered Y-TZP Cercon Base blanks
were milled.
• The specimens were placed at an angle of 45 degree under
universal testing machine to the long axis of the tooth, with
the application point midway between the lingual slope of
the buccal cusp.
• The mode of failure was recorded for each specimen and
classified as either a favorable fracture above the CEJ
(repairable) or a catastrophic fracture of the root below the
CEJ (nonrepairable).

• The load required to fracture the zirconia custom post was higher compared to
the fiber post and cast post and core.
• The fiber post resisted a load higher than the cast post and core.

• Effect of Post Material and Length on Fracture Resistance of
Endodontically Treated Premolars: An In-Vitro Study .
• G S Amarnath, M U Swetha, B C Muddugangadhar, Radhika
Sonika.
• Journal of International Oral Health 2015; 7(7):22-28
Aim- to compare the fracture resistance and mode of failure of endodontically
treated teeth restored with two different post systems of three different lengths.
Sixty freshly extracted human mandibular
premolars were endodontically treated
Group I: SS/4, 4 mm insertion length.
Group II: SS/7, 7 mm insertion length.
Group III: SS/10, 10 mm insertion length.
Group IV: FP/4, 4 mm insertion length.
Group V: FP/7, 7 mm insertion length.
Group VI: FP/10, 10 mm insertion length.

Drills were used for post space preparation. An additional 3 mm of post
length was allowed to extend coronal to the CEJ.
Cementation of the stainless-steel and fibre posts using paracore dual core
resin cement.
Core formers were used for core build-up up
to 4 mm from the coronal tooth floor.
A universal testing machine with a custom made
loading plunger was used to load the specimens at
90° to the long axis and 3 mm from the toothcore
interface with a crosshead speed of 0.5 mm/min
until primary failure occurred.

1.Post length increased the fracture resistance of the teeth to an extent of
two-third the root length restored with SS posts and thereafter it decreased.
2.Fracture resistance of the teeth proportionately increased with increase in
FP length.

• Effect of ferrule on the fracture resistance of mandibular
premolars with prefabricated posts and cores.
• Ae-Ra Kim, Hyun-Pil Lim, Hong-So Yang, Sang-Won Park.
• J Adv Prosthodont 2017;9:328-34
Aim- 1.To evaluate the fracture resistance with various ferrule lengths.
2. To compare the fracture load with and without posts on endodontically treated mandibular
premolars restored with prefabricated posts.
One hundred extracted mandibular premolars were randomly divided
into 5 groups (n=20) .
1. Intact teeth restored with a crown (NR, no root canal treatment).
2. ETT restored with a crown without a post (NP,no post ).
3. ETT restored with a prefabricated post, core, and crown
incorporating a 0 mm ferrule (F0) .
4. ETT restored with a post, core, and crown incorporating a 1 mm
ferrule (F1).
5. ETT restored with a post, core, and crown incorporating a 2 mm
ferrule (F2)

Coronal tooth structure was
reduced to a height of 6 mm
occlusal to the CEJ in NR and NP,
at the CEJ in F0, at a height of 1
mm occlusal to the CEJ in F1, and
at 2 mm occlusal to the CEJ in F2
One week after the root canal treatment, the experimental groups was prepared
with a # 2 Pesso reamer to remove 9 mm of gutta percha apical to the CEJ.
Post space was prepared using a Parapost & core was being fabricated using
Paracore.
A thermal cycling test was performed for 1,000
cycles. Loading was applied at an angle of 135
degrees to the axis of the tooth using a universal
testing machine with a crosshead speed of 2.54
mm/min.

Group Fracture loads (Mean)
NR 262.6
NP 155.6
F0 98.8
F1 152.8
F2 237.7
Fracture resistance of ETT depends on the length of the ferrule, as shown
by the significantly increased fracture resistance in the 2 mm ferrule group
(F2) compared to the groups with shorter ferrule lengths (F0, F1) and
without post (NP)

Conclusions-
The ferrule effect acts to protect the underlying tooth and
improves the resistance of the restoration to failure. While
post in other hand does not increase the fracture resistance
of the teeth. But it can reduce the chance of non repair able
damage.

Bibliography
1. Tilk MA, Lommel TJ, Gerstein H. A study of mandibular and maxillary root widths to determine
dowel size. Journal of endodontics. 1979 Mar 1;5(3):79-82
2. Singh SV, Chandra A, Pandit IK. A new classification of post and core. Ind J Rest Dent.
2015;4(3):56-8.
3. Sorensen JA, Engelman MJ. Ferrule design and fracture resistance of endodontically treated
teeth. The Journal of prosthetic dentistry. 1990 May 1;63(5):529-36.
4. Peroz I, Blankenstein F, Lange KP, Naumann M. Restoring endodontically treated teeth with
posts and cores--a review. Quintessence international. 2005 Oct 1;36(9).
5. Kim AR, Lim HP, Yang HS, Park SW. Effect of ferrule on the fracture resistance of mandibular
premolars with prefabricated posts and cores. The journal of advanced prosthodontics. 2017
Oct 1;9(5):328-34.
6. Zicari F, Van Meerbeek B, Scotti R, Naert I. Effect of ferrule and post placement on fracture
resistance of endodontically treated teeth after fatigue loading. Journal of dentistry. 2013 Mar
1;41(3):207-15.
7. Abduljabbar T, Sherfudhin H, AlSaleh SA, Al-Helal AA, Al-Orini SS, Al-Aql NA. Fracture
resistance of three post and core systems in endodontically treated teeth restored with all-
ceramic crowns. King Saud University Journal of Dental Sciences. 2012 Jan 1;3(1):33-8.
8. Sherfudhin H, Hobeich J, Carvalho CA, Aboushelib MN, Sadig W, Salameh Z. Effect of different
ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth
restored with fiber posts and all-ceramic crowns. Journal of Applied Oral Science. 2011
Feb;19(1):28-33.