UNIVERSIDADE ESTADUAL PAULISTA
“JÚLIO DE MESQUITA FILHO”
Instituto de Ciência e Tecnologia
Campus de São José dos Campos
ORIGINAL ARTICLE DOI: https://doi.org/10.4322/bds.2023.e3775
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
The effect of different framework’s material on strain induced in
distal abutment in mandibular Kennedy’s class II: an in-vitro study
O efeito de diferentes materiais de estrutura na deformação induzida na distal do pilar da classe II de Kennedy mandibular:
um estudo in vitro
Noha Mohamed EL HUSSIENY FAYAD1 , Dina Essam BAHIG1
1 - Oral and Maxillofacial Prosthodontics Department, Ain Shams University. Cairo, Egypt.
How to cite: El Hussieny Fayad NM, Bahig DE. The effect of different framework’s material on strain induced in distal abutment
in mandibular Kennedy’s class II: an in-vitro study. Braz Dent Sci. 2023;26(3):e3775. https://doi.org/10.4322/bds.2023.e3775
ABSTRACT
Objective: This study aims to compare the strain induced in the supporting structures of unilateral mandibular
removable partial denture frameworks retained by extra-coronal attachments fabricated with three different
materials. Material and Methods: Three mandibular class II digitally designed and printed acrylic models with
detachable abutments were used to fabricate three removable partial denture framework with extra coronal
attachments from three different materials. A total of 33 models were prepared for strain testing (n=11). Models
were divided into three groups according to framework’s material: porcelain fused to cobalt chromium (PFM),
polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) group. Unilateral load of 60 N was applied
in the three groups and strains were measured around the main abutment and saddle area using strain gauge.
Results: Statistical analysis was performed using Shapiro-Wilk’s test and by checking data distribution. Data
were found to be non-parametric and were analysed using Kruskal-Wallis test followed by Dunn’s post hoc
test with Bonferroni correction. PFM group showed signicantly the highest strain values around abutment,
slot 1 (1mm distal to the socket of the last abutment) and slot 2 (1 cm away from slot 1) respectively (843.00±23.08,
91.00±6.52 and 1274.00±65.71) than the other tested groups (p<0.05) at same tested sites respectively followed
by PEKK group (384.00±37.48, 81.00±2.24 and 135.00±0.00) and PEEK group (29.00±4.18, 63.00±4.47 and
52.00±5.70). Conclusions: PEEK and PEKK for partial denture framework with extra coronal attachments are
adequate alternative to PFM due to their good mechanical response applying less strain on supportive structures
in free-end cases. PEEK induces lower strain magnitude on the supporting structures when compared to PEKK.
KEYWORDS
Denture precision attachment; Dental stress analysis; Partial denture; Polyetheretherketone; Removable partial denture.
RESUMO
Objetivo: Este estudo tem como objetivo comparar a tensão induzida nas estruturas de suporte de estruturas
de próteses parciais removíveis mandibulares unilaterais retidas por encaixes extracoronários fabricados com
três materiais diferentes. Material e Métodos: Três modelos mandibulares de classe II digitalmente projetados
e impressos em acrílico com pilares destacáveis foram usados para fabricar três estruturas de próteses parciais
removíveis com encaixes extracoronários de três materiais diferentes. Um total de 33 modelos foram preparados
para testes de deformação (n=11). Os modelos foram divididos em três grupos de acordo com o material da
estrutura: porcelana fundida com cobalto-cromo (PFM), poliétercetonacetona (PEKK) e polieteretercetona
(PEEK). Carga unilateral de 60 N foi aplicada nos três grupos e as deformações foram medidas em torno do pilar
principal e área de sela usando medido de tensão. Resultados: A análise estatística foi realizada por meio do
teste de Shapiro-Wilk e com a vericação da distribuição dos dados. Os dados mostraram-se não paramétricos e
foram analisados pelo teste de Kruskal-Wallis seguido pelo de Dunn com correção de Bonferroni. O grupo PFM
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
mostrou signicativamente os maiores valores de tensão ao redor do pilar, slot 1 (1mm distal do último pilar)
e slot 2 (1 cm de distância do slot 1) respectivamente (843,00±23,08, 91,00±6,52 e 1274,00±65,71) do que
os outros grupos testados (p<0,05) nos mesmos locais testados, respectivamente, seguido pelo grupo PEKK
(384,00±37,48, 81,00±2,24 e 135,00±0,00) e grupo PEEK (29,00±4,18, 63,00±4,47 e 52,00±5,70). Conclusão:
PEEK e PEKK para estrutura de prótese parcial com encaixes extracoronários são alternativas adequadas ao PFM
devido à sua boa resposta mecânica aplicando menos tensão nas estruturas de suporte em casos de extremidade
livre. O PEEK induz menor magnitude de deformação nas estruturas de suporte quando comparado ao PEKK.
PALAVRAS-CHAVE
Análise de tensão dentária; Encaixe de precisão para próteses; Polieteretercetona; Prótese parcial; Prótese parcial removível.
Extra coronal attachments as direct retainers
that extend from the full coverage crown of
abutments can provide a rigid, movable, or
resilient connection between abutments and
RPD [8-14]. Proper materials selection of RPDs’
framework fabrication affects stresses transmitted
to the supportive structures [11].
RPD framework fabrication material may
be metallic or non-metallic. Cobalt-chromium
(CoCr) alloy is the most commonly used metallic
material for casting or printing RPD framework
material. Many drawbacks are detected with
metallic RPD framework fabrication materials
where aesthetics and metallic taste are of major
concern. Non-metallic RPD framework materials
with polymeric nature provide a wide range of
physical and chemical properties that have solved
many of the major problems encountered with
metallic RPD framework materials [15,16].
Poly aryl ether ketone (PAEK) family is a
thermoplastic polymeric material which has been
used in the engineering field since 1980s with
excellent mechanical properties and chemical
resistance. PAEK family includes two polymeric
material polyetheretherketone (PEEK) and
polyetherketoneketone (PEKK) [17,18]. PEEK was
the rst version of PEAK family that was widely
applied in many dental elds including implantology,
prosthetics and maxillofacial elds [11,19].
PEKK is the latest generation of the PAEK family
showing higher quality. Unlike PEEK, PEKK shows
both amorphous and crystalline material properties
which gives PEKK unique interesting mechanical,
physical and chemical properties [11,20]. Digital
workow for the fabrication of RPD from polymeric
material as PEEK & PEKK provides RPD frameworks
with dimensional accuracy and adaptation to the
underlying structures leading to good retention
and support [11,21,22].
INTRODUCTION
Kennedy class I and II free end saddle cases
are one of the most challenging prosthetic clinical
situations due to absence of posterior abutments
and variable compressibility of supportive dental
and saddle area [1]. Different treatment options
for these cases have been introduced in literature
including the insertion of distal dental implants
with an implant supported prosthesis or a properly
designed classic removable partial denture (RPD).
RPD in distal extension cases represents a great
challenge due to multiple factors. These factors
include dental, patient and RPD design aspects.
RPD is a biomechanical device. Its components
are exposed to various loads and forces which are
consequently transferred to the supportive dental
and saddle structures during function as well as
during insertion and removal of RPD [2-6].
Load within the physiological limit of the
abutments and supportive saddle area leads to
the torsional force of abutments as well as less
destructive bone resorption effect on the saddle
area. But, even with controlled application of load
in free end saddle cases, they are still subjected
to stresses during function that affect the support
as well as stability of RPD leading to the need for
frequent relining [2,7]. Good clinical prognosis
of RPD in classic Kennedy class II requires
optimal design of RPD on solid biomechanical
principles. In such instances the selection of a
suitable retainer becomes a critical component
to control stresses applied on the supportive
abutments [8-11].
Attachment retained RPD is the treatment
modality that can facilitate both an aesthetic
and functional replacement of missing teeth
and oral structures [12]. Elimination of labial
or buccal clasp arms increases the patient’s
psychological acceptance of the denture [8-13].
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Mechanical behaviour of variable materials in the
dental eld can be measured with different techniques
including photoelasticity measurement, strain
gauge-based measurements, optic measurement,
and computational nite analysis [15,23]. A strain
gauge is a tool designed to measure the strain of an
entity [3,4,8,10]. Strain gauge evaluation is a method
for measuring micro-strains, by measuring electrical
resistance [8,13,24].
Strain induced by partial dentures on the
supporting structures can be detrimental. The goal
of this study was to assess how partial denture
frame work with extra coronal attachment
fabrication materials affects the biomechanical
behaviour using strain gauge analysis. The
null hypothesis was that different fabrication
materials for partial denture with extra coronal
attachment would result in different outcomes.
MATERIALS AND METHODS
Construction of 3D model of lower class II
A mandibular 3D educational acrylic model
simulating mandibular Kennedy class II with
the rst premolar as the principal abutment was
used for this study. It was scanned using desktop
scanner (DOF swing scanner, DOFlabs, Seoul,
South Korea) for designing and modifying the
virtual model.
Designing & modication of virtual model
and virtual abutments preparation
Virtual abutment preparation was done
separately after removal from their sites in the
virtual model to obtain separate STL les for the
detachable abutments designed (Exocad Dental
CAD, Exocad Inc. Darmstadt, Germany). For
mucosal simulation, two mm cut back was done
virtually on a 3D model for creating space for
mucosal simulation material to be injected using
a printed mucosa key index.
Two slots for strain gauge were designed on
the virtual model where the rst slot was 1mm
distal to the socket of the last abutment and the
second slot was 1cm away from the rst slot.
Digital printing for the modied virtual
model and detachable prepared abutments
Three models with their detachable abutments
were printed (Form 2 3D printer, formlabs,
Somerville, Massachusetts, United States).
Mucosal simulating material (Gingisil, Soft
Endharte Shore a 45,dent-e-con e.k, Germany)
was injected through printed mucosa key index
around the roots of the dies and into saddle area
of the printed casts Figure 1.
Splinted crowns and attachments fabrication
Printed models with detachable dies were
rescanned to obtain STL files to design two
splinted on the two main detachable abutments
with I-rod extra coronal attachments using the
three different materials Figures 2-4.
Figure 1 - Digital printed lower-class II model with detachable abutments
with mucosal simulating material and two slots for strain gauge.
Figure 2 - Splinted porcelain fused to metal crowns with metallic
extra coronal attachment.
Figure 3 - Splinted PEKK crowns with PEKK extra coronal attachment.
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Study grouping
PFM group: Eleven porcelain fused to
cobalt chrome partial denture frame works with
extra coronal attachments were fabricated with
conventional casting lost wax technique.
PEKK group: Eleven PEKK chrome partial
denture frame works with extra coronal attachments
were fabricated with milling technique for PEKK
blank.
PEEK group: Eleven PEEK chrome partial
denture frame works with extra coronal attachments
were fabricated with milling technique for PEEK
blank.
Partial denture framework fabrication
Splinted crowns with extra coronal attachments
in the three groups were cemented to the abutments
of the printed models then rescanned to design
the partial denture frame works virtually. Three
different materials were used to fabricate the
splinted crowns with extra coronal attachments in
the three groups.
Design of partial denture frameworks
The scanned model was virtually surveyed to
adjust the proper path of insertion with buttery
clasp design on the intact side for cross arch
stabilization with occlusal rests on the second
premolar and rst molar designed (Exocad Dental
CAD, Exocad Inc. Darmstadt, Germany). The
designed STL le was imported to the milling
machine to mill the two frame works of PEKK
&PEEK while the casted conventional frame
work was fabricated after printing a wax pattern
to be used in lost wax technique to fabricate
conventional CoCr partial denture frame work.
Figure 4 - Splinted PEEK crowns with PEEK extra coronal attachment.
Figure 5 - Group I porcelain fused to CoCr metal attachment and RPD.
Figure 6 - Group II PEKK attachment and RPD.
Figure 7 - Group III PEEK attachment and RPD.
Artificial teeth were set and waxed up on a
duplicated cast then nal denture bases were
fabricated for the three frameworks in the three
groups from conventional heat cured acrylic resin
and pick up for the female part of extra coronal
attachment was done with cold cured acrylic resin
as showed in Figures 5-7.
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Strain analysis
Strain gauges installation and load application
Three strain gauges (KFGS-2N-120-C1-
11L1M2R, Kyowa electronic instruments co.,
Japan) were glued using cyanoacrylate adhesive
on the cast around the distal abutment on the
buccal surface of the socket in respective slot
and in the two pre planed slots one and two
(Figures 8 and 9). The ends of the strain gauge
wires were inserted into four channel strain
meters (Kyowa, kyowa Electronic Instruments Co,
Ltd, Tokyo, Japan) to calculate the micro strains
induced by the applied load [25].
Each model was xed to the lower metal
plate of the universal testing machine (Lloyd LRX;
Lloyd Instruments Ltd., Fareham, UK) where
calibration was done by applying load from
10-60N load ve times in 10N steps at a speed
of at speed 100 mm/s in a progressive manner
until full magnitude of load was reached.
Unilateral 60 N load was applied using I bar
load applicator (8mm in diameter and 22 cm
in length) perpendicular to and centralized over
central fossa of the first molar as showed in
Figure 10.
STATISTICAL ANALYSIS AND SAMPLE
SIZE CALCULATION
A power analysis was designed to have
adequate power to apply a statistical test of the null
hypothesis that there is no difference between tested
groups regarding accuracy. By adopting an alpha (α)
and beta (β) levels of (0.05) (i.e. power=95%)
and an effect size (f) of (0.733) calculated
based on the results of a previous study [26].
The minimal required sample size (n) was found
to be (33) samples (i.e., 11 samples per group).
Sample size calculation was performed using
G*Power version 3.1.9.7.
RESULTS
The results were analyzed using Kruskal-Wallis
test followed by Dunn’s post hoc test with
Bonferroni correction. The signicance level was
set at p<0.05 within all tests. Statistical analysis
was performed with R statistical analysis software
version 4.3.0 for Windows. Numerical data was
represented as mean, standard deviation (SD)
median and interquartile range values (μm/μm).
Figure 8 - Strain gauges bonded in their sites.
Figure 9 - Three strain gauges bonded on the cast around the
distal abutment on the buccal surface of the socket and in the two
pre-planned slots (one and two).
Figure 10 - Unilateral load applied using I bar load applicator.
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Results of intergroup comparisons and
summary statistics for strain values are presented
in Table I. there was a significant difference
between the three tested groups with all post
hoc pairwise comparisons being statistically
signicant (p<0.001).
The strain mean values which was the
highest value was for the abutment measures
in PFM framework group (843.00 ± 23.08A)
followed by PEEK framework (29.00 ± 4.18B) &
PEEK framework group (384.00 ± 37.48C).
For slot 1 and slot 2 strain values were also
found to be the highest for PFM framework group
respectively (91.00±6.52A, 1274.00 ± 65.71A)
but less strain values were detected in PEKK
framework group respectively (81.00 ± 2.24B,
135.00 ± 0.00B) and the lowest strain values
were detected in PEEK framework group
(63.00 ± 4.47C, 52.00 ± 5.70C).
DISCUSSION
Distal extension RPD abutments along with
the saddle supportive tissues act as an important
source of support and retention. A disadvantage
of the metallic removable partial dentures is the
inferior esthetics. This led to the development
of attachments whether precision or resilient to
help give more esthetic results. The advantage
of resilient attachment is that it dissipates forces
permitting denture base movement towards the
tissues during function leading to a decrease in
the torque falling on the abutments [27-29].
The partial denture design and material
play a critical role in the dissipation of the
masticatory applied load. If the partial denture
fails to distribute these stresses equally the
tension created will lead to local irritation and
excessive bone resorption which will affect RPD
stability and function and the health of the
supporting structures [15].
The difference in compressibility of the
supportive structures in free end saddle cases leads
to inevitable tissue ward rotation of the denture.
Although actual movement of RPD is minimal, a
lever force is created at the terminal abutment
leading to an increase in the stress induced [30].
So, proper design and selection of fabrication
material is crucial to control stresses induced in
the supporting tissues to reduce bone loss [31,32].
The results of this study showed highly
significant difference in strain induced around
abutment, slot 1 and slot 2 in PFM framework
group in comparison to the PEEK framework and
PEEK framework groups that showed less strain
mean values. Such nding were in line with the
study of Fayyad [33] that showed that porcelain
fused to CoCr metal might initiate higher strain
values around the abutments due to the stiff
nature of the material [9,33]. This nding is due
to high modulus of elasticity of cobalt-chromium
(210MPa) which is more rigid in comparison to the
low value of modulus of elasticity of PEKK (15GPa)
and PEEK (3.6GPa). PEEK & PEKK are almost like
dentine and bone so they are exible and at the
same time elastic with strong damping power to
decrease torque and stresses on abutments with
the RPD settling. The rigidity of cobalt chromium
transmits great rotational and lateral stresses on
the abutment. According to the recent literature,
the modulus of elasticity and nano-hardness of a
material are factors that directly affect the amount
of pressure transmitted by the material and the
extent of the area to which it is transmitted [11,33].
Results comparing strain induced around
abutment showed higher value in PEKK framework
group when compared to PEEK framework group
which was in line with the ndings of Sadek [13]
where strain gauge assessment method revealed
that, PEEK is the material of choice as it showed
the most suitable stress dissemination in all parts
particularly throughout the abutment teeth due
to its exure behaviours [13,34-38].
Table I - Intergroup comparisons of strain values
Measurement area PFM PEEK PEKK h-value p-value
Abutment Mean±SD 843.00±23.08A29.00±4.18B384.00±37.48C
12.54 <0.001*
Median (IQR) 840.00 (25.00)A30.00 (5.00)B385.00 (55.00)C
Slot 1 Mean±SD 91.00±6.52A63.00±4.47B81.00±2.24C
12.42 <0.001*
Median (IQR) 90.00 (10.00)A60.00 (5.00)B80.00 (0.00)C
Slot 2 Mean±SD 1274.00±65.71A52.00±5.70B135.00±0.00C
12.99 <0.001*
Median (IQR) 1270.00 (85.00)A50.00 (5.00)B135.00 (0.00)C
Values with different superscript letters within the same horizontal row are significantly different. *significant (p<0.05).
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Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Regarding results at slot 2, PEEK group
showed lesser strain value in comparison to PEKK
group which was In contrast to the ndings of
Bagley and Bell [39] and Alsadon et al. [40]
who reported that PEKK shows better mechanical
values when compared to PEEK (pure and
glass-reinforced) in the tensile strength, exural
strength and compressive strength and better
stress distribution. Also Lee et al. [41] and
Sirandoni et al. [42] reported that the shock
absorbing property of PEEK is limited to the site
of its presence. But distant sites received higher
stresses when PEEK was compared to other rigid
materials.
Finally, a limitation of this study was that
it was carried out in-vitro, without taking into
consideration the effect of individual patient
variation regarding the supporting structures for
the fabricated prostheses. Thus, future clinical
trials should be carried out as such in-vitro
researches do not eradicate the requirement for
clinical ones. The null hypothesis was rejected
as there was signicant difference between the
three groups in regard to the strain induced on
the supporting structures.
To reduce detrimental forces falling on
the abutment and free end saddle area in class
II Kennedy cases, it is recommended to use a
polymeric material for the construction of RPD
framework. Apart from their better aesthetics,
they have a mechanical advantage and can
be used to better preserve the supporting
structures.
CONCLUSION
Within the limitations of this study it could
be concluded that the use of polymers like
PEKK and PEEK for the construction of RPD
frameworks can be a promising treatment option
when compared to PFM frameworks. Moreover
PEEK induces the least strains on the supporting
structures due to its resilient nature and ability
to dissipate forces effectively.
Author’s Contributions
NMEHF: Conceptualization, Methodology,
Software, Validation, Writing – Original Draft
Preparation, Visualization, Supervision, Project
Administration. DEB: Formal Analysis, Investigation,
Resources, Data Curation, Writing – Review &
Editing.
Conict of Interest
The authors have no proprietary, nancial,
or other personal interest of any nature or kind
in any product, service, and/or company that is
presented in this article.
Funding
This research did not receive any specic
grant from funding agencies in the public,
commercial, or not-for-prot sectors.
Regulatory Statement
The approval code for this study is: FDASU-
Rec ER112222.
REFERENCES
1.
El-Rahman A, Aladdin N, El-Sharkawy AM, Mohy El-Din MH, Saad MS.
sStrain evaluation of peek cantilever bars around implants assisted
mandibular overdentures (in vitro study). Alex Dent J. 2022;47(3):138-45.
2.
Mousa MA, Abdullah JY, Jamayet NB, El-Anwar MI, Ganji KK, Alam
MK,et al. Biomechanics in removable partial dentures: a literature
review of FEA-based studies. BioMed Res Int. 2021;2021(4):5699962.
http://dx.doi.org/10.1155/2021/5699962. PMid:34485518.
3. Lynch CD. Successful removable partial dentures. Dent
Update. 2012;39(2):118-20. http://dx.doi.org/10.12968/
denu.2012.39.2.118. PMid:22482269.
4. Benso B, Kovalik AC, Jorge JH, Campanha NH. Failures in the
rehabilitation treatment with removable partial dentures. Acta
Odontol Scand. 2013;71(6):1351-5. http://dx.doi.org/10.3109/0
0016357.2013.777780. PMid:23834529.
5. Alsharif HN, Ganji KK, Alam MK, Manay SM, Bandela V, Sghaireen
MG,etal. Periodontal clinical parameters as a predictor of bite
force: a cross-sectional study. BioMed Res Int. 2021;2021:5582946.
http://dx.doi.org/10.1155/2021/5582946. PMid:34046498.
6. Bhathal M, Batra J, Attresh G, Sambyal S. A review on
stresses-induced by removable partial dentures. Int J Contemp
Dent Med Rev. 2015;5:1-15.
7. Costa L, do Nascimento C, de Souza VO, Pedrazzi V.
Microbiological and clinical assessment of the abutment and
non-abutment teeth of partial removable denture wearers.
Arch Oral Biol. 2017;75:74-80. http://dx.doi.org/10.1016/j.
archoralbio.2016.11.002. PMid:27825678.
8. Saleh MM, Aldori D. Effects of new modification in the design
of the attachments retaining distal extension partial denture
on stress distribution around the abutments and residual
ridges: an in vitro study. Dent Hypotheses. 2020;11(4):112-7.
http://dx.doi.org/10.4103/denthyp.denthyp_38_20.
9. McKenna G, Tada S, Woods N, Hayes M, DaMata C, Allen PF.
Tooth replacement for partially dentate elders: a willingness-to-
pay analysis. J Dent. 2016;53:51-6. http://dx.doi.org/10.1016/j.
jdent.2016.07.006. PMid:27421987.
10. Tribst JP, Dal Piva AM, Borges AL. Biomechanical tools to study
dental implants: a literature review. Braz Dent Sci. 2016;19(4):5-11.
http://dx.doi.org/10.14295/bds.2016.v19i4.1321.
11. El-Baz R, Fayad M, Abas M, Shoieb A, Gad M, Helal MA. Comparative
study of some mechanical properties of cobalt chromium
and polyether ether ketone thermoplastic removable partial
8
Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
denture clasps: an In-vitro Study. Braz Dent Sci. 2020;23(3):6-10.
http://dx.doi.org/10.14295/bds.2020.v23i3.1935.
12. Makkar S, Chhabra A, Khare A. Attachment retained removable
partial denture: a clinical report. Inter J of Clin Dent Sci.
2011;2(2):13-9.
13. Sadek SA. Comparative study clarifying the usage of PEEK as
suitable material to be used as partial denture attachment and
framework. Open Access Maced J Med Sci. 2019;7(7):1193-7.
http://dx.doi.org/10.3889/oamjms.2019.287 PMid:31049106.
14. Alkhodary MA, Class II. Kenn edy implant assisted mandibular
removable partial dentures with and without cross arch stabilization:
a strain gauge in vitro study. Egypt Dent J. 2020;66(2):1173-82.
http://dx.doi.org/10.21608/edj.2020.23987.1010.
15. Chen X, Mao B, Zhu Z, Yu J, Lu Y, Zhang Q, et al. A
three-dimensional finite element analysis of mechanical function
for 4 removable partial denture designs with 3 framework
materials: CoCr, Ti-6Al-4V alloy and PEEK. Sci Rep. 2019;9(1):13975.
http://dx.doi.org/10.1038/s41598-019-50363-1 PMid:31562391.
16. Chen J, Cai H, Suo L, Xue Y, Wang J, Wan Q. A systematic
review of the survival and complication rates of inlay-retained
fixed dental prostheses. J Dent. 2017;59:2-10. http://dx.doi.
org/10.1016/j.jdent.2017.02.006. PMid:28212978.
17. Alqurashi H, Khurshid Z, Syed AU, Habib SR, Rokaya D, Zafar
MS. Polyetherketoneketone (PEKK): an emerging biomaterial for
oral implants and dental prostheses. J Adv Res. 2020;28:87-95.
http://dx.doi.org/10.1016/j.jare.2020.09.004 PMid:33384878.
18. Villefort RF, Diamantino PJ, Von Zeidler SL, Borges AL,
Saavedra GD, Tribst JP. Mechanical response of PEKK and
PEEK as frameworks for implant-supported full-arch fixed
dental prosthesis: 3D finite element analysis. Eur J Dent.
2022;16(1):115-21. http://dx.doi.org/10.1055/s-0041-1731833.
PMid:34560810.
19. Maharana T, Sutar AK, Routaray A, Nath N, Negi YS.
Polyetheretherketone (PEEK): applications as a biomaterial.
encyclopedia of biomedical polymers and polymeric biomaterials.
2014;35(1):1701-8
20. Sanath S, Kamalakanth K, Rajesh S, Vidya B, Mallikarjuna R,
Abhishek CK. Pekk (Polyetherketoneketone) as a prosthetic
material- a review. Int J Recent Sci Res. 2018;9(4):25724-6.
21. Li RW, Chow TW, Matinlinna JP. Ceramic dental biomaterials
and CAD/CAM technology: state of the art. J Prosthodont Res.
2014;58(4):208-16. http://dx.doi.org/10.1016/j.jpor.2014.07.003
PMid:25172234.
22. Whitty T. PEEK: a new material for CAD/CAM dentistry. Juvora
Dental Innovations. 2014;7(2):123-40.
23. Ahmed MA, Hamdy AM, Fattah GA, Effadl AK. Prosthetic
design and restorative material effect on the biomechanical
behavior of dental implants: strain gauge analysis. Braz Dent Sci.
2022;25(3):e3380. http://dx.doi.org/10.4322/bds.2022.e3380.
24. Ramadan RE, Mohamed FS, Gepreel MA. Evaluation of implant-
assisted mandibular overdenture with new metal to metal interface
attachment system (in vitro study). Alex Dent J. 2020;45(1):106-11.
http://dx.doi.org/10.21608/adjalexu.2020.79970.
25. Saleh MM, Aldori D. Effects of new modification in the design
of the attachments retaining distal extension partial denture
on stress distribution around the abutments and residual
ridges: an in vitro study. Dent Hypotheses. 2020;11(4):112-29.
http://dx.doi.org/10.4103/denthyp.denthyp_38_20.
26. Rady AA, Abdel Nabi N. Stress analysis of two different
attachments for a two implant retained mandibular overdenture.
Egypt Dent J. 2017;63(4):3447-57. http://dx.doi.org/10.21608/
edj.2017.76263.
27. El-Baz R, Fayad M, Abas M, Shoieb A, Gad M, Helal MA.
Comparative study of some mechanical properties of cobalt
chromium and polyether ether ketone thermoplastic removable
partial denture clasps: an In-vitro Study. Braz Dent Sci.
2020;23(3):6. http://dx.doi.org/10.14295/bds.2020.v23i3.1935.
28. Mutto JC, Sato TP, da Silva JM, Borges AL, Uemura ES.
Retentiveness comparison of individual clasps made from
polyamide, acetate resin and cobalt-chrome for removable
partial dentures. Braz Dent Sci. 2019;22(4):483-7. http://dx.doi.
org/10.14295/bds.2019.v22i4.1802.
29. Mamdouh RI, El-Sherbini NN, Mady YO. Treatment outcomes
based on patient’s oral health related quality of life (OHRQoL)
after receiving conventional clasp or precision attachment
removable partial dentures in distal extension cases: a randomized
controlled clinical trial. Braz Dent Sci. 2019;22(4):528-37.
http://dx.doi.org/10.14295/bds.2019.v22i4.1819.
30. Sabri LA, Abdulkareem JF, Salloomi KN, Faraj SA, Al-Zahawi
AR, Abdullah OI, et al. Finite element analysis of class II
mandibular unilateral distal extension partial dentures.
J Mech Eng Sci. 2022;236(17):9407-18. http://dx.doi.
org/10.1177/09544062221096634.
31.
Al-Okl A, Al Samahy M, Amin H, Khashaba U. Stresses induced
by integrated and’nonintegrated extracoronal semi-precision
attachments for maxillary distal extension bases. Al-Azhar Dent J for
Girls. 2018;5(3):297-304. http://dx.doi.org/10.21608/adjg.2018.17195.
32. Ragghianti MS, Greghi SL, Lauris JR, Sant’Ana AC, Passanezi
E. Influence of age, sex, plaque and smoking on periodontal
conditions in a population from Bauru, Brazil. J Appl Oral
Sci. 2004;12(4):273-9. http://dx.doi.org/10.1590/S1678-
77572004000400004. PMid:20976396.
33. Fayyad A. Comparison between two different unilateral
mandibular partial denture designs retained by extra-coronal
attachment: an in-vitro study. Egypt Dent J. 2022;68(3):2479-85.
http://dx.doi.org/10.21608/edj.2022.127727.2024.
34.
Elgamal M. PEEK versus Metallic Framework for extracoronal
attachment mandibular bilateral distally extended Removable Dental
Prosthesis (RDP) evaluation of abutments bone height changes
and patient satisfaction. A Randomized Clinical Trial. Egypt Dent J.
2022;68(1):631-45. http://dx.doi.org/10.21608/edj.2021.93903.1778.
35.
Stawarczyk B, Beuer F, Wimmer T, Jahn D, Sener B, Roos M,etal.
Polyetheretherketone a suitable material for fixed dental prostheses?
J Biomed Mater Res B Appl Biomater. 2013;101(7):1209-16.
http://dx.doi.org/10.1002/jbm.b.32932 PMid:23564476.
36. Schwitalla AD, Spintig T, Kallage I, Müller WD. Flexural
behavior of PEEK materials for dental application. Dent
Mater. 2015;31(11):1377-84. http://dx.doi.org/10.1016/j.
dental.2015.08.151 PMid:26361808.
37. Tekin S, Cangül S, Adıgüzel Ö, Değer Y. Areas for use of PEEK
material in dentistry. J. Int. Dent. 2018;8(2):84-92. http://dx.doi.
org/10.5577/intdentres.2018.vol8.no2.6.
38. Skirbutis G, Dzingutė A, Masiliūnaitė V, Šulcaitė G, Žilinskas J.
PEEK polymer’s properties and its use in prosthodontics: a review.
Stomatologija. 2018;20(2):54-8. PMid:30531169.
39. Bagley D, Bell M. Method for producing sealing and anti-extrusion
components for use in downhole tools and components
produced thereby. United States Patent Application US
10/112,172. 2002 Dec 26.
40. Alsadon O, Wood D, Patrick D, Pollington S. Fatigue
behavior and damage modes of high-performance
poly-ether-ketone-ketone PEKK bilayered crowns. J Mech Behav
Biomed Mater. 2020;110:103957. http://dx.doi.org/10.1016/j.
jmbbm.2020.103957. PMid:32957248.
41. Lee KS, Shin SW, Lee SP, Kim JE, Kim JH, Lee JY. Comparative
evaluation of a four implant–supported poly ether ketone
ketone framework prosthesis: a three-dimensional finite element
analysis based on cone beam computed tomography and
computer aided design. Int J Prosthodont. 2017;30(6):581-5.
http://dx.doi.org/10.11607/ijp.5369. PMid:29095963.
42. Sirandoni D, Leal E, Weber B, Noritomi P, Fuentes R, Borie E.
Effect of different framework materials in implant-supported
fixed mandibular prostheses: a finite element analysis. Int J
Oral Maxillofac Implants. 2019;34(6):e107-14. http://dx.doi.
org/10.11607/jomi.7255. PMid:31711084.
9
Braz Dent Sci 2023 July/Sept 26 (3): e3775
El Hussieny Fayad NM et al.
The effect of different framework’s material on strain induced in distal abutment in mandibular Kennedy’s class II: an in-vitro study
El Hussieny Fayad NM et al. The effect of different framework’s material on strain
induced in distal abutment in mandibular Kennedy’s class II:
an in-vitro study
Noha Mohamed El Hussieny Fayad
(Corresponding address)
Oral and Maxillofacial Prosthodontics Department, Ain Shams University, Cairo, Egypt.
Email: nohafayad@dent.asu.edu.eg
Date submitted: 2023 Mar 03
Accepted submission: 2023 May 21
