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New Material Options for Innovation in Restorative and
Prosthetic Dentistry
2011
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New Material Options for Innovation in Restorative and Prosthetic Dentistry
Crowns and Bridges
PEEK Based Polymers for Dental
In-Vitro Fracture Resistance of Three-Unit Fixed Dental Prostheses
PEEK 3-Unit Bridge Wear Resistance to In-Vitro Ageing
Compressive Fracture Load of 3-Unit Bridges with Different Connector Sizes
Compressive Fracture Load of Molar Crowns
Veneering Systems
Cement System and Surface Preparation of PEEK Substructures
CAD/CAM Machining Tool Life
Polymer Typical Mechanical Properties (Granular)
Polymer Physical Properties
Colour and Radiolucency
Acknowledgements
Key Literature Overview
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New Material Options for Innovation in Restorative and Prosthetic Dentistry
Invibi Biomaterial Solutions develope and launched its flagship biomaterial
PEEK-OPTIMA - the first-ever advanced thermoplastic biomaterial to be used in
implantable medical devices in 1999. Over 3 million medical devices now benefit from a
set of unique properties that have been utilised in spine, orthopaedic and sports medicine
applications.
Invibios PEEK materials have been successfully used by world leading dental companies in
applications such as healing caps and temporary abutments due to its mechanical strength, aesthetic
qualities, soft tissue response and the ability to shape PEEK easily. However the long term
biocompatibility of PEEK means that the material can provide solutions in a wider range of implant
applications within restorative and prosthetic dentistry.
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Crowns and Bridges
Mechanical properties and biocompatibility for permanent metal-free crowns and bridges
Veneer repair without the need for crown removal and natural tooth loss
Allows diagnostic treatment without substructure removal
Material stiffness aimed at improving comfort with excellent preservation of antagonist
natural tooth
The present document provides technical information and guidance to the dental device manufacturer and dental practicing regarding the use of PEEK based polymer for dental crowns and
bridges permanents.
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PEEK Based Polymers for Dental
PEEK-OPTIMA offers exceptional product purity, quality testing and control. Invibio provides
assurance agreement, guaranteeing its long term specification and production methods.
Its proven biocompatibility and biostability is supported by US FDA Drug & Device Master files and
thousands of regulatory approved implantable devices. In fact, no other implantable PEEK is as
extensively used in US FDA, CE-marked and other regulatory body approved devices.
Invibio have been optimising the properties of PEEK based materials for permanent crowns and
bridges. Shapes for CAD/CAM have been successfully injection moulded. Its ability to be machined
from a block using a Cerec milling machine has been determined. We have generated the following
information, necessary to provide guidance towards dental substructure and cement and veneer
system selection.
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In-Vitro Fracture Resistance of Three-Unit Fixed Dental Prostheses
PEEK dental three unit fixed prostheses showed excellent performance during in-vitro investigation.
No damage occurred to the frameworks or decementations were observed during the prolonged
chewing simulation time used to simulate oral stress conditions equivalent to 5 years intraoral use.
PEEK restorations have greatly exceed the fracture resistance required to withstand masticatory
forces assumed for anterior (300N) and posterior regions (500-600N) Behr et al. 2001, Clinical Oral
Implants Research 12: 174-178. Therefore PEEK substructures could be used in clinical applications.
* Kolbeck et al. 2008, Clin. Oral Impl. Res., 19: 1049-1053
** Beuer et al. 2008, European Journal of Oral Sciences, 116: 381-386
*** Scientific Documentation IPS e.max Ceram , Ivoclar Vivadent
Literature values are of a comparative nature, but were not tested under the exact same conditions.
The CAD/CAM milled PEEK frameworks were cemented on to PMMA models using commercial
available Dentsply Calibra Esthetic Resin Cement. The frameworks were veneered with 3M ESPE
SinfomyTM Indirect Lab light-curing Composite. After 24h of storage in 37 distilled water the
marginal areas were cleaned and polished and transferred to the chewing simulation. The dentures
were aged using a human molar as antagonising tooth with 1.2x106 mechanical loads of 50N and
6000 alternating thermal cycles of 5 and 55C. This simulation is expected to have comparable
effects to 5 years of intraoral stress. Krejci et al. 1990, Schweizer Monatsschrift Zahnmedizin 100:8-4;
Rosentritt et al. 1977. Materialprfung, 39:77-80. All restorations survived and were mechanically
loaded until failure in a universal testing machine (Zwick, Germany). Force was applied in the pontic
centre using a steel ball and a tin foil to avoid force peeks at the cusp tips. Fracture force (N) was
recorded.
950
659
770
1331
2055
0 500 1000 1500 2000 2500
Lithium Dislicate Glass Ceramic ***
Glass-Infiltrated Alumina **
Alumina Strengthened with Zirconia **
Zirconia Y-TZP *
PEEK Dental
Fracture Force (N)
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PEEK 3-Unit Bridge Wear Resistance to In-Vitro Ageing
In contrast to ceramic and metal materials it was shown that PEEK dental 3-unit bridge substructures
were not weakened by in-vitro ageing. Results below show that PEEK 3-unit bridge fracture
resistance was maintained even after chewing simulation.
* Beuer et al. 2008, European Journal of Oral Sciences, 116: 381-386
Literature values are of a comparative nature, but were not tested under the exact same conditions.
CAD/CAM milled PEEK based dental polymer 3-unit bridges were cemented on to PMMA models
(Dentsply Calibra Esthetic Resin Cement) and exposed to thermal cycling and mechanical loading
(TCML: 6000x5C/55C; 1.2x106x50 N). Fracture force was measured using a universal testing
machine (Zwick, Germany).
0
500
1000
1500
2000
Frac
ture
Fo
rce
(N)
PEEK Dental Y-TZP Zirconia * Alumina Srengthened
with Zirconia *
Glass-Infiltrated
Alumina *
AgedNo Ageing AgedNo Ageing AgedNo Ageing AgedNo Ageing
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Compressive Fracture Load of 3-Unit Bridges with Different Connector Sizes
In order to provide guidance towards bridge design and morphology, 3-unit bridge PEEK
substructures with different connector dimensions were tested for compressive fracture load. All
PEEK substructures showed high fracture resistance demonstrating its potential for clinical use even
with small connector dimensions.
1411
1534
1783
0 500 1000 1500 2000
10
12.3
15
Fracture Force (N)
Bri
dge
Co
nn
ect
or S
ize
(mm
)
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Compressive Fracture Load of Molar Crowns
Un-veneered and veneered (3M ESPE SinfomyTM Indirect Lab Composite) PEEK crowns were bonded
on to identical epoxy resin models and subject to compressive loading to simulate clinical conditions.
PEEK crowns were shown to withstand very high compressive loads.
* Knowles et al 1998, J Mat Sci: Materials in Medicine, 9: 555-559
** Scientific Documentation IPS e.max CAD , Ivoclar Vivadent
Literature values are of a comparative nature, but were not tested under the exact same conditions.
2070
0 500 1000 1500 2000 2500 3000
Feldspathic Ceramic **
Lithium Dislicate Glass Ceramics **
Leucite Reinforced Ceramic *
Glass Infiltrated Alumina *
PEEK Dental Veneered Restoration
PEEK Dental Substructure
Fracture Force (N)
Max
Min
Min Max
Max
Max
Max
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Veneering Systems
Standard techniques were used to fabricate restorations from the PEEK based dental polymer
substructures. Good results were obtained using a range of commercial available veneering
composites. In the case of veneer chipping, PEEK substructures can allow repair without the need for
crown or bridge replacement.
* Beuer et al. 2008, European Journal of Oral Sciences, 116: 381-386
Literature values are of a comparative nature, but were not tested under the exact same conditions.
Please contact Invibio Ltd if looking for additional veneer systems.
160
219
242
0 50 100 150 200 250
Zirconia Y-TZP
PEEK/3M Espe Filtek Silorane
PEEK/Voco Admina Ormocer
PEEK/3M Espe Filtek Z250
Bi-axial Flexural Strength (MPa)
Min Max
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Cement System and Surface Preparation of PEEK Substructures
Restorations fabricated with PEEK based dental polymer can be cemented using a range of
commercial available systems. The internal configuration of the PEEK substructure should be
roughened using a diamond bur and degreased using acetone. This procedure will increase the bond
strength of the PEEK dental material and the luting systems.
* Kumbuloglu et al. 2006, Operative Dentistry, 31-2: 248-255; zcan et al. 2008, Clin Oral Invest, 12:
279-282 Literature values are of a comparative nature, but were not tested under the exact same conditions.
11.2
11.8
21.1
0 5 10 15 20 25
Zirconia Y-TZP *
PEEK/Panavia 21 EX, Kuraray Dental
PEEK/Rely X Unicem Aplicap, 3M ESPE
PEEK/Calibra Esthetic Resin Cement, Dentsply
Bond Strength (MPa)
Max Min
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CAD/CAM Machining Tool Life
PEEK dental injection moulded shapes allow CAD/CAM milling of dental substructures with reduced
tool wear and improved margin control allowing for tight fit restorations. PEEK blocks can be
successfully machined using a CEREC milling machine and standard burs. For the CEREC milling of
PEEK blocks, the machine can be set up as if to mill either CadWaxx or InCerami alumina blocks. Even
after 50 (fifty) PEEK 3-unit bridges have been milled, there was no need to change CEREC milling bur.
Polymer Typical Mechanical Properties (Granular)*
Property Method Units PEEK Based Polymers for Dental
Flexural Strength ISO 178 MPa 320
Flexural Modulus ISO 178 GPa 20
Tensile Strength (at yield) ISO 527 MPa 190
Youngs Modulus ISO 527 GPa 19
Compressive Strength ISO 640 MPa 240
Tensile Elongation (at break) ISO 527 % 1.0
Notch Izod Impact ISO 180 kJ/m2 8
* Testing performed on direct injection moulded sample.
Please contact Invibio Ltd for flexural strength properties according to ISO 10477
0 10 20 30 40 50
Ceramics
PEEK Dental
3-units Bridges Milled
Tool Life
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Polymer Physical Properties
PEEK polymers present high chemical resistance with extremely low levels of extractables and leachables, allowing for excellent in-mouth stability and inertness. PEEK displays very low thermal conductivity and is electrically non-conductive, providing excellent in-mouth natural feel. PEEKs excellent strength to weight ratio provides low weight substructures, improving comfort. Patients have reported natural mouth feeling and no foreign object sensation when using PEEK based dental solutions.
Property Method Units PEEK-OPTIMA Dental
Density ASTM D792 g.cm-3 2.0
Colour and Radiolucency
PEEK polymer is naturally radiolucent and compatible to imaging techniques such as X-ray, MRI and Computer Tomography (CT). PEEK dental polymer radiolucency allows clinical diagnostics and treatment through PEEK substructure without need for substructure removal and replacement. PEEK is available in natural and white for improved aesthetics.
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Acknowledgements
The in-vitro fracture resistance of PEEK based dental polymer three-unit fixed dental prostheses
work was conducted in collaboration with C. Kolbeck and M. Rosentritt at the Regensburg University
Medical Centre, Department of Prosthetic Dentistry, Regensburg, Germany.
The compressive fracture load of PEEK based dental polymer crowns and three-unit fixed dental
prostheses, veneer system and cement system testing, surface preparation of PEEK substructures
and CAD/CAM machining guidance was conducted in collaboration with D. Wood and A. Johnson at
the University of Sheffield, School of Clinical Dentistry, Sheffield, UK.
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Key Literature Overview
PEEK-OPTIMA Polymer Materials in Dental Applications
This summary provides a sample of the most recent and historical literature pertaining to PEEK
polymer in dental clinical evaluations
Paper Key Findings
Effect of different surface pre-treatments and
luting materials on shear bond strength to PEEK
Schmidlin PR, Stawarczyk B, Wieland M, Attin T,
Hmmerle CH, Fischer J.
June 2010, Dental Materials
The study shows that strong bonds can be
achieved between PEEK and dental resin
composites. Observations suggest that the pre-
treatment of the PEEK surface greatly improved
its adhesion to the hydrophobic bonding agent
tested. The results demonstrate potential for the
use of PEEK in dentures and encourage further
research in PEEK application in dentistry.
Bonding of Polyetheretherketone (PEEK) for
Indirect Restorations
Wood DJ, Johnson A, Van Noort R, Sereno N.
March 2011, International Association of Dental
Research
In this study the bound strength to reinforced
PEEK polymer aimed at use in dental crown and
bridges was tested using a range of commercial available cement composites.
Each of the three cement systems showed good
bond strength to the PEEK material samples with
Dentsply Calibra Esthetic Resin Cement resisting
to higher loads.
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Fracture Strength and Failure Mode of Maxillary
Implant-Supported Provisional Single Crowns:
A Comparison of Composite Resin Crowns
Fabricated Directly Over PEEK Abutments and
Solid Titanium Abutments
Santing HJ, Meijer HJ, Raghoebar GM, Ozcan M.
December 2010, Clinical Implant Dentistry &
Related Research
The study showed that PEEK abutments provide a
viable alternative to titanium abutments for use in
the aesthetic zone of the maxilla.
It has been demonstrated that PEEK abutments
are able to withstand intraoral masticatory forces
to a similar level as titanium abutments.
PEEK abutments can also be processed in the
dental surgery, allowing a chair-side approach,
and their white colour makes it easier to achieve a
good aesthetic result.
A New Transitional Abutment for Immediate
Aesthetics and Function
Tetelman ED, Babbush CA.
July 2008, Implant Dentistry
This paper describes how important the choice of
the right provisional prosthesis such as the PEEK
abutment displaying stable aesthetics and
function during the healing phase, is important in
maintaining patients comfort and satisfaction.
The PEEK abutment provides a cost effective
versatile solution allowing chair-side modification
in the dental surgery at the time of implant
placement.
Furthermore PEEKs proven soft tissue behaviour supports the good recovery of gingival tissue.
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SNB Swiss Non-Ligating Bracket. A New and
Promising Bracket
Karp J.
July 2010, ESLO congress, Excellence in Lingual
Orthodontics
A new bracket solution made from PEEK polymer
with two parallel slots allows for a more efficient
way of controlling the torque and the
enhancement of stability of the buccal segments.
As well as therapeutical advantages the PEEK
bracket displays low friction resulting in a
reduction of treatment time.
Metal as connector between implant and
prosthetic called in question: The PEEK a new,
durable and simple solution
Spahn F.
October 2010, 46th SFCMFS congress
The paper describes the positive benefits of the
use of PEEK basal implants and PEEK dental
abutments in the clinic. PEEK basal implants
proved valuable in clinical cases with low or poor
bone levels. PEEK abutments have been
successfully used to treat implant failure without
the need of implant removal.
Nano Hydroxyapatite Coated PEEK Implants:
Pilot Study in Rabbit Bone
Barkarmo S, Wennerberg AE, Hoffman M, Kjellin
P, Stenport V.
March 2011, International Association of Dental
Research
In this study the surface of the PEEK implants
was coated with nanocrystalline hydroxyapatite (HA) in order to improve osseointegration to
bone tissue.
It was shown that PEEK coated with nano HA
may be a successful approach to improve
osseointegration, however good primary stability
is necessary for optimal healing
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Osseointegration of one-piece zirconia implants
compared with a titanium implant of identical
design: a histomorphometric study in the dog
Koch FP, Weng D, Krmer S, Biesterfeld S, Jahn-
Eimermacher A, Wagner W.
March 2010, Clinical Oral Implant Research
The study demonstrated that PEEK dental
implants survived implantation testing with no
indications of damage to the implant.
Histomorphometric analysis indicated a positive
bone-to-implant contact for PEEK of 27%.
Surface Modification of PEEK -Parallel
Investigations of Primary Human Osteoblast
Cytocompatibility and Bacterial Adhesion
Poulsson A.
April 2010 Scandinavian Society for Biomaterials.
The brief exposure of PEEK-OPTIMA to oxygen
plasma treatment resulted in an increase in
surface energy of the PEEK. Following treatment,
primary human osteoblast-like cells
demonstrated an increased rate of adhesion to
the surface. A corresponding increase in cell functionality
was also observed at an earlier time point than
that seen on the untreated surface.
Taken together, these results suggest that
plasma treatment of PEEK may increase its
osseointegrative potential. Importantly, such
treatment did not increase the susceptibility of
PEEK to bacterial adhesion.