New Material Options for Innovation in Restorative and

Prosthetic Dentistry

2011

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

New Material Options for Innovation in Restorative and Prosthetic Dentistry

Invibiƻ Biomaterial Solutions developeŘ 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.

Invibio’s 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.

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.

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.

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 55°C. 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. Materialprϋfung, 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)

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: 6000x5°C/55°C; 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

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

)

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

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

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; Özcan 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

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

Young’s 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

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. PEEK’s 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.

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.

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,

Hämmerle 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.

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 patient’s 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 PEEK’s proven soft tissue behaviour supports the good recovery of gingival tissue.

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

Osseointegration of one-piece zirconia implants

compared with a titanium implant of identical

design: a histomorphometric study in the dog

Koch FP, Weng D, Krämer 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.