1

Introduction

PEEK (poly-ether-ether-ketone) is well known as a high-performance thermoplastic polymer able to replace metallic components. Since April 1998, PEEK has also been commercially offered as implant material for long-term implantation (Invibio, Ltd., Thornton-Cleveleys, United Kingdom) . Due to its elastic modulus, similarly to that of cortical bone, it plays an important role as viable alternative to conventional implant materials such as titanium in the field of orthopedics and traumatology . Also in the field of dentistry, where traditionally a wide range of alloplastic materials is used, the application of PEEK increases replacing those conventional dental materials . This can be associated with distinct problems. Besides hypersensitivities against distinct components of dental composites on the one hand, even titanium, which is known as a proven biocompatible metal, has recently been suspected to provoke inflammatory reactions on the other hand . Additionally, more and more patients desire metal free reconstructions , to avoid the risk of oral galvanism for instance .

Due to its mechanical properties, which can be influenced by adding different compound materials such as carbon fibers (CFR-PEEK) , PEEK might represent a viable biomaterial, not only able to replace conventional polymers, but also even metals, alloys and ceramics in the field of dentistry.

The aim of this study was to evaluate the mechanical properties of different commercial PEEK compounds via three-point-bending tests, since the load distribution corresponds to a three-unit bridge in principle.

2

Materials and method

The materials (samples) examined are quoted in Table 1 .

Specimens in the shape of small bars were manufactured from the 11 PEEK-compounds by means of a diamond circular saw (Vari/Cut VC-50, Leco Corporation, St. Joseph, Michigan, USA), which was performed under continuous water cooling.

These specimens were 15 mm long at a ratio of width and height of 2:1. The manufactured small bars were supposed to be 2.0 to 2.5 mm in width, their height 1.0 to 1.5 mm.

All in all, 150 specimens were manufactured. In a number of n ≥ 5 they were tested after dry storage on the one hand and after incubation in Ringer solution (Braun Melsungen AG, Melsungen, Germany) at 37 °C on the other hand for one day ( t ₁ ), 7 days ( t ₂ ), 28 days ( t ₃ ) and 84 days ( t ₄ ).

The three-point-bending tests were performed using a universal testing machine (Z010, Zwick GmbH & Co, Ulm, Germany), in accordance to DIN EN ISO 178, 02/1997 (“Bending tests at synthetic materials”), at a feed speed of 1 mm/min.

In this procedure, the small bars were placed upon two supports, which were spaced at 10 mm from each other, while the small bars were exposed to the load of a wedge-shaped indenter with a curved edge of a cross section radius of 0.5 mm ( Fig. 1 ).

Test set-up of the 3-point bending test.

Both the material parameters, flexural modulus and flexural strength were evaluated in the bending tests.

The statistical evaluation of these findings was performed using the OriginPro 7.5G SR2 program (OriginLab Corporation, Northampton, MA, USA).

The significance level for differences in the findings was at p < 0.05.

2

Materials and method

The materials (samples) examined are quoted in Table 1 .

Table 1

Summary of the different evaluated PEEK types.

Sample name	Product name, manufacturer	Compounds	Production process	Semi-finished product form	Raw material biocompatibility tested according to ISO 10993-1 recommendations for	For industrial application(industrial grade)
U 1	VESTAKEEP ® M4 R, Evonik Industries, Essen, Germany		Extrusion	Round rod, Ø 6 mm	Permanent skin contact, prolonged mucosal membrance contact
U 2	PEEK-OPTIMA ® LT1, Invibio Ltd., Thornton Cleveleys, UK		Extrusion	Round rod, Ø 8 mm	Permanent contact duration implant devices
Ti-10	PEEK-CLASSIX ® BC1-WH, Invibio Ltd., Thornton Cleveleys, UK	10% TiO 2 powder	Extrusion	Round rod, Ø 47 mm	Prolonged contact implant devices
Ti-20	VESTAKEEP ® DC4420 R, Evonik Industries, Essen, Germany	20% TiO 2 powder	Extrusion	Round rod, Ø 6 mm	Permanent mucosal membrance contact
Ba-6	PEEK-OPTIMA ® LT16BA, Invibio Ltd., Thornton Cleveleys, UK	6% BaSO 4 powder	Extrusion	Round rod, Ø 8 mm	Permanent contact duration implant devices
Ba-20	PEEK-OPTIMA ® LT120BA, Invibio Ltd., Thornton Cleveleys, UK	20% BaSO 4 powder	Extrusion	Round rod, Ø 8 mm	Permanent contact duration implant devices
G-30	VICTREX ® PEEK™ 450GL30, Victrex Ltd., Thornton Cleveleys, UK	30% multi-directional chopped glass fibers	Injection molding	Square plate, ≈100 × 100 × 10 mm		X
C 1 -30	PEEK-OPTIMA ® LT1CA30, Invibio Ltd., Thornton Cleveleys, UK	30% multi-directional chopped carbon fibers	Extrusion	Square rod, 22 × 22 mm	Permanent contact duration implant devices
C 2 -30	VICTREX ® PEEK™ 450CA30, Victrex Ltd., Thornton Cleveleys, UK	30% multi-directional chopped carbon fibers	Injection molding	Square plate, ≈100 × 100 × 10 mm		X
C 1 -50	CF/PEEK, Icotec AG, Altstätten, Switzerland	>50% multi-directional continuous carbon fibers; individual tantalum wires	Pultrusion	Round rod, Ø 5.5 mm	Permanent contact duration implant devices
C 2 -50	PEEK-OPTIMA ® Ultra Reinforced, Invibio Ltd., Thornton Cleveleys, UK	>50% uni-directional continuous carbon fibers	Pultrusion	Round rod, Ø 4 mm	Permanent contact duration implant devices

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Conversion, shrinkage, water sorption, flexural strength and modulus of re-mineralizing dental composites
2. In vitrobioactivity of Bioroot™ RCS, via A4 mouse pulpal stem cells
3. Dental composite components induce DNA-damage and altered nuclear morphology in gingiva fibroblasts
4. A systematic review about antibacterial monomers used in dental adhesive systems: Current status and further prospects
5. Fatigue induced changes in conical implant–abutment connections
6. Is secondary caries with composites a material-based problem?

Stay updated, free dental videos. Join our Telegram channel

Join