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SCIENCE / CLINICAL RESEARCH logo 16 • the CAMLOG Partner Magazine • June 2017 logo 16 • the CAMLOG Partner Magazine • June 2017 6 7 The CERALOG Implant System is the innovative product of a strong cooperation between CAMLOG Biotechnologies AG and Axis biodental SA, a high-tech company specialized in the development of dental ceramic implants. This development has resulted in an ideal combination of material, surface, and design within the innovative concept of the CERALOG Implant System. CERALOG is based on more than 10 years of dedicated research and development for the benefit of the patient. Besides the original Monobloc design, the portfolio features the CERALOG Hexalobe Implants, the first two-piece ceramic implants with reversible screw-retained PEKK abutments. SCIENCE / CLINICAL RESEARCH CERALOG ® IMPLANT SYSTEM − FACTS AND FIGURES AT A GLANCE Françoise Peters BSc. MPH, Dr. sc. tech. Markus Kraft, Frédéric Wehrli MSc., Basle Zirconium dioxide – the implant material The CERALOG implants are made of yttria- stabilized tetragonal zirconia (Y-TZP) [1] – a ceramic widely used in the dental industry and other highly demanding fields. Zirconia is a chemically inert material, which makes it especially suitable as an implant materi- al. Thanks to an additional process step known as hot isostatic pressing (HIP), it of- fers an outstanding combination of excel- lent mechanical properties and high tensile strength (Fig. 1). PEKK – the abutment material Polyether ketone ketone (PEKK) is a high- performance polymer that belongs to the polyarylether ketone (PAEK) family. It combines excellent mechanical tensile strength with outstanding thermal properties and chemical stability [2]. As a material for implant applications, PEKK is largely prescribed for CMF applications such as cranial repair and for spinal applications such as fusion cages, lumbar posterior fusion rods (Fig. 2). The biocompatibility of PEKK implant material has been established by Oxford Performance Materials Inc. in accordance with the ISO 10993-1 standard [3]. PEKK vs PEEK Although PEKK and PEEK (polyether ether ketone) have a similar chemical structure and belong to the same polymer family (PAEK), PEKK offers significantly improved properties for implant dentistry applications: • Higher mechanical stability • Higher creep resistance • Compression resistance up to 80% superior in comparison to PEEK • Less sensitive to water absorption (Fig. 3) Hexalobe – an ideal implant-abutment design The design of the CERALOG Hexalobe im- plant- abutment connection was developed in close collaboration with the Swiss Federal Institute of Technology of Lausanne (EPFL). Finite element analysis simulations demon- strate that the Hexalobe connection is the most appropriate shape to transmit torque to a ceramic implant. [4]. Compared to a traditional hexagonal con- nection, the Hexalobe connection, with 0° drive angle, optimizes torque transmission and eliminates radial stresses (Figs. 4 a–d). Dual surface texture CERALOG implants are produced by Ce- ramic Injection Molding (CIM). This technol- ogy makes it possible to manufacture com- plex shapes with various surface textures without using any post-treatment. These surface textures ensure the proliferation of osteoblasts as evaluated in an in-vitro study performed at the University of Geneva [5] (Figs. 5 a–b). 0 500 1000 1500 2000 Compressive Strength (MPa) Tensile Strength (MPa) Shear Strength (MPa) Young‘s Modulus (GPa) Titanium Zirconia Fig. 1: Comparison of the most important static mechanical properties of titanium Grade 4 and Y-TZP zirconium dioxide [source – Titanium: Titanium Grade 4 MatWeb (http://www.matweb.com ) | Zirconium dioxide: Y-TZP zirconium dioxide, AXIS biodental SA] Fig. 2: Overview of polymers and their properties: the high-performance polymer PEKK has an outstanding combination of properties. PEEK PET PBT POM PE semi-crystalline PA PP LCP PES PSU PC PMMA ABS PS SAN amorphous increase of performances PEI Engineering polymers High performance polymers Commodity polymers PEKK Fig. 3: Comparison of the main properties of PEKK and PEEK [source: PEKK: OXPEKK ® -IG 300 (implantable), OPM Inc. | PEEK – OPTIMA LT1 (implantable), Invibio Inc.] PEKK PEEK Modulus of elasticity (GPa) 4.5 4.1 Tensile strength (MPa) 138 100 Transversal strength (MPa) 193 165 Compressive strength (MPa) 207 135 Elongation at break (%) > 30 40 Melting temperature (°C) 360 340 Water absorption after 24h (%) < 0.2 0.5 Density (g/cm3) 1.3 1.3 Fig. 4: Compared with hexagonal connections, the Hexalobe connection (a) results in a major reduction in load levels during torque application (c–d). As a result, there is a significant increase in the maximum torque that can be applied (b). 0 50 100 150 200 Hexalobe Connection Hexagonal Connection Ncm (a) (b) (c) (d) Titanium Zirconium dioxide