NEW - Nanoimplant - nanostructured implants
NANOIMPLANT (TM) - first dental implant system in the world made from nanostructured titanium!
The material for dental implants is required to be biocompatible, mustn’t be toxic and also shouldn’t cause allergic reactions. It must have high ultimate strength Rm and yield point Rp with desirable low density r and low modulus of elasticity E.
Alloys of stainless steels, cobalt alloys, titanium and titanium alloys representing traditional metallic materials used for dental substitutes.
Titanium, in form of commercial pure Ti (cpTi) or Ti-based alloys, is used for medical and dental applications as a bioinert material from the second half of sixties of the 20th century . Nowadays, titanium is preferred to stainless steel and cobalt Ti alloys due to its excellent biocompatibility.
Consequently to the development of Ti alloys for aerospace and armament industry, there is wide range of alloys developed for medical applications.
At the beginning the purpose of the development was to take advantage of high strength of Ti alloys to cpTi. Typical material of this generation is beta alloy Ti-6Al-4V.
But later toxicity of vanadium (V) was proved and also aluminium (Al) is considered to be potentially a toxic element.
Therefore in further development prevails effort to substitute toxic and potentially toxic elements in Ti alloys with nontoxic ones such as tantalum (Ta), molybdenum (Mo), niobium (Nb) or zirkonium (Zr). At the same time there are developed bTi alloys that are characterized by low values of modulus of elasticity. However, Ti alloys with elements of very different density and melting point require special production technologies that noticeably increase the production costs and the final price of a product. A problem in the course of the development of metallic biomaterials represents not only their actual or potential toxicity but also their allergenic potential.
Sensitivity of the population to allergens dramatically increases. An allergy on metals is caused by metallic ions, which are released from metals by body liquids. Share of particular metals on origin of the allergies is different. Ni, Co and Cr are the main alloying elements of stainless steels and cobalt alloys. Also some Ti-based alloys, e.g. Ti-20Cr-0.2Si, Ti-20Pd-5Cr and Ti-13Cu-4.5Ni, used in dental applications contain elements classified as allergens.
Approximately 20% of European women and 5% of men up to 30 years were reported sensitive on Ni during the first half of the 20th century,. Sensitivity of continental population on Ni from the end of the last century is ascending.This trend of this sensitivity surely develops even nowadays.
Commercial pure cpTi stays the preferred material for dental applications. It is desirable to increase its other mechanical properties without using even potentially toxic or allergenic elements preserving its low value of modulus of elasticity. The use of nanostructured Ti is the possible way.
Nanostructured materials
Nanomaterials are materials with structural elements of nanometer size, i.e. of 10-9 m. They stand for materials of the third millennium and its application extends many fields, including new developed medical products, going far beyond the borders of yesterday’s science-fiction.
The replacement of tissues using so called bulk nanostructured metals as biomaterials is of interest. For such purpose, materials with very fine grain in dimensions about 1- 100 nm are regarded.
Underneath the size of some natural structures measured in nanometres to nTi is compared.
DNA 2,5 nm
Molecule of Aspirin 1 nm
Protein 5 – 50 nm
Virus 75 – 100 nm
Bacteria 1 000 – 10 000 nm
Red blood cell 7 000 nm
White blood cell 10 000 nm
Hair 50 000 nm
Grain of Ti 25 000 – 50 000 nm
Grain of nTi 100 – 300 nm
Various methods for production of nanostructured materials have been developed, which can be classified into two categories based on their approach.
The first is the „bottom up“ approach, which builds material atom by atom or atom cluster by atom cluster. Methods in this category, they include inert gas condensation and other nano-powder production methods.
The second approach for nanostructured materials production is the "top down" approach, which refines coarse-grained metals through Severe Plastic Deformation (SPD).
The SPD techniques have significant advantages superior to the other synthesizing techniques. The nanostructured materials produced by SPD are 100% dense (this is an important issue for mechanical properties) and contamination free (important for biomedical properties).
Some important methods that are in this category include High Pressure Torsion (HPT), Accumulative Roll Bonding (ARB), Multipass Coin-Forging (MCF), Reppetitive Corrugation and Straightening (RCS), Conshearing process (CP) and Continuous Strip Shearing (C2S2). The most developed SPD technique is equal channel angular pressing (ECAP) Moreover SPD techniques have the capability of producing bulk nanostructured materials in size feat for dental applications.
Technology combines ECAP and rolling was used for production of nTi semi-product referred.
Properties
Bulk nanocrystalline materials are distinguished by exceptional mechanical properties, with high strength, high yield point and relatively low elastic limit being especially important for dental implants.
Mechanical properties of metallic substitute material are assessed related to its density as so called specific properties. Modulus of elasticity of nTi was measured by Three-point Bending Test on VSB-Technical University of Ostrava.
Implant from nTi
The objective of our development was to produce an implant of smaller dimensions preserving the load capacity comparable to any ordinary 3.5 mm diameter titanium implant, which can be used as a pillar in indications of insufficient thickness of alveolar bone.
Material properties of mini-implants available on the market made from Ti-based alloys with diameter of 2 mm don’t allow full loading and they are assigned rather for supportive function, most often for hybrid prosthesis or interstitial pillar. Certified system of quality Timplant® according to standard ČSN EN ISO 13485:2003 was respected during development of implant Nanoimplant®. The first set was produced from nTi Gr 4. Optimal diameter of intraosseal part 2.4 mm was specified by calculation as an equivalent of strength of implant with thickness 3.5 mm. The lengths range of the spiral intraosseal parts varying from 10, 12, to 14 mm, followed by the polished gingival conic part, with the conic abutment ending enabling fixation of prosthetic part with screw, makes the unique and versatile design of the implant . Exposure of nanostructure surface of the implant was achieved by the etching the intraosseal part and concurrently sufficient roughness of surface is guaranteed, which is comparable to the surface of cpTi. An enlarged proportion of the screw thread diameter to the cylindrical part of the implant body (without screw thread), which is 1.29, contributes to primary stability. Mini-implants use to have this ratio up to 1.22, for implants with 3.5 mm diameter it is reported up to 1.18. Capacity calculation of implants was simulated in a plane of transition between intraosseal (echted) and gingival (burnished) part of implant Nanoimplant®.
Immediate treatment with implants in lower jaw
Nanoimplants were used for the restoration of a frontal dentition defect in a 55 years old male. He lost all of his four lower incisors by severe parodontal disease, the teeth 32 and 31 were spontaneously eliminated at the beginning of 2005, teeth 42 and 41 were extracted with consequent surgical treatment without application of augmentative material. 7 months following the extractions 3 nanoimplants with diameter 2.4 mm were inserted to the frontal segment of the lower jaw.
No complications occurred either during immediate postoperative period or in subsequent healing period. At present, i.e. 5 months after implant insertion, all 3 implants are stable covered with a definite ceramic bridge and are clinically firm without signs of inflammation or resorption of the adjacent bone.
In this time were inserted several thousands of Nanoimplants with very good fruitfulness in all possible indications except sinus lift. For clinical causes see chapter PRACTICE.
Novelty – Nanoimplant T - T for Thick – with diameter of intraoseal part 3.5 mm, gingival and prosthetic part is the same as in diameter 2.4 mm. It is manufactured in lengths 8, 10 ,12 and 14 mm with coding A08T, A10T, A12T and A14T. For its implementation it is necessary to order the drill N126T and depth gauge N166T - see Catalogue
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| timplant_web_angl4_en.wmv | VIDEO NANOIMPLANT | 07.01.2009 |