OsseoSpeed™ is the implant with a chemically modified surface and a unique nanoscale topography. The OsseoSpeed implant has clearly improved results compared to earlier generations of implants. The following summaries of the pre-clinical and clinical scientific articles reveal the mechanisms behind the performance and clinical outcome.
Pre-treatment of titanium implants with fluoride improves their retentioSn in bone
Purpose: The purpose of this study was to investigate the reaction between fluoride ions on a titarfium surface and bone to determine if a chemical bond exists.
Materials and Methods: Test implants 5 mm long and tapered from a diameter of 3 mm to 2 mm at the apical end were fabricated from commercial pure titanium. A total of 64 implants were placed into the bilateral ulnas of 16 chinchilla rabbits. Two groups of implants were created, a control group which were left as machined and a test group which received one of three types of fluoride acid wash pre-treatment at a pH of 3.0 or 3.5 and a concentration of 0.5% or 4% NaF to create a thin fluoride layer on the titanium surface. In the first group, one test and one control implant were placed unilaterally into osteotomies that allowed a frictionless insertion under a load of 360 g. Four weeks later a second test and control implant were inserted into the contralateral ulna. After a further four weeks of healing the animals were sacrificed and the two groups of implants subject to push out tests, using an Instrom tensile testing machine, with a load applied to the apical end of the tapered implants. Peak tensile loads were recorded. The surface of the implants was analyzed using scanning electron microscopy at 85 and 500 times magnification. The ulnas were then prepared for histological analysis of the implant sites using 15 pm sections stained with toluidine blue.
Results: The fluoride treated implants yielded higher push out values consistently at after both 4 and 8 weeks of healing, with a 3 to 4 fold increase in resistance. The higher concentration also gave rise to the greatest push out values. While there was some variation in the values for the test implants between 4 and 8 weeks, the control implants demonstrated a consistent lack of resistance regardless of time. The electron microscopy revealed an almost clean metallic surface for the control implants, compared to the presence of tissues on the test implants which indicated bone had fractured within the tissue itself leaving a layer adherent to the implant surface. This was supported by the histology which indicated the existence of an intimate bone-to-implant contact for test implants even in the cancellous compartment. Such an appearance was lacking for control implants.
Discussion: Calcium cations are divalent and are important in the establishment of a bone-to-implant contact when presented with a Ti01 surface at physiologic pH. In addition the precipitation of calcium phosphate has been shown to be enhanced by the presence of TiO2. The use of fluoride ions is thought to further optimize the process by allowing selective bonding of phosphate to the titanium surface by the release of fluoride forming a covalent bond with titanium. In addition fluoride has been shown to stimulate osteoprogenitor cells in vitro and may depress osteoclast activity through the formation of fluorapatite, which is less soluble. Fluoride has also been shown to increase alkaline phosphatase activity which is an indication of bone formation. All these responses will be dose dependant and in the current study concentration was seen to impact upon push out values. Certainly it can be concluded that the ability of fluoride to prevent the adhesion of protein moieties by the selective binding of phosphate as well as the formation of fluoridated hydroxyapatite and fluorapatite give rise to an increase in the bone-to-implant bond strength, which may be of value in osseointegrated technology.
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