A state in which living bone and the implant surface are in direct contact without intervening fibrous tissue and can transfer load. It was discovered with titanium dental implants.
Japanese name: オッセオインテグレーション
Osseointegration appears in 1 practice question across 1 topic, including Biomaterials.
Field: Biomaterials
Osseointegration is a phenomenon found by Brånemark in Sweden in the 1950s, when titanium observation chambers placed in rabbit bone became so firmly united with the bone that they could not be removed. It is defined as a state in which living bone and the implant surface are in direct contact, without fibrous tissue between them at the magnification of the light microscope, and can transmit load. Building on this idea, clinical use of titanium dental implants began in the 1960s. Today the same idea is also used in orthopedics, for example in fixing artificial joints without cement.
Whether osseointegration is achieved is not decided by the material alone. The surface properties, a surgical technique that does not damage the bone, and the way load is applied during healing must all be right. Heat when drilling bone is a major enemy: it has been reported that bone cells are damaged if the bone is held at about 47 °C for only about 1 minute, so drilling is done slowly with cooling. If the implant moves a lot relative to the bone early in healing, it becomes surrounded by fibrous tissue instead of bone. Micromotion beyond roughly 50–150 µm is generally said to hinder bone formation, so good fixation right after placement (primary stability) is important.
The osseointegration of titanium refers mainly to a state in which bone and surface are in direct contact and interlock, and it is distinguished from bioactivity, in which bone bonds chemically through an apatite layer formed on the surface, as with hydroxyapatite and bioactive glass. However, the titanium surface is also covered by a thin passive film of TiO₂ that adsorbs calcium and phosphate from body fluid, so the boundary between the two is not entirely clear. It is known that treating the surface with acid or moderately roughening it by blasting increases the fraction of bone contact and shortens the healing period.
In animal studies, the implant is removed together with the bone, sections are prepared, and the fraction of the surface length in direct contact with bone (bone-implant contact) is measured. Clinically, the strength of fixation is evaluated from the torque needed to turn the implant or from the resonance frequency of a small transducer attached to it. Once achieved, osseointegration is not necessarily maintained forever. In dentistry, bone can be lost through peri-implantitis, a bacterial inflammation around the implant, and excessive load can also cause bone resorption. Cleaning and control of load are conditions for long service.
Answer: A. A state in which bone and the implant surface are in direct contact without intervening fibrous tissue and can transfer load
Osseointegration is a phenomenon discovered by Brånemark with titanium, and it refers to a state in which living bone and the implant surface are in direct contact without intervening fibrous connective tissue and can transfer load. The titanium surface is covered by a TiO₂ passive film a few nm thick that is stable in body fluids, so bone forms along that surface. Moderately roughening the surface helps bone interlock with it and speeds fixation. The term mainly expresses direct contact with bone, as distinct from chemical bonding such as that of hydroxyapatite. Being resorbed in the body and replaced by bone is a property of bioresorbable materials such as β-TCP, and fixation with bone cement is a different method called cemented fixation.
In Brånemark's original protocol, the guideline was to wait without load for about 3 months in the lower jaw and about 6 months in the upper jaw. The period depends on bone quality and surface treatment, and with roughened implants or good primary stability, protocols that load the implant earlier are also used.
Yes. Direct contact of bone without intervening fibrous tissue has also been reported for tantalum, niobium, zirconia ceramics and others. Titanium and its alloys are the most widely used because they combine strength, corrosion resistance, ease of processing and a long clinical record.
A natural tooth is attached to bone through a thin fibrous tissue, the periodontal ligament, which lets it move slightly to cushion impacts and senses biting forces. An osseointegrated implant is fixed directly to bone with no periodontal ligament, so it hardly moves and its sensation differs from that of a natural tooth.
Osseointegration is a phenomenon discovered by Brånemark with titanium, and it refers to a state in which living bone and the implant surface are in direct contact without intervening fibrous connective tissue and can transfer load.
Which statement correctly describes osseointegration, as th…Passivity Hydroxyapatite Bone cement Biocompatibility Biodegradable polymer Stress shielding Superelasticity β titanium alloy