Osseointegration derives from the Greek
osteon,
boneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
, and the Latin
integrare, to make whole. The term refers to the direct structural and functional connection between living
boneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
and the surface of a load-bearing
artificial implantAn implant is a medical device manufactured to replace a missing biological structure, support a damaged biological structure, or enhance an existing biological structure. Medical implants are man-made devices, in contrast to a transplant, which is a transplanted biomedical tissue...
. Osseointegration has enhanced the science of
medicalMedicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
bone and
joint replacementReplacement arthroplasty [from Greek arthron, joint, limb, articulate, + -plassein, to form, mould, forge, feign, make an image of], or joint replacement surgery, is a procedure of orthopedic surgery in which the arthritic or dysfunctional joint surface is replaced with an orthopaedic prosthesis...
techniques.
Definition
Osseointegration is also defined as : "the formation of a direct interface between an implant and bone, without intervening soft tissue".
Osseointegrated implant is a type of
implantAn implant is a medical device manufactured to replace a missing biological structure, support a damaged biological structure, or enhance an existing biological structure. Medical implants are man-made devices, in contrast to a transplant, which is a transplanted biomedical tissue...
defined as "an endosteal implant containing pores into which osteoblasts and supporting connective tissue can migrate". Applied to oral implantology, this thus refers to
boneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
grown right up to the
implantA dental implant is a "root" device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth....
surface without interposed soft tissue layer. No
scar tissueScar tissue can refer to:*Granulation tissue, a product of healing in major wounds*The tissue of a scar*"Scar Tissue", a Red Hot Chili Peppers song*Scar Tissue , the autobiography of Anthony Kiedis, lead singer of the Red Hot Chili Peppers...
,
cartilageCartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
or
ligamentIn anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
fibers are present between the bone and implant surface. The direct contact of bone and implant surface can be verified
microscopicallyA microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
.
Osseointegration may also be defined as :
- Osseous integration, the apparent direct attachment or connection of osseous tissue
Osseous tissue, or bone tissue, is the major structural and supportive connective tissue of the body. Osseous tissue forms the rigid part of the bone organs that make up the skeletal system.-Formation:Bone tissue is a mineralized connective tissue...
to an inert alloplastic material without intervening connective tissue.
- The process and resultant apparent direct connection of the endogenous material surface and the host bone tissues without intervening connective tissue.
- The interface between alloplastic material and bone.
History
In 1952,
Per-Ingvar BrånemarkPer-Ingvar Brånemark is a Swedish orthopedic surgeon and research professor, touted as the "father of modern dental implantology." The Brånemark Osseointegration Center , named after its founder, was founded in 1989 in Gothenburg, Sweden....
of Sweden conducted an experiment where he utilized a titanium implant chamber to study blood flow in rabbit bone. At the conclusion of the experiment, when it became time to remove the titanium chambers from the bone, he discovered that the bone had integrated so completely with the implant that the chamber could not be removed. Brånemark called the discovery "osseointegration," and saw the possibilities for human use.
In
dental medicineDentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...
the implementation of osseointegration started in the mid-1960s as a result of Brånemark's work. In 1965 Brånemark, who was at the time Professor of Anatomy at the University of Gothenburg, placed dental implants into the first human patient - Gosta Larsson. This patient had a cleft palate defect and required implants to support a
palatal obturatorA palatal obturator is a prosthesis that totally occludes an opening such as an orinasal fistula . They are similar to dental retainers, but without the front wire. Palatal obturators are typically short-term prosthetics used to close defects of the hard/soft palate that may affect speech...
. Gosta Larrson died in 2005, with the original implants still in place after 40 years of function.
In the mid-1970s Brånemark entered into a commercial partnership with the Swedish defense company
BoforsThe name Bofors has been associated with the iron industry for more than 350 years.Located in Karlskoga, Sweden, the company originates from the hammer mill "Boofors" founded 1646. The modern corporate structure was created in 1873 with the foundation of Aktiebolaget Bofors-Gullspång...
to manufacture dental implants and the instrumentation required for their placement. Eventually an offshoot of Bofors, Nobel Pharma, was created to concentrate on this product line. Nobel Pharma subsequently became Nobel Biocare.
Brånemark spent almost 30 years fighting the scientific community for acceptance of osseointegration as a viable treatment. In Sweden he was often openly ridiculed at scientific conferences. His university stopped funding for his research, forcing him to open a private clinic to continue the treatment of patients. Eventually an emerging breed of young academics started to notice the work being performed in Sweden. Toronto's Professor Zarb, a Maltese dentist working in Canada, was instrumental in bringing the concept of osseointegration to the wider world. The 1983 Toronto Conference is generally considered to be the turning point, when finally the worldwide scientific community accepted Brånemark's work. Today osseointegration is a highly predictable and commonplace treatment modality.
More recently the procedure has been introduced for cranial and
maxillofacialOral and maxillofacial surgery is surgery to correct a wide spectrum of diseases, injuries and defects in the head, neck, face, jaws and the hard and soft tissues of the oral and maxillofacial region. It is an internationally recognized surgical specialty...
reconstruction as well.
Applications
- Dental implant
A dental implant is a "root" device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth....
s, including Mini dental implantsMini dental implants are small diameter dental implants.Dental implants may be split into two separate categories based on the diameter of the device...
, are by far the main field of application
- Retention of a craniofacial prosthesis
Craniofacial prostheses are prostheses made by individuals trained in anaplastology or maxillofacial prosthodontics who medically help rehabilitate those suffering from facial defects caused by disease , trauma or birth defects...
such as an artificial ear (ear prosthesis), eye (orbital prosthesisAn orbital prosthesis is a type of craniofacial prosthesis used to replace an absent eye socket/eye. Typically made of polydimethylsiloxane, an orbital prosthesis is flexible and made to move with the skin. It is retained to the patient daily by using an adhesive or osseointegrated implants....
), or nose (nose prosthesis)
- Bone anchored hearing conduction amplification (Bone Anchored Hearing Aid
A Bone-anchored hearing aid is a type of hearing aid based on bone conduction. It is primarily suited to people who have conductive hearing losses, unilateral hearing loss and people with mixed hearing losses who cannot otherwise wear 'in the ear' or 'behind the ear' hearing aids...
)
- Knee
Knee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve the pain and disability of osteoarthritis. It may be performed for other knee diseases such as rheumatoid arthritis and psoriatic arthritis...
and joint replacementReplacement arthroplasty [from Greek arthron, joint, limb, articulate, + -plassein, to form, mould, forge, feign, make an image of], or joint replacement surgery, is a procedure of orthopedic surgery in which the arthritic or dysfunctional joint surface is replaced with an orthopaedic prosthesis...
Theories
Two theories regarding the chemical mechanism by which endosteal implants integrate with bone have been proposed. Osseointegration, as defined above. That type of integration contrasts with
fibrosseous integration, in which soft tissues such as fibers and/or cells are interposed between the two surfaces.
Brånemark’s theory of osseointegration
Brånemark proposed that implants integrate such that the bone is laid very close to the implant without any intervening connective tissue. The
titanium oxideTitanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
permanently fuses with the bone, as Brånemark showed in 1950s.
Weiss' theory of fibro-osseous integration
Weiss' theory states that there is a fibro-osseous ligament formed between the implant and the bone and this ligament can be considered as the equivalent of the periodontal ligament found in the
gomphosisGomphosis is a joint that binds the teeth to bony sockets in the maxillary bone and mandible. The fibrous connection between a tooth and its socket is a periodontal ligament...
. He defends the presence of
collagenCollagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
fibres at the bone-implant interface. He interpreted it as the peri-implantal ligament with an osteogenic effect. He advocates the early loading of the implant.
Osseointegration versus Biointegration
In 1985, Dr. C. de Putter proposed two ways of implant anchorage or retention as mechanical and bioactive. Mechanical retention can be achieved in cases where the implant material is a metal, for example, commercially pure titanium and titanium alloys. In these cases, topological features like vents, slots, dimples, threads (screws), etc. aid in the retention of the implant. There is no chemical bonding and the retention depends on the surface area: the greater the surface area, the greater the contact.
Bioactive retention can be achieved in cases where the implant is coated with bioactive materials such as hydroxyapatite. These bioactive materials stimulate bone formation leading to a physico-chemical bond. The implant is
ankylosedAnkylosis or anchylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular structures outside the joint or of...
with the bone.
Technique
For osseointegrated Dental implants, metallic, ceramic, and polymeric materials have been used, in particular
titaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
. To be termed osseointegration the connection between the os and the implant needs not be 100 percent, and the essence of osseointegration derives more from the stability of the fixation than the degree of contact in histologic terms. In short it represents a process whereby clinically asymptomatic rigid fixation of alloplastic materials is achieved, and maintained, in bone during functional loading. When osseointegration occurs, the implant is tightly held in place by the bone. The process typically takes several weeks or months to occur which is well enough for the implant dentist to complete the restorations. The fact is that the degree of osseointegration of implants is a matter of time. First evidence of integration occurs after a few weeks, while more robust connection is progressively effected over the next months or years. Though the osseointegrated interface becomes resistant to external shocks over time, it may be damaged by prolonged adverse stimuli and overload, which may result in implant failure. In studies performed using 3M™ ESPE™ MDI
Mini dental implantsMini dental implants are small diameter dental implants.Dental implants may be split into two separate categories based on the diameter of the device...
, it was noted that the absence of micromotion at the bone-implant interface was necessary to enable proper osseointegration. Further, it was noted that there is a critical threshold of micromotion above which a fibrous encapsulation process occurs, rather than osseointegration. Already Brånemark stated that the implant should not be loaded and left out of function during the healing period for osseous integration to occur.
Other complications may arise even in the absence of external impact. One issue is the growing of
cementCementum is a specialized calcified substance covering the root of a tooth. Cementum is excreted by cells called cementoblasts within the root of the tooth and is thickest at the root apex. These cementoblasts develop from undifferentiated mesenchymal cells in the connective tissue of the dental...
. In normal cases, the absence of cementum on the implant surface prevents the attachment of
collagenCollagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
fibers. This is normally the case due to the absence of cementum progenitor cells in the area receiving the implant. However, when such cells are present, cement may form on or around the implant surface, and a functional collagen attachment may attach to it.
Advances in materials engineering: metal foams
Since 2005, a number of orthopedic device manufacturers have introduced products that feature
porous metal constructionA metal foam is a cellular structure consisting of a solid metal, frequently aluminium, containing a large volume fraction of gas-filled pores. The pores can be sealed , or they can form an interconnected network . The defining characteristic of metal foams is a very high porosity: typically...
. Clinical studies on mammals have shown that porous metals, such as titanium foam, may allow the formation of vascular systems within the porous area. For orthopedic uses, metals such as
tantalumTantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, the name comes from Tantalus, a character in Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion resistant. It is part of the refractory...
or
titaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
are often used, as these metals exhibit high
tensile strengthUltimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
and corrosion resistance with excellent
biocompatibilityBiocompatibility is related to the behavior of biomaterials in various contexts. The term may refer to specific properties of a material without specifying where or how the material is used , or to more empirical clinical success of a whole device in...
.
The process of osseointegration in metal foams is similar to that in bone grafts. The porous bone-like properties of the metal foam contribute to extensive bone infiltration, allowing
osteoblastOsteoblasts are mononucleate cells that are responsible for bone formation; in essence, osteoblasts are specialized fibroblasts that in addition to fibroblastic products, express bone sialoprotein and osteocalcin.Osteoblasts produce a matrix of osteoid, which is composed mainly of Type I collagen...
activity to take place. In addition, the porous structure allows for soft tissue adherence and vascularization within the implant. These materials are currently deployed in
hip replacementHip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant. Hip replacement surgery can be performed as a total replacement or a hemi replacement. Such joint replacement orthopaedic surgery generally is conducted to relieve arthritis pain or fix severe...
and
knee replacementKnee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve the pain and disability of osteoarthritis. It may be performed for other knee diseases such as rheumatoid arthritis and psoriatic arthritis...
surgeries.
See also
- Mini dental implants
Mini dental implants are small diameter dental implants.Dental implants may be split into two separate categories based on the diameter of the device...
- Osseoincorporation
Osseoincorporation refers to the healing potential of bone onto an implant surface and into an implant structure. Three dimensional, porous implantable materials utilized in the orthopedic and dental implant industries offer the potential for ingrowth as well as ongrowth or...
- Abutment (dentistry)
In dentistry, an abutment is a connecting element. This is used in the context of a fixed bridge , partial removable dentures and in implants In dentistry, an abutment is a connecting element. This is used in the context of a fixed bridge (the "abutment teeth" referring to the teeth supporting the...
- Dental implant
A dental implant is a "root" device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth....
- Periodontology
Periodontology or Periodontics is the specialty of dentistry that studies supporting structures of teeth, diseases, and conditions that affect them...
- Oral and maxillofacial surgery
Oral and maxillofacial surgery is surgery to correct a wide spectrum of diseases, injuries and defects in the head, neck, face, jaws and the hard and soft tissues of the oral and maxillofacial region. It is an internationally recognized surgical specialty...
- Oral Surgery
Oral Surgery is a recognized international specialty in dentistry. It includes the diagnosis, surgical and related treatment of diseases, injuries and defects involving both the functional and esthetic aspects of the hard and soft tissues of the head, mouth, teeth, gums, jaws and neck.It involves,...
- Prosthesis
In medicine, a prosthesis, prosthetic, or prosthetic limb is an artificial device extension that replaces a missing body part. It is part of the field of biomechatronics, the science of using mechanical devices with human muscle, skeleton, and nervous systems to assist or enhance motor control...
- Dentistry
Dentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...
- European Association for Osseointegration
The European Association for Osseointegration is a non-profit organisation founded in Munich in 1991 to serve as an international, interdisciplinary and independent science based forum for all professionals interested in the art and science of Osseointegration....
- British Society of Oral Implantology
The British Society of Oral Implantology is dedicated to the advancement of education and training in implant dentistry.- External links :*...
External links