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Osseointegration derives from the Greek osteon, bone, and the Latin integrare, to make whole. The term refers to the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant. Osseointegration has enhanced the science of medical bone, and joint replacement techniques.

[edit] Definition

Osseointegration is also defined as : "the formation of a direct interface between an implant and bone, without intervening soft tissue"^[1]. Osseointegrated implant is a type of implant defined as "an endosteal implant containing pores into which osteoblasts and supporting connective tissue can migrate"^[2]. Applied to oral implantology, this thus refers to bone grown right up to the implant surface without interposed soft tissue layer. No scar tissue, cartilage or ligament fibers are present between the bone and implant surface. The direct contact of bone and implant surface can be verified microscopically. Osseointegration may also be defined as :

1. Osseous integration, the apparent direct attachment or connection of osseous tissue to an inert alloplastic material without intervening connective tissue.
2. The process and resultant apparent direct connection of the endogenous material surface and the host bone tissues without intervening connective tissue.
3. The interface between alloplastic material and bone.

[edit] History

Titanum implant (black) integrated into bone (red): Histologic section

In 1952, Per-Ingvar Brånemark 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 medicine the implementation of osseointegration started in the early 1980’s as a result of the work of Prof. Brånemark^{[3] [4] [5] [6]}.

More recently the procedure has been introduced for cranial and maxillofacial reconstruction as well.

[edit] Applications

• Dental implants are by far the main field of application
• Retention of a craniofacial prosthesis such as an artificial ear (ear prosthesis), eye (orbital prosthesis), or nose (nose prosthesis)
• Bone anchored hearing conduction amplification (Bone Anchored Hearing Aid)

[edit] 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^{[7] [8]}.

[edit] 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 oxide permanently fuses with the bone, as Brånemark showed in 1950s.

[edit] 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 gomphosis. He defends the presence of collagen 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.

[edit] 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 ankylosed with the bone.

[edit] Technique

For osseointegrated implants, metallic, ceramic, and polymeric materials have been used^[9], in particular titanium^[10].To be termed osseointegration the connection between the os and the implant needs not be 100 per cent, 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^[11]. 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^[12]. 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^{[13] [14]}. 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 cement^[15]. In normal cases, the absence of cementum on the implant surface prevents the attachment of collagen 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^[16].

[edit] Notes and References

1. ^ Benjamin F. Miller, and Claire B. Keane (1992).Encyclopedia & Dictionary of Medicine, Nursing, & Allied Health. W.B. Saunders Company ed., Fifth Edition, 1073 pp., ISBN 0-7216-3456-7.
2. ^ Mosby's Medical, Nursing and Allied Health Dictionary (2002). Mosby editor, Sixth edition, p. 1240. ISBN 0-323-01430-5.
3. ^ Per-Ingvar Brånemark (September 1983). "Osseointegration and its experimental background". Journal of Prosthetic Dentistry, 50(3), pp. 399-410. ncbi.
4. ^ Per-Ingvar Brånemark, George A. Zarb, and Tomas Albrektsson (1989). Tissue-Integrated Protheses: Osseointegration in Clinical Dentistry. Quintessence Publishing Co, Chicago (Illinois).
5. ^ Tomas Albrektsson, and George A. Zarb (eds) (1989). The Brånemark Osseointegrated Implant. Quintessence Publishing Co, Chicago (Illinois), 262 pp., ISBN 9780867152081.
6. ^ John Beumer, and Steven G. Lewis (1989). "The Brånemark Implant System: clinical and laboratory procedures". Ishiaku EuroAmerica Publ., St. Louis, ISBN 0912791624.
7. ^ George W. Bernard, Fermin A. Carranza, and Sascha A. Jovanovic (1996). "Biological Aspects of Dental Implants". In: Fermin A. Carranza, and Michael G. Newman (eds). "Clinical Periodontology ", W.B. Saunders Company, Philadelphia, 8th edition, ISBN 0-7216-6728-7, p. 687.
8. ^ Hans-Peter Weber, and David L. Cochran (January 1998). "The soft tissue response to osseointegrated dental implants". The Journal of Prosthetic Dentistry, 79(1), pp. 79-89, ProsDent.
9. ^ Mosby's Dictionary (2002).
10. ^ Arturo N. Natali (ed.) (2003). "Dental Biomechanics". Taylor & Francis, London / New York, 273 pp., ISBN 9780-415-30666-9, pp. 69-87.
11. ^ George A. Zarb, and Tomas Albrektsson (1991). "Osseointegration – A requiem for the periodontal ligament ?". International Journal of Periodontology and Restorative Dentistry, issue 11, pp. 88-91.
12. ^ Tomas Albrektsson, Tord Berglundh, and Jan Lindhe (2003). "Osseointegration: Historic Background and Current Concepts". In: Jan Lindhe, Thorkild Karring, and Niklaus P. Lang (eds), "Clinical Periodontology and Implant Dentistry", Blackwell, Munksgaard, 4th edition, 1044 pp., ISBN 1-4051-0236-5, p. 815.
13. ^ ibid., p. 816.
14. ^ Flemming Isidor (1996). "Loss of osseointegration caused by occlusal load of oral implants: A clinical and radiographic study in monkeys". Clinical Oral Implant Research, Issue 7, pp. 143-152.
15. ^ Nathalie Pauletto, Brian J. Lahiffe, and Joanne N. Walton (November/December 1999). "Complications associated with excess cement around crowns on osseointegrated implants: A clinical report". The International Journal of Oral & Maxillofacial Implants, 14(6), pp. 865-868. PubMed, Quintpub.
16. ^ Bernard, Carranza, and Jovanovic (1996), pp. 688-689.

[edit] Further Reading

• George A. Zarb, and Adrianne Schmitt (July 1990). "The longitudinal clinical effectiveness of osseointegrated dental implants: The Toronto study. Part II: The prosthetic results". Journal of Prosthetic Dentistry, 64(1), pp. 53-61, ScienceDirect.
• Peter Apse, George A. Zarb, and Adrianne Schmitt, D. W. Lewis (July 1991). "The longitudinal effectiveness of osseointegrated dental implants. The Toronto Study: peri-implant mucosal response". International Journal of Periodontology and Restorative Dentistry, 11(2), pp. 94-111, ncbi.
• Doug V. Chaytor, George A. Zarb, Adrianne Schmitt, and D. W. Lewis (July 1991). "The longitudinal effectiveness of osseointegrated dental implants. The Toronto Study: bone level changes". International Journal of Periodontology and Restorative Dentistry, 11(2), pp. 112-125, ncbi.
• Andrew J. Barber, Chris J. Butterworth, and Simon N. Rogers (April 2010). "Systematic review of primary osseointegrated dental implants in head and neck oncology". British Journal of Oral and Maxillofacial Surgery, 48(3), PubMed.
• Margareta Hultin, Anders Gustafsson, and Björn Klinge (February 2000)."Long-term evaluation of osseointegrated dental implants in the treatment of partly edentulous patients". Journal of Clinical Periodontology, 27(2), pp. 128-33, PubMed, Interscience.
• Jordi Olivé, and Carlos Aparicio (1990). "The periotest implant as a measure of osseointegrated oral implant stability". The International Journal of Oral & Maxillofacial Implants, 5(4), pp. 390-400.
• Eric P. Holmgren, Robert J. Seckinger, Leslie M. Kilgren, and Francis Mante (April 1998). "Evaluating Parameters of Osseointegrated Dental Implants Using Finite Element Analysis". Journal of Oral Implantology, 24(2), pp. 80-88, JOI Online.

[edit] See also

• Dental implant
• Periodontology
• Oral and maxillofacial surgery
• Oral Surgery
• Prosthesis
• Dentistry
• European Association for Osseointegration
• British Society of Oral Implantology

[edit] External links

• Academy of Osseointegration
• Bioimplants Lab - Osseointegration
• Bicon Dental Implants
• Clinical research on osseointegrated dental implants
• Failure mechanisms of osseointegrated oral implants
• A system for the universal identification of osseointegrated dental implants. A proposal

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Osseointegration".