Osseointegration; process and definition.
The possibility of permanently retaining titanium fixture in vital remodeling bone with a capacity of considerable load bearing depends on an adequate comprehension of the osseointegration process. Professor Per-Ingvar Branemark coined Osseointigration as a term in the early 1970s. Its current definition-a direct contact between living, haversian bone and the loaded implant surface-is based on histological and ultrastructural observations but is not yet fully defined.
However, it is well supported by long-term radiographic and clinical studies demonstrating perifixtural bone adaption and remodeling as well as long-term fixture stability and load-bearing capacity.
There is no instant osseointegration. Its gradual and slow development must be fully understood in order for a successful clinical outcome to be achieved.
Achieving osseointegation
The mere use of titanium as an implant material is by no means any guarantee of achieving osseointegration. Managing the host organism and tissues should attract at least as much interest as the properties and handling of the implant.
Preoperative host factors
General patient conditions
No investigations so far have been undertaken systematically to evaluate the influence of diseases, medications, and drugs that may theoretically affect wound healing-especially bone healing and remodeling-after installation of titanium fixtures. Several such patient preconditions could be considered:
l. Age
2. Sex (due to postmenopausal osteoporosis)
3. Malabsorption syndromes (eg, ulcerative colitis)
4. Bone metabolic diseases (eg, osteoporosis, osteomalacia, gyperparathyroidism, Paget' s
disease)
5. Rheumatic diseases (eg, rheumatoid arthritis, Sjogren' s syndrome, systemic lupus
erythematosus)
6. Hormonal diseases (eg, diabetes, Cushing' s syndrome, gyperparathyroidism)
7. Coagulation disorders and anticoagulation medications
8. Systemic treatment with glucocorticoides
9. Alcohol abuse
10. Tobacco smoking
Studies have initially indicated that a higher chronological patient age alone is not a determining factor for the outcome of treatment with fixtures, whereas tobacco smoking maybe. So far, there is insufficient evidence to support the installation of fixtures in growing jaws. Experimental studies and a few clinical trials indicate that the fixtures may not move with increasing vertical height of the jaw. Rheumatoid arthritis is not regarded as a contraindication for the use of osseointegrated implants in orthopedic surgery.
Among the more than 35,000 patients the world over who have been treated with implant fixtures, a number are known to be medically compromised by one or several of the factors listed above with little or no influence on the treatment outcome. This especially applies to postmenopausal osteoporosis. Women are very，英语论文网站，英语毕业论文 |
