Osseointegrated Titanium Implants:Requirements for Ensuring a Long-Lasting, Direct Bone-to-Implant Anchorage in Man

Abstract

A total of 2895 threaded, cylindrical titanium implants have been inserted into the mandible or the maxilla and 124 similar implants have been installed in the tibial, temporal or iliac bones in man for various bone restorative procedures. The titanium screws were implanted without the use of cement, using a meticulous technique aiming at osseointegration--a direct contact between living bone and implant. Thirty-eight stable and integrated screws were removed for various reasons from 18 patients. The interface zone between bone and implant was investigated using X-rays, SEM, TEM and histology. The SEM study showed a very close spatial relationship between titanium and bone. The pattern of the anchorage of collagen filaments to titanium appeared to be similar to that of Sharpey's fibres to bone. No wear products were seen in the bone or soft tissues in spite of implant loading times up to 90 months. The soft tissues were also closely adhered to the titanium implant, thereby forming a biological seal, preventing microorganism infiltration along the implant. The implants in many cases had been allowed to permanently penetrate the gingiva and skin. This caused no adverse tissue effects. An intact bone-implant interface was analyzed by TEM, revealing a direct bone-to-implant interface contact also at the electron microscopic level, thereby suggesting the possibility of a direct chemical bonding between bone and titanium. It is concluded that the technique of osseointegration is a reliable type of cement-free bone anchorage for permanent prosthetic tissue substitutes. At present, this technique is being tried in clinical joint reconstruction. In order to achieve and to maintain such a direct contact between living bone and implant, threaded, unalloyed titanium screws of defined finish and geometry were inserted using a delicate surgical technique and were allowed to heal in situ, without loading, for a period of at least 3--4 months.

Orthopedic bioactive implants: Hydrogel enrichment of macroporous titanium for the delivery of mesenchymal stem cells and strontium

“…Representative micrographs showing calcified matrix stained by AR-S are reported in Figure 3(b). The osteo-inductive effect of SrCl 2 was evident also on type I collagen gene expression, with cells cultured in osteogenic medium with 5 lg/mL SrCl 2 showing the highest expression of this marker [P < 0.05, Fig. 3(c)].…”

“…Freeze-dried CMCA polymer was solubilized (1.7% W/V) in ddH 2 O together with N-hydroxysuccinimide at molar ratio 1 : 1 with CMCA. 1,3-diaminopropane (Merk) was added in a ratio of 1 : 2 with CMCA and pH was adjusted to 4.7 with HCl.…”

“…Further improvement of this feature by the association of TT with a hydrogel enriched with an osteo-inductive factor appears a very promising strategy to improve implant osseointegration that grants prosthetic stability. [1][2][3] Recently, factors such as VEGF and FGF-2 have been incorporated in hydrogel coatings to obtain bioactive titanium. 15,16 Preliminary experiments demonstrated that SrCl 2 can be included in the CMCA hydrogel and subsequently released (data not shown).…”

“…The integration between bone and implant is crucial in cementless prostheses where bone ingrowth is required to grant fixation. The achievement of an optimal osseointegration can lead to a reduction in the risk of implant mobilization and, consequently, in the number of revision procedures, [1][2][3] which have major drawbacks such as patients' morbidity and relevant costs for National Health Systems. With this aim, cementless implant technology has evolved with the introduction of porous metallic materials to maximize bone ingrowth and bone-to-implant contact.…”

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“…The clinical success of dental implants is related to early osseointegration [25]. is critical for the short-and long-term success of dental implants.…”