Biomedical Engineering Reference
In-Depth Information
was cracks connecting two consecutive Haversian canals if the stress was big
enough. Each Haversian system is a relative independent structure, but it will release
the stress energy to adjacent Haversian systems if it cannot use out the high stress
brought from cracks alone. The fourth type was cracks propagating at interstitial
lamella (among the Haversian system) linearly.
In sum, fretting is complex at the dental implant-bone interface rather than a
radial or tangential fretting mode. Nevertheless, the above experimental data,
obtained from two simple fretting tests, indicate that the contact condition of the
bone-implant interface will be changed during the use of dental implants, and thus
surface damage will inevitably occur to the cortical bone under the repeated loading
effect. Therefore, for the dental-implant interface, a similar evolution is believed to
occur due to complex masticatory motions; loosening of the dental implant should
be considered after a certain time of service due to the accumulated damage.
7.3
Remarks
In fact, the damage produced by fretting and the healing and the osseointegration at
the dental implant interface occur at the same time. Both processes involve bone
formation, and both are infl uenced by the mechanical environment. It is very impor-
tant for patients to optimize the structural design of dental implants to reduce a risk
of damage induced by fretting and extend the service life of a dental implant
system.
An ideal dental implant interface should be similar to the natural interface
between the tooth and jawbone, which is both bioactive and absent mechanical
damage. Therefore, much work remains to be done not only on the surface treat-
ment of implant materials, but also on the tribological design of the shape, size, and
structure of the dental implant screw.
References
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anchorage of dental prostheses. I. Experimental studies. Scand J Plast Reconstr Surg
3:81-100
4. Brånemark P-I, Hansson BO, Adell R, Breine U, Lindstrom J, Hallen O et al. (1977)
Osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year
period. Scand J Plast Reconstr Surg 16(11):1-132
5. Schroeder A, Pohler O, Sutter F (1976) Gewebsreaktion auf ein Titan-Hohlzylinderimplantat
mit Titan-Spritzschichtoberfl ache. Schweiz Monatsschr Zahnheilk 86:713-727
