Flexible (Polyactive®) versus rigid (hydroxyapatite) dental implants

In a beagle dog study, the peri-implant bone changes around flexible (Polyactive®) and rigid hydroxyapatite (HA) implants were investigated radiographically by quantitative digital subtraction analysis and by assessment of marginal bone height, with the aid of a computerized method. A loss of approximately 1 mm of marginal bone height was observed for both the dense Polyactive and the HA implants, after 6 months of loading. This value appeared to be stable from 12 weeks of loading onward. Along the total length of the implant during the first 6 weeks of loading, both the flexible (dense Polyactive) and the rigid (HA) implants showed a decrease in density. However, after this 6-week period, the bone density around the implants increased, and after 18 weeks the original bone density was reached. The flexible Polyactive implants provoked less decrease in density than the rigid HA implants, although not to a statistically significant level. This finding sustains the hypothesis that flexible implant materials may transfer stresses to the surrounding bone more favorably

[Surgical dilemmas. Medical restrictions and risk factors],[Surgical dilemmas. Medical restrictions and risk factors]

Item does not contain fulltextIn principle, only patients with an ASA (American Society of Anaesthesiologists)-score I or II qualify for an elective surgical procedure, such as an implantation treatment. Surgical risks are weighed against the potential benefits offered by oral implants. Counter-indications to implant rehabilitation include recent myocardial infarction and cerebrovascular accident, immunosuppression, active treatment of malignancy, drug abuse, as well as long-standing intravenous bisphosphonate use. In the case of patients with an endocarditis risk, and also in the case of patients with an orthopedic prosthesis, implants should be placed with some reluctance. If the decision is made for treatment, then consultation with the treating specialist is recommended. Beside absolute counter-indications, there are also conditions which compromise the success of an implant treatment, such as radiation of the jaw or long-term smoking. Concerning the effect which medical conditions have on the life-expectancy of the implant, little is known. There appear to be few existing factors which actually have a negative influence on the chance that an implant will survive