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Implant osseointegration has not been accepted over time, considering that in fact the implant integration is performed only in the soft tissue of the host. For this reason, the implant has never been sufficiently integrated into the host tissue immediately after insertion. Experiments performed in Branemark laboratories in the early 1960s, with a new type of implant, which required a direct anchorage to bone tissue for clinical function, this anchorage was called osseointegration. It has been shown that it is possible to achieve direct osseointegration if the Branemark method is considered, which was published a few years later in the first clinical report. The authors of this article come up with new contributions that validate the implant osseointegration process. Inside this article we present our methodology for evaluating the osseointegration of endosseous implants: ESEM (environmental scanning electron microscope) studies of the implant-bone tissue interface. [ABSTRACT FROM AUTHOR]

Objective. Comparative evaluation of the accuracy and dimensional stability of modern impression materials, given that often the casting is not done at a short interval after impression. Materials and methods. 4 modern impression materials were studied as follows: alginate (Tropicalgin-Zhermack), condensing silicone (Speedex-Coltene), addition silicone (Elite-Zhermack) and polyether (Impregum-3M/ESPE). With each of them was taken an impression of the same occlusal surface of an extracted molar, using a monophase technique . Both the control and the samples of impression materials obtained were subjected to stereomicroscopy investigations. Each sample was analyzed immediately (one hour after the impression), one day, 3 days and 7 days after the impression, respectively, taking the same reference marks for measurements identical to those on the control sample. Following the analysis, the dimensional variation of the analyzed materials compared to the control sample could be measured. The thickness of an enamel ridge bordered by two imagistically obvious ditches was taken as a reference. Results. Alginate suffers the greatest contraction at 24 hours (1.94%), but also at 7 days (0.91%). Addition silicones have the lowest shrinkage at 24 hours (0.03%) and polyethers the smallest variation over time (0.25% at 24 hours and 0.53% at 7 days). The polyethers also show the highest accuracy, the initial value (2,799 μm) being the closest to the value of the control sample (2,805 μm). Conclusions. All the impression materials studied undergo dimensional variations, the maximum contraction being in the first 24 hours, followed by a slight expansion due to postpolymerization de-stressing. Addition silicones show the lowest volumetric variation one day after registration, and polyethers 7 days after. Polyethers have the highest accuracy, while irreversible hydrocolloids have major dimensional changes and low accuracy compared to other materials. [ABSTRACT FROM AUTHOR]