The original study design called for twenty patients. Fourteen patients with 13 implants have thus far been recruited for a prospective proof of principle study to assess the effect of addition of Platelet Rich Fibrin (PRF) on interproximal papillary height (I.P.H.) at the restorative line angles when used during the second stage uncovering procedure for dental implants. The secondary objective of this study was to assess the effect on the height of the direct interproximal tissue thickness (I.T.T.) at 6 weeks following uncovering. Implants placed 3 or more months prior at Boston University School of Dental Medicine Periodontics Department were scheduled to be uncovered by the principal investigator. Second stage uncovering was performed with a conventional mid-crestal incision to place standard healing abutments. PRF membrane(s) were inserted around the implants before flap closure in an attempt to augment or thicken the interproximal papillary area. The I.P.H. was measured at the four line angles of each abutment at the highest aspect of the interproximal tissue immediately following the uncovering procedure and at 2, 4 & 6 week intervals. I.T.T. was also measured prior to surgical exposure and at 6 weeks following the uncovering procedure. Results: The use of PRF membranes around dental implants did not significantly improve I.P.H. However, a positive correlation was observed between the use of P.R.F and I.T.T. Further studies are warranted to assess the effect of PRF on the peri-implant papillary tissue.

The thesis deal with the soil sealing and the rehanding with the uncovering of soil cultural layers. This problem is describe on the example of the industrial zone Kolín - Ovčáry. In the thesis there is the evaluation of the soil characteristics and their changes in areas where due to the trensfer of the cultural layer was created completely new structure of soil cover compact of soil units with artificial stratigraphy of profile. For this area the new classification subsumtion is suggested. The overall impacat of the soilsealig and implementation of the uncovering of soil cultural layers, despite of local incerase of soil fertility parameters, we evaluate as the degradation of soil cover.