Comparison of the transfer precision of three different impression materials in combination with transfer caps for the Frialit-2 system.

Transfer of the precise position of implants to a master cast is a prerequisite for accurate and passive fit of the superstructure. Implants lack the mobility of natural teeth and, therefore, inaccurate frameworks result in stress within the mechanical parts and the implant-bone interface. Various impression methods have been described to achieve accurate reproduction of the intra-oral relation of the implants. The aim of this experimental study was to compare three different impression materials (polyether, polyvinyl siloxane, hydrocolloid) with the Frialit(R)-2 system and with the indirect technique. In addition, the use of transfer caps (TCs) to improve transfer precision was tested with all three materials. All measurements were performed using a three-dimensional (3D) co-ordinate measuring machine that is capable of locating points in space and calculating the relative distortions as angles of tilt (rot-XY, rot-XZ, rot-YZ) and 3D displacement. The results suggest that addition-silicone (a-silicone) and polyether are the materials of choice for implant transfer procedures. The use of TCs resulted in a significantly reduced rotation in the XY-plane but did not improve the absolute 3D displacement. A-silicone with the use of TCs proved to be most precise. Comparison between polyether and polyvinyl siloxane showed significant differences in the XY-rotation and the 3D displacement in favour of the silicone. Because the mean distortions between the original model and the master casts were about 100 microm, absolutely precise fit may be unattainable owing to the physical properties of the materials. Further studies will have to evaluate the amount of tolerable stress at the implant-bone interface.

Reversal of Borrelia burgdorferi associated dilated cardiomyopathy by antibiotic treatment?

It is suggested that Borrelia burgdorferi infection could be associated with dilated cardiomyopathy (IDC). Stanek et al. were able to cultivate Borrelia burgdorferi from myocardial biopsy tissue of a patient with longstanding dilated cardiomyopathy. Here we present a study in which we examined the effect of standard antibiotic treatment on the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy associated with Borrelia burgdorferi infection. In this study we assessed the serum (IgG, IgM Elisa) and history of 46 IDC patients with specific regard to Borrelia burgdorferi infection (mean LVEF 30.4 +/- 1.3%, measured by cardiac catheterization and echocardiography with the length-area-volume method). All 46 patients received standard treatment for dilated cardiomyopathy: ACE inhibitors, digitalis, and diuretics. Eleven (24%) patients showed positive serology and a history of Borrelia burgdorferi infection; nine of these also had a typical history of tick bite and erythema chronicum migrans (ECM) and/or other organ involvement, and two had no recollection of tick bite or ECM but showed other Borrelia burgdorferi-associated disorders (neuropathy, oligoarthritis). These 11 patients with Borrelia burgdorferi infection received standard antibiotic treatment with intravenous ceftriaxone 2 g bid for 14 days. Six (55%) recovered completely and showed a normal LVEF after 6 months, three (27%) improved their LVEF, and two (18%) did not improve at all. This amounts to nine (82%) patients with recovery/improvement in the Borrelia burgdorferi group. The 35 patients who did not show positive serology or a history of Borrelia burgdorferi infection did not receive antibiotic treatment. In this group without Borrelia burgdorferi infection 12 (26%), showed recovery/improvement following the standard treatment of dilated cardiomyopathy (see earlier). Our results indicate that Borrelia burgdorferi infection could play a decisive role in the development of dilated cardiomyopathy, especially in a geographical region such as Graz, where Borrelia burgdorferi is endemic. While we are aware of the small number of Borrelia burgdorferi patients in this study, we nevertheless conclude that in a remarkable number of patients with signs of Borrelia burgdorferi infection, dilated cardiomyopathy could be reversed and LVEF improved.