Vergleichende Untersuchungen zur Lagerstabilität verschiedener Checkbiß-Registratmaterialien

Das Ziel dieser Untersuchung lag darin, die Dimensionsstabilität von Registraten nach 48-stündiger Lagerzeit zu ermitteln. Die Untersuchungsbedingungen sollten den klinisch relevanten Umständen angepaßt sein, die auch der Zahnarzt im täglichen Praxisalltag antrifft. An 81 vollbezahnten und möglichst füllungsfreien Probanden wurden Registrierungen mit sieben verschiedenen gesperrten Checkbißregistraten durchgeführt. Gesperrte Checkbißregistrate werden eingesetzt, um bei weitgehend vollbezahnten Patienten die zentrische Kondylenposition als Referenzhaltung des Unterkiefers festzulegen. Von den sieben verschiedenen gesperrten Checkbißregistraten wurden jeweils drei Einzelstücke hergestellt. Direkt nach der Fertigstellung am Probanden wurden die Registrate zum ersten Mal vermessen. Nach der ersten Messung bewahrten wir die gesperrten Checkbißregistrate bei Raumtemperatur an der Umgebungsluft auf. Im Anschluß an die Lagerung von exakt 48 Stunden wurden die Registrate nochmals vermessen. Die Messungen der dreidimensionalen räumlichen Abweichungen erfolgten im Bereich der Kondylarboxen mit Hilfe eines Meßartikulators. Zusammen mit den Kontroll-, Zwischen- und den Lagerzeitmessungen ergaben sich für jeden Probanden 52 Einzelmessungen. Alle von uns verglichenen Materialien zeigten ohne Ausnahme Dimensionsveränderungen im Beobachtungszeitraum von 48 Stunden. Sie lagen zwischen 0,25 und 0,33 mm mit einer Standardabweichung von 0,08 mm, wenn man 90% aller untersuchten Stichproben (90%-Quantil) betrachtet. Die in der Praxis oft verwendeten Wachsplattenregistrate erzielten mit Werten von 0,25 mm geringfügig positivere Resultate. Dieses Ergebnis fanden wir sowohl beim unkorrigierten wie beim korrigierten Wachsplattenregistrat, wobei beim korrigierten Wachsplattenregistrat die Standardabweichung mit 0,03 mm besonders klein ausfiel. Trotz sorgfältigster Handhabung ließen sich Fehler von maximal 2,54 mm (Silikon) nicht vermeiden. Bei den besten Ergebnissen lagen die Werte bei allen Registraten unterhalb von 0,02 mm. Zusammenfassend war für alle untersuchten Registratmaterialien festzustellen, daß sie Uber den Untersuchungszeitraum vergleichbar lagerungsstabil waren

Imaginierte, inszenierte und experimentelle Räume

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A Priori Information Based Time-Resolved 3D Analysis of the Trajectory and Spatial Orientation of Fast-Moving Objects Using High-Speed Flash X-ray Imaging

This paper shows that the X-ray analysis method known from the medical field, using a priori information, can provide a lot more information than the common analysis for high-speed experiments. Via spatial registration of known 3D shapes with the help of 2D X-ray images, it is possible to derive the spatial position and orientation of the examined parts. The method was demonstrated on the example of the sabot discard of a subcaliber projectile. The velocity of the examined object amounts up to 1600 m/s. As a priori information, the geometry of the experimental setup and the shape of the projectile and sabot parts were used. The setup includes four different positions or points in time to examine the behavior over time. It was possible to place the parts within a spatial accuracy of 0.85 mm (standard deviation), respectively 1.7 mm for 95% of the errors within this range. The error is mainly influenced by the accuracy of the experimental setup and the tagging of the feature points on the X-ray images

High-speed rotational atherectomy before paclitaxel-eluting stent implantation in complex calcified coronary lesions: the randomized ROTAXUS (Rotational Atherectomy Prior to Taxus Stent Treatment for Complex Native Coronary Artery Disease) trial

OBJECTIVES This study sought to determine the effect of rotational atherectomy (RA) on drug-eluting stent (DES) effectiveness. BACKGROUND DES are frequently used in complex lesions, including calcified stenoses, which may challenge DES delivery, expansion, and effectiveness. RA can adequately modify calcified plaques and facilitate stent delivery and expansion. Its impact on DES effectiveness is widely unknown. METHODS The ROTAXUS (Rotational Atherectomy Prior to TAXUS Stent Treatment for Complex Native Coronary Artery Disease) study randomly assigned 240 patients with complex calcified native coronary lesions to RA followed by stenting (n = 120) or stenting without RA (n = 120, standard therapy group). Stenting was performed using a polymer-based slow-release paclitaxel-eluting stent. The primary endpoint was in-stent late lumen loss at 9 months. Secondary endpoints included angiographic and strategy success, binary restenosis, definite stent thrombosis, and major adverse cardiac events at 9 months. RESULTS Despite similar baseline characteristics, significantly more patients in the standard therapy group were crossed over (12.5% vs. 4.2%, p = 0.02), resulting in higher strategy success in the rotablation group (92.5% vs. 83.3%, p = 0.03). At 9 months, in-stent late lumen loss was higher in the rotablation group (0.44 ± 0.58 vs. 0.31 ± 0.52, p = 0.04), despite an initially higher acute lumen gain (1.56 ± 0.43 vs. 1.44 ± 0.49 mm, p = 0.01). In-stent binary restenosis (11.4% vs. 10.6%, p = 0.71), target lesion revascularization (11.7% vs. 12.5%, p = 0.84), definite stent thrombosis (0.8% vs. 0%, p = 1.0), and major adverse cardiac events (24.2% vs. 28.3%, p = 0.46) were similar in both groups. CONCLUSIONS Routine lesion preparation using RA did not reduce late lumen loss of DES at 9 months. Balloon dilation with only provisional rotablation remains the default strategy for complex calcified lesions before DES implantation

The Essential DNA Damage Response Complex MRN Is Dispensable for the Survival and Function of Purkinje Neurons

MRE11, RAD50, and NBS1 form the MRN complex in response to DNA damage to activate ATM, a gene responsible for Ataxia-Telangiectasia (A-T). Loss of any components of the MRN complex compromises cell life. Mutations in MRE11, RAD50, and NBS1 cause human genomic instability syndromes Ataxia-Telangiectasia-like disorder (A-TLD), NBS-like disorder (NBSLD), and Nijmegen Breakage Syndrome (NBS), respectively. Among other pathologies, neuronal deficits, including microcephaly, intellectual disabilities, and progressive cerebellar degeneration, are common in these disorders. Nbs1 deletion in neural stem cells of mouse models resulted in cerebellar atrophy and ataxia, mimicking the A-T syndrome suggesting an etiological function of MRN-mediated DDR in neuronal homeostasis and neuropathology. Here we show that deletion of Nbs1 or Mre11 specifically in Purkinje neurons of mouse models (Nbs1-PCΔ and Mre11-PCΔ, respectively) is compatible with cerebellar development. Deleting Nbs1 in Purkinje cells disrupts the cellular localization pattern of MRE11 or RAD50 without inducing apparent DNA damage, albeit impaired DNA damage response (judged by 53BP1 focus formation) to ionizing radiation (IR). However, neither survival nor morphology of Purkinje cells and thus locomotor capabilities is affected by Nbs1 deletion under physiological conditions. Similarly, deletion of Mre11 in Purkinje cells does not affect the numbers or morphology of Purkinje cells and causes no accumulation of DNA damage. Mre11-deleted Purkinje cells have regular intrinsic neuronal activity. Taken together, these data indicate that the MRN complex is not essential for the survival and functionality of postmitotic neurons such as Purkinje cells. Thus, cerebellar deficits in MRN defect-related disorders and mouse models are unlikely to be a direct consequence of loss of these factors compromising DDR in postmitotic neurons such as Purkinje cells