Impact of storage conditions on profilometry of eroded dental hard tissue

The aim of the present study was to analyze in how far drying of eroded dentin and enamel surfaces influence the results of profilometrical determinations with a stylus profilometer. Each five dentin and enamel samples were eroded with HCl (pH 2.6, 2 min). Surface profiles of the samples were recorded with a stylus profilometer in three series. In series 1, the samples were measured while stored in water and in series 2, under ambient conditions (21°C, 35% humidity). In series 3, samples were completely desiccated and then rewetted. Profilometry was conducted at various time intervals for a period of up to 181 min (series 1 and 2) and 72 h (series 3). Only the dentin samples were affected by the storage conditions. Stable profilometrical readings for the eroded dentin samples were only feasible when the specimens were stored in water during the complete period of the experiment, including the profilometrical measurement. Thus, for erosion experiments using profilometrical analysis with a stylus profilometer, it is advised to store and measure dentin samples under wet conditions.     

Caffeic acid phenethyl ester inhibits PDGF-induced proliferation of vascular smooth muscle cells via activation of p38 MAPK, HIF-1α, and heme oxygenase-1

Hyperproliferation of vascular smooth muscle cells (VSMCs) is critically involved in the onset of atherosclerosis and restenosis. Although caffeic acid phenethyl ester (CAPE, 1), one of the main constituents of honeybee propolis, has been shown to exert a beneficial effect in models of vascular injury in vivo, detailed mechanistic investigations in vascular cells are scarce. This study has examined the antiproliferative activity of 1 in platelet-derived growth factor (PDGF)-stimulated primary rat aortic VSMCs and aimed to shed light on underlying molecular mechanisms. Compound 1 inhibited the proliferation of VSMCs upon exposure to PDGF in a dose-dependent manner by interfering with cell cycle progression from the G0/1- to the S-phase. Enhanced phosphorylation of p38 mitogen-activated protein kinase (MAPK) as well as stabilization of hypoxia-inducible factor (HIF)-1α and subsequent induction of heme oxygenase-1 (HO-1) could be identified as molecular events contributing to the observed growth arrest in PDGF-activated VSMCs upon exposure to 1.     

Load-bearing capacity and failure types of anterior zirconia crowns veneered with overpressing and layering techniques

Objectives

The aim of this study was to test whether the load bearing capacity of anterior zirconia crowns veneered with overpressed or layered, is similar and to evaluate the failure types.

Methods

Standardized zirconia frameworks were fabricated and randomly divided into 8 groups (N = 120, n = 15 per test group). Four groups were veneered with one of the layered veneering porcelains: Zirox, GC Initial ZR, VITA VM9 or IPS e.max Ceram and the other four groups were veneered with overpressed veneering porcelains: PressX Zr, GC Initial LF, VITA PM9 or IPS e.max ZirPress. The crowns were cemented on their corresponding CoCr abutment and the specimens were loaded at an angle of 45° in a Universal Testing Machine to determine the fracture load. Data were analyzed using one-way and two-way ANOVA, followed by a post hoc Scheffé test, t-test and Weibull analysis (alpha = 0.05).

Results

Within three manufacturers of veneering porcelain, fracture load values were not statistically significant between overpressed and layered porcelain systems. Within one manufacturer of veneering porcelain, the overpressed crowns (IPS e.max ZirPress: 1519 ± 334 N) demonstrated significantly higher (p < 0.05) fracture load than that of the layered one (IPS e.max Ceram: 894 ± 160 N). Except with IPS e.max ZirPress, where exclusively only chipping of the veneering porcelain was observed, all other porcelain systems showed predominantly framework fractures together with fracture of the veneering porcelain.

Conclusion

Overpressed veneering porcelains for zirconia frameworks exhibited similar or better fracture load compared with layered ones.     

Near-normal gait pattern with peroneal electrical stimulation as a neuroprosthesis in the chronic phase of stroke: a case report

van Swigchem R, Weerdesteyn V, van Duijnhoven HJ, den Boer J, Beems T, Geurts AC. Near-normal gait pattern with peroneal electrical stimulation as a neuroprosthesis in the chronic phase of stroke: a case report.In recent years, the use of functional electrical stimulation (FES) of the peroneal nerve has increased as an alternative for an ankle-foot orthosis (AFO) to treat stroke-related drop foot. We present a chronic stroke patient demonstrating an almost normal gait pattern with peroneal FES as a neuroprosthesis. A 60-year-old survivor of a right hemisphere infarction 21 months ago, who regularly used a polypropylene AFO, was provided with a surface-based peroneal FES device for severe drop foot. In a second instance, he received an implanted FES system because of skin problems with the surface stimulator. With both FES devices, the patient achieved an adequate foot elevation. Moreover, his hip and knee flexion angles during walking increased to normal values and his ankle push-off power increased. His gait pattern became almost symmetrical and less variable than with the AFO. Furthermore, his ability to avoid a sudden obstacle improved to normal values with FES. Our patient showed benefits from peroneal FES beyond what can be attributed to improved foot lift alone. With regard to the potential working mechanisms underlying this response to FES, biomechanical benefits related to improved ankle push-off are suggested as the main mechanism.