Objective. To investigate the role of Wnt/beta-catenin signaling in regulation of IVD development and organization.
Summary of Background Data. beta-catenin dependent Wnt signaling is one of the central regulators in cartilage development during limb skeletal formation. Little is known,
however, about the physiologic relevance of this signaling pathway to IVD development and organization.
Methods. Temporal-spatial distribution of Wnt/beta-catenin signaling activity Selleck Sapanisertib was examined in IVD using Wnt/beta-catenin reporter (TOPGAL) mice. The structural changes in the mouse IVD components such as the nucleus pulposus (NP), endplate (EP), annulus fibrosus (AF), and the growth plate (GP) of the vertebral body were analyzed after transient activation of Wnt/beta-catenin signaling or deletion of beta-catenin in the mice.
Results. Selleck BIRB 796 Activity of Wnt/beta-catenin signaling was high in EP, AF, and GP in the embryonic stages and decreased at the postnatal stage; it was undetectable in the embryonic NP but upregulated after birth. The transient activation of Wnt/beta-catenin signaling caused severe deterioration of the GP and the AF, whereas deficiency of beta-catenin accelerated bone formation in between EP and GP.
Conclusion. The findings in this study
suggest that proper regulation of Wnt/beta-catenin signaling is required for development and organization of IVD.”
“Objective. The aim of this study was to determine the influence of operator experience on the shaping ability of ProFile and K3 nickel-titanium rotary instruments in simulated root canals.
Study design. One hundred sixty simulated canals consisting of 4 different shapes in terms of angle and position of curvature were prepared by experienced and inexperienced operators. One experienced operator prepared 80 canals and 2 inexperienced operators prepared 80 canals with a crown-down technique using either ProFile
or K3 .06 taper instruments. Images of the canals were taken, using a camera attached to a computer with image analysis software, before surgery and this website after preparation to sizes 20, 25, and 30 to working length. Postoperative images were combined with the preoperative image to highlight the amount and position of material removed during preparation as well as the shape of the prepared canal.
Results. Overall, there was a highly statistically significant difference (P < .001) between the instruments for the time taken to prepare the canals, with K3 instruments taking a mean of 4.9 minutes and ProFile 6.0 minutes. Six instruments fractured (3 in each operator category); 4 were ProFile instruments. Four instruments deformed, all with the inexperienced operators; 3 were K3. No perforations or zips were observed; however, 1 danger zone (created by the experienced operator using K3 instruments) and 1 ledge (created by an inexperienced operator using K3 instruments) were created.