SUMMARY Objectives: The objective of this in vitro study was to compare, with a threshold value of 200 nm, the surface roughness obtained when using 12 different polishing systems on four different composite resins (microfill, nanofill, and two nanohybrids). Methods and Materials: A total of 384 convex specimens were made using Durafill VS, Filtek Supreme Ultra, Grandio SO, and Venus Pearl. After sandblasting and finishing with a medium-grit finishing disc, initial surface roughness was measured using a surface roughness tester. Specimens were polished using 12 different polishing systems: Astropol, HiLuster Plus, D♦Fine, Diacomp, ET Illustra, Sof-Lex Wheels, Sof-Lex XT discs, Super-Snap, Enhance/Pogo, Optrapol, OneGloss and ComposiPro Brush (n=8). The final surface roughness was measured, and data were analyzed using two-way analysis of variance. Pairwise comparisons were made using protected Fisher least significant difference. Results: There were statistical differences in the final surface roughness between polishing systems and between composite resins (p<0.05). The highest surface roughness was observed for all composite resins polished with OneGloss and ComposiPro Brush. Enhance/Pogo and Sof-Lex Wheels produced a mean surface roughness greater than the 200-nm threshold on Filtek Supreme Ultra, Grandio SO, and Venus Pearl. Data showed that there was an interaction between the composite resins and the polishing systems. Conclusions: A single polishing system does not perform equally with all composite resins. Except for Optrapol, multi-step polishing systems performed generally better than one-step systems. Excluding Enhance/Pogo, diamond-impregnated polishers led to lower surface roughness. Durafill VS, a microfill composite resin, may be polished more predictably with different polishers.

We demonstrate the measurement of whole-cell biophysical parameters with quantitative-phase digital holographic microscopy and flow assays. For different cell types, whole-cell mechanical properties and refractive index, mean cell thickness and absolute cell volume were obtained.

The lack of understanding on how to treat pancreas-related diseases and develop new therapeutics is partly due to the unavailability of appropriate models. In vitro models fail to provide a physiological environment. Testing new drug targets in these models can give rise to bias and misleading results. Therefore, we developed an in vivo model for drug testing on full pancreatic digests, which maintains the interactions between endo- and exocrine tissues and allows retrieving the samples for further analyses. The use of full pancreatic digest eliminates the need to isolate islets, reducing time and cost. In this model, four different conditions can be implanted subcutaneously within the same animal. Each condition consists of full pancreatic tissue digests embedded in alginate beads. All alginate beads in one animal contained full pancreatic digest of the same donor and, after 5-day implantation, were retrieved for analysis focusing on survival, function, and/or organization. Proof-of-principle of the platform was evidenced by showing the effect of hyaluronic acid and vascular endothelial growth factor on the overall function of the full pancreatic digest and on endothelial cells in the pancreatic digest, respectively. Retrieval from identical animals allows direct comparison between conditions. Metabolism (MTT) quantification, dithizone staining, and glucose-stimulated insulin secretion assessment allow to discriminate, using a minimal number of animals, between treatments and validate the system. Because of its simplicity, the model is highly adaptable to specific needs of the user.

We demonstrate label-free cell phenotyping by measuring various biophysical parameters with a multimodal imaging system based on quantitative-phase digital holographic microscopy. Different developments allowing the monitoring, in various paradigms, of specific biophysical parameters are presented.