Interest in intraoral scanners (IOSs) has increased in dentistry since the introduction of the CEREC system in 1984. 1 The rapid pace of innovation in digital scanners has increased the indications for use to include more complicated completearch prostheses, removable prostheses, extensive implantsupported prostheses, and orthodontic aligners. 2-6 Intraoral digital scans are now acceptable for complete arch prostheses supported by nonparallel implants, which is a testament to how far the technology has advanced. 7 These expanded indications combined with an increase in the ease of use have increased the adoption of digital workflows. This results in increased patient comfort, shortened treatment time, and the potential for decreased overhead, all while maintaining the quality of conventional systems. 8-11 Additionally, intraoral Declaration of Interest: A.M. and W.R. have lectured for Planmeca at CE events and received honoraria. M.L. has lectured for Dentsply Sirona at CE events and received honoraria.

Objective This in vitro study compares the newest generation of intraoral scanners to their older counterparts, and tests whether material substrates affect the trueness and precision of intraoral scanners (IOS). Material and methods A custom model, used as the reference standard, was fabricated with teeth composed of different dental materials. The reference standard scan was obtained using a three‐dimensional (3D) optical scanner, the ATOS III. Experimental scans were obtained using eight different IOS, operated by experienced clinicians, using the manufacturer's recommended scanning strategy. A comprehensive metrology program, Geomagic Control X, was used to compare the reference standard scan with the experimental scans. Results For all scanners tested, except Trios3, the substrate does influence the trueness and precision of the scan. Furthermore, differences exist when comparing the same substrate across different scanners with some of the latest generation scanners clearly leaping ahead of the older generation regarding both trueness and precision. Conclusions Substrate type affects the trueness and precision of a scan. Active Triangulation scanners are more sensitive to substrate differences than their parallel confocal counterparts. Some scanners scan certain substrates better, but in general the new generation of scanners outperforms the old, across all substrates. Clinical significance The substrates being scanned play an import role in the trueness and precision of the 3D model. The new generation of scanners is remarkably accurate across all substrates and for complete‐arch scanning.

Companies who make digital impression systems often recommend a scan pattern specific for their system. However, every clinical scanning scenario is different and may require a different approach. Knowing how important scan pattern is with regards to accuracy would be helpful for guiding a growing number of practitioners who are utilizing this technology.

Steatotic livers are not used for transplantation because they have a reduced tolerance for ischemic events with reduced ATP levels and greater levels of cellular necrosis, which ultimately result in total organ failure. Mitochondrial uncoupling protein-2 (UCP2) is highly expressed in steatotic livers and may be responsible for liver sensitivity to ischemia through mitochondrial and ATP regulation. To test this hypothesis, experiments were conducted in lean and steatotic (ob/ob), wild-type, and UCP2 knock-out mice subjected to total warm hepatic ischemia/reperfusion. Although ob/ob UCP2 knock-out mice and ob/ob mice have a similar initial phenotype, ob/ob UCP2 knock-out animal survival was 83% when compared with 30% in ob/ob mice 24 h after reperfusion. Serum alanine aminotransferase concentrations and hepatocellular necrosis were decreased in the ob/ob UCP2 knock-out mice when compared with ob/ob mice subjected to ischemia. Liver ATP levels were increased in the ob/ob UCP2 knock-out animals after reperfusion when compared with the ob/ob mice but remained below the concentrations from lean livers. Lipid peroxidation (thiobarbituric acid-reactive substances) increased after reperfusion most significantly in the steatotic groups, but the increase was not affected by UCP2 deficiency. These results reveal that UCP2 expression is a critical factor, which sensitizes steatotic livers to ischemic injury, regulating liver ATP levels after ischemia and reperfusion.Complications from liver steatosis represent a significant clinical concern, especially for liver surgeries including resection and transplantation. This is of escalating importance as nonalcoholic fatty liver disease is independently correlated to obesity and insulin resistance, which are both epidemic in the Unites States (1, 2). Steatotic livers are considerably more sensitive to acute stressors including ischemia/reperfusion (I/R) 2 as experienced in transplantation, and organs meeting this criterion are routinely turned down for donation (3-6). Under I/R conditions, steatotic livers are ATP-depleted, and the predominant hepatocellular fate is shifted from apoptosis to oncotic necrosis, strongly implicating inappropriate energy homeostasis as the primary cause of liver sensitivity (7-10).In a state of energy substrate abundance and forward shift in cellular redox potential, hepatocytes are thought to combat mitochondrial electron transport chain-derived reactive oxygen species (ROS) production through mitochondrial uncoupling. In normal lean livers, mitochondrial uncoupling protein-2 (UCP2) is confined to Kupffer cells; however, hepatocellular concentrations of UCP2 greatly increase with steatosis (7,11,12). Although the mechanism is not known, UCP2 facilitates passive proton conductance across the mitochondrial inner membrane into the matrix during respiration (13,14). Maximum employment of electrochemical potential at ATP synthase is sacrificed by UCP2, and heat, rather than ATP, is produced. Proton conductance is thought to require posttranslational activ...

Hepatic steatosis increases the extent of cellular injury incurred during ischemia/reperfusion (I/R) injury. (-)-