Torsion and linear accuracy in intraoral scans obtained with different scanning principles

PurposeFew investigations have examined the production of single restorations using intraoral scanners (IOS). Data on full-arch scans are rare, and data regarding torsion within the entire arch are very sparsely reported. Therefore, the aim of this study was to examine the deviations of torsion and linear distances in full-arch scans of three IOS based on different scanning principles.MethodsA cobalt-chrome-molybdenum alloy master model (CCMM) with four hemispheres was fabricated by laser sintering. The CCMM was digitized using a laboratory scanner (ATOS-Core/GOM) and scanned with three IOS (Omnicam/Sirona(OC); True Definition/3M(TD); TriosII/Cara-Version/Kulzer(TR)). All scan data were exported in a standard STL-file format and were analyzed with GOM Inspect software (V7.5/GOM). Torsion between the right and left side of the arch and linear accuracy (trueness and precision) were evaluated. After normality was confirmed, all data were subjected to parametric statistical analyses.ResultsThe torsion ranged from 0.07 ± 0.03°(OC) to 0.29 ± 0.14°(TD). Pairwise comparisons showed significant differences between the OC and TD scanners and between the TR and TD scanners. The linear distances ranged from 6 ± 5 μm(OC) to 298 ± 317 μm(TD). Significant differences were observed among all investigated IOS (p = 0.05).ConclusionsAlthough the highest torsion was observed for the TD scanner, it is still not clear whether the differences between the IOS are related to the scanning principle or to the scanning algorithm. Due to the high clinical relevance of full-arch restorations, future studies should consider torsion. Regarding linear accuracy, no general difference related to the scanning principles of the IOSs was observed.     

Outcomes After Aortic Valve Replacement for Asymptomatic Severe Aortic Regurgitation and Normal Ejection Fraction

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Recipient hypertonic saline infusion prevents cardiac allograft dysfunction

Objective

Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

Pleural flap to prevent lobar torsion: a novel technique

Lobar torsion is reported as very rare but sometimes catastrophic complication if overlooked during the early postoperative period following a lobectomy, though it is totally preventable. In this novel technique, a piece of parietal pleural flap is harvested from the posterior wall of the chest using a hook diathermy while keeping its upper border as close to the apex as possible. Finally, distal end of the flap is secured to the upper edge of the lobe using a fine monofilament absorbable suture. This procedure not only protects the lobe from rotation but also maintains continuous expansion of the lung in the early postoperative period and may, therefore, be a good option to prevent such a serious complication in selected patients following a lobectomy.