Dimeric Rh Complexes Supported by a Bridging Phosphido/Bis(Phosphine) PPP Ligand.

Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a phosphide. Three bimetallic Rh complexes containing the diamandoid Rh2P2 core (P = phosphido) have been structurally and spectroscopically characterized. The Rh-Rh interaction in these three dimers was examined by way of structural comparisons and DFT investigations.

A technique for digital alignment of cross-articulated casts in a computer-aided design software program for complete-mouth rehabilitation.

With the advent of computer-aided design and computer-aided manufacturing (CAD-CAM), dental restorations are no longer fabricated in an entirely analog fashion. Successful execution of complete-mouth rehabilitations requires articulation of definitive maxillary and mandibular casts with tooth preparations, as well as cross-articulation with the patient's interim restorations. These cross-articulated records serve as a guide for the dental laboratory technician in fabricating the definitive restorations. In the CAD-CAM workflow, cross-articulation and overlaying of a patient's interim casts over the definitive casts of tooth preparations poses some challenges because of loss of common anatomic data points such as incisive papilla, rugae, and the palate. This article describes a straightforward technique to overcome this common challenge, where a dental laboratory technician can predictably overlay the digitized interim casts to allow for cross-articulation and proceed with designing and fabricating the definitive restorations.

The Role of Digital 3D Scanned Models in Dental Students' Self-Assessments in Preclinical Operative Dentistry.

The aim of this study was to determine how dental student self-assessment and faculty assessment of operative preparations compared for conventional visual assessment versus assessment of scanned digital 3D models. In 2016, all third-year students in the Class of 2018 (N=35) at Harvard School of Dental Medicine performed preclinical exams of Class II amalgam preparations (C2AP) and Class III composite preparations (C3CP) and completed self-assessment forms; in 2017, all third-year students in the Class of 2019 (N=34) performed the same exams. Afterwards, the prepared typodont teeth were digitally scanned. Students self-assessed their preparations digitally, and four faculty members graded the preparations conventionally and digitally. The results showed that, overall, the students assessed their preparations higher than the faculty assessments. The mean student-faculty gaps for C2AP and C3CP in the conventional assessments were 11% and 5%, respectively. The mean digital student-faculty gap for C2AP and C3CP were 8% and 2%, respectively. In the conventional assessments, preclinical performance was negatively correlated with the student-faculty gap (r=-0.47, p<0.001). The correlations were not statistically significant with the digital assessments (p=0.39, p=0.26). Students in the bottom quartile significantly improved their self-assessment accuracy using digital self-assessments over conventional assessments (C2AP 10% vs. 17% and C3CP 3% vs. 10%, respectively). These results suggest that digital assessments offered a significant learning opportunity for students to critically self-assess themselves in operative preclinical dentistry. The lower performing students benefitted the most, improving their assessment ability to the level of the rest of the class.