Comparing the accuracies of freehand, static computer-assisted and robot-assisted dental implant placements: an in vitro study.

OBJECTIVE: To compare the accuracies among three oral implant surgical techniques: freehand (FH), static computer-assisted implant surgery (sCAIS), and robotic computer-assisted implant surgery (rCAIS). METHODS: The polyurethane and bovine femur implant models were fabricated, and 126 and 96 implant sites were designed on them. The implant sites were divided into three groups: FH, sCAIS, and rCAIS, according to the implantation method. The deviation between the actual implant position and the planned position was analyzed and compared by cone beam computed tomography. RESULTS: In the polyurethane model test, the entry deviation, entry-level deviation, apical deviation, apical level deviation, and angle deviation in sCAIS and rCAIS groups were significantly reduced compared with those in the FH group (P<0.05). No significant differences were observed in all kinds of deviations between the sCAIS and rCAIS groups (P>0.05). In the bovine femur model test, the entry deviation, entry-level deviation, apical deviation, apical level deviation, and angle deviation in both sCAIS and rCAIS groups were significantly reduced compared with those in the FH group (P<0.05). No significant differences were observed in all kinds of deviations between the sCAIS and rCAIS groups (P>0.05). CONCLUSION: This in vitro study shows that the rCAIS technique is superior to the freehand, but has the same accuracy as the sCAIS.

Nitrogen and Phosphorus Dual-Coordinated Single-Atom Mn: MnN2P Active Sites for Catalytic Transfer Hydrogenation of Nitroarenes.

The coordination environment of atomically metal sites can modulate the electronic states and geometric structure of single-atom catalysts, which determine their catalytic performance. In this work, the porous carbon-supported N, P dual-coordinated Mn single-atom catalyst was successfully prepared via the phosphatization of zeolitic imidazolate frameworks and followed by pyrolysis at 900 °C. The optimal Mn1-N/P-C catalyst with atomic MnN2P structure has displayed better catalytic activity than the related catalyst with Mn-Nx structure in catalytic transfer hydrogenation of nitroarenes using formic acid as the hydrogen donor. We find that the doping of P source plays a crucial role in improving the catalytic performance, which affects the morphology and electronic properties of catalyst. This is the first Mn heterogeneous catalyst example for the reduction of nitroarenes, and it also revealed that the MnN2P configuration is a more promising alternative in heterogeneous catalysis.