Background Recently developed imaging techniques, such as cone beam computed tomography (CBCT) and CAD/CAM technology, have facilitated reliable implant planning and implant surgical guide production by 3D printing. This study compared the accuracy of implant-guided surgery using the R2GATE® program with CBCT before and after surgery. Patients and methods The study included patients who visited the Department of Oral and Maxillofacial Surgery at Chonnam National University Hospital from September 2021 to March 2022. Twenty-four implants were placed in eleven patients. Using R2GATE® Windows (Megagen implant, Daegu, Korea) software, implant placement was planned. The difference was measured by the CBCT before and after surgery. The cervical and apical distance and angular deviation of the implants were measured. Statistical analysis was performed using an independent t-test, Pearson correlation, and multiple regression analyses. Results The three-dimensional linear distance difference between the planned implant and the placed implant was 0.97 ± 0.37 mm at the cervical and 1.13 ± 0.36 mm at the apical. The difference in angle deviation between the planned implant and the placed implant was 3.42 ± 2.12°. Among the variables affecting the accuracy of implant placement, a statistically significant difference was found when using a tissue-supported implant guide, implant diameter and implant length. Conclusion Based on these results, using the R2GATE® program is useful to use an implant digital surgical guide, and it will be used in various clinic.

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Magnetic induction and resonance wireless power charging generally operates in a high frequency range, and its efficiency is degraded by the generation of heat at high frequency. This makes it necessary to develop new soft magnetic materials capable of maintaining their characteristics even at high frequency. The purpose of this study is to minimize the heat generated by the eddy currents when charging, and to improve the charging efficiency under an alternating magnetic field. In this study, Fe-Si-B alloys containing Cu, Zr and Ca elements were melt-spun to prepare amorphous ribbons. The amorphous ribbons were heat treated to crystallize nanograins, The structure was analyzed by TEM and EELS, As a result, it was found that Zr was distributed mainly at the grain boundaries after heat treatment, whereas Ca was uniformly distributed only along the grain boundaries. It could be concluded that the Ca and Zr elements effectively suppressed the grain growth, and thus maintained the very fine nanograin structure.

We have developed a flexible image sensor using hydrogenated amorphous silicon thin film transistor (a‐Si:H TFT) on metal foil. The metal foil was treated by electrolytic polishing and thus its RMS surface roughness was reduced from 1205 to 71.6 Å. The sensor has 160 × 128 pixels, where a pixel has one switching TFT, one sensor TFT and a storage capacitor. A clear image was demonstrated on the metal foil using conventional pixel having two transistors and one cap.

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