RESUMEN

PURPOSE: To assess the implant-abutment discrepancy of complete-arch frameworks manufactured using milling and additive electron beam melting (EBM) technologies, before and after acrylic resin veneering application. MATERIALS AND METHODS: A definitive implant cast with six implant replicas was digitized using a laboratory scanner. A software program was used to design an implant-supported framework which was manufactured using milling (M group) and EBM (EBM group) technologies (n = 10). In the M group, titanium milled specimens were fabricated. In the EBM group, titanium EBM specimens were obtained. A coordinate measurement machine (CMM) was used to assess the implant-abutment discrepancy at x-, y-, and z-axed between the specimens and the implant-abutment replicas of the definitive cast. The implant replicas positioned on the lateral incisor positions were not able to be assessed. The 3D gap discrepancy was calculated: 3 D = x 2 + y 2 + z 2 $3D\ = \sqrt {{x^2} + {y^2} + {z^2}}$ . Acrylic resin veneering procedures were finished and the same CMM measurements were completed. Three-way analysis of variance (ANOVA) test was used to analyze the data (α = 0.05). RESULTS: The manufacturing method (df = 1, F = 7.00, p = 0.009) and implant position (df = 3, F = 129.82, p < 0.001) were significant predictors of the x-axis discrepancy. The veneering procedures (df = 1, F = 21.55, p < 0.001) and implant position (df = 3, F = 95.42, p < 0.001) were significant predictors of the y-axis discrepancy. The manufacturing method (df = 1, F = 11.79, p = 0.001) was a significant predictor of the z-axis discrepancy. Lastly, the manufacturing method (df = 1, F = 5.11, p = 0.026), implant position (df = 3, F = 11.36, p < 0.001), and veneering procedures (df = 1, F = 41.56, p < 0.001) were significant predictors of the 3D gap discrepancy in which the manufacturing method explains the 2.37% of variation in the 3D gap discrepancy, the implant position explains the 15.82% of variation in the 3D gap discrepancy, and veneering procedures explain the 19.29% of variation in the 3D gap discrepancy results. CONCLUSIONS: The manufacturing methods, veneering procedures, and implant position influenced the linear implant-abutment discrepancy. The milled technique tested obtained lower linear implant-abutment discrepancy compared with the EBM method evaluated. The acrylic resin veneering procedures increased the implant-abutment discrepancy.

Asunto(s)

Implantes Dentales , Titanio , Resinas Acrílicas , Diseño Asistido por Computadora , Prótesis Dental de Soporte Implantado , Electrones

RESUMEN

High-precision indoor localisation is becoming a necessity with novel location-based services that are emerging around 5G. The deployment of high-precision indoor location technologies is usually costly due to the high density of reference points. In this work, we propose the opportunistic fusion of several different technologies, such as ultra-wide band (UWB) and WiFi fine-time measurement (FTM), in order to improve the performance of location. We also propose the use of fusion with cellular networks, such as LTE, to complement these technologies where the number of reference points is under-determined, increasing the availability of the location service. Maximum likelihood estimation (MLE) is presented to weight the different reference points to eliminate outliers, and several searching methods are presented and evaluated for the localisation algorithm. An experimental setup is used to validate the presented system, using UWB and WiFi FTM due to their incorporation in the latest flagship smartphones. It is shown that the use of multi-technology fusion in trilateration algorithm remarkably optimises the precise coverage area. In addition, it reduces the positioning error by over-determining the positioning problem. This technique reduces the costs of any network deployment oriented to location services, since a reduced number of reference points from each technology is required.

RESUMEN

Customized manufacturing of a miniaturized device with micro and mesoscale features is a key requirement of mechanical, electrical, electronic and medical devices. Powder-based 3D-printing processes offer a strong candidate for micromanufacturing due to the wide range of materials, fast production and high accuracy. This study presents a comprehensive review of the powder-based three-dimensional (3D)-printing processes and how these processes impact the creation of devices with micro and mesoscale features. This review also focuses on applications of devices with micro and mesoscale size features that are created by powder-based 3D-printing technology.