Semi-adjustable articulator with mounted casts. An articulator is a mechanical device used in dentistry to which casts of the maxillary (upper) and mandibular (lower) teeth are fixed, reproducing recorded positions of the mandible in relation to the maxilla.
The Greek scholar Heron of Alexandria created the earliest known automatic door in the 1st century AD during the era of Roman Egypt. The first foot-sensor-activated automatic door was made in China during the reign of Emperor Yang of Sui (r. 604â618), who had one installed for his royal library.
'It's never had to have any sort of maintenance and the only thing that's ever gone is the lightbulb for the door,' added Mr Stephens. The world's first microwave oven was built in America in 1947 by technology firm Raytheon, which filed the first patent after employee Percy Spencer made the breakthrough.