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.
1 It can cost $200-$500 for a solid wood door, and $500-$1,000 or more for a more decorative interior door in high-end wood like walnut or mahogany.2  For example, Lowe's store brand ReliaBilt 30. 3  Wide 6-Panel Hollow Composite Door Slab costs about $33. It can cost $200-$500 for a solid wood door, and $500-$1,000 or more for a more decorative interior door in high-end wood like walnut or mahogany.