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 A basic knob and lock set costs $50 to $100; designer exterior door hardware costs more. 2  Exterior door installation is a manageable DIY project. 3  However, an exterior door install for solid-wood doors, sliding glass doors or French doors can be quite complicated. 4  Below are some links for how to install exterior door: Home exterior doors make a statement, as they are one of the first things people will notice about your house. 2  Wood is the most popular choice for an exterior front door. 3  An exterior wood door made of wood veneer and engineered wood costs around $200 to $500.