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. Difference between slab doors and pre-hung doors. A slab door is just that: a door. It doesn't come with a handle, hinges or a latch. It can be hollow core or solid wood, and it is the responsibility of the homeowner or installer to choose the proper hardware and mount it correctly. Slab doors offer essentially a blank slate: Everything but the door type is malleable. RELATED: 5 Tips for Replacing Interior Doors. Pre-hung doors come with the frame already attached to a slab, as well as hardware and hinges. The door could be opened and closed if it's propped up â but this is a bad idea.