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.
Composite Doors. Composite doors are made from a selection of materials including wooden or steel cores, glass reinforced plastic (GRP), foam as well as uPVC. This is so the end user can enjoy features including: Pros. 1  Security â a sturdy door frame and tough materials to form the door make for a rigid entry system.omposite Doors. Composite doors are made from a selection of materials including wooden or steel cores, glass reinforced plastic (GRP), foam as well as uPVC. This is so the end user can enjoy features including: Pros. 1  Security â a sturdy door frame and tough materials to form the door make for a rigid entry system.