Articulators hold upper and lower casts in a fixed spatial relationship and simulate jaw movements — protrusive, lateral, and hinge motion — so technicians can design restorations that respect a patient's natural occlusion. Facebows record the maxillary arch's relationship to the temporomandibular hinge axis and transfer this measurement to the articulator, so mounted casts replicate the patient's true bite dynamics. Together they support crown, bridge, denture, and orthodontic appliance fabrication by helping technicians identify and correct occlusal interferences before a restoration reaches the patient's mouth, reducing chairside adjustment time.