Abstract: A steel for a gear includes, based on a total weight of the steel: C: 0.10-0.30 wt %, Si: 0.60-0.80 wt %, Mn: 0.25-0.75 wt %, Cr: 1.80-2.20 wt %, Ni: 0.50-1.50 wt %, Mo: 0.20-0.40 wt %, Nb: 0.025-0.050 wt %, V: 0.030-0.050 wt %, and a balance of Fe and inevitable impurities, wherein contents of Nb and V satisfy the following <Relationship Formula 1>: 0.055<[Nb]+[V]<0.100??<Relationship Formula 1>, wherein [Nb] represents a content of Nb and [V] represents a content of V.

Abstract: Disclosed is a dental model articulator configured to combine maxillary and mandibular dental model casts with each other. The dental model articulator includes a frame, an arm member rotatably and reciprocatively supported to the frame, an elastic bias unit frontward elastically pressing the arm member with respect to the frame, a first connecting unit formed in the arm member to be connected with the maxillary dental model cast, and a second connecting unit connected to the frame to move reciprocatively through at least one penetration hole and combined with the mandibular dental model cast.

Abstract: Disclosed is a dental model articulator configured to combine maxillary and mandibular dental model casts with each other. The dental model articulator includes a frame, an arm member rotatably and reciprocatively supported to the frame, an elastic bias unit frontward elastically pressing the arm member with respect to the frame, a first connecting unit formed in the arm member to be connected with the maxillary dental model cast, and a second connecting unit connected to the frame to move reciprocatvely through at least one penetration hole and combined with the mandibular dental model cast.