Review Article DOI: 10.18231/2455-8486.2017.0013 Annals of Prosthodontics & Restorative Dentistry, April-June 2017:3(2):57-59 57 Mandibular Movements: Record and analysis from time immemorial Archana Nagpal 1 , Surbhi Abrol 2,* , Karan Duvedi 3 , Yamini Ruthwal 4 , Payal Kashyap 5 1 Professor, 2,3,4,5 PG Student, Dept. of Prosthodontics, HDC, Sundernagar, Himachal Pradesh *Corresponding Author: Email: drsurbhi.abrol90@gmail.com Introduction We are blessed with a dynamic masticatory system which allows us to function and exist. It is a highly intricate unit and primarily related to chewing, speech and swallowing. The ever so delicate balance between the various components of the system is monitored by the neuromuscular control. (1) Maxillo-mandibular relationships establishment has got the attention of prosthodontists ever since the dynamic and static positions of the condyles in the glenoid fossa were interpreted and understood. In an edentulous patient, the teeth along with periodontal nerves are lost. Mandibular movement is defined as “any movement of the lower jaw” and is determined by the simultaneous activities of the TMJ. The form of the bilateral temporomandibular joints and their function facilitate the mandible in making a variety of movements mainly carried out in three different planes namely the sagittal, the frontal and the horizontal planes. Mainly these movements produce rotational (turning) and translational (sliding) motions. The rotatory or the hinge like movement occurs between the condyle and the articular disc. Basically, there are a couple of movements of the mandible:  The functional movements which are characteristic naturally occurring movements that occur during mastication, speaking and yawning.  The parafunctional movements which are non- characteristic movements like clenching, tapping etc. The maximum movement in a plane or direction is termed the border movement. There is a wide range of movement called intraborder movement that occurs within the confines of the border movements. Border movements are reproducible. Hence, they can be measured mechanically. Intraborder movements cannot be measured with accuracy as they are not reproducable. Just a precise mandibular movement is required to move the teeth efficiently across each other. It is, therefore, very important for a clinician to know thoroughly the various movements of the mandible. History A lot of research and studies have been conducted to study the movements of the mandible right from 18 th century. Phillip Pfaff [1756] (2) studied mandibular movements and designed plaster articulator known as slab articulator. Jb Gariot [1805] (3) stated that mandible moves in a hinge like fashion and designed the “Hinge joint articulator “to simulate mandibular movements. WGA Bonwill[1858] (2) designed and developed the first articulator with a effort to mimics the mandibular movements in eccentric positions. He gave the equilateral triangle theory, in which there was a distance of 4 inches between the condyles and between each condyle and incisor point. It was proposed that the teeth movement is in relation to each other guided by the condylar controls and the incisal point. It is known “Bonwill theory of occlusion.” Gilmor [1862] proposed individual orientation on an articulator by the measurement of individual distances between the joints and the incisors. Hayes [1889] (2) noticed the condylar path and introduced sloping joint paths in an articulator. Later, Snow [1889] introduced “face bow “for the reproduction of the upper jaw position with respect to the condyles and Luce (5) photographed the sunlight reflection from beads placed opposite to the condyles in the same year. WE Walker [1896] (5) stated that the absence of condylar inclination is the dictating factor and said that the dentures balanced using Bonwill’s articulator did not balance in the mouth. He gave “facial clinometer" for the measurement of the condylar movements. In the beginning of the 20 th century, Norman Bennett [1908] (5) traced the light pathway positioned opposite the condyles. He gave a direct immediate shift of the working side condyle known as Bennett shift as he studied the lateral mandibular movements. He also gave a Bennett angle on the balancing side [angle between sagittal axis and medial movement of balancing condyle]. Alfred Gysi of Zurich [1908] devised Gysi adaptable articulator having the condyles at lower member, condylar paths inclined at 30 degree, and incisal guidance fixed at 60degree. Later in 1914, “Gysi simplex articulator” (3) was introduced as an mean value articulator which has fixed condylar guidance at 33 degree. RE Hall [1915] devised “Hall automatic articulator” based on conical theory of occlusion. This theory stated that lower teeth move over the surfaces of upper teeth as over the surface of a cone, producing an angle of 45 degree having the central axis of the cone tipped 45 degree to the occlusal plane. A maxillo- mandbular instrument based upon spherical theory of occlusion was given by GS Monson [1918] which said that the lower teeth move over the surface of upper teeth as over the surface of a sphere with a Diameter of 8 inches (20cm). The center of the sphere was situated