Biomechanics of the Temporomandibular Joint

*Pablo Andrés Crespo Reinoso, Emilio Ruiz Delgado and James Jerez Robalino*

## **Abstract**

Biomechanics is the study of mechanics applied to living beings, it analyzes loads, stress, tension, movement, size, shape, and structure of the body. The temporomandibular joint in physiological states is subject to the interaction of various bone (jaw and temporal), nervous, cartilaginous, and muscular components. When there is an alteration in any of the components, normal biomechanics are affected. Knowing in detail how each element works individually and is essential for the diagnosis and treatment of the different pathologies of the temporomandibular joint. The reconstructive procedures must carefully assess all these factors to achieve long-term success. The purpose of this chapter is to analyze the temporomandibular joint encompassing anatomy, physiology with a biomechanical approach for its diagnosis and treatment.

**Keywords:** temporomandibular joint, temporomandibular biomechanics, temporomandibular anatomy, temporomandibular physiology

## **1. Introduction**

The temporomandibular joint (TMJ) can be classified by its function and by its anatomy. Functionally it is ginglymoarthrodial, a term derived from ginglymus, meaning a hinge joint, allowing movement only forwards and backwards in one plane, and arthrodial, meaning a joint allowing sliding movement of surfaces [1]. Anatomically, it is a diarthrodial joint, defined as the discontinuous articulation of two bones that allow freedom of movement. The movement of the TMJ is dictated by muscles and limited by ligaments, its capsule of fibrous connective tissue is innervated, vascularized and strongly attached to the joint surfaces. It is also a synovial joint, whose fluid acts as a joint lubricant and supplies its metabolic and nutritional needs [2]. When occluding the mandible, it will be subjected to loads, a unilateral occlusion will result in load peaks at the contralateral TMJ. In addition, the condyle is an adaptable and regenerative unit with the ability to maintain functions despite trauma and degenerative changes [3]. The TMJ is the only joint in the human body that houses a growth center, resulting in the perpetual need for the left and right joints to work coordinated [4].

Biomechanics is the study of mechanics applied to living beings, it analyzes loads, efforts, tension, movement, size, shape and structure of the body. The temporomandibular joint is subject to forces produced by the masticatory muscles and the occlusion stress that is supported by the teeth [3]. In addition, it analyzes and helps understand the interaction of form, function and mechanism of the temporomandibular disorders to prevent, diagnose and cure these disorders [5]. A total joint replacement should function as close to a healthy joint as possible. It must be able to withstand the same forces and must produce the same movements as a normal joint [6].
