Lubrication of the Temporomandibular Joint

Abstract

Although tissue engineering of the temporomandibular joint (TMJ) structures is in its infancy, tissue engineering provides the revolutionary possibility for treatment of temporomandibular disorders (TMDs). Recently, several reviews have provided a summary of knowledge of TMJ structure and function at the biochemical, cellular, or mechanical level for tissue engineering of mandibular cartilage, bone and the TMJ disc. As the TMJ enables large relative movements, joint lubrication can be considered of great importance for an understanding of the dynamics of the TMJ. The tribological characteristics of the TMJ are essential for reconstruction and tissue engineering of the joint. The purpose of this review is to provide a summary of advances relevant to the tribological characteristics of the TMJ and to serve as a reference for future research in this field. This review consists of four parts. Part 1 is a brief review of the anatomy and function of the TMJ articular components. In Part 2, the biomechanical and biochemical factors associated with joint lubrication are described: the articular surface topology with microscopic surface roughness and the biomechanical loading during jaw movements. Part 3 includes lubrication theories and possible mechanisms for breakdown of joint lubrication. Finally, in Part 4, the requirement and possibility of tissue engineering for treatment of TMDs with degenerative changes as a future treatment regimen will be discussed in a tribological context.

Biomechanics of the Temporomandibular Joint

“…The articular surfaces of the condyle and the fossa are covered with cartilage (Ide et al, 1991). The disc divides the joint cavity into two compartmentssuperior and inferior (Ide et al, 1991;Tanaka et al, 2008b). The two compartments of the joint are filled with synovial fluid which provides lubrication and nutrition to the joint structures (Tanaka et al, 2008b).…”

“…The disc divides the joint cavity into two compartmentssuperior and inferior (Ide et al, 1991;Tanaka et al, 2008b). The two compartments of the joint are filled with synovial fluid which provides lubrication and nutrition to the joint structures (Tanaka et al, 2008b). The disc distributes the joint stresses over broader area thereby reducing the chances of concentration of the contact stresses at one point in the joint.…”

“…The disc distributes the joint stresses over broader area thereby reducing the chances of concentration of the contact stresses at one point in the joint. The presence of the disc in the joint capsule prevents the bone-on-bone contact and the possible higher wear of the condylar head and the articular fossa Tanaka et al, 2008b). The bones are held together with ligaments.…”

“…TMD is seen most commonly in people between the ages of 20 and 40 years, and occurs more often in women than in men (Detamore and Athanasiou, 2003;Detamore et al, 2007). Some surveys have reported that 20-25% of the population exhibit symptoms of TMD while it is estimated that 30 million Americans suffer from it, with approximately one million new patients diagnosed yearly (Detamore and Athanasiou, 2003;Detamore et al, 2007;Tanaka et al, 2008b;Wolford, 1997). Disc displacement is the most common TMJ arthropathy and is defined as an abnormal relationship between the articular disc and condyle (Tanaka et al, 2000).…”

Differential Regulation of Proteoglycan-4 Expression by IL-1.ALPHA. and TGF-.BETA.1 in Rat Condylar Chondrocytes

“…To maintain these functions during the lifetime, the fundamental biomechanical mechanisms must exist to protect cartilage by minimizing various damages. Compelling evidence has demonstrated that boundary lubrication of articular cartilage plays key roles in reducing shearing and friction coefficient of cartilage surfaces (Tanaka et al 2008b). However, such joint protection conferred by this mode of lubrication is imperfect and insufficient for optimal functionality of TMJ as evidenced by the common prevalence of osteoarthritis in human population.…”