Analysis of Occlusal Parameters and of the Jaw Jerk in Healthy Subjects and in Patients Affected by TMJ Pain-Dysfunction Syndrome

Temporomandibular joint (TMJ) pain-dysfunction syndrome is considered a multifactorial pathology and many researchers have attempted to elucidate possible causes of occlusion that contribute to this pathology. Many authors 1-4 have observed that there are abnormalities in the masticatory patterns of TMJ patients, but because current investigative methods lack standardization we cannot yet explain the physiopathologic mechanism of such differences. Bird5 showed in an animal study that the speed of the opening-and-closing phase changes continually and not only in the occlusal phase. Many investigation methods have been proposed including radiographic examination, magnetic resonance analysis, pantographic examination, axiographs of functional traces, and kinesiographic research using electrognathograph. All these methods have technical limits that have been analyzed and discussed at length by various authors.6-8 Electrognathography has the advantage of reducing the intraoral disturbances to a minimum, but has the limitation of not reproducing mandibular torsion.9 Our aim was to analyze certain occlusal parameters and correlate them with the biomechanical and neuromuscular systems in order to construct a hypothesis on the possible physiopathologic mechanisms.