An analysis of mandibular incisor and condylar paths during maximum jaw opening and closing movement in subjects with normal occlusion

• Published in: The Journal of Japanese Society of Stomatognathic Function Vol. 5; no. 1; pp. 11 - 20
• Main Authors: Wakimoto, Yasuo, Kuwahara, Yosuke, Fukui, Tadayoshi, Tsuruta, Masahiko, Tokiwa, Hajime, Hiromatsu, Shinichi
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Stomatognathic Function 30.09.1998
• Subjects: condylar path; incisor path; mandibular kinetics; normal occlusion; velocity curve
• ISSN: 1340-9085; 1883-986X
• DOI: 10.7144/sgf.5.11

The aim of this study was to analyze the mandibular movement paths in subjects with normal occlusion. Fourteen adults who were free of signs and symptoms of TMJ disorders were selected. The movements of the incisal point and condylar point during maximum jaw opening-closing phase were recorded and analyzed with the Gnathohexagraph, JM-1000, a comprehensive analyzing system for stomatognathic function. The movement paths of the incisor and condyles were analyzed for: (1) Maximum displacement, (2) maximum velocity, (3) the amount and rate of displacement reached to the maximum velocity, (4) pattern of velocity curve. Maximum displacements of incisor and condylar paths were 50.2mm and 15.5mm, respectively. Maximum velocities of incisor movements during opening and closing phases were 289.6mm/s and 330.6mm/s and those of condylar movement were 90.8mm/s and 160.6mm/s, respectively. The amount and rate of displacement reached to the maximum velocities of incisor movement during the two phases were 16.1mm (32.1%) and 25.5mm (52%) . Those of condylar movement were 9.5mm (59%) and 8.1mm (52%), respectively. Three patterns of velocity curves were found in both incisor paths and condylar paths. The results of this study indicated that the analyzing parameters for incisor movement path and condylar movement path of this study might be useful for mandibular kinetics.