The Intra-articular Distance within the TMJ during Free and Loaded Closing Movements

Abstract

Previous studies on free opening and closing movements of the mandible have demonstrated that the opening movement traces of the condylar kinematic center (i.e., the condylar point for which the protrusive and the opening movement traces coincide) lie closer to the articular eminence than the closing traces. This indicates the presence of an intra-articular distance within the joint during free closing. Since the mandible behaves like a class III biomechanical lever, a counteracting mechanical load on the mandible during closing will press the condyle-disc complex against the articular eminence. Therefore, in this study the hypothesis was tested that the difference between opening and closing movement traces of the kinematic center is reduced when the closing movements are counteracted by a mechanical load. From 10 healthy participants, 20-second movement recordings were obtained by a six-degrees-of-freedom opto-electronic jaw movement recording system (OKAS-3D) for three types of movements: (1) free opening and closing movements, (2) free opening and loaded closing movements (i.e., the participants closed against a small or high manually applied downward-directed force to the chin), and (3) gum chewing. Off-line, the opening and closing movement traces of the kinematic center were reconstructed, and the average difference between the traces (the intra-articular distance) was calculated. The average intra-articular distance was significantly smaller during loaded closing than during free closing, whereas no significant differences were found in the intra-articular distances between the loaded situations of low and high manual loading and contralateral chewing (ANOVA and post hoc Bonferroni multiple comparisons of means test, p < 0.005). In conclusion, loading of the mandible during closing movements reduces the intra-articular distance within the temporomandibular joint.

Keywords

kinematic center temporomandibular joint condylar movements loading intra-articular distance.

Get full access to this article

View all access options for this article.

References

Catiç A. , Naeije M. (1999). Location of the hinge axis and the kinematic center in asymptomatic and clicking temporomandibular joints. J Oral Rehabil 26:661-665.

DuBrul EL (1988). Oral anatomy. St. Louis, MO: Ishiyaku EuroAmerica, pp. 107-132.

Gibbs CH , Lundeen HC (1982). Jaw movements and forces during chewing and swallowing and their clinical significance. In: Advances in occlusion . Lundeen HC , Gibbs CH , editors. Boston: John Wright , pp. 2-32.

Kohno S. (1968). A study on condylar movements with reference to the mandibular movement in the sagittal plane; analysis of sagittal axis with the multiple electronic flush apparatus. J Jpn Prosthet Soc 12:350-380.

Koolstra JH , Van Eijden TM (1997). The jaw open-close movements predicted by biomechanical modelling. J Biomechan 30:943-950.

Krebs M. , Gallo LM , Airoldi RL , Meier D. , Boesiger P. , Palla S. (1994). Three-dimensional animation of the temporomandibular joint. Technology and Health Care 2:193-207.

Krebs M. , Gallo LM , Airoldi RL , Palla S. (1995). A new method for three-dimensional reconstruction and animation of the temporomandibular joint. Ann Acad Med Singapore 24:11-16.

Naeije M. , Van der Weijden JJ , Megens CC (1995). OKAS 3D: an opto-electronic jaw movement analysis system with six degrees of freedom. Med Biol Eng Comput 33:683-688.

Osborn JW (1989). The temporomandibular ligament and the articular eminence as constraints during jaw opening. J Oral Rehabil 16:323-333.

10.

Osborn JW (1993). A model to describe how ligaments may control symmetrical jaw opening movements in man. J Oral Rehabil 20:585-604.

11.

Palla S. , Krebs M. , Gallo LM (1998). Jaw tracking and temporomandibular joint animation . In: Science and practice of occlusion. McNeill C , editor. Chicago: Quintessence Publishing Co., pp. 365-378.

12.

Peck CC , Murray GM , Johnson Cwl , Klineberg IJ (1997). The variability of condylar point pathways in open-close jaw movements. J Prosthet Dent 77:394-404.

13.

Proschel P. , Feng H. , Ohkawa S. , Ott R. , Hofmann M. (1993). Untersuchung zur Interpretation des Bewegungsverhaltens kondylarer Punkte. Dtsch Zahnärztl Z 48:323-326.

14.

Visscher CM , Huddleston Slater Jjr , Lobbezoo F. , Naeije M. (1999). Kinematics of the human mandible for different head postures. J Oral Rehabil (in press).

15.

Yatabe M. , Zwijnenburg A. , Megens CC , Naeije M. (1995). The kinematic center: a reference for condylar movements. J Dent Res 74:1644-1648.

16.

Yatabe M. , Zwijnenburg A. , Megens CC , Naeije M. (1997). Movements of the mandibular condyle during jaw opening and closing. J Dent Res 76:714-719.

17.

Zwijnenburg A. , Megens Ccej , Naeije M. (1996). Influence of choice of reference points on the condylar movement paths during mandibular movements. J Oral Rehabil 23:832-837.