Abstract
We have previously demonstrated that the head moves rhythmically and coordinately with the mandible during functional mandibular movements; however, in those studies we could not provide information on the movement of the head as a whole because only the mandibular and maxillar incisal points were tracked. The objective of the present study was to assess sagittal head movement through analysis of the vectors of several reference points in the head and a mandibular incisal point during open-close tapping movements of different frequency.
The same 6-degree-of-freedom measuring device employed in our previous studies was used again to analyze data from four male adults, age 26-27 years old.
Results:
1) During mandibular tapping movement, head reference points moved in a rotation-like movement; i.e., during opening the head moved clockwise and counter-clockwise during closing in the left side's sagittal plane.
2) There were no significant differences of angulation of the vectors between 1 Hz tapping movement and 3 Hz in all reference points. However, the range of motion of all reference points depended on the frequency of tapping movements in this case. The motion of the 1Hz tapping movement was larger than the 3 Hz one.
3) The hypothetical rotation center was located above the cervical vertebrae, and its sagittal position was dependent on each tapping movement.
