Movements of soft tissues surrounding the oral cavity, especially lips and cheeks, have a great influence on the masticatory and the phonetic functions. These movements could indicate the state of harmony between a denture and the soft tissues and the muscles surrounding it.
The purpose of this study was to investigate the movements of the facial surface during oral functions by applying 35mm nonmetric SLR camera as a three dimensional measurement system.
Total of 101 subjects with normal range occlusion were selected. Forty-one selected points were placed on the skin surface of the face of each subject. The movements of these points under the condition of thrusting lips, pulling mouth corners backward, intentional occlusion and smile were measured in three dimensions.
The findings were as follows;
1. This three dimensional measurement system was applicable to study the movements of facial surface.
2. The mouth corner points showed the greatest and the most characteristic movement among 41 points.
3. The significant correlation was indicated between the movement of the mouth corner point and the movements of most of other points. This suggested that the mouth corner point could indicate the movements of the facial surface most significantly.