The effect of extreme vertical overlap on masticatory strokes

Abstract

Cinefluorographic studies of the direction of jaw movement during mastication were made of a group of subjects who had a severe vertical overlap of the anterior teeth. The results indicated that: 1. Mandibular movements in a vertical direction were seldom found in 1,048 masticatory cycles in 8 subjects. 2. The smallest percentage of masticatory strokes in a vertical direction occurred with a tough fibrous food. 3. Chewing was completely unilateral and confined to the left side in 5 subjects. 4. Considerable mastication occurred bilaterally in 2 subjects. 5. Masticatory strokes in a vertical direction were not required when chewing occurred on both sides, simultaneously. 6. Chewing in a vertical direction did not seem to be a causative factor in the development of extreme vertical overlap of anterior teeth or in prevention of periodontal disturbances in these subjects. Cinefluorographic studies of the direction of jaw movement during mastication were made of a group of subjects who had a severe vertical overlap of the anterior teeth. The results indicated that: 1. Mandibular movements in a vertical direction were seldom found in 1,048 masticatory cycles in 8 subjects. 2. The smallest percentage of masticatory strokes in a vertical direction occurred with a tough fibrous food. 3. Chewing was completely unilateral and confined to the left side in 5 subjects. 4. Considerable mastication occurred bilaterally in 2 subjects. 5. Masticatory strokes in a vertical direction were not required when chewing occurred on both sides, simultaneously. 6. Chewing in a vertical direction did not seem to be a causative factor in the development of extreme vertical overlap of anterior teeth or in prevention of periodontal disturbances in these subjects.