Sub-atmospheric Pressures and Forces Recorded from the Labio-Buccal Surfaces of Teeth during Swallowing in Adult Males

In order to assess whether, during physiological activity, the cheeks and lips exert direct force on the teeth or whether they are sucked in by negative intra-oral pressures concurrent measurements were made of the force from the lips and cheeks and the barometric pressures in the same areas. The areas studied were the maxillary and mandibular right central incisor and the first molar regions in ten adult male subjects. The activities studied were saying the letter “M”, swallowing 3 ml of water and swallowing on command. The letter “M” produced coincident increases in pressure and force, but on many occasions, swallowing resulted in an increase in force being accompanied by a sustained decrease in pressure below the atmospheric level. It is concluded that increases in force on the labio-buccal surfaces of teeth which follow swallowing, reported Previously, may be due in some subjects to sucking in of the lips and cheeks.