William R. Proffit

Linguopalatal pressure in children

I t. is clear that tongue function plays some role in the devc~lopment of the dental arches. The distortions of the arches which accompany microor macroglossia, as well as the less dramatic but clinically significa.nt effects of such oral habits as tongue-thrusting, illustrate the possible effects. Theories of normal and abnormal oral development, particularly those concerning the functional matrix concepts of van der Klaauw and MOSS,~ have emphasized muscle function in recent years. This may reflect a return toward a middle ground after overemphasis on function in the 1920’s and relative neglect in the 1940’s. Several investigators have now presented data concerning lingual, labial, and buccal pressures against the dentition of youn g adults, using electronic pressure-recording techniyues.‘-4 Lear’s” recent work has confirmed the belief of most workers that it is not possible to demonstrate a true balance of cstcrnal forces on stable adult dentitions. In ordrr to study more closely the relationship between lingual function and dental arch development in growing chiltlrcn, mc began a longitudinal study of a group of 5 to 8-year-old children 2 years ago. This article presents the first data concerning linguopalatal pressures in this age group and discusses the implications of these initial findings with regard to dental arch development..

Inhibition of Bone Growth in vitro by Endotoxin: Histamine Effect

BECAUSE bacteria are found in close proximity to soft tissue and bone in the oral cavity, it seems logical that bacterial endotoxin could affect the metabolism of bone and contribute to the bone loss seen in periodontal disease. We investigated the effects of bacterial endotoxins on rapidly growing bone in an organ culture system. Also, because there is evidence that histamine affects the activity of endotoxin1–3, we cultured bones in an environment containing both endotoxin and histamine, and found that synthesis of structural protein was inhibited without affecting cell turnover.

Lingual and Intraoral Air‐Pressure Variations as a Function of Vocal Intensity

The relationship between tongue pressure and intraoral air pressure during variations in vocal intensity was investigated. Simultaneous recordings of the two intraoral pressures were collected during the phonations of nine young adult males repeating syllables at three distinct vocal intensity levels. Both intraoral pressures were shown to increase as the subjects increased their vocal level from low to medium to high. These results demonstrate that an interaction between tongue activity and respiratory air flow occurs, which accounts for variations in intraoral air pressure during changes in vocal intensity. These data when combined with previously reported data for consonants demonstrates the relationship between air pressure and tongue pressure.