الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
 |  | from | 138 |  |  |
| | | from | 138 | | |
Abstract
Keith (1925) compared the people of the Neolithic period with the
present population of Britain and found that there was a tendency in
modem people to crowding and irregularities of the teeth, and to
narrowing and elongation of the face. The nose looked narrow and the
palate contracted and the vault was high. The teeth were not worn down
as in Neolithic men, they were very liable to be attacked by caries.
The front teeth, when the jaws were closed, did not meet edge to edge as
in primitive races, but they overlapped with the lowers passing behind
the uppers like the blades of scissors. Moreover, the incidence of retarded
mandibular growth appeared to have risen during the past few thousand
years (Moh/in, Sagne and Thilander, 1978).
What was the reason for these changes ? It was believed that the
physical character, i.e. consistency of food and the manner in which it
was eaten had an important effect on the growth and development of
jaws and that the high incidence of dental disease was caused by the soft,
non-stimulating diets that were consumed by the majority of civilized
people. The use of soft diet was responsible for the trend toward
increased malocclusion from dental crowding which implied narrower,
shorter jaws (Waugh, 1937; Wood, 1971; and Inoue, 1980).
Other investigators as Kiliaridis, Bresin, Holm and Strid (1996)
reported functional alterations in the mandible induced by feeding
growing rats a soft diet