Abstract
Aims of this research to study the effect of surface area on retention
of complete denture. Materials and methods: Oral examination
clinically, some of physical and biochemical analysis of human
unstimulated whole saliva have been studied. They constituted in
three groups (25 in each the first and the third group) and (50 in the
second group). The first group was healthy and aged (20-30) years,
the second group was healthy and aged (50-70) years, also the third
group aged (50-70) years but with systemic diseases.The following
parameters were studied: flow rate, pH, total protein, density, surface
tension, viscosity and film thickness. Total protein concentration was
responsible for physical and chemical changes specially viscosity.
There was a direct positive correlation between total protein and
surface tension, viscosity, density and film thickness, while there was
a negative correlation between total protein and with flow rate and
pH. The measurement of force due to surface tension of these
samples have been done by preparing two pairs of circular discs of
(PMMA) of (5.2,6.5) cm in diameter and compare of force between
these groups, also compare these physical analysis with mathematic
analysis. Results: indicated that in both the first and the third groups,
the physical and mathematic analysis for retention showed non
significant changes while in the second group showed significant
changes. Conclusions :there was a positive correlation between force
and wetted area and this force was due to wettability and not to
water sorption.
