28
failed to stimulate the flow ofsaliva. For pH read-
ings, the paper strip had to remain in contact with
the floor of the mouth for 25 to 30 sec in orderto
absorb sufficient saliva. In most instances it was
difficult for the subject to produce the 5 miof
saliva necessary for pH determination in a period
<10to 15 min. The pH values ranged from 6.0 to
7.9, with an average of 6.3
Utirik Population
The Utirik population exhibited oral findings
similar to those of the Rongelapese. Their stand-
the incidence of peridontal disease and caries in
adults was practically identical. In the Utirik
children less evidence was seen of bunching ofthe
lower anterior teeth, and jaw development was in
harmonywith general body growth.
Conclusions
These examinationsled to the following con-
clusions.
1. There was nosignificant difference in either
caries rate or incidence of peridontal disease be-
tween the exposed and the unexposed people of
Rongelap. The level of oral hygiene appeared to
be somewhat better in the children examined at
Majuro and at Utirik, but the incidence ofcaries
was about the samein the two groups, and higher
mate best fit by eye. The values of the criteria
generally either increase or decrease with increasing age. Many changes, such as greying of the
hair, batding, arteriosclerosis (peripheral and
retinal), and skin looseness andretraction, are not
appeciably manifest in the Marshallese until after
age 35 to 40. There is a tendency for values of
criteria such as blood pressures, greying of the
hair, loss of visual acuity, and accommodation to
level off, or even to show slightly reduced values
in the oldest groups. The number ofpeople in
these groups is too small to make this observation
certain. However, American statistics on blood
pressure (systolic and diastolic) also show a plateau
effect beyond about 60 years of age and evena
slight tendency to lowering of blood pressures beyond this age.*® By the age of 65 to 70, arcus
senilis in all Marshallese showed a 4+ change
and, therefore, the plateau was at a maximum.
Some curves showed lower maxima. For example,
baldness in women showedonly a 35% maximum,
and arteriosclerosis of the retina only 45%. The
differences in maxima probably were due largely
to differences in the degree of changeassociated
with the various criteria but also partly to the
arbitrary nature of the scoring. The sexual differ-
ences in hand strength and baldness were ex-
pected. In the neuromuscular functiontest, slight
muscle fatigue may have beena factor in the lower
female scores, necessitating separate evaluation.
than in the Rongelapese children.
2. The poor oral hygiene generally observed in
irradiated parents.
STUDIES OF AGING CRITERIA
The results of aging criteria studies are plotted
in Figures 13 to 31. Individual readings are plotted
S
#De
oF EXPOSED
* UNEXPOSED
°3MEAN BOTH GROUPS
-—™ o
9
a
2
(sec)
225
nog
3. No difference was perceptible in theclinical
appearance of developing dentition amongthe exposed children, the nonexposed, and those born to
lOO
a
the Marshallese people had its usual results: a
high caries rate in teen-age children, severe peridontallesions in adults (heavy calculus,loss ofalveolar bone); and edentulous mouthsin the aged.
oO
va
ards of oral hygiene were somewhatsuperior, but
increasing age is represented bya line of approxi-
oH
tion of the tissues by mouth mirror and explorer
people combined. Thetrend ofeach criterion with
&
Almost all the Rongelapese exhibited marked
xerostomia. The oral mucosa felt damp butnot
wet. During the dental examination, manipula-
(open circles, exposed people; closed circles, unexposed people) to show the spread of the data, and
the mean valuesare also plotted (squares) for each
3-year age group with exposed and unexposed
ba
h
those >>35, exposed and unexposed, werefree of
clinically detectable peridontal disease. In the
aged, many of the remaining teeth were simply
held in position by the gingival attachment.
Figure 13. Skin retraction time, 1958-1959.