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Ecology of dental disease.

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Ecology of Dental Disease
L. E. ST. HOYME AND R. T KORITZER
Department of Anthropology, Smltksonznn Instztutmn,
Wushrngton, D.C. 20560
KEY WORDS Illinois . Virginia Indians . Dental paleopathology
Enamel trace elements Sex differences . Age changes.
.
ABSTRACT
Trace elements in the dental enamel of 43 prehistoric Indians
from Illinois, Maryland and Virginia show concentration differences by age,
sex and geographical locality. Sample areas on a n incisor or first molar were
blocked off with paraffin, washed twice with distilled water and etched 7 times
with 6N HCl. An optical emission spectrophotometer was used to analyze the
9 samples, representing surface contamination and sequential enamel layers.
A ,B, Ba, Cu, Fe, K, Mg, Mn, Na, Si, Sr, and Ti were present in most samples
in micro or trace quantities; other elements were detected with less regularity.
Comparisons of the 2 water washes with the 3 superficial, 4 deep and 7 total
acid etches, suggest that during burial the residual inorganic portion of the
enamel exchanged little or nothing with the soil. Enamel from archeological
teeth may therefore be utilized in host factor studies in dental paleopathology.
The Jy 50 Illinois Indians differ hom the Potomac Creek, Virginia, Indians
both in quantities of elements present and i n internal sample variability. In
each group, the sexes differ in 4 or more elements, both as to content and variability. Similarly, the older half of each sample differs from the younger. Patterns of sex and age difference are irregular, suggesting cultural differences,
rather than physiological, in utilizing the environment during enamel-forming
years. Enamel composition, as affected by differential environment utilization,
may partially explain sex, age and geographical differences in dental pathology
rates.
Physical anthropologists examining the
teeth of prehistoric populations frequently find increases in dental disease accompanying increases in use of cultivated
plant foods. One of us (Hoyme and Bass,
’62) has blamed a high caries rate on “a
soft diet high in carbohydrates,” having in
mind both the lack of abrasive matter for
wearing down the pits and fissures of the
teeth where caries frequently begins, and
the chemical environment created by the
attacking organisms.
While changes in human life styles
may alter the ecological setting of the
organisms that attack our teeth, they may
also alter the dental enamel, the tissue
which is being attacked. Such alterations,
occurring during the childhood years when
enamel is being formed, may include structural variations, observable as enamel hypoplasias (ranging from conspicuous
transverse grooves to defects visible only
under high magnification) and variants in
AM. J. PHYS. ANTHROP.,4 5 : 673-686.
chemical constitutents of the enamel (Orban, ’57; Molnar and Ward, ’75). These
and other kinds of variant could increase
or decrease the tooth’s susceptibility to
caries and/or attrition. This paper focuses
on the microchemical variants in enamel,
as a factor in the ecology of dental disease.
Over 95% of enamel is inorganic, the
major constituents being calcium, phosphorous, carbonate and magnesium (Zipkin, ’70). A number of other minor elements are present frequently enough to be
considered “usual” constituents of enamel;
but some other elements are present in
variable, butoften trace, quantities. These,of
course, are derived from the environment
during enamel formation. Their effect on
the enamel may depend less on their
presence alone than on their concentration. Just as trace elements in other situations may range from deficiency through
an optimal concentration to toxicity, the
673
674
L. E. ST. HOYME AND R. T. KORITZEK
effect of a single enamel element may be
cariostatic, apparently neutral, or cariogenic depending on concentration (Curzon and
Losee, ’76). And, in enamel, as elsewhere,
the presence of one substance may inhibit or facilitate the reactions of another.
The primary limitations on trace and microchemical constituents in dental enamel
are their presence and availability in the
utilized portion of the micro-environment.
Basically, geological processes, which provide the parent rocks from which soils are
formed, and the pedological processes of
millennia provide a major part of the
chemical raw material; the remainder is
provided by solutes in the available water,
which could represent land upstream with
quite a different geological history (Butzer, ’71). Peoples occupying different geographical provinces with other soil formations could be expected to have different
trace mineral profiles in their dental
enamel.
Occupancy of the same geographical
province, while permitting similarities in
enamel trace elements in populations located there, does not make this inevitable.
Let us assume that local plants and animals used as foods provide one of the
means for ingesting the minerals incorporated i n the enamels. Not all plant species
concentrate trace elements from the soils
to the same degree; indeed, differences in
utilization of trace elements are among
the physiological characters used by plant
taxonomists, and by pedologists, as indicators of soil chemistry. If one food species
becomes extinct, through climatic change,
blight, or other natural cause, the food
species substituted could provide quite a
different trace element assortment. Cultural choices could also lead to adopting or
abondoning a food species, or to restricting
its use to a particular age, sex, or other
subpopulation. Nor are plants evenly distributed through a region: microclimatic
zones, such as the opposing slopes of a n
east-west ravine, will differ markedly i n
temperature, humidity, insolation, and
therefore also in vegetation and soil chemistry. Tops and bottoms of a ravine will
also have somewhat different soil drainages-with
consequent alterations i n pH,
and other factors which affect trace elements solubility, and availability (cf. Loneragan, ’75; Beckwith et al., ’75). Thus a
move of only a few miles in distance, or a
few hundred feet in altitude, could markedly change the assortment of trace elements available to a human group. Again,
how these are absorbed i n the human body
and finally deposited in the enamel may
depend on many factors, including the
presence and relative concentration of
other elements.
In short, not all of the elements present
in the environment are necessarily equally available or equally utilized by humans.
Soil, water, plant, and animal samples may
give some idea of the elements available
for ultimate inclusion in the enamel, but
only the roughest estimate of which elements and the concentrations that will
actually be present. To complicate matters
further, unless analyses are done by the
same technique, results may not be comparable, i.e., a n element may be more
readily detectable by one method than another. Rather than trying to predict from
the environment what ought to be in the
enamel, it seemed more practical to start
with a n examination of the enamel itself,
by a procedure standardized as carefully
as possible so as to produce comparable
results.
Until population differences in the microconstituents of dental enamel have been
demonstrated, it is useless to speculate as
to how these arose-whether
through ingestion of dirt with food; via water used
for cooking or drinking; from plant or
animal dietary components, or the mysterious “exhalations from the soil” so dear
to the hearts of 19th century social scientists. Regardless of the mechanism by which
it reached the tooth, the microconstituent
had to be present in the environment, in
some sense of the word, at the time the
enamel was being laid down.
One can look first for interpopulation differences associated possibly with environmental difference :
(1) Widely separated geographical areas,
will probably have different geological
histories, with soils and water supply derived from different parent rocks, by different soil-forming processes, with therefore different trace element profiles. (2)
Even areas fairly close together or of similar geological origin, may differ significantly through time as climatic changes
have altered plant cover, exposure, erosion,
drainage, and other local factors.
In addition there are intrapopulation dif-
ECOLOGY OF DENTAL DISEASE
ferences that may arise from differential
utilization of local resources during childhood. Sex differences could arise in a number of ways: from cultural restrictions on
the activities of boys vs. girls, such as
food taboos; from growing up in another
area, as when marriage customs include
preference for exogamy; or simply from sex
differences i n trace element requirements
and individual variations or i n selective
assimilation. Similarly, age differences
could arise if foods available to the other
generation were no longer utilized by the
younger; if new foods were substituted,
or if the group abandoned a n area and
moved a few miles away. Marked individual
differences may mean that the person is
an intruder of some sort. Finally, intraindividual differences, between teeth in the
same dentition, may reflect variations i n
a person's environment during the years
of enamel formation and maturation. Individual microenvironmental sampling,
may result ultimately in deposition of
enamel elemental concentration bands.
MATERIALS AND METHODS
For testing we selected populations from
sites in Jersey County, Illinois, and Stafford County, Virginia, well separated in
time, space and ecology. Chronologically,
the series from Jersey County Mound 50
dates to about 600 A.D., (Griffin, personal
communication) and was excavated i n
the 1930's by the late Dr. P. F. Titterington (Titterington, ' 3 5 , '42; Shalkop, '49).
The Virginia group comes fiom Ossuary
3 at the Potomac Creek site, excavated at
about the same time by the late Judge W.
Graham. In the case of the Mound 50 specimens, several years elapsed between excavation and transfer to Washington, and
conditions of storage then are not known.
The Potomac Creek material was received
in the Museum very shortly after excavation. Since these materials reached the
U.S. National Museum, treatment has consisted only of rinsing off excess mud, using
the local water supply, and some bone repairs. No "preservative" solutions were applied in the Museum; and repaired teeth
were not used. There may have been some
contamination from room dust before the
specimens were put into dust-topped boxes
for storage after cataloging. Fortunately,
some of the specimens had been cleaned
less carefully than others, providing slight-
675
ly larger samples of their previous environments. The Potomac Creek Ossuary series
represents a group of people who probably
died within a narrow time span, perhaps
ten years, and were buried in a single pit,
We feel (Koritzer, '76) that the people from
Jy 50 in Illinois might also represent a short
time period of deposition although Struever
(personal communication) suggests a much
longer time. The samples approximate as
nearly as possible population cross sections, rather than longitudinal samples.
One individual from Ossuary 4, (378735)
was included with Ossuary 3 and a specimen
from a Maryland site a few miles up the
Potomac River (381,926) was used in preliminary tests. While the statistical analysis of the data from Potomac Creek
Ossuary 3 and Jy 50 was in progress, data
for 12 specimens fiom Mound 69 (Jy 69)
became available, but could not be analyzed
fully.
Samples were taken from enamel in
either the central incisor or first molar,
from areas being laid down during ages
3-5 years. One of us specified the tooth
and location to be sampled. The subsequent procedures were carried out by Mr.
Harold Westley, a n experienced technician
in the Conservation and Analytical Laboratory of the Smithsonian Institution, under
Dr. R. M. Organ. Details of the procedure
followed are given by Koritzer ('76). The
tooth to be sampled and the adjoining teeth
were covered with pure paraffin, and a window 2 rnm2 was punched in the paraffin
on the lingual surface, near the enamel
margin but not near calculus, to restrict
sampling to this exposed area only. Fixed
quantities of distilled water were washed
over the sample area first, to solubilize any
partially broken down enamel constituents
and also to remove any surface contaminants. Then, fixed quantities of analytically pure 6N HC1 were washed over the
sample area for periods ranging from 5
minutes to 82 seconds, to obtain comparable series of stratified enamel samples.
For each tooth, then, there were 9 samples. 2 water washes, from the tooth surface, giving a n estimate of the mineral
constituents of the soil in which the tooth
had been buried, and 7 sequential acid
etches, representing successive stages of
enamel deposition.
The samples were dried, weighed and
analyzed using a n optical emission spectro-
676
L. E. ST. HOYME AND R. T. KORITZEH
graph. The spectra were recorded on comparison, but included in the age comEastman Kodak photographic plates. A parisons.
dozen or more elements were read opticalThese 43 specimens, then, yielded 387
ly and recorded. These determinations to- samples for spectrographic analysis. Means
gether with the individual’s age and sex, (arithmetic, rather than geometric), standwere then subjected to computer analysis. ard deviations and other statistical conThe dozen elements most consistently ob- stants were obtained, for each of the 12
served, in addition to calcium and phos- elements, €or the water washes and for
phorous were aluminum, boron barium, the superficial, deep and total acid etches,
copper, iron, potassium, magnesium, man- for each total population and for each
ganese, sodium, silicon, strontium, and population subdivided by age and by sex.
titanium. A few other elements, including Intergroup comparisons consisted of Stulead, molybdenum, zinc, and zirconium, dent’s t , F, and Mann-Whitney U tests.
appeared too infrequently to permit statistical analysis. Still other elements may
RESULTS
have been present, but were not detectComparisons of water washes and
able by the method and instrument used.
acid etches
Therefore analysis was confined to the
The first question to be considered is
12 elements listed above.
As the first step in the statistical anal- whether the acid etches represent a closed
ysis, we used CalComp plots for each enamel system, or whether there has been
element, using 1 1 Illinoians and the Mary- interchange of elements with the soil or
land specimen. This preliminary analysis some other contaminant. Some postmortem
revealed several things: first, the Mary- alteration in the teeth can be expected.
land specimen stood apart from the .Jy Teeth long buried are likely to have lost
50 group in almost every determination, most of the surface “trash layer,” and
indicating clear geographical differences. much of the organic material making up 3Second, the 2 water washes, in almost all 5 % of the enamel, leaving only the inorcases, were clearly distinguishable from ganic residuum. Ground water may medithe following acid etches. Third, the 7 ate chemical exchange with the enamel
acid etches, while showing some variabil- crystals and gradually remove or add
ity for each individual, showed no clear soluble materials. Elements strongly bonded
trends fi-om the most superficial etch to to the apatite crystals would be less likely
the deepest, suggesting that such differ- to be exchanged in reactions with ground
ences, if they existed, would not be great. water, unless allowed by specific condiPart of this might be due to variability tions. While such replacements might be
in HC1 solubility of the different elements. more frequent nearer the tooth surface,
Accordingly, it seemed most practical to they are more likely to be random and opgroup the first three acid etches together portunistic than regular.
Comparing water washes with acid
into a “superficial” sample (S), the remaining four into a “deep” sample (D), for com- etches, significant differences should inparison with the water washes (W), each dicate that there has been little or 110 inother, and the “total” sample (T) of all terchange of elements; insignificant difseven acid etches. The Jy 50 series was ferences, on the other hand, can mean
then increased to 21 individuals, and 20 contamination from the soil, leaching
individuals from Potomac Creek Ossuary out from the enamel, or a n initial basic
similarity between soil and enamel. De3 and 1 from Ossuary 4 were added. These
42 could be broken down into the following cisions as to which explanation is most
likely will depend on the behavior of all
subpopulations :
Potomac
Creek
JY 50
of the elements, and the relationship beOlder half
11
10
tween the superficial and deep etches.
Younger half
10
11
A gradient will exist in a chemical interAll males
12
10
change unless a static end point has been
All females
9
8
Sex (children)
3
reached. In a dynamic chemical milieu
The children were eliminated from the sex consisting of soil, ground water and dental
ECOLOGY OF DENTAL DISEASE
enamel, and involving different solubility
products for numerous chemical species,
such an end point seems most unlikely.
After removal from the ground by archeologists no further chemical interchange
could occur, and components needed to
reach equilibrium end points that would
be uniform throughout the enamel would
cease to be available.
If a gradient existed, either because of
contamination or leaching, one would expect less difference between water and superficial etches (W:S) than between water
and deep (W:D). The water versus total
(W:T) comparisons, then should be intermediate since the T series i s simply the sum
of the S and D series. It is not likely that
the distilled water would pick up a great
deal of anything from the enamel itself during the brief washing. The water washes
should represent primarily surface contaminants including particles of the soil in
which the specimens were buried and
perhaps a very low surface elemental
profile,
Accordingly, the element concentrations
found in the water washes were compared
first with the total acid sample and then
with the superficial and deep etches. Next,
the superficial and deep etches were compared with each other. For these comparisons, the subdivisions used were Illinois
(Jy 50) older (ILO), Illinois younger (ILY),
Potomac Creek older (PCO) and Potomac
Creek younger (PCY). For the comparisons
of superficial to deep, Illinois females
(ILF), Illinois males (ILM), Potomac Creek
females (PCE) and Potomac Creek males
(PCM) were added.
Of the 144 t tests, (fig. l a ) all except 16
were significant at 0.05 levels or better.
Usually, the level of significance was the
same for W:T, W:S and W:D for any element for a population. Thus 15 of these
16 insignificant differences involve 3
populations and 4 elements : barium (PCO,
PCY), potassium (ILO), silicon (ILO),
and titanium (PCO). There are four cases
in 48 pairs where W:S is significant at
0.05 and W:D at 0.01; and one curious
case (silicon, PCY) in which W:T is highly significant, W : S of slightly lower significance and W:D insignificant. The few
similarities in means between the water
washes and their respective acid etches
677
would seem to be due to chance alone.
There is no clear evidence of any gradients.
The F tests (fig. l b ) show analogous differences in variability between the water
washes and acid etches. Of the 144 F
tests, 13 are insignificant and 1 is of
borderline significance (0.1). In 2 cases,
the difference between W: S is insignificant;
in 2 (4 tests), neither W:S nor W:T is significant; and i n 2 cases (6 tests) neither
W:T, W:S, nor W:D is significant. This
might suggest some sort of trend, if there
were not 2 cases i n which W:D is insignificant, while the corresponding W: S is
highly significant.
As to the populations, none of them
seems to have a n undue proportion of insignificant or borderline differences, by
either the t or F tests. Similarly, the 12
elements under examination seem to behave
in a random fashion, since insignificant differences are found in 7 of the 12, and without apparent pattern as to age or area.
There appears to be a clear difference
between the water washes and the acid
etches, both in mean concentrations and
in variability, for both areas and for each
age subdivision. Furthermore, differences
between the water washes and the total,
superficial and deep etches seem to be
consistent, suggesting that for interarea
population comparisons, at least, similar
results would probably be obtained regardless of whether the total, superficial or
deep etch were used.
Comparison of superficial and deep etches
As a further check on the possibility
of gradients, concentration of the 12 elements in the superficial and deep etches
were compared (figs. 2a, b). If, as the preceding comparison of water washes and
acid etches leads us to believe, there are
few or no gradients, one would expect few
significant differences. Of the 48 t tests, for
the ILO, ILY, PCO and PCY series, there
is one difference significant at 0.01, two
at 0.05, seven at 0.1; and the remaining
38 are insignificant. This is much as one
would expect. Subdividing the series by sex,
out of 48 comparisons one is significant
at 0.01; five at 0.05, and nine at 0.1. Of
the 48 Jy 50 t tests, only five are significant at 0.01 or 0.05, and six are of borderline significance. Of the 48 Potomac
678
L. E. ST. HOYME AND R. T. KOHITZER
ECOLOGY OF DENTAL DISEASE
IL
0
Y
PC
F M
O
Y
6 79
IL
F
M
t tests
0
Y
PC
F M
O
Y
F
M
F tests
Fig. 2 Comparison of enamel element content of superficial and deep etches by age and
sex for the Jy 50 and Potomac Creek specimens.
Creek t tests, four are significant, 14 are
of borderline significance and the remaining 30 are insignificant. The Potomac Creek
series seems somewhat more variable
than the Jy 50.
As to the F tests, the Potomac Creek
series seems to have considerably greater
internal variability than the Jy 50. Of the
48 Jy 50 F tests, 10 are significant, and 3
are of borderline significance. By contrast,
33 of the Potomac Creek F tests are significant, most of them highly so, 2 are
of borderline significance, and only 13
insignificant. Of the 12 elements only K
and Mn seem variable at both sites, Ba
and Cu only at Jy 50. Other variations
are borderline and show no clear pattern.
The variability seen in the F tests may
arise from either of two sources. Both S
and D series include, respectively, 3 and 4
acid etches from each individual. And the
age series included both males and females. As will be seen, there are clear sex
and age differences for several of the elements in both Jy 50 and Potomac Creek
series. The F test used cannot distinguish between heterogeneous individuals with
homogeneous enamel, and homogeneous
individuals with variegated enamel. One
can only say that one sample is more or
less variable than another, without specifying the source of the variability. Nevertheless, in view of the t tests, one would
suspect that the Variability was due more
to interindividual variability than to intraindividual variation.
Whereas the W:T, W:S and W:D comparisons showed sharp differences between
the water and acid etches, the S and D
samples are clearly similar in mean ele-
680
L. E. ST. HOYME AND R. T. KORITZER
mental content. This supports the hypothesis that the enamel structure is organized and consistent. There is no evidence
that elements from the soil penetrated
superficially and “stuck,” nor that elemental components leached outward and
“stuck” in the superficial layers. For interand intrapopulation comparisons, therefore, it would seem to make little difference whether the sample used was the s,
D or T, since all gave approximately the
same results. More important is the kind
of statistical tests used. The t tests may
be sufficient for interpopulation comparisons, if one assumes that total elemental
content is more significant than internal
variability, which could reflect a number
of factors. For intrapapulation comparisons,
both F and t tests should be used since
variability patterns may be even more significant than total content.
IL0:PCO
T
S
Comparison of Potomac Creek and
Jy 50 series
If only because of the wide geographical
separation arid the dissimilar parent rocks
from which the soils were derived, one
would expect quite different mean values
for the various trace elements. Dividing
the Potomac Creek and Jy 50 series into
older and younger, (figs. 3a, b), 56 of the
72 t tests are significant, with 16 insignificant or barely significant (P s 0.1).
Nine of these insignificant differences between the Potomac Creek and Jy 50 series
are in aluminum and silicon; this is not
surprising, since these are major constituents of clay. The remaining 7 are in
the younger series, for iron, magnesium
and titanium.
Differences in variability should be at
least equally marked, if the two groups,
1LY:PCY
D T
S
1LO:PCO
T
O
S
I L Y :PCY
D T
S
D
A1
B
Ba
cu
Fe
K
Mg
Mn
Na
Si
Sr
Ti
t tests
F tests
Fig. 3 Comparison of enamel element content in older (IL0:PCO) and younger (11,Y:PCY)
specimens at the Jy 50 and Potomac Creek sites.
68 1
ECOLOGY OF DENTAL DISEASE
having different mineral environments,
also utilize them differently. Of the 72
F tests, 6 are insignificant, 4 are barely
significant, and the remaining 62 are significant at 0.05 or 0.01. The insignificant
differences show no particular patterns,
appearing i n 5 of the 12 elements (alurninum, barium, magnesium, sodium, titanium); 6 are in the younger series, 4 in the
older.
Regardless of age or depth of etch, differences between the two sites are clear,
both for mean content and for variability,
for all 12 elements. The only exceptions
to this appear to be means for aluminum
and silicon, but even these show some differences.
nificant differences i n one-third or more of
the elements (figs. 4a, b). While all of the
t tests for either the Potomac Creek or Jy
50 water washes are insignificant, in the Jy
50 series there are 5 , 3 and 4 significant
differences for the T, S and D etches respectively and for Potomac Creek, there
were 4, 3 and 4 respectively. Significant
differences appear in boron and silicon
at both sites; in titanium at Jy 50 only,
and in barium, sodium and strontium at
Potomac Creek only.
Variability, as seen in the F tests, is
somewhat greater at Potomac Creek than
at the Illinois site. In the water washes,
which showed no significant differences
in content by the t tests, 8 elements for
the Jy 50 group and 9 for the Potomac
Creek show significant differences. Except
for barium, no element shows sex difference at both sites.
Comparisons by sex
The acid etches of the two populations,
when separated by sex, show statistically sig-
ILM: ILF
W
T
ILM: ILF
PCM: PCF
S D , W T
S
W
D
T
S D - W
PCM: PCF
T
S
A1
B
Ba
cu
Fe
K
Mg
Mn
Na
Si
Sr
Ti
t tests
F tests
Fig. 4 Comparison of enamel element content in the two sexes from Jy 50 (1LM:ILF)
and Potomac Creek (PCM:PCF).
D
682
L. E. ST. HOYME AND R. T. KORITZER
For the acid etches, half (18 of 36) of
the F tests in the Illinois series and threequarters (26 of 36) of those for the Potomac
Creek series show significant sex differences. Except for potassium and manganese, the elements showing insignificant
sex differences in variation are not the
same at the two sites.
Sex differences in elemental enamel
content can be accounted for in a number of ways. It is possible that growing
boys and girls utilize some elements differently, as a biochemical sex difference.
If this were so, one would expect that
these elements would show analogous
sex differences i n several populations.
Boron and silicon appear at first to fall
into this category. Inspection of the raw
data, however, shows that at both sites
there were single individuals, both females, who had boron readings far higher
than the range of variation for the rest
of the series. When these two individuals
were eliminated and the statistics recalculated, most of the sex difference disappeared. Nevertheless, because the residual
sex difference in boron, though not large,
tended to be in the same direction and
magnitude at both sites, and because these
two women showed similar deviations, this
element deserves further attention. Consistencies, even in widely separated areas,
can, however be cultural as when exposure to a n element varies with some
common sex-related activity, such as use
of grinding stones, This might explain
parallel sex differences in silicon, except
that a sex difference in exposure from
this cause might be less likely at the age
when enamel was forming.
One expects most sex differences to be
both random and variable if they are associated with culture. If a group was exogamous, the incoming spouses should have
spent their childhoods elsewhere, at one
or possibly more sites. The wider the area
the spouses represent, the more variable
the quantities of elements i n their enamel,
although the differences between means
for the sexes might not be very great. One
would expect that any sex differences which
appeared would be as likely to affect one
element as another, but to be dependent
upon the distribution in the microecosystern. It is quite possible for two ossuaries,
mounds, or other burial groupings, at the
same site, to have dissimilar sex differences;
and the likelihood of this increases with
their separation in time. The sex difference in water wash variability at both
sites, despite burial in a common grave
and exposure to a common environment
after death, may be due to different chemical
substrate, i.e., enamel composition by sex,
resulting in different reactions with soil
chemicals.
Com.parisons by age
Dividing each series into older and
younger halves, t tests give significant differences in around half of the 36 tests
for each series (figs. 5a, b). For the Jy 50
series, 1 4 tests are significant, 4 are of
borderline significance, and the remaining 18 are insignificant. For Potomac
Creek, the differences are stronger: 1 7
significant tests, 6 of borderline significance, and only 13 insignificant. At both
sites, at least 2 of the 3 etches show significant differences for barium, magnesium
and strontium; only for titantium, at both
sites, are there no significant differences.
For 5 other elements, the Jy 50 series
shows no or slight differences between old
and young; for 3, no or slight differences
were seen at Potomac Creek. Age differences, like the sex differences, seem to
be random as to the elements affected.
From this evidence, there seems somewhat
more difference between age groups at
Potomac Creek than at Jy 50.
As to variability, differences between
the groups are quite striking. For the Jy
50 series, 14 of the F tests are significant
at the .01 level; 3 at .05; three at 0.1, and
the remaining 16 are insignificant. For
Potomac Creek 28 are significant at 0.01;
four at 0.05; 1 at 0.1 and only 3 are insignificant. There seems to be no correlation between age differences i n a n element’s
concentration and in its variability at
least for the Jy 50 series. F tests for a n
element may show variability, while t
tests for the same element show no particular change; and vice versa. Manganese
and magnesium, which gave highly significant differences for t tests i n the ,Jy 50
series, had no or slight differences by F
tests. On the other hand, copper, iron, and
potassium, had insignificant differences
by t tests, but highly significant differences by F tests. Using both of these tests,
683
ECOLOGY OF DENTAL DISEASE
ILO: ILY
T
S
D
r
ILO: ILY
PC0:PCY
T
I
S
T
D
1
S
D
PC0:PCY
T
S
D
A7
B
Ba
cu
Fe
K
Mg
Mn
Na
Si
Sr
Ti
t tests
f tests
Fig. 5
Comparison of enamel content in older and younger individuals from Jy 50
(IL0:ILY) and Potomac Creek (PC0:PCY).
we may conclude that there are real differences between the older and younger members of each group; that the differences
appear to have no regular pattern: and are
probably interindividual, rather than intraindividual.
Explanations for age differences may be
physical or cultural. It is possible that, as
a n individual ages, his enamel may undergo some changes. This might be a factor
contributing to post-mortem alteration
susceptibility. This does seem unlikely,
however, in view of the lack of consistent
differences in the water: acid and the
S:D comparisons. If chemical exchange
with the measured elemental residuum
had taken place in the ground, one would
expect greater differences in the W:D
pairs than in the W : S pairs; and these are
rarely found. If enamel elemental exchange
during adult life is a factor, the evidence
for it is not clear. Secular changes in cultural factors in childhood, such as alterations in the area utilized during the seasonal round and/or in utilization of the resources within these areas are much more
likely. It would seem that marked differences i n total element content and i n variability could signal changes in life style of
interest to the anthropologist, as well as affecting dental pathology rates.
DISCUSSION
The data just presented show clearinter- and intragroup differences in enamel
composition by age, sex and geographical
locality. Data previously presented (St.
Hoyme, '72; Koritzer, '72) show clear differences in pathology rates by age, sex
and locality for the same two populations.
Until computer analysis is completed, it is
premature to speculate as to which ele-
684
L. E. ST. HOYME AND R. T. KORITZER
ments or groups of elements are related
to particular pathologies. Nevertheless, it
is possible at this time to examine the pertinence of the chemical analyses to the
pathology.
This first problemis thenatureoftheenamel available from archeological sources.
The analyses reported here justify the inferences that there has been little or no
alteration in the residual chemical composition while in the ground, and that one
can justify attempting to relate composition of archeological enamel to dental
pathology during life. The enamel, of
course, is not precisely the same as during life. the 3-5% o f organic material
has been altered and/or lost. To what extent the organic material included factors
affecting dental pathology cannot be ascertained a t the moment. Certain elements
present in enamel from contemporary
peoples (Zipkin, ’70; Meckel, ’70; Curzon
et al., ’76) are reported by the Smithsonian’s Conservation Analytical Laboratory as “not detectable” i n the teeth examined. Their apparent absence could be
due to various causes: (1) the elements
were in the organic portion and had
been lost; ( 2 ) some elements are more
readily detected by one analytical procedure than by others; and the reported
difference arises from analytical technique rather than absence from the sample;
( 3 ) different content i n the sample, associated with geographical origin, or other
aspect of environmental availability; or
(4) some other factor. Nevertheless, since
the inorganic enamel crystals are destroyed
by attrition and caries, along with the organic matrix, it is reasonable to assume
that crystal structure and composition are
pertinent.
Descriptions of the environmental resources and their utilization by the Jersey
County and Potomac River Indians (cf.
Shalkop, ’49; Ubelaker, ’74; Koritzer, ’76)
point up a number of cultural and ecological dissimilarities. Presumably differences in the food plants and animals available and in their preparation, were important factors in producing the enamel
differences seen. However, without chemical analyses of these and other sources
of trace and microconstituents-which
are rarely available even for modern foods
-it is useless to speculate on the mechanisms by which the element traveled from
the environment to the enamel.
Cultural and ecological factors with
which we can deal, however, are estimated
population size, estimated food supply, and
their interaction to influence the territory
exploited by the populations during enamelforming years. We can predict a correlation between territory and variability i n
the enamels of the individuals. Similarly,
we can infer that differences between
population subdivisions may represent differences in their childhood environments.
Ubelaker (‘74) estimates 1.2 person per
km2 for the Potomac River valley, which
corresponds well with Captain John Smith’s
comments (in Arber, 1884) that the population was small and that “the land is
not populous.” Similarly constructed analyses have not been done for the Illinois
River Valley. However, the ratio between
the total available area, its carrying capacity and the number of inhabitants is not
identical with the relationship between
the territory utilized and the number of
people living from it. From the archeological evidence summarized (Koritzer, ’76)
the later lllinois occupation sites tended to
be larger, nucleated type of village settlements, with abundant and varied resources
fairly close at hand. The Potomac Creek
population, however, seems to have been
engaged i n a wide seasonal round, less
concentrated and therefore exploiting resources from a larger total area. They
probably moved about more, not only during the course of a year, but also over
the years.
Looking only at the enamel, one could
predict certain overall differences between
the people from Potomac Creek and Jy
50. As expected, total element content differs markedly, for both the younger people
and the older, in most of the 12 elements,
The degree of variability also differs. As
noted earlier, the F tests used do not distinguish between intra-individual and interindividual variation. Such a pattern is compatible with the hypothesis of differences
in utilized area and i n manner of utilization. Comparing each site subdivided by
enamel depths, age, and sex, significant
differences for both t and especially F
tests are much more common in the
ECOLOGY O F DENTAL DISEASE
685
Fotomac Creek series than in the Illinois, disease rates, and worthy of further inpointing to much greater internal variation vestigation.
i n the Virginia population. A very minor
LITERATURE CITED
amount of this might be accounted for
by the inclusion of one individual from Arber, E., ed. 1884 Capt. John Smith, Works,
1608-1631. The English Scholar's Library. 16,
Ossuary 4, but is not sufficient to affect
Birmingham.
trends or significant values to any marked
Beckwith, R. S., K. G. Tiller and E. Suwadji
degree. The variation is more likely to be
1975 The cffects of flooding on the availabilassociated with farther-ranging seasonal
ity of trace metals to rice in soils of differing
organic matter status. In: Trace Elements i n
rounds in Virginia. It should be noted that
Soil-plant-animal Systems. D. J. B. Nicholas
the ossuaries represent the dead of a numand A. R. Egan, eds. Academic Press, New
ber of settlements, and thus represent an
York. pp. 135-150.
area comparatively larger than any single Butzer. K. W . 1971 Environment and archeology. Aldine and Atherton, New York, 524 pp.
village. Similarly one cannot absolutely
state that the Jy 50 group used represents Curzon, M. E. J., F. L. Losec and S. D. Macalister
1976 'Trace elements i n human enamel. Variaa single Jersey county village (Struever,
tion within populations. J. of Dent. Res., 55
personal communication). Subsistence pat(special issue B):B160, art. 395.
terns are also likely to shift bases over a Hoyme. L. E., and W. M. Bass 1962 Human
skeletal remains from the Tollifero (Ha6j and
period of time, i.e., between the childhood
Clarksville (Mc14) sites, John H. Kerr Reserof the older individuals and that of the
voir Basin, Virginia. Bull. Bur. Amer. Ethnol.,
younger. Movements which now appear
182: 3 2 9 4 0 0 .
more or less random would affect the pat- Koritzer. R. T. 1972 Measurement of dental
paleopathology. Am. J . Phys. Anthrop., 37:
terns of variability, but one could not
p. 443. (Abstract)
predict which elements would vary, or in
1976 Archeological inferences developed
what direction.
from dental enamel trace element data. Ph.D.
dissertation, American University, Washington,
Similarly, sex differences at the two sites
D.C.; University Microfilms, Ann Arbor.
do not involve the same elements, suggestLoneragan, J . F. 1975 The availability and
ing culturally mediated rather than physabsorption of trace elements i n soil-plant sysiological processes alone. Cultural factors
tems and their relation to movement and concentration of trace elements in plants. In: Trace
could include exogamous marriage, sex
Elements in Soil-plant-animal Systems. D. J .
taboos on food, or other differential utilizaB. Nicholas and A. R. Egan, eds. Academic
tion of the environment during childhood.
Press, New York, pp. 109-134.
These could also account for some of the Meckel, A. H. 1970 Structural elements of the
teeth. Dental Science Handbook. L. W. Money
different degrees of variability observed
and R. J. Nelsen, eds. DHEW (NIH) 72-336,
in the two sexes.
Washington, D.C., pp. 22-36.
The variability patterns in enamel ele- hlolnar, S., and S . Ward 1975 Mineral metabment content resemble those for dental
olism and microstructural defects in human
teeth. Am. J. Phys. Anthrop., 4 5 : 3-17.
disease. In both the Jy 50 and Potomac
B. J. 1957 Oral histology and embryCreek populations reported earlier (St. Orban,
ology. C. V. Mosby, St. Louis.
Hoyme, '72), there were sex differences St. Hoyme, L. E. 1972 Dental pathology in
in pathology rates; but these were not
crania of Mongolians, Egyptians and American
Indians, Am. J. Phys. Anthrop., 37: 451. (Abconsistent. At one site, females might have
stract j
a higher caries rate, while showing a low- Shalkop,
Robert L. 1949 The Jersey bluff archeer rate at another. The same can be said
ological focus. Master thesis, University of Chiof rates for periodontal disease, attrition,
cago.
and antemortem tooth loss. Again, when Titterington, P. F. 1935 Certain bluff mounds of
western Jersey County. Am. Antiq., 1 : 6-80.
these populations were divided by age,
1942 The Jersey County, lllinois, Bluff
rates differed between older and younger,
Focus. Am. Antiq., 9: 240-245.
but not in a regular and predictable Ubelaker, D. H . 1974 Reconstruction of demographic profiles from ossuary skeletal samples:
fashion. While there may be some sex or
A case study from the Tidewater Potomac.
age differences i n the attacking factor
Smiths. Contr. Anthrop., 18: 79 pp,
in these dental diseases, the demonstrated Zipkin, I. 1970 Biology of the oral encironment.
variation in the enamel attacked seems a
In: Dental Science Handbook, DHEW (NIH) 72336, Washington, D.C., pp. 3 7 4 6 .
more likely explanation of the observed
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