United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S5-87/001 May 1987
x°/EPA Project Summary
Analysis of Costs for the
Treatment of Dental Fluorosis
E. Collins and R. M. Clark
This research project was initiated to
provide basic data to be used in a cost/
benefit analysis for communities
whose fluoride levels exceed the drink-
ing water maximum. Much has been
written regarding the technology and
associated costs for removing fluoride
from community water supplies. How-
ever, little information is available con-
cerning the economic benefits or dis-
benefits associated with various levels
of fluoride in drinking water. This study
focuses on the costs of remediation for
high levels of fluorosis in community
water supplies.
The initial data set used in this study
was from a project conducted by the
University of Texas at San Antonio for
the Environmental Protection Agency's
Health Effects Research Laboratory.
This earlier project, entitled "A Clinical
Study of the Dental Effects in a Critical
Zone," was used to select representa-
tive cases of fluorosis from a selected
set of Texas communities with water
fluoride levels from optimum to 4.0 mil-
ligrams per liter (mg/L). The clinical
findings of each case were presented to
a panel of clinical practitioners for diag-
nosis of the extent of cosmetic deform-
ity and dental dysfunctional effects
present in the dentition as a result of
excessive fluoride. Cost estimates were
made for the remedial care proposed
for each subject by each panel member.
Using these data an evaluation was
made of the beneficial effects of opti-
mum water fluoride levels (savings re-
sulting from caries reduction) against
the adverse costs of excessive fluoride.
Optimum fluoride level is defined by
reference to the National Interim Pri-
mary Drinking Water Regulations
where optimum levels are defined ac-
cording to temperature. In general, the
optimum level is approximately 1 mg/L.
This Project Summary was devel-
oped by EPA's Water Engineering Re-
search Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The Food and Nutrition Board of the
National Research Council has stated
that fluoride is a normal constituent of
diet, and is an essential nutrient. In addi-
tion, fluoride in drinking water will pre-
vent dental caries. When the concentra-
tion is optimum no ill effects will result
and the caries will be 60% to 65% below
the rates in communities with little or no
fluoride. Optimum is defined by refer-
ence to the National Interim Primary
Drinking Water Regulations where
"optimum" levels are defined accord-
ing to temperature. In general, the opti-
mum level is approximately 1 mg/L. Ex-
cessive fluoride in drinking water
supplies produces objectionab'e dental
fluorosis which increases with increas-
ing fluoride concentration above the
recommended upper control limits.
Other expected effects from excessively
high intake levels are: (a) bone changes
from water containing 8-20 mg fluoride
per L consumed over a long period of
time; (b) crippling fluorosis when 20 or
more mg of fluoride from all sources is
consumed per day for 20 or more years;
(c) death when 2,250-4,500 mg of fluo-
ride is consumed in a single dose. The
optimum fluoride level for a given com-
munity depends on climatic conditions
because the amount of water (and con-
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sequently the amount of fluorides)
ingested by children is primarily influ-
enced by air temperature. This relation-
ship was first studied and reported by
Gallagen and Associates in the 1950's,
but has been further investigated and
supported by Richards et al. in 1967.
The control limits for fluoride supple-
mentation are simply the optimum con-
centrations for a given temperature
zone as determined by the Public Health
Service, DHEW, plus or minus 0.1 mg/L
Many communities with water supplies
containing less fluoride than the con-
centration given as the upper limit for
the appropriate air temperature range
have provided fluoride supplementa-
tion.
The First Study
In order to more fully understand the
issues related to fluoride ingestion, a re-
search project was initiated by the Uni-
versity of Texas at San Antonio. This
research project was intended to iden-
tify significant dental changes (mottled
enamel) that occur in a human popula-
tion continually ingesting water from a
supply which contains naturally occur-
ring fluoride and to identify the level at
which these changes occur. A second
objective was to conduct a random sur-
vey to elicit community attitudes rela-
tive to what is objectionable in terms of
mottling and discoloration of teeth. In
this study, information regarding mot-
tling and discoloration of teeth was cor-
related with fluoride levels in the public
water supply of 16 communities.
Subjects were recruited through the
public school system in each commu-
nity. Students from grades 2-6 and 9-12,
whose families used water delivered by
the community water system, served as
a source of volunteers. An oral exami-
nation was performed to determine the
degree of enamel mottling and dental
caries. The urine specimens taken from
a random sample of subjects were ana-
lyzed for fluoride. Information regard-
ing personal and health background
was obtained, using specially designed
questionaires. An opinion survey of
high school subjects, mothers of sub-
jects, and random sampling of adults in
the community was conducted regard-
ing perception of enamel mottling. The
opinion survey found that the appear-
ance of anterior teeth with very mild
and mild mottling was generally accept-
able by community standards. How-
ever, the majority of mothers of high
school students with moderate visible
mottling are dissatisfied with the ap-
pearance of such teeth. In households
studied where water fluoride was more
than twice the optimum level, 25% of
the adults were willing to pay $2.50
extra per month for their city water to
prevent enamel mottling, while another
25% of these adults were unwilling to
do so. The other half of the adults sur-
veyed in the cities were "neutral" to
"willing" to pay for defluoridation. One-
third of the respondents in the "mother
survey" were very "willing" to pay,
while only one-sixteenth of them were
unwilling.
Enamel mottling was strongly associ-
ated with the fluoride level of the com-
munity water supply. The dental caries
rate was found to vary inversely with
the fluoride level of the community
water supply. There was a steady de-
cline in the DMFS (decayed, missing
and filled surfaces) score in both age
groups (7-12 and 14-18), with increasing
levels of fluoride. However, the 7-12
group experienced a greater reduction
in average score from 0.38 to 0.15 as the
water fluoride level increased from 0.5
times optimal to 0.5-2.9 times optimal.
There appears to be a direct and
nearly proportional relationship be-
tween the communities' water fluoride
level and average fluoride intake. A
strong dose response relationship was
observed between the median fluoride
level of the city schools and the average
urinary fluoride concentrations of the
students. It was observed in the data
that as the level of fluoride increases
well beyond the optimum range there
appeared to be a U-shaped curve asso-
ciated with the DMFS score. Apparently
as the fluoride level increased above the
optimum, the negative benefits associ-
ated with fluorides increased. The
proper remedial action for fluorosis is to
perform a series of dental procedures.
In order to gather information on these
negative benefits a second study was
conducted by the University of Texas at
San Antonio in which a dental panel
was convened and cost information
was collected in order to assess the re-
mediation costs associated with the cor-
rection of fluorosis. These data are
unique and the second study, which is
the subject of this report, is described
below.
The Second Study
There are no documented reports of
controlled studies to indicate the extent
of dollar expenditures for the cost of
dental care to repair either cosmetic
and/or functional dental defects due to
fluorosis. A lack of data in this facet of
fluoride research led to an assumption
by the dental profession that the effects
of tooth mottling are limited to the cos-
metic discoloration of teeth. In order to
test this premise, a study to assess the
extent of the effects of mottling and the
potential costs for repair of these de-
fects was conducted. The specific objec-
tives of this study were to:
1. Evaluate the extent of cosmetic
and dysfunctional effects at-
tributed to fluoride.
2. Determine the costs for restoring
the cosmetic appearance and dys-
function to a level acceptable in the
community.
Selection of Panel
Dental practitioners were interviewed
as potential members of a panel to eval-
uate the economic impact of dental fluo-
rosis. Each practitioner selected for the
panel was practicing in or located adja-
cent to a community where water fluo-
ride levels have resulted in mottled
enamel defects requiring some type of
remedial treatment. A further require-
ment was that each panelist have expe-
rience in providing remedial care for
subjects with mild, moderate, and
severe mottling.
After being selected for the panel,
each clinician traveled to the University
of Texas Dental School at San Antonio
where an orientation session was con-
ducted by the research staff prior to
case evaluation.
Selection of Cases
The records of all subjects examined
in the communities with water fluoride
levels from optimum to 4.0 mg/L were
screened to identify representative
cases for study and evaluation. Repre-
sentative cases were selected from all
the Dean's categories (a numerical rat-
ing of 1 to 6 that defines severity of mot-
tling) with the exception of normal,
questionable, and very mild. The docu-
mentation on each subject selected for
study consisted of a complete visual
and tactile examination of all surfaces of
all teeth for dental decay and mottling.
These data were reproduced on a
graphic chart of the dentition. Addition-
ally for each case selected, five color
transparencies with views of the denti-
tion from right, left, upper occlusal, and
inner occlusion were provided to the
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panelists. A total of 55 representative
cases were selected for presentation to
the panel.
Results
There was a large variability in the
numbers and types of procedures (a
procedure is a type of treatment, e.g.,
amalgam filling, gold crown, etc.) that
each consultant suggested for the same
case. This finding was not surprising as
the consultants were recruited from
widely separated geographic regions in
the United States. This diversity proba-
bly reflects the diverse economic condi-
tions under which they practice and
their prior training.
The types of treatment recommended
for each subject were classified as either
optimum care or minimum care. Mini-
mum care generally consisted of cor-
recting the cosmetic discoloration using
materials and procedures which are not
considered permanent, meaning that
they will probably need to be replaced
one or more times throughout the indi-
vidual's lifetime. Correction of the dys-
functional problem is generally accom-
plished using methods and materials
that are less durable and less expensive
than those recommended for optimum
care.
Optimum care implies use of the most
durable and aesthetic materials and
procedures currently available. This
level of service would be considered
permanent and should last the lifetime
of the individual providing they main-
tained good oral hygiene and received
periodic professional care.
It should be noted that bleaching
comprised a significant number of the
procedures proposed by all of the con-
sultants. The long-term aesthetic results
are apparently satisfactory to the point
where additional treatment is seldom
required. This type of procedure repre-
sents the least costly form of care for
the cosmetic problem of mottling. Other
types of procedures, e.g., mastique or
laminate, are more costly, yet are not
considered a permanent type of restora-
tion. Use of the bleach procedure,
where indicated, greatly reduces the
overall cost of treatment, particularly of
the moderate and severe cases. In most
instances, if treatment is indicated for
mild cases, bleaching would probably
solve the aesthetic problem with the
least possible cost and discomfort to the
subject.
It has been assumed that the primary
cost in dealing with the problem of mot-
tling was the cost for correcting the cos-
metic discoloration present on the
tooth. The pool of subjects being stud-
ied were initially divided into three sub-
groups according to their mottling
score (Dean's Score of 4, 5, or 6).
Each consultant was requested to de-
velop a treatment plan for each case
under a minimum care treatment plan
and an optimum care treatment plan. In
addition, they were requested to clas-
sify and separate the treatment as cos-
metic or functional. A further division
was made for sequencing of treatment.
Treatment was divided into "current
care" and "later care" (deferred). Cur-
rent care is treatment that should be
performed now or in the very near fu-
ture. Later care is treatment that would
probably bo necessary later in their life
so as to maintain normal functioning
occlusion. This projection is based on
the consultant's prior experience with
similar cases in their own private prac-
tice.
Treatment costs were divided into
cosmetic and functional types. Cos-
metic treatment consists of those proce-
dures required for correction of tooth
discoloration. Functional types of treat-
ment are required where there has been
excessive wear, breaking, or fracturing
of teeth so that mastication is impaired.
Cosmetic and functional treatments
were also divided into current and later
categories. Current treatment is treat-
ment that should be rendered now,
whereas later treatment includes proce-
dures necessary at a future date to cor-
rect the cosmetic and/or functional
problems.
A comparison of the mean costs for
cosmetic and functional treatment
shows that cosmetic costs exceed func-
tional costs in the mild and moderate
cases, however, the reverse is true in
the severe cases (Dean's Score of 6). A
comparison of the costs for cosmetic
and functional treatment indicates that
the estimate for functional treatment
exceeds the cosmetic costs in the
severe mottling cases. A mean cost for
all consultants shows that the estimated
costs for restoring function exceeds the
cosmetic costs in all categories except
the minimum later costs. This repre-
sents a new finding and raises an issue
that has been overlooked or ignored by
previous investigators and the profes-
sion, i.e., that repair of the cosmetic dis-
coloration was the only cost involved,
or that repair of dysfunction was never
considered to be a problem.
The costs for repairing dysfunction
are a result of the excessive wear, chip-
ping, and fracturing of teeth which ap-
pears to occur in subjects who have
moderate and/or severe mottling. Since
the majority of the subjects in our study
were teenagers, the projected costs
(later costs) are estimates based on the
future care that will be needed to main-
tain or reestablish their normal func-
tional occlusion.
The problems encountered may in
fact increase in severity during later life.
No data exists at this point in time to
permit an accurate assessment of the
problem. Only anecdotal information
and preliminary findings in our investi-
gations suggest possible outcomes for
subjects with moderate to severe fluo-
rosis. These findings consist of exces-
sive cusp wear, breaking, and chipping
of the teeth.
An additional analysis was made
using the Visible Mottling Score (a mot-
tling score based on the six upper ante-
rior teeth and the six lower anterior
teeth). Dean's Classification of mottling
was also used to compute the score.
The group was then divided into three
subgroups according to their mottling
score (Dean's Score of 3, 4, or 5). The
size of the subgroups in the first analy-
sis, using the entire mouth, as com-
pared to the subgroups in the second
analysis is substantial. Using the visible
mottling score results in more subjects
being classified as mild and fewer sub-
jects classified as moderate and severe.
There is wide variability in costs be-
tween the consultants in many of the
categories. Since they represent differ-
ent geographic regions of the country
as well as different economic levels (in
terms of patients treated), this differ-
ence is to be expected. The mean costs
per subgroup, i.e., Dean's Score of 4, 5,
or 6, increase as the severity of mottling
increases. Later costs appear minimal
for the group classified as Dean's Score
of 4, whereas those classified as Dean's
Score of 5 or 6 had substantial cost for
the treatment plan.
Since the severity and prevalence of
tooth mottling is related to the water
fluoride levels, it is important to exam-
ine the various facets of the problem
and determine a dose-response rela-
tionship. Using Dean's Score allows for
the classification of subjects into mild,
moderate, and severe categories and to
examine the projected costs for each
case.
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The type of procedures used for the
minimum care treatment generally
have a useful life of 5 to 7 years. Thus to
assess the lifetime cost requires re-
placement of these fillings on an aver-
age of once each 7 years. The treatment
of a subject is usually completed by age
20. Using an arbitrary age 62 as the av-
erage life span of subjects would re-
quire replacement of all fillings six
times between the ages of 20 and 62,
providing the subject did not lose any of
their teeth.
The procedures used for the optimum
type of treatment are considered per-
manent restorations. Thus a yearly
maintenance program should provide
adequate care for preserving the denti-
tion in a good state of health. Treatment
under this plan should be completed by
age 20. Using the age 62 as the average
life span of subjects requires a mainte-
nance period of 42 yrs. The estimated
yearly maintenance cost is $50. Thus,
the estimated total cost for optimum
care is the initial current and later costs
plus the number of years times $50. (Ini-
tial cost plus years [42] plus yearly cost
[$50.00]).
Regression analysis was used to es-
tablish a formula to relate the average
cost per dentist (minimum and opti-
mum) to mottling severity and age of
the subject. Costs were standardized by
use of a cost index to facilitate ease of
comparison. The best equations given
the data and the variables for minimum
and optimum have been calculated. In
order to measure significance, "t"
values have been given in parenthesis
below each variable (the higher the "t"
value the more significant the variable):
Equation 1
MC = 181.43 + 0.27A2 + 20.509D2
(-2.92) (5.30) (4.35)
(R2 = 0.44; F2 = 20.81)
Where
MC = Minimum costs/case
A = Age
D = Dean's Index
and for optimum standard costs:
Equation 2
S = -1581.12 - 2.333(A)2 + 147.74(D)2
(3.58) (6.38) (4.60)
(R2 = 0.51; F2 = 26.07)
Where
S = Optimum costs/case.
The focus of the analysis was to as-
sess the dental treatment costs of life-
time residents of a community who
were exposed to water fluorides
throughout their lives. Any assessment
of the impact of defluoridation must in-
clude its effect on the caries activity in
the community. The average DMFS
scores determined by Segreto and
Collins in the first study were used to
develop the treatment cost based on the
water fluoride level. The dollar cost was
computed using the DMFS for each
water fluoride level multiplied times 28
(teeth) times $15 (per surface). The re-
sulting figure would be the per capita
costs of treatment for dental caries.
Major Conclusions From the
Study Were as Follows
1. The mean minimum treatment
costs for correcting cosmetic discol-
oration exceeded the costs of restoring
dental function (using Dean's Classifica-
tion). However, the costs for restoring
function in the severe category ex-
ceeded the costs for correcting cos-
metic discoloration. These findings
were also true when the cases were
evaluated using the Visible Mottling
Index.
2. The mean optimum treatment
costs for correcting cosmetic discol-
oration exceeded the costs for restoring
dental function for mild and moderate
mottling (using Dean's Score and the
Visible Mottling Index), however, the
costs for restoring function exceeded
the costs for correcting cosmetic discol-
oration in the severe category (using
both Dean's Score and the Visible Mot-
tling Index).
3. Where indicated, bleaching is an
effective treatment for the cosmetic dis-
coloration of teeth resulting from dental
fluorosis.
The full report was submitted in fulfill-
ment of Cooperative Agreement No.
CR809403 by the University of Texas
Health and Science Center under the
sponsorship of the U.S. Environmental
Protection Agency.
E. Collins is with University of Texas Health Science Center, San Antonio, TX
78284.
Robert M. Clark is the EPA Project Officer (see below).
The complete report, entitled "Analysis of Costs for the Treatment of Dental
Fluorosis." (Order No. PB 87-170 817/AS; Cost: $13.95, subject to change)
will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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