Background: Although fluoridation of public water supplies has continued to offer reductions in dental caries, concerns have
been raised about fluorosis of the upper anterior teeth. Photographs were taken of the upper front teeth of children living in
three areas of NSW; one area without afluoridated public water supply, a location with an established long term fluoridation
scheme and a third area that was only recently fluoridated. The photographs were randomised and scored for fluorosis by an
independent examiner. The scoring was a blind assessment as a child's location would not be known.
Methods: Following an intra-oral examination for dental caries, consented children had their upper incisors cleaned with
gauze, dried for 15 seconds and a photograph of their upper central incisor teeth was taken using a SOPRA Intra Oral Camera.
An independent examiner scored the upper central adult incisors for fluorosis utilising the TF Index.
Results: The majority of participants in all three areas did not have any detectable fluorosis, 55.8% for the non-fluoride area, 72.1% for the established fluoride area and 66.5% for the newly fluoridated location.
The unfluoridated area had the highest proportion of children with TF scores of 3+ (3.1%) compared with the established
fluoridated area (2.5%) and the newly fluoridated area (1.5%).
Conclusions: There was no evidence of water fluoridation causing aesthetic problems in the upper central incisor teeth of
10-12 year old children in New South Wales Australia.
Keywords: Fluorosis; Water fluoridation; Children photographs; Blinded study
New South Wales (NSW) has a long history of water fluoridation
 and the 2007 Child Dental Health Survey 
showed that children living in fluoridated communities had
less dental caries than those not consuming fluoridated water.
In addition fluorosis of the incisors was not reported as
an aesthetic problem. However worldwide there is an association
between dental fluorosis and the level of fluoride in the
water supplies. The majority of evidence on this issue relates
to countries such as parts of India and China where naturally
occurring fluoride levels are up to four to five times greater
than water in Australia which has community water schemes
where the fluoride level is adjusted to 1ppm  Never the less concern has been raised by some commentators
 that examiner bias may be an issue when scoring
fluorosis and assessing caries in comparative studies. There
may indeed be an inherent bias not to score enamel defects in
a known fluoridated community. One way to deal with this
criticism is to photograph teeth and employ an independent
examiner, who has no knowledge of a child's location to examine
the teeth for fluorotic lesions. If the photographs are
randomised it is possible to argue that a blinded study has
been undertaken, as the examiner will be unaware of the level
of fluoride in each participant's local water supply.
Photographs have been used before to assess fluorosis [5-7]
and have been shown to be a useful tool. The opportunity
arose to utilise photographs to record fluorosis in different
areas of NSW, as a study was underway to monitor a new
fluoridation scheme in the Local Government Area (LGA)
of Gosford (NSW). Two other areas were included in the research study the Wyong Local Government Area which has
been fluoridated for over forty years and the unfluoridated
Shires of Ballina and Byron Bay. Children aged 10-12 years
living in the three areas, whose parents consented, received a
dental examination in School. In addition, as part of the project,
the children had all their upper central incisors photographed
so that enamel defects could be recorded.
The objective of this paper is to report on the levels of fluorosis
seen on the photographs and assessed by an independent examiner
using the TF index.
Children aged 10-12 years from three areas of NSW who were
enrolled in a study to monitor the impact of water fluoridation
on dental caries8also had photographs taken of their two
upper permanent incisors (11 and 21) after the clinical examination.
This was part of an investigation to determine the
potential value of using images to provide a way of blinding
examiners to the geographical location of the participants, so
that the fluoridation status of an area would not be known. The
incisorswere cleaned with gauze, and air-dried for 15 seconds
before the photograph was taken. The children were examined
in a supine position on a mobile dental chair. Teeth were excluded
if they had tooth coloured restorations, orthodontic
bands in place, only partially erupted, or presented a blurred
The camera used to capture the images was a SOPRA Intra
Oral Camera (617 PAL) which has a built in light source. The
images were stored on a laptop computer. Following the collection
of the images, the study coordinator randomised the
images and kept an independent master list so that the results
could be linked to the three study areas. A researcher who was
not involved in the main fluoridation study was recruited to
score the images of the anterior teeth for Fluorosis using the
TF index . The diagnostic codes for the TF index are shown
0 The normal translucency of the glossy creamy white enamel remains
after wiping and drying of the surface.
1 Lines are seen running across the tooth surface. Such lines are
found on all part of the surface. The lines correspond to the position
of the perikymata. In some cases, a slight "snow-capping" of incisal
edge may also be seen.
2 The opaque white lines are more pronounced and frequently merge
to form small cloudy areas scattered over the whole surface. "Snow
–capping" of the incisal edges is common.
3 Merging of the white lines occurs, and cloudy areas of opacity occur
over many parts of the surface. In between the cloudy areas white
lines can also be seen.
4 The entire surface exhibits a marked opacity, or appears chalky
white. Parts of the surface exposed to attrition or wear may appear
to be less affected.
5 The entire surface is opaque, and there are losses of enamel surface
of any size.
X Not recorded/Excluded in Figure 1. The data were recorded on an Excel spreadsheet.
Five per cent of the images were scored to check for internal
examiner consistency and another trained examiner (P.M)
re-read 50 images to ensure the diagnostic standards had not
altered since an initial one day training program. Intra-and inter-
examiner reliability of the TF scores was determined by
calculating Kappa statistics. Kappa values range from negative
values to a maximum value of 1.0 when there is complete
agreement. Uni-variable ordinal logistic regression was used
to determine differences in enamel lesions between study sites.
All the images were scored on the same computer and monitor.
For the purposes of this paper only the data for the upper
right central incisor will be reported as it will make the tables
easier to read.
The study was approved by the State Education Research
Process (SERAP) of the NSW Department of Education and
Training. The Catholic Education Commission also gave permission
to involve schools within their jurisdiction (SERAP
number 2008052). The South West Area Health Service
(SWAHS) Human Research Ethics Committee granted ethical
approval for the school based surveys HEREC 2008 / 314.18
(2758): All RED 08/WMEAD/57.
Seven hundred and forty four images were assessed for the
LGA of Gosford, 360 for the Shires of Ballina / Byron and 723
for the LGA of Wyong (Table 1). It can be seen that the majority
of participants in Gosford (66.5%) Ballina /Byron (55.8%)
and Wyong (72.1%) did not have any detectable fluorosis (Table 1).
Table 1 also shows that 32.0 per cent (n=238) of the participants
in Gosford had barely detectable or perceptible fluorosis
(TF=1 or 2) compared with Ballina/Byron 41.1 per cent
(n=148) and Wyong 25.4 per cent (n=184). Ballina / Byron had the highest proportion (Table 1) of participants
with T/F scores of 3 and 4 (3.1%; n=11) compared with
Gosford (1.5%; n=11) and Wyong (2.5%, n=18)
The ordinal regression analysis (Table 2) shows that the differences
between Wyong and Ballina / Byron and Wyong and
Gosford are statistically significant, with the non-fluoridated
community of Ballina/Byron having a higher prevalence of
fluorotic lesions than Wyong, and also the newly fluoridated
area of Gosford has a higher prevalence of lesions than Wyong.
The number of teeth which could not be assigned a TF score
was higher (Table 3) in Ballina and Byron, 11.7 per cent compared
with Gosford 2.6 per cent and Wyong 3.2 per cent. There
was a higher proportion (3.0%; n=23) of non fluorotic lesions
in Wyong than in Gosford (0.6%; n=5) and in Ballina/Byron
(0.3%; n=1). The intra-examiner mean Kappa score was 0.76
when the repeat examinations for Fluorosis were assessed.
Whilst the Kappa Score for inter-examiner agreement for the
50 joint assessments was 0.61.
The intra-examiner mean Kappa score was 0.66 (95% CI 0.54 -
0.77) when the ten percent of repeat examinations for fluorosis
were compared with the original recordings. The Kappa score
for the inter-examiner agreement for the 50 joint assessments
with the gold standard Trainer was 0.61 (95% CI; 0.57 – 0.73).
This paper presents the results of a photographic assessment of
the presence of enamel defects on the upper right central incisor
of children aged 10-12 years living in three areas of NSW
with different water fluoridation histories. It is not possible to
assign a direct cause and effect for the presence of fluorotic
lesions as there are many confounders which could influence
the outcome. Never the less the photographs were scored blind
to the area of residence and little difference was noted in the
prevalence of enamel lesions between any of the areas, despite
one location having been fluoridated for over 40 years.
The use of the camera enabled the T/F scores to be recorded
blind to a participant's area of residence. The examiner was not
aware of whether an individual image came from a fluoridated
or unfluoridated area. This is important as critics of fluoridation
research argue that there is an inherent bias towards finding
positive results from any fluoride investigation. The results
from this study cannot be considered to have a problem with
location bias, which is the most positive benefit. The major issue
associated with using cameras as a diagnostic tool is the
time factor. The screening examination takes longer because
of the need to carefully position the participant so as to capture
a readable image and then there is the time spent examining the pictures at a central location. Using cameras for all dental
surveys may well not be economically feasible, but there could
be a place for this technique in population based fluoridation
The teeth were cleaned with gauze and then dried with compressed
air for 15 seconds, before being photographed. This
is a somewhat artificial situation as teeth exist in a moist environment.
However photographing teeth wet can compromise
the quality of the image and minor fluorotic lesions can
be missed when the enamel surface is wet, however drying
does highlight enamel defects . The SOPRA camera gave
a good crisp image and proved to be robust and reliable in the
field. The software is well written and examiners did not find
it difficult to save images and export them to the study laptop
computers. The inter-examiner agreement between the independent
researcher and the trainer was fair (Kappa 0.61) and
reflects issues with the T-F index  when it comes to deciding
on the difference between developmental anomalies, white
spots and fluorosis. However the independent examiner did
remain relatively consistent when undertaking the repeat examinations
The levels of fluorosis recorded at T/F 3 and above were low
for all areas and fluoridated Wyong did not match the fluorosis
diagnosis of T/F 3+ of 7 percent reported in a photographic
study in the fluoridated city of Newcastle UK. A potential
weakness of our study is that fluorosis was only measured in
the permanent central incisors, because it is more straightforward
to gain reasonable images of these teeth.
The NSW study also provides information in the three areas on
how fluoride influences the early maturation of tooth enamel
on the upper permanent incisors for both water fluoridation
and fluoride toothpaste . Reporting on the whole dentition
is difficult but clearly aesthetics is one of the most important
parameters, hence the focus on the upper front teeth.
However the finding that the fluoridated Local Government
Area ofWyong has a smaller proportion of T/F3+ scores than
the shires of Ballina/Byron which is not fluoridated is an interesting
result. This difference may well be due to non-response
bias, as the country shires had a lower positive consent rate
than the two Central Coast LGA's. The smaller proportion of
T/F 3+ scores in Gosford will not have been influenced by the
recent addition of fluoride to the public water supplies in 2008
because the children in our study were 10-12 years of age, and
enamel maturation for the central incisors is nearly complete
by around four years of age. So our concerns about non response
bias are not necessarily correct given the results from
the newly fluoridated area.The high proportion (44.2%) of
children from unfluoridatedBallina/Byron Shires is somewhat
unusual and is higher than proportions recorded by Tavener,
et al. . and Tabari, et al.  which were around 36 and 23
per cent respectively for air dried upper incisors. The study did
not examine the age at which brushing with a fluoride toothpaste
began, as this can impact on the prevalence of noticeable
fluorosis especially if a child under four years of age swallows
large amounts of toothpaste . However it is unlikely that
brushing behavior would be markedly different between the
three study areas. The finding of most significance from this
'blinded' study is that noticeable fluorosis (T/F3+) is not a problem in any of the three areas of NSW and is not directly
related to a communities' water fluoridation status. The low
levels of fluorosis are supported by the NSW 2010 Teen Survey
which also found low levels of 3+ TF scores in both fluoridated
(0.1%) and the unfluoridated (2.0%) communities. In
this study low levels of fluorosis recorded by the Thylstrup and
Fjerskov (TF)9Index suggest that a more detailed assessment
process may well be helpful. One potential index that could
be used is Russell's Differential Diagnosis Criteria18to differentiate
fluoroticdiscolouration. This study provides interesting
findings and is worthy of more research on other age groups,
geographical locations and the use of different assessment indicies.
In this study the number of noticeable fluorotic lesions of (T/F
3+) recorded in the three NSW study areas by photographs
and scored 'blind' was low and was not related to the water
fluoridation status of the communities.
The majority of the expenditure was funded by the Centre for
Oral Health Strategy (NSW Health), and Northern Sydney and
Central Coast Area Health Service. Contributions to the cost
of the cameras were provided by Colgate Palmolive (Australia)
and the Australian Dental Association (NSW Branch). The
research would not have been possible without the administrative
skills of Mrs Cathy Davison and the secretarial assistance
of Mrs Rachael Moir. The research team would like to thank
the teachers, parents and children for their kind co-operation