Sugar Restriction for Caries Prevention: Amount and Frequency. Which Is More Important?

Abstract

The World Health Organization guideline to use less sugar may be an opportunity and support for dentistry in its goal to get the message of using less sugar across to the public. Two ways (with all the combinations of these) to achieve a reduction of sugar consumption are the reduction of the amount of sugar in products or the reduction of the frequency of consumption of sugar-containing products. Which sugar-reducing strategy is best for caries prevention? To answer this question, this manuscript discusses the shape of the dose-response association between sugar intake and caries, the influence of fluoridated toothpaste on the association of sugar intake and caries and the relative contribution of frequency and amount of sugar intake to caries levels. The results suggest that when fluoride is appropriately used, the relation between sugar consumption and caries is very low or absent. The high correlation between amount and frequency hampers the decision related to which of both is of more importance, but frequency (and stickiness) fits better in our understanding of the caries process. Reducing the amount without reducing the frequency does not seem to be an effective caries preventive approach in contrast to the reciprocity. Goals set in terms of frequency may also be more tangible for patients to follow than goals set in amount. Yet, in sessions of dietary counselling to prevent dental caries, the counsellor should not forget the importance of quality tooth brushing with fluoride toothpaste.

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Current Topic
Caries Res
Sugar Restriction for Caries Prevention: Amount
and Frequency. Which Is More Important?
Cor van Loveren
Department of Cariology, Academic Centre for Dentistry (ACTA), University of Amsterdam and Vrije Universiteit
Amsterdam, Amsterdam , The Netherlands
Received: January 30, 2018
Accepted after revision: April 17, 2018
Published online: August 9, 2018
Cor van Loveren
Department of Cariology, Academic Centre for Dentistry (ACTA)
University of Amsterdam and Vrije Universiteit Amsterdam
Gustav Mahlerlaan 3004, NL–1081LA Amsterdam (The Netherlands)
E-Mail C.van.Loveren @ acta.nl
© 2018 The Author(s)
Published by S. Karger AG, Basel
E-Mail karger@karger.com
www.karger.com/cre
DOI: 10.1159/000489571
Keywords
Sugar restriction · Dental caries
Abstract
The World Health Organization guideline to use less sugar
may be an opportunity and support for dentistry in its goal
to get the message of using less sugar across to the public.
Two ways (with all the combinations of these) to achieve a
reduction of sugar consumption are the reduction of the
amount of sugar in products or the reduction of the frequen-
cy of consumption of sugar-containing products. Which sug-
ar-reducing strategy is best for caries prevention? To answer
this question, this manuscript discusses the shape of the
dose-response association between sugar intake and caries,
the influence of fluoridated toothpaste on the association of
sugar intake and caries and the relative contribution of fre-
quency and amount of sugar intake to caries levels. The re-
sults suggest that when fluoride is appropriately used, the
relation between sugar consumption and caries is very low
or absent. The high correlation between amount and fre-
quency hampers the decision related to which of both is of
more importance, but frequency (and stickiness) fits better
in our understanding of the caries process. Reducing the
amount without reducing the frequency does not seem to
be an effective caries preventive approach in contrast to the
reciprocity. Goals set in terms of frequency may also be more
tangible for patients to follow than goals set in amount. Yet,
in sessions of dietary counselling to prevent dental caries,
the counsellor should not forget the importance of quality
tooth brushing with fluoride toothpaste.
© 2018 The Author(s)
Published by S. Karger AG, Basel
Introduction
It is beyond debate that the consumption of sugars
containing foods imposes a risk on the integrity of our
teeth. The actual risk of a certain food is modulated by
many factors that are divided in food-related factors and
consumer-related factors. Food-related factors involve
the release of the sugars, the stickiness of the product al-
though this may be less important at sites where food is
impacted, and to a lesser extent, the type and concentra-
tion of the sugar. Consumer-related factors are the fre-
quency of sugar consumption, the drinking and chewing
habits, the chewing and swallowing efficiency, salivary
flow and composition, the presence of cariogenic dental
This article is based on a contribution to the Joint ORCA-EADPH
Symposium on Sugar and Oral Health, July 6, 2016.
is article is licensed under the Creative Commons Attribution-
NonCommercial-NoDerivatives 4.0 International License (CC BY-
NC-ND) (http://www.karger.com/Services/OpenAccessLicense).
Usage and distribution for commercial purposes as well as any dis-
tribution of modied material requires written permission.

vanLoveren
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plaque and the use of fluorides. It is a common observa-
tion that with the comparable number of sugar-contain-
ing products, some people are able to manage the risk and
will not develop caries, while others develop significant
amounts of dental caries.
Reducing sugar consumption seems to be an important
preventive measure to reduce caries risk. The new World
Health Organization (WHO) guideline advocates to re-
duce free sugar consumption below 10% of the energy in-
take (10 E%) or even below 5 E% of the diet. Free sugars
are defined as all monosaccharides and disaccharides add-
ed to foods by manufacturer, cook or consumer and sugars
naturally present in honey, syrups, fruit juices and fruit
juice concentrates [WHO, 2015]. Assuming a daily energy
intake of 2,000 kcal, 10 E% equals 50 g of sugar a day and
5 E% equals 25 g a day. At the moment, for instance in the
Netherlands, the average daily energy intake from free
sugars is 14% for the whole population but varies from
20% for children and adolescents to 11% for those over the
age of 50 [Sluik et al., 2016]. Added sugars constitute ap-
proximately 80–90% of this energy intake from free sug-
ars. Significant contributors, for approximately 80%, are
non-alcoholic beverages (sugar sweetened beverages and
fruit drinks), sweets and candy and dairy products (with
the exception of milk) [Sluik et al., 2016].
The WHO guideline to use less sugar may be an op-
portunity and support for dentistry in its goal to get the
message of using less sugar across to the public. Two ways
(of course with all the combinations of these) to achieve
a reduction of sugar consumption are reduction of the
amount of sugar in products or reduction of the number
of consumptions of sugar containing products, which
may or may not result in a reduction of the frequency of
consumption. The main question is: Which sugar-reduc-
ing strategy is best for caries prevention? To answer this
question, 3 issues are of importance: (1) the shape of the
dose-response association between sugar intake and car-
ies, (2) the influence of fluoridated toothpaste usage on
the association of sugar intake and caries and (3) the rela-
tive contribution of frequency and amount of sugar in-
take to caries levels [Bernabé et al., 2016].
In order to be able to advice properly, the quality of
evidence has to be taken into account. Normally, high-
quality evidence is necessary to support preventive mea-
sures. Unfortunately, there are no high-quality random-
ized controlled trials that study the relationship between
sugar intake and dental caries. So we have to rely on a few
clinical and in situ intervention studies, prospective co-
hort studies, retrospective cohort and retrospective case
control studies, and cross-sectional studies. Conclusions
of these types of studies should well fit in the bio-chemical
model of caries development, which predicts that more
demineralization time and periods and less remineraliza-
tion time and periods increase caries risk.
Dose Response Curve between Sugar Consumption
and Caries
In the late 1970s, before fluoride was widely used and
when the quality of oral hygiene was generally poor, Sree-
bny (1982) compared caries prevalence among 12-year-
old children in 47 nations with the availability of sugar
per capita. Of the 47 nations, 21 had sucrose availability
below 18 kg (approximately 10 E%) per person per
year,19 had availabilities of 18–44 kg (approximately 10–
24 E%) per person per year and seven nations had avail-
abilities of over 44 kg (> 24 E%) per person per year. The
mean number of decayed, missing or filled permanent
teeth(DMFT) of the 21 countries with a sugar supply be-
low 18 kg per capita per year was 1.2 ± 0.6. For 9 of the 19
countries, with an average sugar supply between 18 and
44 kg per person per year, the mean DMFT was 2 ± 0.7,
while for the other 10 of these countries the mean DMFT
was 4± 0.9. In the 7 countries where sugar supply exceed-
ed 44 kg per capita per year, the mean DMFT was 8 ± 2.4.
A regression calculation with these data revealed an in-
crease of 1 DMFT at the age of 12 for every 25 g sugar
availability in a day. A similar comparison for 6-year-old
children in 23 nations showed a less strong correlation:
1dmfs for every 50 g of sugar availability a day [Sreebny,
1982]. Sreebny (1982) considered that 18.25 kg (approxi-
mately 10 E%) per person per year may represent an up-
per limit of safe, or at least “acceptable,” sugar consump-
tion form the perspective of caries activity. Based on the
data of Sreebny (1982) and the effect of the wartime diets
[Tacheuki, 1962], Sheiham (1983; 1991) suggested that
the relationship between sugar intake and caries levels is
sigmoid. Below approximately 15 kg/person/year most of
the population will not develop dental caries. Between 15
and 35 kg there is a steep increase in the rate of caries.
Beyond 35 kg, the dose-response curve flattens. In many
western societies, the sugar availability is around or above
40 kg/person/year. The sigmoid relationship would ex-
plain why the relative small differences in sugar con-
sumption between persons in these societies are not nec-
essarily reflected in differences in caries experience. No
other studies, however, confirm the sigmoid curve. Most
studies found no, a linear or a log-linear relationship be-
tween sugar consumption and caries.

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Effect of Fluoride on the Relationship between
Sugars and Caries
In more recent studies in countries where fluoride
supplements are widely used, the relationship between
sugar availability and caries was less clearly observed.
Woodward and Walker (1994) studied the relationship
in 61 developing countries and 29 industrialised coun-
tries. In the developing countries, approximately 26% of
the variation in the caries data was explained by sugar
availability. In the industrialized countries, less than 1%
was explained, suggesting that, where fluoride is avail-
able, variation in the availability of sugar may be of less-
er importance as determinant of caries prevalence and
severity. Ruxton et al. (1999) used data from Sreebny
(1982) and Woodward and Walker (1994) to inventory
sugar availability and dental caries in more than 60
countries in the 1970s and 1980s to assess the relation
between caries rates and the sugar supply. In 18 coun-
tries, both DMFT and the sugar supply declined, where-
as in 25 countries, DMFT declined and sugar supply in-
creased. In another 18 countries, the incidence of caries
and the sugar supply increased. The authors concluded
that the relationship between sugar reduction and caries
on a nation-wide basis was clearly unreliable. In 2008,
Downer et al. (2008) reported the relationships between
dental caries experience of 12-year-old children in 29
countries of Europe and four independent variables: na-
tional wealth (GDP), population per active dentist; sug-
ar disappearance (kg/capita/year); and volume sales of
toothpaste (L/capita/year). Mean DMFT showedastrong
negative association with national GDP (r = –0.729, p <
0.01), while toothpaste sales showed a statistically sig-
nificant positive association with GDP (r = 0.599, p <
0.05) as did sugar disappearance (r = 0.575, p < 0.01).
Paradoxically, caries experience yielded a strong nega-
tive correlation with sugar disappearance (r = –0.561,
p< 0.01). The authors suggested as possible explanation
for the anomalous association of low mean DMFT with
high sugar disappearance in Western Europe that the
extensive use of, mainly fluoride-containing, tooth-
pastes neutralise the potential damage from high sugar
consumption [Downer et al., 2008]. A recent global eval-
uation [Masood et al., 2012] confirmed that among
high-income countries, there is a negative correlation
between sugar disappearance (kg/capita/year) and den-
tal caries level, while in low-income countries, this cor-
relation is a positive one. In the ensuing discussion,
Masood et al. (2012) explain their findings by the acces-
sibility to fluoride.
The low correlation between sugar consumption (dis-
appearance/availability) and caries prevalence when fluo-
ride is used indicates that proper use of fluoridated tooth-
paste has a major preventive effect on caries prevalence,
although this is not easily achieved at every site in the
mouth. This low correlation is no licence not to regard the
reduction of sugar intake as a caries-preventive measure.
But at least, even during dietary counselling the para-
mount importance of fluoride should always be stressed.
Another token of the importance of fluoride use on the
relationship between caries is the fact that the dramatic
decline in dental caries prevalence that occurred over the
past thirty years in most Western industrialized countries
cannot be attributed to reduction of the availability of
sugars. Ecological observations in many countries con-
firm that sugar consumption remained virtually un-
changed high in this period of caries decline [Nyvad,
2003; Einarsdottir and Bratthall, 1996]. In a special issue
of the European Journal of Oral Sciences, experts from all
over the world attributed the decline in caries prevalence
to the widespread use of fluoride toothpaste [Bratthall et
al., 1996].
Seventeen primary studies on the association between
sugars and caries published between 1995 and 2006 were
reviewed by Ruxton et al. (2010). Ten of them were epi-
demiological studies either cross-sectional or longitudi-
nal and 7 of them were experimental with surrogate out-
comes. The outcomes were classified as no association
(5out of the 10 epidemiological studies), a positive asso-
ciation (1 out of the 10 epidemiological studies) or a com-
plex association meaning statistically significant associa-
tion in certain subgroups (4 out of the 10 epidemiological
studies). The subgroups in which the association between
the use of sugars and caries was demonstrated were the
groups that brushed the teeth once a day or less [Ruxton
et al., 2010]. An example of a study with a complex out-
come was the cross-sectional National Diet and Nutrition
Survey of children aged 1.5–4.5 years [Gibson and Wil-
liams, 1999]. Caries was associated with sugar confection-
ary (amount and frequency) but only in children whose
teeth were brushed less than twice a day.
Out of the 7 experimental studies, 3 were classified as
having no association, 2 showing a positive association
and another 2 showing a complex association. A positive
association was found in a randomised controlled trial
where subjects exposed enamel attached to prosthetic de-
vices to sugar (10%), starch (2%) or the combination. The
solutions were dripped onto the blocks 8 times per day.
Greatest demineralisation was found with starch/sucrose
combination > sucrose > starch = water [Ribeiro et al.,

vanLoveren
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2005]. In the other positive experiment, lactic acid pro-
duction in saliva was examined while rinsing with solu-
tions containing 5, 10, 15, 20 and 30% sucrose (w/v). Lac-
tic acid in saliva was significantly increased with increas-
ing sucrose concentrations up to 15% sucrose then levelled
out at higher concentration [Linke and Birchmeier, 2000].
The latter 2 studies are relevant as the first one suggests
that starch is an important co-determinant of cariogenic-
ity, while the second one touches upon the topic to what
extent sugar should be reduced in products to make these
less acidogenic.
At the 2001 National Institutes of Health Consensus
Development Conference on Caries, Burt and Pai (2001)
reported that of the 69 studies on diet and caries pub-
lished between January 1980 and July 2000, only 2 showed
a strong diet-caries relationship. Of the other studies, 16
showed a moderate relationship and 18 showed a weak
relationship. Burt and Pai (2001) emphasized that the
findings of their review differed from sugar-caries studies
published in the decades before fluoride use. Although
the papers reviewed indicated a decline in caries risk in
relation to sugar intake, Burt and Pai (2001) attributed the
decrease to fluoride use. They concluded that sugar con-
sumption is likely to be a more powerful indicator for risk
of caries infection in persons who do not have regular
exposure to fluoride [Burt and Pai, 2001].
Amount versus Frequency of Sugars Consumption
Several studies examined the relationship between car-
ies and sugar consumption expressed in multiple ways
based on the same data collection being, for example, a
diet registration, prospective or retrospective for a vary-
ing number of days, or a food frequency questionnaire.
The relationship between various expressions of sugar
consumption is logically high and, for instance, Bernabé
et al. (2016) showed that amount and frequency of con-
sumption correlated positively with r = 0.64. This predicts
that the logistic regression coefficients for the various ex-
pressions of sugar consumption vary within a limited
range. When calculating these coefficients, the number of
values of the independent variable (sugar consumption)
may be important for the statistical significance. Many
values would spread the participants in a veil cloud, while
fewer values would compress them in a thick cloud result-
ing in a larger deviation from the mean.
Rugg-Gunn et al. (1984) showed that the bivariate cor-
relations with caries were higher when the sugar variables
were calculated for snacks alone than for all intakes. The
differences were smaller when only fissure caries was as-
sessed. Burt et al. (1988) showed the energy from total
sugars and meal sugars was not significant different be-
tween low caries children compared to high caries chil-
dren, but the energy from snacks, snack carbohydrate and
snack sugars was significant. Bernabé et al. (2016) showed
in Finnish adults that DMFT increased over a period of
4–11 years by 0.15 and 0.1 units for every additional oc-
casion of sugars consumption and every 10 g of sugars
consumed respectively. In the mutually adjusted model,
only the amount of sugars intake remained significantly
associated with DMFT levels although the coefficient re-
duced to 0.09. When the population was divided in those
who used fluoride daily versus those who used fluoride
less frequently the coefficient for amount was 0.08 and for
frequency 0.12 for the frequent F-users and 0.26 and 0.43
at infrequent fluoride use. This is again a strong indica-
tion of the importance of the daily use of fluorides.
Dusseldorp et al. (2015) operationalised the number of
eating moments in more than 7 a day versus less than 7 a
day, which is the nationally recommended maximum fre-
quency of food and drinks consumption per day in the
Netherlands. With this operationalisation, the number of
foods and drinks consumed per day had impact on caries
prevalence in the primary teeth of 9 year olds (OR 2.78,
95% CI 1.21–6.40), but not on the caries experience in the
primary teeth of 9 year olds (OR 0.97, 95% CI 0.65–1.44)
or prevalence and experience in the permanent dentition
of 15- or 21-year-olds. The authors concluded that the
used number of eating moments is an appropriate cut-off
point for recommendations. In this study, caries preva-
lence was approximately 52 and 78% for the 15-year-olds
and 21-year-olds respectively.
A study conducted in nursery homes showed that
3-year-old low socio-economic schoolchildren with the
highest frequency of sugar consumption (4 ± 5 times per
day) at the nursery were 4.7 times more likely to have a
high caries increment over 1 year, compared to those with
the lowest frequency (1 ± 2.9 times per day; OR 4.7, 95%
CI 2.7–8.2; p < 0.001). Daily frequency of sugar intake at
the nursery showed a dose-response trend with the risk of
having high caries increment. Children having more than
32.6 g of sugar daily at the nursery were 3 times more like-
ly to have high caries increment than those having less
than that amount (OR 2.99, 95% CI 1.82–4.91; p < 0.001)
[Rodrigues and Sheiham, 2000]. Feldens et al. (2010)
studied the relationship between feeding practices in the
first year of life and the occurrence of severe early child-
hood caries at 4 years of age. A total of 340 children were
examined. The multivariable model showed a higher ad-

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justed risk of severe early childhood caries for the follow-
ing dietary practices at 12 months: daily breastfeeding fre-
quency at 12 months 0–2, 3–6, or ≥7 times showed RR
values of 1.00, 2.04 (95% CI 1.22–3.39), 1.97 (95% CI 1.45–
2.68; p < 0.001) respectively; number of daily meals and
snacks at 12 months < 7, 7–8, > 8 showed RR values of 1.00,
0.99 (95% CI 0.70–1.39) and 1.42 (95% CI 1.02–1.97; p =
0.025) respectively, bottle use for fruit juices/soft drinks at
12 months (No/Yes) demonstrated RR 1.41 (95% CI1.08–
1.86) for the users (p = 0.025); high density sugar foods at
12 months (> 50% of simple carbohydrates in unit of food)
(No/Yes) gave RR of 1.43 (95% CI 1.08–1.89; p = 0.003);
bottle use for liquids other than milk gave a RR 1.41 (95%
CI 1.08–1.86). The studies of Rodrigues and Shieham
(2000) and Feldens et al. (2010) strongly indicate that the
increased frequency of sugary foods impose caries risk in
the low socio-economic populations studied.
When considering the amount versus frequency issue,
the findings of the Vipeholm study are still relevant. As
much as 300 g additional sugar during the mean meals
did not increase caries risk, while the addition of sugary
snacks between meals did so significantly [Gustafsson et
al., 1954].
These data still support the scientific basis for dental
health professionals to focus their dietary advice on re-
ducing the frequency of intake of sugars. Also the type of
products, sugar sweetened beverages and fruit drinks,
sweets and candy, and sweetened diary products (milk
excepted) contributing to the intake of sugar [Sluik et al.,
2016] lend themselves to skip, to combine or to reduce the
moments of intake.
When Do Two Occasions Count for Two or One
It is generally accepted that a pH drop after a sugary
intake takes 30 min, implying that a second intake within
this 30 min is less harmful than a second intake after these
30 min. Probably, this time span was concluded from the
original experiments of Stephan and Miller (1940). PH-
telemetry experiments, however, showed that the pH
drop in dental plaque can continue far beyond these 30
min [Imfeld, 1977]. Obviously stickiness of the product
may be a determinant of this. Arcella et al. (2002) assessed
the relationship between the frequency of sugars and
starch intake and dental caries in 16-year-olds. Once
lunch and dinner were excluded, the mean number of
separate eating events was counted with no separating
time interval (i.e. every eating event was separately count-
ed) up to a separating interval of 60 min. The correlation
coefficients between DMFT and the frequency of eating
occasions thus established varied from 0.3 with no sepa-
rating interval time to 0.31 for the 45 min interval to sep-
arate the eating occasions. These results suggest that not
all separate eating events within the 45 min intervals nec-
essarily contribute to an increased caries risk. The authors
suggest that characterisation of eating events in real-life
conditions deserves more attention. An interesting ob-
servation by Arcella et al. (2002) was that the correlation
between the number of intakes of sugars and starches and
DMFT was significantly higher for boys than for girls,
which the authors ascribed to poorer oral hygiene and
thus fluoride use of boys.
Breakfast
When advising patients, dental professionals should
not only convey the rules but also make them realize why
sugar is consumed so frequently. Besides the nice taste, an
important reason might be having feelings of appetite or
being hungry. This may be the result of insufficient quality
or skipping of the main meals, which has an effect on blood
glucose levels and ghrelin; both are involved in regulating
this hunger feeling. Dusseldorp et al. (2015) showed for 9
and 15-year olds that a low breakfast frequency per week
was related with having caries experience, while the fre-
quency of brushing teeth per day was related with the de-
gree of caries experience. Also, other studies [Nagel et al.,
2009; Cinar et al., 2011; Bruno-Ambrosius et al., 2005] con-
firmed a relationship between caries and skipping break-
fast. Having breakfast has also been associated with tooth
brushing twice a day [Macgregor et al., 1996; Levin and
Currie, 2010]. An explanation for this might be that both
behaviours are symptoms of lifestyle structure and regular-
ity. Dusseldorp et al. (2015) observed that the lifestyle fac-
tors were not significant determinants of caries experience
or the degree of caries experience for the 21-year-olds. This
indicates that life style factors may become less significant
at an older age. It is of importance to recognize that skip-
ping breakfast is also suggested to contribute to childhood
obesity [Szajewska and Ruszczynski, 2010].
Reducing the Amounts of Free Sugar in Products
Several manufacturers and retailers assist clients to re-
duce the intake of free sugars by clearly indicating wheth-
er products are high in sugars > 29 g per 100 g, middle to
high in sugars (17–29 g per 100 g) low to middle in sugars

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(5–17 g per 100 g) and low in sugars (0–5 g per 100 g)
[Heijn, 2016]. It would be interesting to compare the car-
iogenicity of products from these various categories. PH
telemetric measurements showed the pH curve in dental
plaque upon sucrose challenges with increasing concen-
trations (Fig.1) [Imfeld, 1977]. These data suggest that
maximum acid production is reached with concentra-
tions at or just above 10% sucrose. This would imply that
differences of cariogenicity of the products in the upper
3 categories of the manufactures/retailers “health” list
cannot be discerned, while products in the lowest cate-
gory may not be or may be cariogenic. Furthermore, it
has been claimed that the relative cariogenicity of a food
is not correlated with the amount of carbohydrates it
contains and it is not possible to estimate the minimal
cariogenic concentration of sugars in foods, since this
threshold varies with too many factors [Kandelman,
1997].
Intrinsic Sugars
The dietary advice for the reduction of caries is com-
plicated by the claim that so-called intrinsic sugars are not
cariogenic. Intrinsic sugars are sugars within the struc-
ture of fruits and vegetables. Indeed, when not released in
the oral cavity, these sugars may not contribute to caries.
But it is probably unrealistic to consume fruits without
releasing the intrinsic sugars, and experimental studies
indicate that consuming fruits maybe as cariogenic as
consuming fruit juices [Issa et al., 2011; Zaura et al., 2005].
There are multiple arguments that it is better to replace
foods high in free sugars with fresh fruit and the dental
health professionals should encourage people to do so,
but they should still be alert not to increase the frequency
of intake.
Dietary Advice
Dietary advice by dental health professionals should be
consistent and not conflict with advices from other health
professionals, based on the evidence in the various pro-
fessional fields and based on the national dietary guide-
lines. In this respect, it has to be remarked that not all
national boards of health or nutrition have (yet) adapted
the WHO-guidelines and that national guidelines may be
less strict on the sugar intake. Furthermore, when people
receive dietary advices from the dental health profession-
al, the advices may be more readily accepted when the
professional can make unequivocally clear that the advice
benefits caries prevention. If not, the person may not un-
derstand why the dental professional interferes with his
diet and not accept the advices. This does not dismiss the
dental professional from also explaining the benefits for
general health on limiting or reducing the intake of sug-
ars. There is a risk that an overzealous dental profession-
al may suggest alternatives for sugar take that increase the
15 mL
0.025%
15 mL
1.25%
Sucrose
15 mL
2.5%
Sucrose
15 mL
5%
Sucrose
15 mL
10%
Sucrose
10 mL
3% U
10 mL
3% U
7
6
5
pH
4
PC PC PC PC PC PC
3 7 9 21 24 27 29 41 44 47 49 60 64 67 69 81 86 90 92 104 109 113 min
Fig. 1. pH curves in dental plaque after consecutive rinses with solutions of increasing sucrose concentrations [Imfeld, 1977].

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intake of fats and salt. Under the premise that it benefits
oral health, the dental health professional can make stron-
ger restrictions than the general guidelines as long as they
do not harm general health. If so, dentistry even has the
responsibility to claim at the national boards of health
and nutrition to accept these restrictions. The dental pro-
fessional should recognize the role of diet in patients with
non-communicable diseases and encourage these pa-
tients to seek for adequate professional guidance. In gen-
eral, a diet that is beneficial to both general and dental
health is one that is low in free sugars, saturated fat and
salts, high in fresh fruits, vegetables, nuts and seeds, who-
legrain carbohydrates with modest amounts of legumes,
fish, poultry and lean meat and plenty of fluids preferably
water and milk and thus, modest with sugar sweetened
beverages [Moynihan et al., 2017].
Conclusion
This manuscript discussed (1) the shape of the dose-
response association between sugar intake and caries, (2)
the association between sugar intake and caries at expo-
sure to fluoride toothpaste and (3) the relative contribu-
tion of frequency and amount of sugar intake to caries
levels. Most studies on the association between sugar in-
take and the amount of caries showed a no, a linear or
log-linear association with relatively low correlation co-
efficients. When applying fluoride by appropriate tooth-
brushing twice a day, the association reduces significant-
ly or is virtually absent. The relative contribution of the
frequency versus the amount of sugar intake is difficult
to discriminate because of the high correlation between
frequency and amount. It is clear that the relative cario-
genicity of a food is not directly correlated with the
amount of sugar it contains, unless the amount is very
low and it is clear that it is not possible to estimate the
minimal cariogenic concentration of sugars in foods,
since this threshold varies with too many factors. A mod-
el where frequency is more important fits better in the
biological knowledge of the caries process. Also, the
types of products contributing to the intake of free and
added sugars lend themselves to be skipped or to be com-
bined to reduce the numbers of intake. Goals set in terms
of frequency may also be more tangible for patients to
follow. Yet, in sessions of dietary counselling to prevent
dental caries, the counsellor should not forget to high-
light the importance of quality tooth brushing with fluo-
ride toothpaste and strongly support this.
Disclosure Statement
The author declares no conflicts of interest.
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