TRABAJO DE FIN DE GRADO Grado en Odontología
SOFT DRINKS pH AND ITS RELATION WITH ENAMEL EROSION
Madrid, curso 2020/2021
258
Abstract
Objective: The purpose of this research was to analyze the effect of different soft drinks pH in relation to the critical enamel pH and erosion creation.
Materials and Methods: The present research consisted of two parts: a literature review, including the main concepts of the objectives proposed, and an experimental one, with the pH measurements to analyze its relationship with enamel erosion. Twenty commercially available beverages were used to measure the pH: pH1 (opening 17 – 20ºC) and pH2 (heat 25 – 30ºC). Inclusion criteria was stablished to find scientific articles on electronic databases.
Results: Data were collected and analyzed using a specific software (SPSS).
The pH assessment was analyzed with Paired t-student to identify statistical significance difference in pH values among the groups. The significance level was set at a level of =0.05 for all statistical test. A total of 62 articles were initially found and reviewed. T-test paired student revealed statistical difference between pH1 (opening 17 – 20ºC) and pH2 (heat 25 – 30ºC) with a p-value of 0.0005 (p0.05) and a trust interval of 95%. Conclusions: The acidic beverages have high potential leading erosion problem, increasing the caries formation due to its composition. The decomposition of beverage ingredients by the oral cavity also reduces the pH value and promotes the occurrence of corrosion.
Key words: demineralization, mineralization, remineralization, pH, dental erosion, tooth decay, citric acid, soft drinks, beverages, sweetener.
Resumen
Objetivo: El propósito de esta investigación fue analizar el efecto de diferentes pH de refrescos en relación con el pH crítico del esmalte y la creación de erosión. Materiales y métodos: La presente investigación constó de dos partes: una revisión bibliográfica, en la que se incluyeron los principales conceptos de los objetivos propuestos, y una experimental, con las mediciones de pH para analizar su relación con la erosión del esmalte. Para medir el pH se utilizaron 20 bebidas comerciales: pH1 (apertura 17 - 20ºC) y pH2 (calor 25 - 30ºC). Se establecieron criterios de inclusión para encontrar artículos científicos en bases de datos electrónicas. Resultados: Los datos se recogieron y analizaron mediante un software específico (SPSS). La evaluación del pH se analizó con la prueba t-student pareada para identificar la diferencia de significación estadística en los valores de pH entre los grupos.
El nivel de significación se fijó en un nivel de =0,05 para todas las pruebas estadísticas. Inicialmente se encontraron y revisaron un total de 62 artículos.
La prueba T de estudiante emparejada reveló una diferencia estadística entre el pH1 (apertura 17 - 20ºC) y el pH2 (calor 25 - 30ºC) con un valor p-value de 0,0005 (p<0,05) y un intervalo de confianza del 95%. Conclusiones: Las bebidas ácidas tienen un alto potencial que conduce al problema de la erosión, aumentando la formación de caries debido a su composición. La descomposición de los ingredientes de las bebidas por la cavidad oral también reduce el valor del pH y favorece la aparición de la corrosión.
Palabras clave: desmineralización, mineralización, remineralización, pH, erosión dental, caries, ácido cítrico, refrescos, bebidas, edulcorante.
Index
Introduction………5
THEORETICAL BACKGROUND 1. History of Soft drinks………..9
2. Basic knowledge of soft drinks………..10
3. Food consumption……….12
4. Caries definition, etiology and causes……….13
5. Dental caries classification………..14
6. Relationship between acid and teeth………16
6.1. Demineralization………..18
6.2. Remineralization………..21
7. Biomineralization………22
8. Importance of oral health……….23
9. pH………24
Objectives……….26
Materials and Methods 1. Literature review……….27
2. pH Experiment assessment……….28
3. Statistical analysis of pH assessment……….30
Results 1. Literature review………31
2. pH assessment………...31
Discussion 1. SWEETENER………33
2. Temperature and pH………..36
3. Acidulant……….………….37
Conclusions……….40
Responsibility………..…42
Bibliography……….43
Annexes……….47
INTRODUCTION
Soft drinks are very popular in the entire world, those companies that produce
these products have spent millions of dollars on innovative and user-friendly
production methods and brand promotion to attract consumers. It can be said
that the trend of introducing new products into the beverage market has
arrived.
Besides the existence of thousands of types of drinks, the more noteworthy
point is that the number of “Drinker” has risen significantly. Kantar [22], a professional company headquartered in London, which provides consumer
research, market analysis and media monitoring services, has presented the
2020 edition of its Brand Footprint report. In this report, it had been pointed out
that the Coca-Cola is the most popular brand in the world, which was
purchased 600 million times in 2019 and has won the championship for 7
consecutive years [22].
The penetration rate of Coca-Cola in the world is 42.1%, which means that
from every 10 people, 4 will buy it, and each person will buy it 12.3 times per
year in average [22].
According to record of 2010, by The Coca-Cola Company (fig. 1), the order of
the most popular places is: Latin America, North America, Pacific, Europe,
Eurasia, Africa. This record has a high coincidence with the 2010 world caries
distribution (fig. 2).
It is known that a tooth decay starts with dental erosion, which dissolve the
dental hard tissue chemically, expose inner structure and may cause future
problems (cavitation). The erosion effect of acidic beverages on enamel
surfaces has been fully discussed in the literatures [25-27].
Fig. 1 Worldwide unit case by region in 2010 [32]
Fig. 2 Prevalence of untreated cavitated, dentine carious lesions (%), by region in 2010, in primary and permanent dentition (Kassebaum et al. 2015).
Dental erosion (DE) is defined as chronic pathological loss, localized and
painless of the dental mineral tissues, produced by the chemical action of
acids without the intervention of the action of microorganisms.
It is a multifactorial disease where there are biological factors - such as the
salivary flow, composition or buffering capacity of saliva, and the anatomical
characteristics of teeth and soft tissues - which, together with chemical factors
of solid and liquid foods (pH, buffer capacity and acid present) and behavioral
factors of the individual related to their general state of health, frequent
consumption of carbonated beverages or acidic fruits, oral hygiene and certain
hobbies, determine in each patient about the risk of developing the disease
and the severity of the lesions.
The diagnosis of tooth erosion is usually performed by using visual methods,
which is very subjective; therefore, it is necessary to use indicators with high
detection capabilities and reliability [23]. Nowadays, there are many indices for
evaluating erosive lesions, The BEWE (Basic Erosion and Wear Inspection)
index is the most widely used indicator to specifically measure tooth erosion
[24].
Multiple studies have shown that tooth erosion has become a common oral
health problem, due to frequent consumption of acidic beverages (soft drinks,
sports and energy beverages, and fruit juices) [3~8]. Therefore, the purpose of
this research is to analyze the effect of different soft drinks pH in relation to the
critical enamel pH and erosion creation.
THEORETICAL BACKGROUND
1. HISTORY OF SOFT DRINKS.
The first marketed soft drinks appeared in 17th century. The Compagnie de
Limonadiers, established in Paris in 1676, started selling their product which
mixed the lemonade, water, and sweetened with honey. So, the first vision of
soft drink did not contain so many artificial substances, all ingredients are
natural. However, at the same time, 17th century, carbonated drinks and water
were tried and developed by Europeans to imitate the popular and natural
effervescent water of famous hot springs. Its famous therapeutic value
received wide attention, especially the effervescent characteristic, was
considered the most important factor of its effect. In 1772, Joseph Priestley,
“the father of the soft drinks industry”, demonstrated a small carbonation device, which shows that with the help of a pump, the fixed air may be more
highly immersed in the water. Jacob Schweppe, a Swiss jeweler, read
Priestley and Lavoisier's papers and made up his mind to build a similar
apparatus. In 1794, J. Schweppe successfully produced 3 kinds of bottled
water which were used only for medicinal purpose; common drinking, for
nephritic patients and for severe cases which contained the most alkali. Until
1820, with the help of The Industrial Revolution, the improvement of
manufacturing technology greatly increased the output, and bottled water
became popular. People start adding other ingredients like mineral salts and
flavorings-ginger juice from 1820, lemon from 1830, tonic from 1858. In 1886,
John Pemberton, a pharmacist in Atlanta, Georgia, invented the first cola drink,
Coca-Cola [18].
2. BASIC KNOWLEDGE OF SOFT DRINKS.
To compared with "hard" alcoholic beverages, those drinks which contain
small amount or zero of alcohol are called "soft" beverages, including
carbonated drinks, fruit juice drinks, dilutable, distilled water, bottled water,
sports drinks, and energy drinks. Unsweetened sparkle water can be used as
a substitute for soft drinks by the definition.
However, to meet the public's taste and uniqueness, the composition of soft
drinks is not as single as before, there are many flavors for people to choose.
For example, those modern soft drinks(non-diet) most of them contain water,
carbon dioxide, acids, juices, and flavors, sucrose(sugar) or high-fructose corn syrup, which has strong cariogenic potential; a typical can(350ml) of coca cola
can contain approximately 40g of sugar, equal to 8 times of teaspoon. The
point is the acid is produced by bacteria that are found within the plaque,
which is a sticky and thin film, that repeatedly forms over the teeth. When
consuming sugar, it interacts with the bacteria of the plaque and be
metabolized to produce acid and cause lowering the pH of oral cavity [14].
In 2017, the World Health Organization (WHO) published a systematic
literature review to answer a series of questions about the impact of sugar
on dental caries. The systematic review showed consistent evidence of
moderate quality, supporting the relationship between sugar consumption
and caries development [15]. Besides the sugar, carbonated water, and
other ingredient, which is also acidic, has a great impact by lowering the pH
of oral health, and are likely to lead to the development of obesity and tooth by
tooth erosion leading to debilitating [2].
People like to ice up the drinks to take during hot weather, however there are
some places not doing as so. For example, in some place of Asia, people
could not afford the medical expenses, and because of the misunderstanding,
they do believe that the composition of coke is similar to cough syrup due to its
flavor. Therefore, Coca-Cola became a cheaper drug of their choices.
However, in culture of China, the traditional Chinese medicine are usually
taken hot. Nowadays, the “hot coke” turns into a superstitious medicine in Asia.
3. FOOD CONSUMPTION.
When eating, the food is chewed in the mouth and begins to decompose,
meanwhile contacting with the surface-related microbial cells. They bound
irreversibly and encapsulated in extracellular polymers, which is called the
biofilm, in other word, The Plaque [17]. Dental plaque is the most common and
well-known oral biofilm, after it started eating 20 minutes, the plaque began to
accumulate on teeth surfaces. If the plaque cannot be effectively removed,
tooth decay starts. People who eat sugar regularly have a higher risk of dental
caries, especially with sticky foods or eat between mealtimes. Sugary snacks
and sweetened beverages have a particularly serious impact on teeth [14].
4. CARIES DEFENITION, ETIOLOGY AND CAUSES.
Dental caries is a multifactorial disease that is affected by several factors
including salivary flow and composition, exposure to fluoride, consumption of
dietary sugars, and by oral hygiene practices [28].
For tooth decay to occur, bacteria must first attach to the tooth. Bacteria are
too small for us to see, but we can see the community formed by bacteria
mixed with food residue and saliva, the “dental plaque”, which is the white, yellow tartar on the surface of our teeth [14]. If this dental plaque is not
removed, when food, especially with sugars content enter the oral cavity,
bacteria, such as Streptococcus, will use the food residues as a source of
nutrition to continuously multiply and grow, at the same time producing an
acidic substance as waste, which interacts with teeth surface and causing the
pH dropping below the critical level (pH 5.5). At this point, it slowly dissolves
the calcium phosphate crystal and make it more porous and penetrable. As
time goes by, there are more partial structure lost, forming a small pothole,
which is called "tooth decay", or "dental caries" [29].
When patients present tooth decays, they can fell discomfort because of the
exposure of dentin and increase sensitivity when eating, drinking, and even
when doing daily hygiene cleanse. Besides, a cavity is permanent and
irreversible damage of tooth, that a dentist must repair with a filling.
Although, most of the mild or moderate defects can be treated by non-invasive
or minimally invasive treatment, more complex treatment is needed for those
severe defects, which leading to a large amount of hard dental tissue lost [10].
For those cases that are already affected the dental pulp or caused large
destruction, the patient may need endodontic treatment of removing the nerve
part, or in the end, extract the teeth.
5. DENTAL CARIES CLASSIFICATION
Based on the clinical manifestations of caries lesions, the American Dental
Association (ADA) created the Caries Classification System (CCS) to make
corresponding treatment decisions.
In CCS, it defines four sites where caries can be found: pit and fissure,
interproximal, cervical and smooth surface and root, and has four clinical
manifestations: sound, initial, moderate and advanced.
• The sound surface, that is, the surface of the tooth appears normal white,
with no detectable lesions. We can use sealant as a preventive measure.
• Initial lesion: This is the earliest detectable lesion, which is limited to the surface of tooth enamel or cementum, or only to the first layer of dentin, with
little change in color, showing white spots or brown. At this stage, dental caries
is considered to be non-cavitary lesions that can be restored through
remineralization. On radiography, only the radiolucency of enamel is shown.
• Moderate disease: The demineralization effect in the dentin is greater, and obvious micro-cavitation can be seen on the surface of the enamel. It is easy
to find dark discoloration on pits and cracks or smooth surfaces, and due to the
limitation of direct inspection in the proximal area, it is more difficult to find
cavitation, but we can find that the transparency of radiation has expanded to
three points One of the dentins in radiography.
• Late lesions: The completely cavitation is formed and exposed the dentin part.
In radiography, the transparency of radiation has reached one third of dentin.
6. RELATION BETWEEN ACID AND TEETH.
Thanks to teeth, human beings can utilize teeth for different functions. Incisors
and canines can teer the food; premolars and molars can crush stuffs; all of
them, tolerate heat pressure and temperature (heat/cold), withstand acidic
environment and making a wonderful smile. To be able to do all these things,
they have a special protective system.
According to the dental structure, a tooth can be divided into four parts. From
the outside to the inside, it can be divided into three parts: enamel, dentin, and
pulp. The last part is called cementum, which is the part that covering the root
of the tooth; the crown is covered with enamel.
The enamel is the hardest part, and its main component is hydroxyapatite,
which is also the hardest part of our whole body and is only slightly lower than
diamond. However, it can be demineralized under chemical process. This
process happens when the pH of the solution surrounding the enamel surface
is below 5.5, leading the underlying dentine exposed on the surface [12].
The main bulk of the tooth is composed of dentin. Dentin is the part between
the enamel or cementum and the pulp cavity, presenting in porous and slightly
yellow color. Because tt contain many tiny tubes connecting the pulp and its
hardness is softer than tooth enamel, those bacteria erode the structure faster,
and if not handled properly, it can cause serious tooth decay.
Cementum is a specialized bone like layer covering the surface of dental root,
which connecting the periodontal ligament and dentin. The main role of
cementum is to act as a medium for the periodontal ligament to attach to the
teeth to maintain stability. The cementum-enamel junction (CEJ), which is in
acellular state due to lack of cellular components, covers at least 2/3 of the
tooth root. The cellular cementum covers rest, which is about one-third of the
root, present more permeable.
The most inner part of tooth, dental pulp, is the central part of the tooth filled
with soft connective tissue. These connective tissues include blood vessels
and nerves that enter the tooth from the root canal. The pulp chamber is
mainly in the crown, and the root canal is in the root. These spaces are
continuous with each other and are collectively referred to as pulp cavity.
Dental pulp is often referred to as the "nerve" of the tooth.
6.1. DEMINERALIZATION.
When a tooth is exposed to an acid solution, it faces demineralization.
Demineralization, also known as decalcification or Dental erosion (DE), which
is well known as an irreversible dissolution of dental structure due to chemical
effect of intrinsic (gastrointestinal) and extrinsic (dietary and environmental)
during lifetime, without microbial attack [9]. The demineralization occurs
through a diffusion process, that is, the molecules or ions dissolved in water
move from tooth enamel to saliva because of the difference in the
concentration of acidic water on the surface of tooth enamel. The acidic
solution with contain higher concentration of acid and how pH, diffuse into
tooth structure and going through subsurface of enamel. Then Hydrogen ions
easily dissolve minerals, release calcium and phosphate into the solution,
destroying the tooth structure [13].
At the beginning, dental erosion is usually painless and localized. People may
notice the color change or white plaque on the surface of tooth due to loss of
calcium ions, which represents a precursor to tooth decay. Tooth decay can be
stopped or reversed at this point. Enamel can repair itself by using minerals
from saliva, and fluoride from toothpaste or other sources [31].
So, it is highly recommended to pay more attention to oral cleansing to avoid
expansion of decay. If there are abnormalities, it is advisable to see a doctor
as soon as possible. However, when the cavity is formed, the dental caries
cannot repair itself though “remineralization”. In this case, it needs further treatment (dental filling, incrustation) done by dentist.
Dental decay is a complex disease and a well-known example of
demineralization which processing in our body. The oldest view of its cause is
the "Worm Theory", which was described in Sumerian text from an Assyrian
tablet. Evidence of this belief has also been found in India, Egypt, Japan, and
China.
Paracelsus (1493–1541), Swiss physician, alchemist, pointed out that: the worms starting to grow on bad teeth, picking up the tooth structure immediately,
and then died as soon as it met air. This theory was convinced by the public, people believed that “the tooth caries is inhabited by a demon in the form of a worm”, the belief continued dominating until the 18th century, Age of Enlightenment. Because people began to dare to seek knowledge and think rationally in that era, and the prevalence of caries increased dramatically, the
"tooth worm" theory was no longer accepted by the European medical community. Pierre Fauchard, known as the father of modern dentistry, was
one of the first who reject the idea that worms caused tooth decay and mentioned that the sugar was detrimental to the teeth and gingiva. His book
"Le Chirurgien Dentiste", was published in 1728, which is the first full text of dental diseases.
With the popularization of microscopes, the theory of "tooth warm"
disappeared, and researchers started to notice and focus on the microorganisms on the surface of teeth and caries.
In the 1890s, W. D. Miller proposed a new explanation that the bacteria of the mouth started produce acids that dissolve the tooth structure, caused the demineralization on enamel and dentin when in the presence of fermentable carbohydrates. This explanation is known as the chemo-parasitic caries theory and was influential for many current theories [21].
6.2. REMINERALIZATION
The process of remineralization is the breakdown or transformation of organic
matter into its simplest inorganic forms. Demineralization and remineralization
are essential for the formation of teeth, caries and dental erosion. They are
both working occur on the tooth surface and can be considered as a dynamic
process, which is characterized by the flow of calcium and phosphate from and
back to the enamel. Saliva works as the main stabilizer for balancing the oral
environment and can be affected by oral pH.[31]. During or after tooth
decalcification, if we hurriedly remove the dental plaque and let the oral cavity
recover from the acidic environment, the decalcification will stop, and the free
calcium and phosphoric acid in the saliva will re-enter the surface of the tooth
to form calcium phosphate. Each of us goes through the process of
decalcification and recalcification many times a day. For example, a few
minutes after dinner, the oral cavity falls into acidity and decalcification. After
brushing, the teeth enter the recalcification restoration period when sleeping,
and so on.
If the frequency and amplitude of acid production overwhelm the repair
process, demineralization will occur, facilitated the erosion of bacteria and
resulting in cavitation. If the acid is restricted, remineralization will take
dominate, leading those dissolved mineral ions precipitate out as solid mineral
ions again. Besides, fluoride has been proven to inhibit the activity of
streptococcus, bacteria, help promote tooth recalcification, and can form a
more acid-resistant fluorinated enamel with enamel [31].
7. BIOMINERALIZATION.
The definition of mineralization is a process of mineral concentration; it
converses organic compounds into inorganic compounds and is carried out
through several physical and chemical effects or biochemical effects.
Mineralization also often occurs in the body of organisms, forming because of
biological activity, especially for complex multicellular organisms, which is
called “Biomineralization” [31]. For example, the growth of shells in snail, the growth of bones and teeth of vertebrate, involve a series of mineralization of
calcium. However, biomineralization not only constitutes with important
physiological composition, but also occur as the mechanism of pathological
phenomena (Abnormal biomineralization, pathogenic mineralization). The
biomineral in human can be classified in two type: The essentials and the
unexpected. The essentials are part of our body system including bones and
teeth. We can find 208 bones and 32 teeth in a normal adult. The unexpected
are those pathological deposits like, renal stone, kidney stone, etc. [31]
8. IMPORTANCE OF ORAL HEALTH.
Our mouth is like a factory that works systemically, it has plenty of functions
like expression, phonation, communication and diet. According to World Health
Organization (WHO), oral health is the key point of overall health, well-being
and quality of life which covers range of condition and diseases like, dental
caries, periodontal disease, tooth loss, oral cancer, oral manifestations of HIV
infection, oral dental trauma. There are many studies have shown that oral
disease is highly relate to non-communicable diseases (cardiovascular
diseases, cancer, chronic respiratory diseases, and diabetes). Besides, they
are also associated to personal habits; tobacco use, alcohol consumption and
unhealthy diets high in sugars [15].
9. pH.
According to the British Encyclopedia, the pH is the quantitative measurement
that has been widely used in chemistry, biology, and agronomy field. It
examines the acidity or alkalinity of the solutions, it other say, to test how acid
or base it is. Pure water under 25°C is consider as neutral solution with pH 7,
the more acidic the smaller number; the more alkali the greater the number
[11].
In 1890, Arrhenius, Swedish chemist, put forward the “Arenis theory” of electrolyte ionization in aqueous solution, which bring the whole world the
basic relationship between hydrogen and hydroxide ions, and provides the
possibility of determining the dissociation constant of water. Through this
concept, it explains that why the electrolyte solutions can conduct electricity
and why solid salts cannot. He won the Nobel Prize of Chemistry by this theory
in 1903, and many concepts are still be used today [19].
In 1904, Friedenthal used an indicator to test 14 known solutions. Examined
the color of the indicator changes according to the hydrogen ion concentration.
This is the first-time acidity scale is established [7].
In 1909, Sø rensen, defined pH with a concentration range of 0-14 (at 25°C)
derived from the ionic product of water. Because the inconvenience in reading
and writing due to measuring the hydrogen ion concentration, his original
purpose was to make the predigestion of those number. Sø rensen used the
decadal logarithm of the hydrogen ion concentration multiplied by (-1) and
called "pondus Hydrogenii". In 1923, Debye and Hückel published the theory
of the interaction between ions. With this knowledge, the acceptable definition
of pH was proposed based on the activity of hydrogen ions in solution, which is
still highly used at present:
pH = −lg aH = −lg(mHγH/m°)
*aH is the relative (molality basis) activity and γH is the molal activity coefficient of the hydrogen ion H+ at the molality mH, and m° is the standard
molality [20].
OBJECTIVES
Main objective:
To analyze the effect of soft drink pH in relation to the critical pH of enamel and
erosion creation.
Secondary objectives:
- To measure pH of different cold (17 – 20ºC) and hot (25 – 30º) soft drinks.
- To analyze the pH effects of different soft drinks on enamel.
MATERIALS AND METHODS
The present research consists of two parts: a literature review, including the
main concepts of the objectives proposed, and an experimental one, with the
pH measurements to analyze its relationship with enamel erosion.
1. LITERATURE REVIEW SEARCH
All paper sources were searched on electronic databases like PubMed,
Medline, Universidad Europea de Madrid library database and Google Scholar.
Keywords used include demineralization, mineralization, remineralization, pH,
dental erosion, tooth decay, citric acid, soft drinks, beverages, sweetener.
These keywords were combined with further “and” and “or” for more relevant articles. Inclusion criteria are shown in table 1.
The complete articles are from year 2000 to the present in English and
Spanish version. Keywords: demineralization, mineralization, remineralization,
pH, dental erosion, tooth decay, citric acid, soft drinks, beverages, sweetener.
Table 1. Inclusion criteria.
Type of research Free access papers, literature reviews.
Type of study In-vitro and experimental in humans.
Language English
Date From January 1991 to December 2020
2. pH EXPERIMENT ASSESMENT
Twenty commercially available beverages were used to measure the pH (table
2): Seventeen carbonated soft drinks, including 3 types of COCA-COLA
(normal, light and zero sugar), Sprite, HOLA-COLA (classic, zero sugar, zero
sugar and without caffeine), LIMON with gas (DIA), GET MOVE orange (DIA),
LIMA LIMON (DIA), DRINK IT ORANGE (with 8% orange juice content), KAS
LIMON without sugar, KAS APPLE, Carbonate soft drink yogurt flavor (HATA),
Ramu carbonate drink grape flavor (SANGARIA), CALPIS SODA, TONIC
water (DIA) and Non-carbonate drinks: JDB herbal tea, CALPIS WATER
(Ocean Bomb), Sparkling water (FONTER), Natural water.
Table 2. Type of beverages used for the pH assessment.
Tested agents Composition
COCA-COLA normal Carbonate water, colorant E150d. Sugar. Acidifier: phosphoric acid citric acid and natural flavorings (include caffeine).
COCA-COLA light without caffeine
Carbonate water, colorant E150d. Sweetener: sodium cyclamate, acesulfame K, aspartame. Acidifier: phosphoric acid citric acid and flavorings.
COCA-COLA zero
sugar/caffeine
Carbonate water, colorant E150d. Sweetener: sodium cyclamate, acesulfame K, aspartame. Acidifier: phosphoric acid citric acid, flavorings, and acidity regulator of sodium citrate.
Sprite Carbonate water. Sugar. Acidity regulator of sodium citrate and citric acid.
Sweetener: acesulfame K, aspartame, neohesperidin DC and natural flavorings of limon and lime.
HOLA-COLA classic Carbonate water, colorant (E150d). Sugar. Acidifier(E338). Natural flavorings, Caffeine.
HOLA-COLA zero sugar Carbonate water, colorant E150d. Acidifier(E338). Sweetener (E952, E950, E951). Acidity regulator(E331). Natural flavorings. Caffeine.
HOLA-COLA zero
sugar/caffeine
Carbonate water, colorant E150d. Acidifier(E338). Sweetener (E952, E950, E951). Acidity regulator(E331). Natural flavorings.
LIMON with gas Carbonate water, orange juice (6%). Sugar. Glucose and fructose syrup.
Acidifier(E330). Stabilizer (E414, E445), conservatives(E202), antioxidant(E300), sweetener(E955), colorant(E161b).
GET MOVE orange Water. Sugar. Acidifier (citric acid). Mineral salts. Corrector of acidity (sodium citrate), antioxidant, stabilizer, sweetener(sucralose), colorant.
LIMA LIMON Carbonate water, orange juice (6%). Sugar. Acidifier (E330, E296).
Stabilizer(E331iii), Conservatives(E202), sweetener(sucralose).
DRINK IT ORANGE Carbonated water, Sugar, Acidifier: Citric Acid, Stabilizer, Natural Orange Flavors, Vitamin C, Colorant, Antioxidant.
KAS LIMON without sugar Carbonated water, glucose and fructose syrup, lemon juice from 4%
concentrate, acidifier: e-330, stabilizers: e-414 and e-445, natural flavors, antioxidant: e-300, preservative: e-202, sweeteners: e-950 and e-955, coloring:
KAS APPLE Carbonated water, glucose and fructose syrup, apple juice from 16% acidifier:
E-296, flavorings, coloring: E-150d, preservatives: E-202 and E-211, sweeteners: E-950 and E -955, antioxidant: E-300.
Carbonate soft drink yogurt flavor
(HATA)
Sugar mixed glucose fructose liquid sugar (cornstarch, tapioca starch, sweet potato starch, potato starch, sugar), acidulant (citric acid (E330)), flavoring (yogurt flavor), coloring (yellow No. 4 (E102)).
Ramu carbonate drink grape flavor
(SANGARIA)
water, fructose glucose syrup, acidulant (E 330), flavor.
CALPIS SODA water, high fructose corn syrup, sugar, non-fat dry MILK, LACTIC acid, acidifier, flavoring, stabilizer
TONIC water (DIA) Carbonated water, glucose and fructose syrup, acidifier: citric acid, flavorings, sweeteners: surculose, conservator.
JDB herbal tea Water, white sugar, fairy grass, frangipani, chrysanthemum, honeysuckle, prunella, licorice.
CALPIS WATER (Ocean Bomb)
Water, High Fructose Corn Syrup, non-fat dry milk (Treated with a lactic acid culture), fructose, lactic acid, natural and artificial flavors, citric acid, soy fiber, sodium citrate.
Sparkling water (FONTER) Water, mineral salt, bicarbonate.
Natural water Water
A multifunctional electronic device sensION+ PH3(HACH, United States) to
measure the initial pH of each acidic beverage was used. Before each analysis,
the standard buffer solutions (HACH, United States) pH 4.0 and 7.0 was used
to calibrate its electrodes. For each test, 50 ml of the freshly opened beverage
at a temperature average between 17 – 20ºC was poured. The pre-calibrated electrode was immersed into the beverage until obtaining a stable reading.
After the measurement of each pH at a cold temperature, same samples were
submitted to a high temperature using an incubator (J.P. SELECTA, Spain).
The temperature of the sample was controlled at 30°C then the initial pH
of each acidic beverage was tested with device pH device: pH50 (XP, Italy) to
measure the change.
3. STATISTICAL ANALYSIS OF pH ASSESSMENT.
Data were collected and analyzed using a specific software (SPSS).
Descriptive analysis including mean, standard deviation, median, interquartile
range, minimum and maximum IQR values were reported. Shapiro-Wilk test
was used to determine the normality distribution of the data. Paired t-student
was used to identify statistical significance difference in pH values among the
groups. The significance level was set at a level of =0.05 for all statistical tests.
RESULTS 1. LITERATURE REVIEW
A total of 67 articles were initially found and reviewed. However, 23 articles
were excluded due to either duplication or low relevance to the topic. The
reasons for excluding these articles include a mismatch between the research
and the topic that the objects were focus on the wear of material filling, which is
unfavorable in this thesis, or the information is directly unrelated to the topic.
2. pH ASSESSMENT
pH values of soft drinks are shown in table 3. Descriptive analysis of Mean (M),
standard deviation (SD), median (p50), interquartile range (IQR), minimum
(MIN) and maximum (MAX) IQR values are shown in Table 4.
T-test paired student revealed statistical difference between pH1 (opening
17 – 20ºC) and pH2 (heat 25 – 30ºC) with a p-value of 0.0005 (p0.05) and a trust interval of 95%.
Table 3. Beverages and their pH.
Beverage pH 1 (17-20 ºC) pH 2 (27 – 31ºC)
Cocacola original 2.52 2.54
Cocacola light 2.61 2.61
Cocola-zero azucar 2.91 2.90
The lowest pH at a temperature between 17 – 20ºC was found with Coca-Cola Original with 2.52, and the lowest with a temperature between 27 – 31ºC was HOLA cola Classic with 2.42. The highest pH was 6.89 of WATER. Herbal JDB
tea and FONTER sparkling water were found to increase their pH with heating,
meaning that their pH was less aggressive when they are hot.
Table 4. Descriptive analysis.
Variable N Mean SD Max Min
pH 1 21 3.36 1.17 6.89 2.52
pH 2 21 3.28 1.23 6.89 2.42
(*N=number of samples, *SD= standard deviation, *Max-Min: pH values, *pH1:
temperature between 17-20 Celsius degree, pH 2: temperature between 25 – 30 Celsius degree)
Sprite bajo azucar 2.86 2.71
Hola Cola Zero sin azucar 2.65 2.53
Hola Cola Zero sin cafeina 2.89 2.79
Hola cola Classic 2.56 2.42
Lima limó n con gas 3.06 2.89
Drink it orange 8% zumo 3.50 3.37
Get move Naranja 2.92 2.79
KAS limon 2.63 2.48
KAS Manzana 2.91 2.82
Tonica 2.70 2.55
JDB Herbal tea 5.60 5.72
Ocean Bomb Calpis water 3.57 3.45
Limó n con gas 2.84 2.65
Ramu Bottle grape Japones 3.03 2.88
Calpis Soda Japonesa 3.52 3.40
HATA Yought Flavor Japanese 2.96 2.87
FONTER sparkling water 5.63 5.77
WATER 6.89 6.89
DISCUSSION
As shown in the result, almost all beverages used in the pH assessment are
acidic. It can clearly be seen that those carbonated drinks pH is obviously
lower than those non-carbonated drinks (herbal tea, sparkling water), which
means that carbonated drinks contain more acidic substance, and have more
enamel erosion potential than the others.
The drinks with/without natural sugar also showed changing small amount of
pH, the use of sweetener seems to be less acidic even in the same brand.
SWEETENER
Sugar is the main carbohydrate source used by bacteria. The bacteria can
incorporate several sugars into the cytoplasm and use them to produce ATP
through glycolysis, as well as the synthesis of bacterial components
(peptidoglycan, lipoprotein acid and nucleic acid) and polysaccharides [33,34].
In the environment/host, there are many types of sugars, including
monosaccharides (glucose, fructose, mannose), disaccharides (sucrose,
lactose, maltose), trisaccharide (raffinose) and amino sugars (glucosamine,
N-acetyl) Glucosamine), some sugar can only be metabolism by some special
type of bacteria [35].
Streptococcus mutans, is a commensal bacterium in the human oral cavity and
a well-known cariogenic pathogen. It plays a key role in the formation of biofilm
(dental plaque), which is the basis of several major oral diseases and tooth
decay. This organism produces glucosyltransferase (GTF), which participates
in the production of water-insoluble viscous glucan by using sucrose. This
insoluble glucan is responsible for the formation of biofilms [36]. In addition,
acid is also product as a pathogenic factor of Streptococcus mutans, by
demineralizing the minerals part of the tooth surface and causes tooth decay
[34]. Besides, acid is a metabolite in the Embden-Meyerhof-Parnas pathway,
which is important for the production of ATP (fig.1).
(Fig3.Streptococcus mutans virulence is related to sugars. GTF: glucosyltransferase;
IPS:intercellular polysaccharide; EPS: extracellular polysaccharide [37])
In 1879, the first artificial sweetener “Saccharin“ was synthesized by Remsen and Fahlberg. Its sweetness is 300 to 500 times that of sugar. Since then, there are many sugar substitutes (xylitol, sorbitol, lycasin, maltitol, mannitol, accesultame-K, aspartame, cyclamate, and saccharin) were developed and
widely used in many products like diet food diet beverages and even in toothpaste [38]. Those sugary foods can be replaced by non-caloric and caloric sugar substitutes in the market. Besides, these sugar substitutes have
low or even no cariogenic potential because the lack of enzyme in our mouth, which means sweeteners can’t degrade or ferment by those bacteria (Streptococcus mutans), causing almost no effect on the pH changes in oral environment. This leads the sweetener becomes important of preventing tooth decay and improving the overall health [39].
However, the use of artificial sweeteners poses a health risk is still
controversial. A study conducted by the University of Texas Health Science
Center in San Antonio in 2005 showed that the use of diet drinks is not a sign
of losing weight, but a sign of weight gain [40]. In 2014, Israeli research
provided experimental evidence that artificial sweeteners may aggravate
In this study, the pH value of sugar substitute or low-sugar beverages is
significantly higher than that of sugar-sweetened beverages. It can be said that
these sugar substitute beverages have relatively lower erosion to teeth, but
they are still considered as highly corrosive beverages(pH<4).
Under the temperature experiment, it can be suggested that the pH of the
sugar substitute beverage also decreases as the temperature rises. Besides,
some sweeteners are heat resistant and is widely used in cooking and baking.
Therefore, the use of sugar substitutes seems not really affect the degree of
erosion under temperature changes [43].
TEMPERATURE AND pH
Temperature plays an important role in pH measurement. As the temperature
rises, the molecular vibrations increase, which causes water to have the ability
to ionize and form more hydrogen ions. As a result, the pH will drop [40].
The decomposition of water into hydrogen and hydroxide ions can be
expressed as: H2O (l) ⇌ H+ (aq) + OH− (aq)
As the results of this research revealed, the pH value decreases with
increasing temperature. This assertion is related to the soft drinks used in this
research, where the hydrogen ion exceeds the hydroxide ion, the solution is
considered acidic [40]. In the case of pure water, there is always the same
concentration of hydrogen ions and hydroxide ions, so the water is still
considered as neutral (even if its pH value changes).
ACIDULANT
Food additives are defined by the WHO/FAO Joint Committee in 1955 (FAO,
1956), and refer to small amounts of food that are usually deliberately added to
food to improve the appearance, flavor, texture, or storage performance of the
food. There are many kinds of industrial agents consider as food additives for
different purposes like preservative, bactericide, antioxidant, bleaching agent,
color retention agent, leavening agent, nutritional, food coloring, Spices,
flavoring agents, etc.
Acidulant, a common flavoring agent, also known as acidity regulator, acidifier,
refers to the additive to obtain the sourness of food [41]. Sour agents are
mainly used to improve the flavor of food, increase appetite, inhibit microbial
growth, protect color, improve viscosity and rheology, improve internal quality,
preservative and extend shelf life. Those common acidulants are shown in
table 5.
Table 5. Acidulant
Name Application
Citric acid (E330) An organic acid naturally present in many fruits (first separated from lemon) and can also be produced through carbohydrate fermentation.
Citric acid is colorless and tasteless. It exists in the form of crystals or crystalline powder and has a strong sour taste. It is easily soluble in water and alcohol, therefore is used in most of the beverages.
Lactic acid (E270) Natural product in many fermented foods and human organic acids and is commercially produced through microbial fermentation of carbohydrate substrates. It has a specific sour taste, no strong smell, can also acts as an antioxidant and a preservative.
Malic acid (E296) Naturally occurring organic acid in many fruits (first isolated from apples). It can exist in the form of crystals or granules. It has a strong sour taste and enhances the fruit flavor well.
Phosphoric acid (E338)
Inorganic acidifying agent obtained by chemical reaction from phosphate rock. It can produce a strong sour taste even at low concentrations. It is responsible for the tangy taste of cola drinks.
Tartaric acid (E334)
Naturally organic acid in many fruits, which is produced during wine fermentation. Tartaric acid is a colorless and odorless crystal with a strong and sharp sour taste. It is very soluble in wate, and commonly used in sour-tasting sweets. It can also be used as an antioxidant.
Acetic acid (E260) Most common organic acid, naturally found in many fruits and fermented foods in vinegar. Acetic acid can be used in liquid form and is highly corrosive at high concentrations. At present, it is used as a natural preservative in many foods.
Succinic acid (E363)
Natural acid found in most fruits and vegetables. Odorless, colorless, white crystalline solid, slightly bitter and sour, easily soluble in water.
Beverages used in the pH measurement part of this research, had Citric acid
(E330) and/or phosphoric acid (E338). These two acidulants may be part of
the reason causing beverages to have high acidic strength and may cause
erosion problem if taking for a long time or in large amounts. Bekir S et al.,
and temperature. The concentration of citric acid of the beverages used in this
investigation is unknown. On the other hand, is known that phosphoric acid is
associated with the apparition of dental erosion [44,45]. It is well-known that
critical enamel pH is around 5.5 and when phosphoric acid is applied on
enamel and dentin, causes demineralization. This dental demineralization is a
short time procedure, and it causes a transitory demineralization of enamel or
dentin, making these substrates regenerated by biomaterials applied. Thus, in
normal mouth conditions, the buffer effect of saliva can help in keeping an
environmental mouth balance.
The relation between acidulants and pH is still not confirmed, but what it is
known is that when the temperature rises, it dissociates and ionize the solution
to form more hydrogen ions [40].
CONCLUSIONS
⚫ Most beverages tested in this research, showed acid pH below 5.5 with
regard dental critical enamel pH.
⚫ The acidic beverage is digested and absorbed since entering the mouth, acidifying the oral environment and causing the possibility of dental
erosion.
⚫ Streptococcus mutans is the main initiator producing acid and lowering
the pH in mouth.
⚫ Sweeteners produce less acid than natural sugar because it cannot be decomposed by our mouth (lacking enzymes), however it might produce
further problem (obesity, metabolic disease).
⚫ Teeth are undergoing remineralization-demineralization every day, however when facing exceed acid, it will be damage and have irreversible
caries problems.
⚫ pH can be modified by changing the temperature: it decreases when heating up in the acidic drinks; the pH increases when heating up in those
less acidic drinks (herbal tea, sparkling water).
⚫ The relation between acidic strength and the temperature still needs to be confirmed.
⚫ All acidulants presented as acid solvent, make the lowering of beverage pH.
RESPONSIBILITY
The present work studied various beverages and its erosion possibility.
Explained the beverage ingredients and the relation with the acidic power. This
work also educated the reader the mechanism of the caries formation and
further problems. With the extremely increase number of drinkers, it is
essential for everyone to know what is happening when drinking beverages,
and what kind of dangers are faced.
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