Vitamin C and Oral Health: A Review

Abstract

Vitamin C is an essential dietary nutrient required as a co-factor for many enzymes. Ascorbic acid is a reduced form of this vitamin, which is an effective antioxidant owing to its high electron-donating power and readily converts back to the active reduced form. In body tissues and fluids, the concentrations of the vitamin C are maintained by interplay between absorption from intestine, cellular transport and excretion. Very small amount of vitamin C is needed to prevent scurvy. Evidence has shown that oxidative damage is a root cause of or at least associated with many diseases, the clinical role of vitamin C becomes very important. Although clinical trials have not confirmed this, but still vitamin C may prove to be effective in people with certain diseases or conditions. However, the evidence that ascorbic acid acts as an important antioxidant in many body tissues is convincing. In healthy individuals, amounts taken greater than the RDA are not helpful.

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462 X INDIAN JOURNAL OF APPLIED RESEARCH
Volume : 3 | Issue : 9 | Sept 2013 | ISSN - 2249-555X
RESEARCH PAPER
Medical Science
Vitamin C and Oral Health: A Review
Dr. Manu Rathee Dr. Mohneesh Bhoria Dr. Renu Kundu
Senior Professor and Head
Department of Prosthodontics
Post Graduate Institute of Dental
Sciences Pt. B.D Sharma University
of Health Sciences Rohtak, Haryana,
India.
Demonstrator
Department of Prosthodontics
Post Graduate Institute of Dental
Sciences Pt. B.D Sharma University
of Health Sciences Rohtak, Haryana,
India.
Post Graduate Student
Department of Prosthodontics
Post Graduate Institute of Dental
Sciences Pt. B.D Sharma University
of Health Sciences Rohtak, Haryana,
India.
KEYWORDS
Ascorbic acid, Periodontitis, Scurvy, Vitamin C.
ABSTRACT Vitamin C is an essential dietary nutrient required as a co-factor for many enzymes. Ascorbic acid is a reduced
form of this vitamin, which is an effective antioxidant owing to its high electron-donating power and readily
converts back to the active reduced form. In body tissues and fluids, the concentrations of the vitamin C are maintained
by interplay between absorption from intestine, cellular transport and excretion. Very small amount of vitamin C is needed
to prevent scurvy. Evidence has shown that oxidative damage is a root cause of or at least associated with many diseases,
the clinical role of vitamin C becomes very important. Although clinical trials have not confirmed this, but still vitamin C
may prove to be effective in people with certain diseases or conditions. However, the evidence that ascorbic acid acts as
an important antioxidant in many body tissues is convincing. In healthy individuals, amounts taken greater than the RDA
are not helpful.
Introduction
Vitamin C or L-ascorbic acid, or simply ascorbate (the anion
of ascorbic acid), is an essential nutrient of the diet for hu-
mans and some other animal species. Vitamin C consists of
a number of vitamers that have vitamin C activity in animals
including ascorbic acid and its salts and many oxidized forms
of the molecule like dehydro-ascorbic acid. Ascorbate and
ascorbic acid, both are present naturally in the body when
any of these is introduced into cells as the forms interconvert
according to pH. In at least eight enzymatic reactions, Vita-
min C is a cofactor including various collagen synthesis reac-
tions. When these synthetic reactions become dysfunctional,
they cause the most severe symptoms of scurvy1.
Ascorbate may also act as an antioxidant agent. The enanti-
omer D-Ascorbate, which is not found in nature, has identical
antioxidant activity to L-Ascorbate but very less vitamin activ-
ity. Ascorbic acid is a weak sugar acid which is structurally
related to glucose. It can be found only at low pH in biologi-
cal systems, but in neutral solutions having pH above 5 it is
predominantly found in its ionized form i.e. ascorbate.
Biological significance
The biological role of ascorbate is to act as a reducing agent
by donating electrons to various enzymatic and a few non-
enzymatic reactions. The one and two-electron oxidized
forms of vitamin C (semi-dehydro-ascorbic acid and dehydro-
ascorbic acid respectively) can be reduced in the body by
glutathione and NADPH- dependent enzymatic mechanisms.
Thus, the presence of glutathione in cells and extracellular
fluids helps maintain ascorbate in a reduced state.
Vitamin C and oral health
Vitamin C has diverse functions in the body at a chemical
and structural level. For example, a major function of ascor-
bic acid is its involvement in the synthesis of collagen fibres
from proline via hydroxyproline. Other metabolic reactions
for which vitamin C is required are the hydroxylation of lysine
into hydroxylysine in collagen, the conversion of folic acid to
the active form of folinic acid in-vivo, the formation of ster-
oids by the adrenal gland, the oxidation of lysine in muscle
proteins, the microsomal metabolism of drugs and the pro-
tective action on enzymes such as p-hydroxyphenylpyruvic
acid oxidase.2
At the tissue structural level vitamin C is involved with the
synthesis of intercellular substances and the collagen fibres
of various forms of the connective tissues in which collagen
forms a part, for example organ capsular/trabecular, tendi-
nous and fascial tissue, the matrix of calcified tissues such as
bone and teeth and the endothelial cells of the entire vascu-
lar system, including capillaries.
In a normal adult man of 70 kg mass and with a vitamin C
reserve of 1500 mg, general scurvy will manifest when the
vitamin C reserve is reduced to 300 mg. This can be caused
by a reduction of 45 mg vitamin C per day for 60 days on a vi-
tamin C-free diet. Scurvy is an avitaminosis resulting from lack
of vitamin C, because without this vitamin, the synthesized
collagen is very unstable to perform its normal function.3 Fea-
tures of Scurvy include the formation of brown spots on the
skin, spongy & swollen gums and bleeding from all mucous
membranes. The spots are more abundant on thighs and
legs; the person looks pale, feels depressed and is partially
immobilized. In advanced stages of scurvy, there are open,
suppurating wounds, loss of teeth and eventually, death.
In scurvy, administration of L-ascorbic acid (in a dose of about
1 g/d for adults) will cause rapid disappearance of subcuta-
neous hemorrhages and nearly complete reversal of symp-
toms. Gingivitis is not caused by vitamin C deficiency per se,
but if the gingivitis exists in a scorbutic patient it seems to be
caused by local irritants. The legendary association of severe
gingival disease with scurvy led to the incorrect presumption
that vitamin C deficiency is a primary factor in the causation
of gingivitis and periodontal disease. It is now believed that
blood ascorbic acid levels bear no relationship to the inci-
dence or severity of gingivitis or periodontal disease in non-
scorbutic patients. Furthermore, vitamin C deficiency does
not cause periodontal pockets; local irritating factors are re-
quired for pocket formation to occur.4 It has been shown that
smokers who have diets poor in vitamin C are at a higher risk
of lung-borne diseases than those smokers who have higher
concentrations of vitamin C in the blood.

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Volume : 3 | Issue : 9 | Sept 2013 | ISSN - 2249-555X
RESEARCH PAPER
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1988. |
Avitaminosis C is associated mainly with defective collagen
synthesis, and symptoms such as the failure of wound healing
or the rupture of capillaries are due to intrinsic intercellular
weakness with lack of connective tissue support of the capil-
lary walls. This vascular fragility leads to a bleeding tendency
which produces petechiae and ecchymoses and is confirmed
by a positive Hess test.
Haematuria, epistaxis, subperiosteal bleeding, haemarthrosis
and bleeding into muscles and deeper tissues also occur. The
general discoloration resulting from the bleeding and blood
breakdown is called ‘scurvy siderosis’. Hemorrhage under the
nails with onycholysis may also occur. The hair follicles may
be hyperkeratotic with vascular congestion and may show
perifollicular hemorrhages. There will be general lassitude
and an increased susceptibility to infections.
On exposure to certain drugs and toxins and usually also
on exposure to stress, more vitamin C is needed to sustain
normal plasma levels in order to meet the altered metabolic
demands. Gingival manifestations of disease in scurvy are
most severe when oral hygiene is poor. The gums do not be-
come involved if the teeth are unerupted or if the patient is
edentulous, although sub-epithelial hemorrhages do occur.
The signs of general scurvy, such as prominence of the hair
follicles because of keratin plugging, dermal perifollicular ec-
chymoses, aching legs, joint effusions, lethargy, vasomotor
instability or pitting edema of the ankles, will appear togeth-
er with gingival lesions in the dentate patient. The gingivae
become hyperemic with a tendency to bleed on interdental
papilla where disintegration of marginal epithelium occurs.3
Recent medical and dental research cited the prevention
of free radical mediated diseases by using specific anti-oxi-
dants, protective role of anti-oxidant supplementation in pre-
vention of precancerous lesions.6 It has been observed that
anti-oxidant vitamin C supplementation for six weeks was
helpful in patients with various dental problems.
Deficiency of vitamin C as a risk factor in progression of
periodontitis
Scurvy and periodontitis both manifest gingival bleeding but
constitute separate entities. The various periodontal diseas-
es are caused by oral micro-organisms in dental plaque, the
body’s reaction to which is strongly influenced by inadequate
or impaired functioning of leucocytes and monocytes. Al-
though various infections and systemic diseases cause gin-
gival bleeding, avitaminosis C does not cause commonly
encountered periodontal disease, but it will aggravate the
already established periodontitis. So, Vitamin C should not
be used for cure or prophylaxis of periodontitis in healthy
well-nourished individuals.5
Studies show that patients with periodontitis are character-
ized by low plasma levels of vitamin C than the normal range,
especially smokers. The intake of citrus fruits such as grape-
fruit leads to an increase in plasma levels of vitamin C and im-
proved scores for sulcus bleeding index. However, long term
studies are required to determine whether other periodontal
outcomes improve with such supplementation especially in
smokers.
Erosion of dental enamel
Chewable vitamin C tablets, used daily, have been reported
to lead to severe erosion of dental enamel because of the
acidity and abrasiveness of these products, but the practical
clinical significance of this effect has not been established.
The dental enamel erosion is brought about by the high acid-
ity of ascorbic acid (pH of 2.8), therefore, if chewable tablets
of vitamin C are properly formulated to a pH of approxi-
mately 4 to 5 using sodium ascorbate or another buffering
agent, erosion of dental enamel should not be a problem.
Chewable vitamin C should not be formulated and marketed
without a buffering formulation.7
Conclusion
Vitamin C (ascorbic acid) is an indispensable cofactor in the
hydroxylation of amino acids such as proline and lysine. It is
required and essential for collagen synthesis and connective
tissue integrity. It is involved in the biosynthesis of histamine,
carnitine and several adrenal steroids. It promotes iron ab-
sorption and mobilization, helps in metabolism of tyrosine,
folate, and xenobiotics. When vitamin C intake is below a
critical level (10 mg/d) for longer periods, a clinical condi-
tion known as scurvy will ensue featuring failure of wounds
to heal, petechial hemorrhages, bleeding gums, follicular hy-
perkeratosis and related abnormalities.
The dietary recommendation are: RDA 3000 mg Vitamin C
i.e. 1000 mg three times daily. According to the Vitamin C
Foundation recommendations every man, woman and child
over the age of 3 years should consume at least 3 g (3000
mg) vitamin C daily in order to enjoy optimum health.