Dental caries is caused by cariogenic bacteria like Streptococcus mutans that produce acids from sugars. Researchers have studied developing a vaccine for S. mutans to prevent tooth decay. Animal studies vaccinating rats and monkeys with S. mutans cells reduced dental caries by 70%. Clinical trials in humans are testing an oral pill containing S. mutans to stimulate protective saliva antibodies with mixed results so far. A safe and effective dental caries vaccine is not yet available due to risks of cross-reactivity with human tissues requiring further research.

2. REFERENCES
 Ole Fejerskov,Dental caries-the disease & its clinical
management(3rd edition)
 KM Shivakumar,SK Vidya,GN Chandu Indian
journal of dental research (2009)
 Mitzi.R.Becker Molecular analysis of bacterial species
associated with dental caries (2002)

3. DEFINED DISEASE PROCESS
EPIDEMIOLOGY
IDENTIFICATION OF CAUSATIVE ORGANISM
STUDY OF ORGANISM STUDY OF IMMUNE RESPONSE
IDENTIFICATION OF PROTECTIVE ANTIGEN
VACCINE TRAIL IN ANIMAL MODEL
TOXICITY TESTING
HUMAN CLINICAL TRIALS
STEPS IN DEVELOPING VACCINE

4. DENTAL CARIES
 Dental caries is the infectious microbiologic disease of
teeth that results in localized dissolution &
destruction of calcified tissues.
 It is one of most common diseases in humans.
 Its prevalence is more in developed & developing
countries & can reach over 90%.
 The development of caries requires the presence of
cariogenic bacteria that are capable of producing
acids,which are responsible for destruction of tooth.

6. CAUSATIVE ORGANISM
 The different caustive organisms are :-
1) Streptococcus mutans
2) Streptococcus sobrinus
3) Lactobacillus acidophilus
4) Actinomyces viscosus
5) Bifidobacterium
6) Non-mutans streptococci

7. STREPTOCOCCUS MUTANS
 It is gram +ve,facultative
anaerobic,coccus shaped
bacteria found in oral cavity.
 It is one of the most
important micro-organism
responsible for dental caries.
 There are 6 distinct species
associated with dental caries-
S.cricetus,S.ferus,S.rattus,
S.downey,S.mutans &
S.sobrinus.

8.  They are most commonly associated with pit & fissure
caries(39%).
 A large proportion of infants become colonized by
S.mutans during the ‘window of infectivity’ around the
time of eruption of first molars at the age of 2 years.
 They mainly metabolize sucrose to lactic acid by using
enzyme glucansucrase.
 Due to the role the S. mutans plays in tooth decay, there
have been many attempts to make a vaccine for the
organism.

9. LACTOBACILLUS ACIDOPHILUS
 It is gram +ve,facultative
anaerobic rod-shaped
bacteria found in oral
cavity.
 They cause carious lesions
in coronal part of the
tooth.
 It is mostly commonly
associated with dental
caries, but to a lesser extent
than streptococci.

10. ANTIGENIC COMPONENTS OF
STREPTOCOCCUS MUTANS
 S.mutans posses various cell surface substances
including Adhesins,Glucosyltransferase & Glucan
binding proteins(GBP).
 These substances are used in vaccine preparation.
 Adhesins :- it forms the two principle human
pathogens of S.mutans & has been purified.
 It has a mol. weight of 185 kDa composed of single
polypeptide chain of approx. 1600 residues.
 It contains proline-rich & alanine-rich regions

11.  These regions have been associated with adhesin activity of
Ag I/II.
 The antibody directed to intact Ag I/II molecule or to its
salivary binding domain blocked adherence of S.mutans of
saliva-coated hydroxyapatite.
 Immunization of mice with synthetic peptide from alanine-rich
region of Ag I/II suppressed tooth colonization with
S.mutans.
 Glucosyltransferase :- S.mutans has three forms of
glucosyltransferase(GTF’s) :-
1) water insoluble glucan synthesizing enzyme(GTF-I)
2) Water insoluble & water soluble glucan synthesizing
enzymes(GTF-S-I)
3) Water soluble glucan synthesizing enzymes(GTF-S)

12.  The genes encoding these enzymes are GTF-B,GTF-C
& GTF-D genes.
 All three genes are important for smooth-surface
caries formation in pathogen-free rat model system.
 Dextranases:- it is an important constituent of early
dental plaque.
 Dextranase is an enzyme produced by mutans
streptococci.
 They destroy dextran & thus bacteria can invade
dextran rich dental plaque.
 Dextranase when used as an antigen,can prevent the
colonization of organism in early dental plaque.

13. VACCINE
 Suspension of attenuated
or killed micro-organisms
administered for the
prevention, amelioration
or treatment of infectious
diseases.
 It stimulates production of
protective antibodies &
other immune
mechanisms.

14. CONCEPT OF DENTAL VACCINE
 The traditional way of managing dental caries was
by “Drill & fill”.
 This approach has slowly evolved into a more
conservative mode.
 Various preventive measures have been implicated
for prevention of dental caries,among which
immunization of population against the disease.
 Many studies have been conducted on development
of an effective vaccine to dental caries,but a safe &
effective vaccine is yet not marketed.

15. HISTORY OF CARIES VACCINE
 Bowen(1969) was the first scientist to achieve
successful immunization of experimental animals
against dental caries.
 Later attempts were made by Russell &
Johnson(1987),Koga(2002) & Smith(2002).
 Despite extensive experimental support for the caries
vaccine,a safe & effective vaccine is yet not marketed
anywhere in the world.

16. MECHANISM OF ACTION OF VACCINE
 Saliva contains 1-3% of immunoglobulin concentration,
majority of which is IgA.
 Saliva also contains IgG & IgM.
 Some of the possible ways antibodies might control
bacterial growth are :-
1) The salivary Ig may act as a specific agglutinin interacting
with the bacterial surface receptors & inhibiting
colonization & subsequent caries formation.This might
also inactivate surface glucosyltransferase,which would
reduce the synthesis of extra-cellular glucan resulting in
reduced plaque formation.

17. 2) The salivary glands produce secretory IgA antibodies
by direct immunization of gut associated lymphoid
tissue(GALT),from where sensitized B-cells are home
to salivary glands.
 The salivary IgA antibodies have direct access to tooth
surface.They may prevent S.mutans from adhering to
enamel surface or they may prevent formation of
dextran by inhibiting the activity of
glucosyltransferase.
 The injected antigen is phagocytosed & undergoes
antigenic processing by macrophages.This causes
sensitization of B & T-cells.This induces helper CD-4
& Cytotoxic CD-8 cell response & results in formation
of antibodies.

18. IMMUNE RESPONSE
 Primary response :- when an antigen is administered
for first time to humans or animals,there is latent
period of induction of 3-10 days before antibodies
appear in blood.
 The first antibody that appear is IgM type.
 The IgM antibody titer rises for 2-3 days,reaches its
peak level & then declines as fast as it developed.
 If the antigenic stimulus is sufficient,the IgG appears
in next few days & reaches its peak level in 7-10 days.

19.  The levels of IgG gradually falls over a period
of weeks or months.
 The important outcome of primary immune
response is education of reticulo-endothelial
system of body.
 Both B & T-lymphocytes produce memory
cells which are responsible for
immunological memory that is established
after immunization.

20.  Secondary or booster response :- the response of
booster dose differs from primary response.
 The secondary response also involves production of IgM
& IgG antibodies.
 There is brief production of IgM antibody,but more
prolonged production of IgG antibody.
 This accelerated response is attributed to
immunological memory.
 The immune response & immunological memory are
basis of vaccination & re-vaccination.

21. ANIMAL STUDIES
 Rodents are attractive as experimental animals
because they are inexpensive & easy to maintain.
 Rapid decay of their teeth can be induced by
Streptococcus mutans when present during the
provision of a sugar containing diet.
 The ability to establish large experimental groups &
to arrive at an accurate diagnosis of caries by
examination of tooth surface also makes rodents a
good choice for laboratory animals.

22.  Immunization experiments with cells of
S.mutans both in rats & monkeys have
consistently resulted in significance decrease in
dental caries.
 Immunization with whole cells of S.mutans or
purified Ag I/II produces a reduction of about
70% in both smooth surface & pit & fissure
caries when compared with controls.

23. CLINICAL TRIALS
 The main objectives for a successful clinical trial
are :-
1) Preliminary data indicating prospects of
success
2) A clear outcome measure of success
3) A compliant with high incidence of disease
4) No confounding external factors likely to come
into effect during the trial

24. ROUTES OF IMMUNIZATION
 There are 4 routes of
immunization used for
Streptococcus mutans :-
1) Oral
2) Systemic (sub-cutaneous)
3) Active gingivo-salivary
4) Passive dental
immunization

25. ORAL ROUTE
 Daily administration of 10 cells of S.mutans in
capsules produced small increase in IgA.
 The oral route failed to reduce caries significently,as
compared with sub-cutaneous immunization.
 Experiments in humans of ingestion of S.mutans in
gelatin capsules resulted in an increase in IgA
antibodies in saliva,although for a limited time.
 Oral route is not ideal because of detrimental effects
of acidity on antigen or because inductive sites are
relatively distant.

26. SUB-CUTANEOUS ROUTE
 Sub-cutaneous
administration of
S.mutans was used
successfully in monkeys &
elicitated pre-dominantly
IgA,IgG & IgM.
 The antibodies find their
way into oral cavity via
gingival crevicular fluid &
are protective against
dental caries.

27. ACTIVE GINGIVO-SALIVARY ROUTE
 There has been some concern expressed regarding
the side-effects of using these vaccines with other
routes.
 In order to limit these potential side-effects & to
localize the immune response,gingival crevicular
fluid has been used as route of administration.
 Its main advantage is that it causes increase in
levels of both IgA & IgG.

28. PASSIVE IMMUNIZATION
 It involves external or passive
supplementation of
antibodies.
 This carries the disadvantage
of repeated applications, as the
immunity acquired is
temporary.
1) Monoclonal antibodies
2) Bovine milk & whey
3) Egg-yolk antibodies
4) Transgenic plants

29. ADJUVANTS FOR CARIES VACCINE
1) Synthetic peptides :- Any antigen derived from
animals or humans have the potential to cause
hypersensitivity.The chemically synthesized peptides
do not cause such reactions.The synthetic peptides
are derived from glucosyltransferase enzyme.
2) Coupling with cholera toxin sub-units :- Cholera
toxin is a powerful mucosal immunoadjuvant,which
is used to enhance the induction of mucosal
immunity to variety of bacterial or viral pathogens in
animal systems.

30. 3) Fusing with Salmonella :- The non-virulent strains
of salmonella are an effective vaccine vector.They are
fused with vaccine by recombinant technologies.
4) Microcapsules & micro-particles :- They are made
up of polylactide-co-glycoside(PLGA) have been
used as local delivery systems because of their ability
to control the rate of release & slow degradation of
capsule.
5) Liposomes :- They are bilayered phospholipids
membrane vesicles manufactured to deliver drugs &
antigens.They increase mucosal immune response by
facilitating M-cell uptake.

31. HUMAN CLINICAL TRIALS
 The rationale is that the immunization with S.mutans
should induce a immune response,which might
prevent the organism from colonizing the tooth
surface & thereby prevent tooth decay.
 The vaccine could be given at the same time as the
vaccines against diphtheria & tetanus.
 As the vaccine would be administered before
deciduous dentition is erupted at about 6 months of
age,it would prevent the disease in children who show
greater incidence of caries.

32.  Immunity could be boosted at intervals to provide life-long
protection.
 Clinical trials are underway to test the use of pill of
S.mutans for control of caries.
 It has been experimented that ingestion of capsules
containing S.mutans stimulates the production of S-IgA.
 According to some reports,there is negative correlation
between S-IgA & caries prevalence.
 Stimulation of serum immunoglobulin in humans has
produced mixed results & no correlation could be
made between caries experience & serum
immunoglobulin stimulation.

33. RISKS IN CARIES VACCINE
 The most serious risk is that the sera of some patients
with rheumatic fever who show serological cross-activity
between heart tissue antigens & certain
antigens from hemolytic streptococci.
 Experiments from anti-sera from rabbits immunized
with whole cells of S.mutans were reported to cross-react
with normal rabbit & human heart tissues.
 Because of the potential of streptococcal whole cells to
produce heart reactive antibodies,the development of
sub-unit vaccine for controlling dental caries has been
subject of intense research interest.

34.  Glucosyltransferase is also tested for cross-reactivity
with human heart tissue & the results
are negative.
 Research also shows that C-terminal part of
Antigen I/II contains an epitope,which is cross-reactive
with human IgG,it is potentially harmful
for immune system.
 The human cross-reactive IgG region is also
present in other mutans streptococci such as
Streptococcus sobrinus.

35. CONCLUSION
 There is strong evidence that S.mutans & S.sobrinus
are closely associated with dental caries.
 Fluoride treatment used abroad has successfully
limited caries progression,but not sufficient to control
this disease even when used together with professional
tooth cleaning & dietary counseling in populations
highly exposed to these cariogenic bacteria.
 Active & passive immunization strategies which
targets key elements in molecular pathogenesis in
mutans streptococci,hold promise.

36.  Along the established methods of caries
prevention, caries vaccine have the potential of
making highly valuable contribution to control
disease.
 Regardless of the mechanism by which immune
protection against dental caries is achieved,further
advances to make immunization caries practical
will depend upon clinical trials aimed at
establishing whether the findings from animal
experiments can be transferred to humans.

37. Presented by :-
Name- Amanjot Singh
Roll no. – 5
BDS IIIrd prof.