Dental Caries Vaccine - It's importance in dentistry.

 Dental Caries Vaccine - it's importance in dentistry.

The use of dental caries Vaccine is beneficial in developing countries where dental caries prevalence has increased. The low dentist to population ratio  and the lack of organized dental health care limit the possibilities of utilizing conventional caries preventive methods.

Hence the use of caries Vaccine could be of a great value as a preventive adjunct in some societies and a major public health measures in others.

INTRODUCTION 

The  term “vaccine” is a Latin word which means a suspension of attenuated or killed microorganisms ( bacteria, viruses or ricketsiae)administered for the prevention,  or treatment of infectious diseases.  

Vaccine is an immuno-biological substance designed to produce specific protection against a given disease. It stimulates the production of protective antibody and other immune mechanism. 

DENTAL CARIES 

• It is an irreversible microbial disease of the calcified tissues of the teeth characterized by demineralization of the inorganic portion and destruction of organic substance of the tooth , leads to cavitation. 
• Dental  caries appears to be a major public health problem which if left untreated can cause considerable pain, discomfort and treatment costs which are very high. 
• Dental caries results from the interaction between the host, the host’s diet and the microflora on the tooth surface bounded by the time factor. 
• A wide group of microorganisms are identified from carious lesions of which Streptococcus mutans, Lactobacillus acidophilus and Actinomyces viscosus are the main pathogenic species involved in initiation and development of dental caries. S. mutans has been implicated as a causative organism of dental caries.

Various preventive measures have been implicated for prevention of caries, among which is immunization of the population against the disease, as dental decay fulfills the criteria of an infectious disease. 

The concept of vaccination against dental caries has existed almost from the time that this disease was recognized to result from colonization of the teeth by acidogenic bacteria, even though the etiological agents were originally thought to be lactobacilli.

Since then, Streptococcus mutans and Streptococcus sobrinus and their relatives, collectively known as mutans streptococci, have become recognized as the principal organisms responsible for initiating caries in humans.

ROUTES  OF  ADMINISTRATION 

Two categories

        - routes of administration in active immunization

        - routes of administration in passive immunization 

PASSIVE IMMUNIZATION 

• Egg yolk antibodies
•  Bovine milk antibodies 
• Murine monoclonal antibody 
• Transgenic plants 

COMMON MUCOSAL PATHWAY 

• Targets all the lymphoid aggregates- NALT, GALT, MALT
• Lymphoid aggregates contain B cells, if injected to these sites, speed of antibody production is increased.
• Mucosal application of dental caries vaccine have sought, since secretory Ig A is the principle immune component of major and minor salivary gland secretions and thus would be considered to the primary effector of adaptive immunity. 

ORAL  ROUTE 

Relied on oral induction of immunity in the GALT.

Antigen was applied by oral feeding, gastric intubation, or in vaccine containing capsules or liposomes.

INTRA NASAL 

Intranasal instillation of antigen, the NALT, has been used to induce immunity to bacterial antigens including those associated with mutans Streptococcus colonization and accumulation.

TONSILLAR 

The tonsillar tissues contain the required elements of immune induction of S-IgA and IgG.

MINOR  SALIVARY  ROUTES 

They populate the lips, cheeks and soft palate.

They have been suggested as potential routes for mucosal induction, given their short, broad secretory ducts that facilitate retrograde access of bacteria & their products & give the lymphatic tissue aggregates.

RECTAL ROUTE 

This region as an inductive location for immune responses in humans is suggested as this site has the highest concentration of lymphoid follicles in the lower intestinal tract.

PARENTRAL ROUTE 

• Intravenous (IV) 
• Subcutaneous (SC)
•  Intramuscular (IM)

PARENTRAL ROUTE 

This route was used successfully and elicited predominantly IgG, IgM and IgA antibodies.The antibodies find their way into the oral cavity via GCF and are protective against dental caries.Studies have shown that IgG antibodies are well maintained at higher titer, IgM antibodies fall progressively and IgA increase slowly. Protection against caries was associated predominantly with increased serum IgG antibodies. 

Active gingivo salivary route 

Directly injected to attached gingiva.

In order to limit the potential side effects and to localize the immune response, gingival crevicular fluid has been used as  the route of administration. It induces both IgA and IgG antibodies.

ACTIVE GINGIVO SALIVARY ROUTE

Directly injected to attached gingiva.

In order to limit the potential side effects and to localize the immune response, gingival crevicular fluid has been used as  the route of administration. It induces both IgA and IgG antibodies

 

 PASSIVE IMMUNIZATION- 

• Murine Monoclonal Antibodies 

Applying it to monkey’s gingiva , resulted in decreased colonization of implanted S. mutans, reduced caries. 

• Bovine Milk 

Ingestion of the food supplemented with immune bovine milk resulted in diminished S. mutans, less plaque and reduced caries in rodents. 

• Egg  Yolk  Antibodies 

Immunization of hens with GTF, followed by purification of the antibody enriched Ig G from egg yolks and the experimental use of this enriched antibody as a dietary additive in rodents. Dental caries reduced by 50 %. 

• Transgenic Plants 

They are the latest developments. 

Researches have developed a caries vaccine from a genetically   modified (GM) tobacco plant.

Vaccine is colorless, tasteless and can be painted onto the teeth

It is the first plant derived vaccine from GM plants.

ADVANTAGES 

Used in patients

Undergoing head and neck therapy

Severe xerostomia 

Chronically sick children on continuous medication presented in high sucrose syrups.

Mentally and physically handicapped unable to practice adequate oral hygiene. 

Window of infectivity – first 6 months and 6 years. 

Ideal time of vaccination before 6 months and booster dose before 6 years along with other  vaccinations. 

DRAWBACKS 

Heart cross reactivity- when animals are injected with whole S. mutans bacteria, they form antibodies which react not only with bacteria, but also with heart tissues, myosin component causing some damage to heart. Earlier Ag II had similarity with heart musle fibres but nowadays it is not used in preparations

Targeted only on S. mutans.

No long term human trials to judge its efficiency.

Chances of hypersensitivity.

RECENT  ADVANCES 

Microcapsules- artificially clubbed with particles for availability of vaccine.

Macroparticles- coupled with Salmonella toxin and cholera vaccine. Increased potency and duration of action.

Transgenic plants/ plantibodies 

Replacement therapy- Dr Jeffrey D Hillman developed a genitically modified strain of S. mutans which is incapable of producing lactic acid(BCS3-L1).