To reduce the number of micro organism and prevent the growth of any new micro organisms.
Rendering contents of canal inert.
FUNCTIONS OF INTRA CANAL MEDICAMENT:
Prevention or control of post treatment pain.
Control of persistent periapical abscess: In weeping canal
TYPES OF MEDICAMENTS:
Camphorated parachlorophenol (CPC)
Iodine – potassium iodine
Heavy metal salts
IDEAL REQUIREMENTS OF INTRACANAL MEDICAMENTS
It should be an effective germicide and fungicide
It should be not irritating to the periapical tissues
It should remain stable in solution
It should be have prolonged antimicrobial effect
It should be active in the presence of blood, serum and protein derivatives of tissues.
It should have low surface tension and easily diffusible
It should not interfere with repair of peripaical tissues.
It should not stain the tooth structure.
It should be capable of inactivation in a culture medium.
It should not induce a cell mediated immune response.
It should be easy to handle (mix & place and remove)
It should not be very expensive
Ultimately no single agents fulfill these criteria.
Phenol is a protoplasm poison and produces necrosis of soft tissue. However because it has a strong inflammatory potential, at present it is rarely used as an ICM.
Eugenol: This is the chemical essence of oil of clove. It is both antiseptic and an anodyne. It is a constituent of most root canal sealer and used as a temporary sealing material. It inhibits intradental nerve impulses
It is a substitution product of phenol.
The aqueous solution of PCP penetrates deeper into the dentinal tubules, than camphorated chlorophenol.
1% solution of PCP is capable of killing many of the micro organisms in the RC and produced mild inflammation.
CAMPHORATED MONO PARACHLORO PHENOL (CMCP)
This consists of 2 parts of parachloro phenol and 3 parts of gum camphor.
Camphor serves as a vehicle and diluent and reduces the irritating effect of pure PCP. It also prolongs the antimicrobial effect.
This is a combination of formalin and cresol in the ration of 1:2 or 1:1. Formalin is a strong disinfectant that combines with albumin to form an insoluble, undecomposable substance and fixes the tissues. It is used as a dressing for pulpotomy to fix the retained pulp tissue.
Formocresol is a non- specific bacterial medicament most effective against aerobic and anaerobic organisms found in root canals.
Formocresol is also mutagenic and carcinogenic.
It is placed on a cotton pellet in the pulp chamber of a tooth in treatment and the vapors will penetrate the entire canal preparation.
It is colorless oil slightly soluble in water. It is a strong disinfectant and fixative.
2% gluatadehyde as an intra canal medicament.
The antimicrobial action of glutaradhyde is bacteriostatic.
It has both antiseptic and obtundent properties. But the antimicrobial effect is less than that of formacresol or CPC – Grossman.
It is less irritating to the tissue.
It is a compound containing paraformaldehyde as the primary ingredient.
It is claimed to be both intra canal medicament and sealer.
If enjoys a wide use among dentists. The constituents of the paste are as following:
Penicillin- effective against gram + ve microorganisms
Bacitracin – effective against penicillin resistant micro organism.
Strephto mycin- effective against gram- ve organisms
Caprylate –as the sodium salt, effective against fungi
Now Nystatin replaces sodium caprylate as the antifungal agent .i.e. PBSN. They are available in a paste form that may be injected into RC’s impregnated on paper points.
Sulfonilanide and sulfanizole are used as medicaments by mixing with sterile distilled water or by placing a moistened paper point into a fluffed jar containing the powder. This medication is suggested for use as intra canal medicament in acute periapical abscess.
Disadvantages: Yellowish tooth discoloration has been reported after use.
It consists of
Potassium pencilin G 1,000,000 units
Bacitracin 10000 units
Streptomycin sulphate 1.0 gram
Sodium caprylate 1.0 gm
Silicone fluid 3ml (vehicle)
Nystatin 10000 units
can be used instead of chemicals in case of wide apical foramen, over instrumented canal etc.
Also chemical antiseptics lose potency within a short duration compared to antibiotics. Hence in case of longer period of appointments antibiotics are preferred than chemicals as intra canal medicaments.
CORTICOSTERIODS- ANTIBIOTICS COMBINATIONS
These medicaments are highly effective in the treatment of over instrumentation. They must be placed in the inflamed tissue by a paper point or reamer to be effective. They are more effective in vital pulps than the necrotic pulp tissue.
The steroid constituent reduces the periapical inflammation and gives instant relief of pain. The antibiotic constituents are present so that overgrowth of micro organisms will be prevented.
Sodium hyplochlorite is also used an ICM. Chlorine is the active ingradient in NaocL.
Naocl reacts rapidly with organic matter and hence its longetivity of its antimicrobial effect is questionable.
Disadvantages: Toxic to the periapical tissues.
It is a mild antiseptic.
It works by inhibiting bacterial protein synthesis.
It has been used more as an irrigant than intra canal medicament, because of its low surface tension.
QUATERNARY AMMONIUM COMPOUNDS:
It is a chlorine compound used in concentration of 5%.
It has good antimicrobial qualities.
It remains stable for a long period of time.
Iodine is highly reactive combines with proteins and forms salts which probably destroys micro organisms.
Iodine – potassium iodide is relatively high antibacterial and relatively low toxic.
1) It may cause staining of the tooth.
2) Allergic reaction.
Introduced by Herman in 1920.
It is one of the commonly used ICM.
It is a broad spectrum anti microbial agent.
It s antiseptic action probably relates to its high pH and its leaching action on necrotic pulp tissue.
It is best used in Weeping canals, where there is a constant clear or reddish exudate associated with large periapical lesion. The tooth will be often asymptomatic, culture will be usually - ve with no support of bacterial growth.
In such cases calcium hydroxide is a excellent medicament to be used.
Calcium hydroxide is best used in paste form when one anticipates an excessive delay between appointments.
Calcium hydoxide has highest effect on endotoxin. i.e. inhibits lipopolysaccharides.
Repair of periapical tissues after RCT of teeth periapical lesions was better when calcium hydoxide was used an ICM or dressing before obturation. Merio Tanomarn.
In cases of apical periodontitis, root canal dressing with calcium hydroxide produce definite signs of healing after only few days .
Calcium hydroxide can be used as a powder with various vehicles such as water, saline, L.A. Propleneglycol, glycerine etc.
It is broad spectrum antimicrobial agent.
CHX is also shown to be an excellent intra canal medicament. Its action may be due to sustained release of the chemical.
Studies have shown that calcium hydroxide and CHX combination was more effective.
CHX is active against a wide range of aerobic an anerobic bacteria as well as candida spices.
LIMITATIONS OF INTRA CANAL MEDICAMENTS
Intra canal environment- The therapeutic action of these medicaments depends on the direct contact on the tissues. But these substances probably do not reach all the areas where bacteria or tissues are present and are limited to the surface action only.
Duration To be effective these agents should remain chemically active during the time of inter appointments. Phenols lose their activity very quickly with in 24 hrs. Calcium hydroxide retains the antimicrobial action for a prolonged period.