disinfection of the root canal
TRANSCRIPT
INTRACANAL MEDICAMENTS
INTRODUCTION
The success of root canal largely depends on the elimination of the microbial contamination from the root canal system.
Although mechanical instrumentation of the root canals can reduce bacterial population, effective elimination of bacteria cannot be achieved without the use of antimicrobial root canal irrigation and medication.1
The common belief
inadequate obturation is the major
cause of endodontic failures-fallacious
In other words, what you take out of a root canal may be equally/more important than what you put in it6.
When we have used the best of instruments and irrigants to eliminate humongous micro-organisms
why intracanal medicament?
THE REASON-
TO ELIMINATE BACTERIA LOCATED IN AREAS –
Thus effectively preventing micro-organisms present in the canal to
invade the periapical tissue
ISTHMUSESRAMIFICATIONSDELTASIRREGULARITIES ANDDENTINAL TUBULES1
USE OF IRRIGANTS + MEDICAMENTS
between appointments
-For elimination and disinfection of organisms --To reduce periapical inflammation and pain.6
To induce healing
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Why between appointments?
Studies have shown that number of residual bacteria following instrumentation is usually low, but should the canals be left empty between appointments, the remaining residual bacteria can multiply to nearly the original levels.2
It is doubtful whether a routine intracanal medicament is needed in pulpectomy and where the root canal contains vital pulp tissue.7
WHAT MICROORGANISMS ARE WE TRYING TO DESTROY?
.
Intracanal medicaments
Requirement :1. Effective germicide , fungicide2. Non- irritating to priapical tissues.3. Should remain stable in solution.4. Have prolonged antimicrobial
effect.5. Active in presence of blood,
serum, protein derivatives of tissue.
Requirement 6. Should have low surface tension.7. Should not interfere with the
repair of the PA tissue.8. Should not stain the tooth.9. Should get inactivated in a culture
medium.10.Should not induce a CMI response.
Uses Of Intracanal Medicaments7:
1. Eliminate any remaining bacteria after root canal instrumentation;
2. Reduce inflammation of periapical tissues
3. Render canal contents inert and neutralise tissue debris;
4. Act as a barrier against leakage from the temporary filling
5. Help to dry persisitent wet canals.
However, most of the indications for intracanal medicaments are questionable.
Intracanal medicament can only be used as a part of controlled asepsis in infected root canals and their role is secondary to cleaning and shaping of the root canal. 7
Bacteriological sampling may be necessary if a tooth does not respond to treatment, to help in the choice of intracanal medicament.
What are the obstructions?
SMEAR LAYER Removal of the smear layer can allow
intracanal medicaments to penetrate the dentinal tubules in infected root canals more readily and consequently cause a better disinfection procedure.
classification
Essential Oils:Eugenol Ca(OH)2 halogens phenolic compd NaOCl
phenol N2 iodide
CMCP FC
glutraldehyde Quats cresatin
ESSENTIAL OILS
Are weak disinfectants. Eugenol: is the chemical essence
of the oil of clove and is related to phenol.
Both antiseptic and anodyne. Can inhibit intra dental nerve
impulse. Can cause allergy.
PHENOLIC COMPOUNDS
Phenol: white crystalline substance has a characteristic odor and is derived from coal tar
Liquefied phenol consist of 9 parts of phenol and 1 part of water.
Is a protoplasm poison and necrotizes the soft tissue.
PHENOLIC COMPOUNDS Para-chloro phenol: this is a
substitution product of phenol in which the chlorine replaces one of the hydrogen atoms
Forms oily liquid with gum camphor Invitro destroyed a number of
microbes Its being shown that aqueous solution
of para-chloro phenol penetrates deeper into the dentinal tubules than camphorated phenol
RATIONALE OF DISINFECTION
Microbes in the canal ,invading the periapical area ,not only cause pain but also, destruction of the bone.
Shown by various studies that intra canal medicaments reduces or eliminates the microbial flora in the canal.
ROOT CANAL FLORA Gram positive, gram negative, yeasts
are present depending upon the case Obligate anaerobes are present in
teeth having periapical lesion. Microbes are present in combination
rather than single species. These have their origin in the mouth,
with most commonest being the Streptococci and Staphylococci. In streptococci is the small group of Enterrococci.
PREDISPOSING FACTORS
Trauma- The tooth under treatment should be dis-occluded if necessary.
Dead tissue remnants- If present will interfere with the repair or disinfection
Dead space- For maximum effect the medicament should be in maximum contact with the microbes in the canal.
Accumulation of the exudate- Exudate should be allowed to drain or removed as it accumulates
This above factors can also counteract disinfection of the canal and delay the healing as well.
REQUIREMENTS OF IDEAL MEDICAMENT
Effective germicide and fungicide. Nonirritating to the periapical
tissues. Stable in the solution. Prolonged effect. Active in presence of blood ,
serum, protein derivatives of the tissue.
Low surface tension . Should not interfere with repair. Should not stain the tooth
structure. Capable of inactivation in the
culture medium. Should not induce a cell mediated
immune response.
VARIOUS DISINFECTANTS
Essential oils
Phenolic compounds
Halogens
Antibiotics
PHENOLIC COMPOUNDS Formocresol : Combination of formalin
and cresol in the proportions of 1:2 or 1:1
Formalin –strong disinfectant that combines with the albumin to form an insoluble , indecomposable substance.
May lead to necrosis and persistent inflammatory and in some cases cell mediated immune response
Non specific bactericidal medicament most effective against aerobic and anaerobic organism found in the canal
PHENOLIC COMPOUNDS
Glutaraldehyde: colorless oil, soluble in water and slightly acidic in reaction
Is a strong disinfectant and fixative
Glutaraldehyde produces no immune reaction
PHENOLIC COMPOUNDS
Cresatin: Also known as metacresylate.
Clear,stable,oily liquid of low volatility.
Antiseptic and obtundant. Less anti microbial and less
irritating.
CALCIUM HYDROXIDE Intracanal medicament As effective as camphorated
chlorophenol. Antiseptic action related to its high pH
and leaching action on necrotic tissue Best intracanal medicament when one
anticipates excessive delay between appointments
Very effective medicament
N2 Contains paraformaldehyde as primary
ingredients. Used as a sealer as well. Contains eugenol , phenyl mercuric
borate and sometimes lead, corticosteroids, antibiotics and perfume.
Antibacterial effect is short lived and dissipated in about a week to 10 days.
HALOGENS Sodium hypochlorite: sometimes used
as a medicament Disinfection action with halogens is
inversely proportional to their atomic weights. Hence chlorine with lowest atomic weight has the greatest disinfectant action of the other halogens.
Since the activity of hypochlorite is short lived ,should be applied to the canal every other day.
HALOGENS Iodides : used as antiseptics for more
than a century Highly reactive combines with the
proteins in a loosely bound manner so its penetration is not impeded
Probably destroys microbes by forming salts that are inimical to their life
2%solution of iodine in potassium iodide; contains 2parts iodine crystals,4parts potassium iodide and 94 parts distilled water. Antibacterial action is short lived and least irritating.
QUATERNARY AMMONIUM COMPOUNDS
Lowers the surface tension of the solutions
Inactivated by the anionic compounds Are positively charged and microbes
are negative charged hence a surface active effect results in which the compound clings to the microbe and reverses the charge.
9-aminoacridine –mild cationic antiseptics , may stain the tooth.
IRRITATION POTENTIAL OF MEDICAMENT
Studied by Black, found some of the essential oils and formocresol highly irritating
Grossman found camphorated chlorophenol and cresatin with a moderate irritating effect
Schilder and Amsterdam –Formocresol is highly irritating and cresatin caused little or no irritation
FREQUENCY OF MEDICATION
Disinfectant dressing should be preferably renewed in a week and not longer than 2 weeks as the dressing may become diluted by the exudates and may get decomposed by the interaction with the microbes.
FREQUENCY OF MEDICATION
Traditionally, a short blunt absorbent point moistened with the medicament is carried into the canal, a cotton pledget from which excess medicament has been expressed is placed in the chamber and the cavity is sealed
In case of narrow canals, a dry point is placed and over it is placed a cotton pledget moistened with medicament. A dry cotton is used to absorb the excess medicament and the cavity is sealed.
FREQUENCY OF MEDICATION Many prefer to dress the canal with a medicated
cotton pellet from which excess medicament has been removed and depend upon the vaporization of the medicament for the anti-bacterial action
Such a method allows space in the canal for the accumulation of the exudates and prevents extrusion of the medicament in the periapical area.
The canal is sealed after placing a sterile dry cotton pellet over the medicated pellet or placing a temporary stop over the medicated pellet and completing the double seal with a outer seal of Cavit, ZOE or IRM .
OUTLINE OF THE TREATMENT
First visit: apply the dam, disinfect the field and prepare the access.
Open into the chamber with sterile burs to obtain a straight line access
Remove the contents of the chamber with a sterile excavator. Locate the orifices with a explorer-D11 instrument. Explore the canal to check the patency. Irrigate.
Carefully establish the working length.
OUTLINE OF THE TREATMENT
Clean and shape the canal with instruments and thorough irrigation, especially with sodium hypochlorite
Seal the medicament in the canal and remove the dam.
OUTLINE OF THE TREATMENT Second visit: apply the dam and disinfect the field of
operation Remove and discard the dressing and if clinical conditions
are satisfactory take a culture:1> Swab the surface of the tooth with alcohol. Let it evaporate
and dry it with a sterile cotton pellet.2> With a sterilized cotton pliers introduce a sterile absorbent
point into the canal and with a wiping motion remove the traces of the medicament. Repeat.
3> Introduce a dry, sterile absorbent point into the canal. Let the point remain for at least 1min..on removal if the tip of the point I wet with the exudate remove the screw cap from the test tube. Flame the lip of the tube and drop the point into the tube of the medium. Replace the cap.
Apply label and place it in a incubator Seal the medicament Recall the patient.
OUTLINE OF THE TREATMENT
Third visit: if culture is negative and no clinical contraindications exist, obturate the canal.
Don’t obturate if culture shows infection or the tooth is symptomatic
TEMPORARY FILLING MATERIAL
Adequacy of the temporary filling is very important.
Requirements include:1> Impervious to fluids of mouth and bacteria.2> Hermetically seal the access cavity.3> Should not pressurize the dressing during
insertion.4>Harden within a few minutes.5>Withstand the force of mastication.6>Easy to manipulate and remove.7>Harmonize with the color of the tooth.
TEMPORARY FILLING MATERIAL
Zinc-oxide, fast setting cements meet the best of the requirements.
Cavit and IRM are satisfactory materials
Cavit should be at least 3.5 mm thick to prevent leakage.
IRM becomes hard shortly after insertion and showed no evidence of leakage.
One may conclude that Cavit and IRM are adequate materials when used properly.
Conclusion: The variety of microorganisms present in root
canal-treated teeth with persistent periapical lesions is more restricted (1-3 species) in comparison to primary root canal infections, which are dominated by E. faecalis, a facultative anaerobic gram-positive coccus that is resistant to intracanal medications, able to form biofilms and able to invade dentinal tubules4. Because the presence of bacteria negatively influences the outcome of root canal treatment,every effort should be made to eradicate infections during treatment5.
1. Ikhlas El Karim et al. The antimicrobial effeccts of root canal irrigation andmedication. oral surgery, Oral Med, Oral radiology, and Endodontology; 2007 ; Vol.103; no 4, April : 560-5692. Bystrom A, Syndqvist G. Bacteriologic evaluation of the effect of 0.5 % sodium hypochlorite in endodontic therapy. Oral surgery, Oral Med, Oral pathol 1983; 55:307-312 4. Sjogren U, Figdor D, Persson, Sundqvist G. Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J1997;30:297-306.5. Sundqvist G, Figdor D, Persson S, Sjogren U. Microbiologic analysis of teeth with failed endodontic treatment and the outcome of conservative re-treatment. Oral Surg Oral MedOral Pathol Oral Radiol Endod 1998;85:86-93. 6. EndodoNtics: Colleagues for Excellence: American Association of Endodontists, Winter 2011 7. B.S.Chong and T.R.Pitt Ford. The role of inracanal medicament in root canal treatment . International Endodontic Journal 1992;25; 97-106
