Intracanal Medicaments In Endodontics

Intracanal Medicaments

Originally, endodontics was mainly a therapeutic procedure in which drugs were used to destroy microorganisms, fi or mummify vital tissue and affect the sealing of the root canal space.

The drugs commonly used were caustics such as phenol and its derivatives which were shown to produce adverse effects on the periapical tissues. Gradually, the reliance on drugs has been replaced by an emphasis on thorough canal debridement. But drugs are still being used as intratreat- ment dressings, although an ever-increasing number of endodontists use them only for symptomatic cases.

Read And Learn More: Endodontics Notes

Functions of Intracanal Medicaments:

• Destroy the remaining bacteria and limit the growth of new arrivals
• In cases of apical periodontitis, for example, in cases of inflammation caused due to over instrumentation

Indications of Using Intracanal Medicaments:

• Remove the remaining microorganisms from the pulp space
• Dry the weeping canals
• Act as a barrier against leakage from an interappointment dressing
• Neutralize the tissue debris

Desirable Properties of an Intracanal Medicaments

It should

• Be effctive germicide and fungicide
• Be nonirritating to pulpal tissue
• Remain stable in the solution
• Have prolonged antimicrobial action
• Remain active in the presence of blood, pus, etc.
• Have low surface tension
• Not interfere with repair of periapical tissue
• Non-staining to tooth
• Be capable of inactivation in the cultural media
• Not induce an immune response

Classifiation Of Intracanal Medicaments

Characteristics Of Intracanal Medicaments

Essential Oils:

Eugenol

It has been used in endodontics for many years. It is a constituent of most root canal sealers and is used as a part of many temporary sealing agents. This substance is the chemical essence of the oil of clove and is related to phenol. The effects of eugenol are dependent on tissue concentrations of the eugenol and can be divided into low doses (beneficial effects) and high doses (toxic effects).

Uses of eugenol:

Used as an intracanal medicament

Used as root canal sealers

Part of temporary sealing agents

Phenolic Compounds:

Phenol:

It was used for many years for its disinfectant and caustic action. However, it has strong inflammatory potential, so, at present, it is rarely used as an intracanal medicament. Liquefied phenol (carbolic acid) consists of nine parts of phenol and one part of water.

Phenolic Compounds Uses:

• It is used for disinfection before periapical surgery
• It is also used for cauterizing tissue tags that resist removal with broaches or fees

Parachlorophenol:

Parachlorophenol (PCP) has been a very popular component of dressing as phenol is no longer used in endodontics because of its high toxicity-to-efficacy ratio.

Parachlorophenol Composition:

• It is a substitution product of phenol in which chlorine replaces one of the hydrogen atoms (C₆H₄OHCl)
• On trituration with gum camphor, these products combine to form an oily liquid

Parachlorophenol Concentration: 1% aqueous solution is preferred.

Parachlorophenol Uses: Used as a dressing of choice for an infected tooth

Camphorated Monoparachlorophenol (CMCP)

It is probably the most commonly used medicament in endodontics, presently, even though its use has decreased considerably in the past few years.

Camphorated Monoparachlorophenol Composition:

Two parts of PCP
+
Thess parts gum camphor
↓
Camphorated monochlorophenol (CMCP)

Camphor is added to PCP because it

• Has diluent action
• Prolongs the antimicrobial effect
• Reduces the irritating effect of PCP
• Serves as a vehicle for the solution

Camphorated Monoparachlorophenol Uses: Used as a dressing of choice for infected teeth.

Cresatin:

Schilder and Amsterdam showed that Cresatin possesses the same desirable qualities and actions as that of CMCP, but is less irritating to periapical tissues

Cresatin Composition: It is a clear, stable, oily liquid of low volatile
nature is known as meta cresyl acetate.

Aldehydes:

• Formaldehyde, paraformaldehyde, and glutaraldehyde are commonly used intracanal medicaments in root canal therapy
• These are water-soluble protein denaturing agents and are considered among the most potent disinfectants
• They are mainly applied as disinfectants for surfaces and medical equipment which cannot be sterilized, but they are quite toxic and allergic and some even may be carcinogenic

Formocresol:

Formocresol contains formaldehyde as its main ingredient and is still widely used medicament for pulpotomy procedures in primary teeth but its toxic and mutagenic properties are of concern

Composition of formocresol:

• Formaldehyde—19%
• Cresol—35%
• Water and glycerine—46%

Formocresol Uses: Used as dressing for pulpotomy to fi the retained pulpal tissue.

Paraformaldehyde:

• It is a polymeric form of formaldehyde and is commonly found as a component of some root canal obturating material like beclomethasone
• It slowly decomposes to give out formocresol, its monomer
• Its properties are similar to formaldehyde that is toxic, allergenic, and genotoxic in nature

Paraformaldehyde Clinical Tips:

All phenolic and similar compounds are highly volatile with low surface tension. If they are placed on a cotton pellet in the pulp chamber, vapors will penetrate the entire canal preparation. Therefore, a paper point is not needed for their application. Only a small quantity of medication is needed for effctiveness, otherwise, chances of periapical irritation are increased.

Calcium Hydroxide:

The use of calcium hydroxide in endodontics was introduced by Hermann in 1920. It acts as a strong base in contact with aqueous solution and dissociates into calcium and hydroxyl ions.

Effects of Calcium Hydroxide:

• Physical
  • Acts as a physical barrier for the ingress of bacteria
  • Destroys the remaining bacteria by limiting space for multiplication and holding substrate for growth
• Chemical
  • It shows antiseptic action because of its high pH and leaching action on necrotic pulp tissues. It also increases the pH of circumpolar dentin when placed into the root canal
  • Suppresses enzymatic activity and disrupts the cell membrane
  • Inhibits DNA replication by splitting it
  • It hydrolyses the lipid part of bacterial lipopolysaccharide (LPS) and thus inactivates the activity of LPS. This is a desirable effect because dead cell wall material remains after the killing of bacteria which may cause infection
• Calcium hydroxide is available in
  • Paste form: Single paste or in combination with iodoform
  • Powder form: Powder form is mixed with saline and anesthetic solution. For placement in root canals, it is coated with the help of paper points, spreaders, or lentils spirals.

Indications of calcium hydroxide

• In weeping canals
• In the treatment of Phoenix abscess
• In resorption cases
• For specification
• During pulpotomy
• For nonsurgical treatment of periapical lesions
• In cases of direct and indirect pulp capping
• As a sealer for obturation
• To decrease postoperative pain after over instrumentation, it is used in combination with Ledermix (1:1)

Advantages of Ca(OH)₂

• Inhibits root resorption
• Stimulates periapical healing
• Encourage mineralization

Disadvantages of Ca(OH)₂ as an intracanal medicament

• Difficult to remove from canals
• Decreases setting time of zinc oxide eugenol-based cements
• It has little or no effect on the severity of post obturation pain

Use of Calcium Hydroxide in Weeping Canal Cases

Sometimes, a tooth undergoing root canal treatment shows constant clear or reddish exudation associated with periapical radiolucency. A tooth can be asymptomatic or tender on percussion. When opened in next appointment, exudates stop but it again reappears in the next appointment. This is known as the “weeping canal.”

In these cases, a tooth with exudates is not ready for filing, since culture reports normally show negative bacterial growth, so antibiotics are of no help in such cases. For such teeth, dry the canals with sterile absorbent paper points and place calcium hydroxide in the canal. By the next appointment, one finds a dry canal, ready for obturation.

It happens because the pH of periapical tissues is acidic in a weeping stage which gets converted into basic pH by calcium hydroxide. Some say that the caustic effect of calcium hydroxide burns the residual chronic inflamed tissue and also calcium hydroxide builds up the bone in the lesion due to its calcifying action.

Halogens:

Halogens include chlorine and iodine which are used in various formulations in endodontics. They are potent oxidizing agents with rapid bactericidal effects.

Chlorine:

Sodium hypochlorite: The disinfectant action of halogens is inversely proportional to their atomic weights. So, when compared to iodine, chlorine shows better disinfectant action. But chlorine disinfectants are not stable compounds because they interact rapidly with organic matter.

Mentz found sodium hypochlorite as an effctive intracanal medicament as well as an irrigant. As the activity of sodium hypochlorite is intense but of short duration, the compound should be changed in the root canal every other day.

Iodides:

Iodine is highly reactive in nature. It combines with proteins in a loosely bound manner so that its penetration is not impeded. It destroys microorganisms by forming salts that are unfavorable to the life of the organism. Iodine is used as iodine potassium iodide and in iodophors, which are organic iodine-containing compounds that release iodine over time.

It is also a very potent antibacterial agent of low toxicity but may stain clothing if spilled. It is used as an irrigating solution and short-term dressing in a 2% solution of iodine in 4% aqueous potassium iodide and as a constituent of gutta-percha points for filing.

2% Chlorhexidine Gluconate:

The antibacterial activity of chlorhexidine gluconate is comparable to sodium hypochlorite. Substantivity, broad-spectrum activity, and low toxicity of CHX make it suitable for irrigation. Attempts are being made to utilize its disinfecting properties in gutta-percha points.

PBSC Paste:

As mentioned by Grossman, PBSC has enjoyed wide use among dentists. The constituents of PBSC paste are as follows:

1. Penicillin—effctive against Gram-positive microorganisms
2. Bacitracin—effctive against penicillin-resistant microorganisms
3. Streptomycin—effctive against the Gram-negative microorganisms
4. Caprylate (sodium salt)—effctive against fungi

Nystatin replaces sodium caprylate as the antifungal agent and is available in the form of PBSN. Both are available in a paste form that may be injected into root canals or impregnated on paper points. Because there is no volatility, the drug must be placed in the canal to have effect in that area.

PBSC may interfere with subsequent culturing procedures; therefore, penicillinase may be added to culture media to inactivate penicillin. Reports of allergic reactions to the drug have been presented, if the patient reports a history of allergy to any of the constituents, the drug should not be used.

With the decline in popularity of intracanal drugs in general and because of the potential for sensitivity due to topical use of antibiotics, PBSN largely has fallen into disuse.

Sulfonamides:

Sulfanilamide and sulfathiazole are used as medicaments by mixing with sterile distilled water or by placing a moistened paper point into a fluffy jar containing the powder. Yellowish tooth discoloration has been reported after use. Sulfonamides are usually recommended while giving closed dressing in a tooth which had been left open after an acute periapical abscess.

N2 by Sargent:

It is a compound consisting of paraformaldehyde as the main ingredient. It contains eugenol, phenyl mercuric borate, and perfumes. Antibacterial effect of N2 is short-lived and dissipated in 7–10 days.

Grossman Paste

Composition

• Potassium penicillin G      1,000,000 units
• Bacitracin                          100,00
• Streptomycin sulfate          1.0 g
• Sodium caprylate               1.0 g
• Silicon flid                           3 mL
• Nystatin                              10,000 units

Chloramines-T:

It is a chlorine compound with good antimicrobial. It is used in the concentration of 5%. It remains stable for a long period of time and is used to disinfect gutta-percha points. It can be used in patients allergic to iodine.

Quaternary Ammonium Compounds:

These are positively charged compounds which attract negatively charged microorganisms; they have low surface tension, for example, aminoacridine. Aminoacridine is a mild antiseptic which is more effc- tive than creation but less effctive than CMCP. It is used more as an irritant than intracranial medicament.

Corticosteroid–Antibiotic Combinations:

• Medications that combine antibiotic and corticosteroid elements are highly effctive in cases of over instrumentation
• They must be placed into the inflamed periapical tissue by a paper point or reamer
• Tetra-Cortril, Cortisporin, Mycolog, and other combinations are available for their use in endodontics
• Ledermix is one of the best known antibiotic-corticosteroid combinations.
• Schroeder and Triadan developed Ledermix in 1960. It contains an antibiotic demeclocycline—HCl (3.2%) and a corticosteroid, triamcinolone acetonide (1%), in a polyethylene glycol base.
• Corticosteroid constituent reduces the periapical inflmmation and gives almost instant relief of pain to the patient who complains of extreme tenderness to percussion after canal instrumentation
• Antibiotic constituents present in the corticosteroid–antibiotic combination prevent the overgrowth of micro-organisms when the inflammation subsides

Placement Of Intracanal Medicament

• Copiously irrigate the canal to remove debris present if any
• Place the master apical file in the canal
• Dry the canal using absorbent paper points
• Place the intracanal medicament on a sterile cotton pellet and place it in the pulp chamber
• Over this, another sterile cotton pellet is placed, which is finally sealed with a temporary restorative material

Limitations of Intracanal Medicaments:

• For an intracanal, medicament to be effctive, it should remain active during the time of interappointment, which does not happen not in every case
• Clinical effctiveness of sustained release delivery systems is unknown
• The therapeutic action of medicament depends upon its direct contact with tissues, but it can be prevented due to the presence of organic tissue/matter

Irrigation And Intracanal Medicaments Conclusion

The success of endodontic treatment depends on the eradication of microbes from the root-canal system and prevent- tion of reinfection. Instrumentation and irrigation are the most important parts of successful endodontic treatment. Irrigant performs many functions, the most important of which are to dissolve tissue and to have an antimicrobial effect.

Commonly used during cleaning and shaping include sodium hypochlorite, chlorhexidine, EDTA, MTAD, etc. None of these irrigants has all of the characteristics of an ideal irrigant. Many chemicals used for irrigation have been chemically modified and several mechanical devices have been developed to improve the penetration and effctive- ness of irrigation.

Intracanal medicaments have been used to disinfect root canals between appointments and reduce interappointment pain. The major intracanal medications currently used in endodontics include calcium hydroxide, though the search for an ideal material and/or technique to completely clean infected root canals continues.