Endodontic pharmacology
Introduction
For decades, many therapeutic agents have been proposed to meet endodontic objectives: root canal debridement, infection control and pain management. While many have disappeared from our therapeutic arsenal, others have stood the test of time and have even seen their indications multiply as research has progressed and clinical results have been obtained.
The evolution of endodontic concepts and techniques has considerably reduced endodontic pharmacology. It is currently limited to a few irrigation solutions and products for medical use. Their choice takes into account the objectives sought, as well as the quality and constraints of the substances used.
1. Endodontic treatment and pharmacology
– The root canal sanitation method combines, during the operation, two interdependent mechanical (instrumentation) and physicochemical (irrigation) components.
– The maintenance of canal sanitation is ensured by a definitive obturation of the cone obtained (after canal preparation).
– When the definitive filling is deferred, it may be advisable to use temporary filling materials, the aim of which is to maintain or optimize canal disinfection by inter-session medication.
2. Pre-operative medications:
The drugs used pre-operatively in endodontics include: Anesthetics and escharification products (see course: Dental anesthetization in dentistry)
3. Intraoperative medications
3.1. Endodontic irrigation solutions
The role of irrigation in endodontics is twofold. Irrigation must have
• a physical action, which is essential to help eliminate organic and mineral debris as well as microorganisms. Suspending the debris prevents its sedimentation and potential blockage of the root canal. Irrigation also provides lubrication of the instruments, which facilitates their cleaning and maintains their cutting efficiency.
- A chemical action combining:
- Good antibacterial efficacy,
- Good solvent action on organic debris,
- An absence of cytotoxicity for the periapex.
Obviously, this last property is difficult to reconcile with the first two, which explains the recommendations to use low-concentration sodium hypochlorite solutions or to resort to other products.
Many authors have concluded that no single solution meets all the required conditions, but that the combination of two or more solutions for canal irrigation could achieve the desired result (Koskin1980, Baumgartner1980).
- The minimum required properties are:
- A solvent action on organic pulp debris and dentinal smear,
- An antiseptic action.
a. Chlorinated derivatives:
They are local antibacterials and antiseptics. Sodium hypochlorite, used at concentrations of 1 to 5%, remains the irrigation solution of choice in endodontics, with the chemical formula “NaOCl” Has a low cost and a lightening action.
These solutions should be stored away from light in opaque containers and away from heat. For this reason, it is recommended to use freshly prepared preparations.
NaOCl is one of the most popular and widely used agents in endodontics due to its antibacterial activity and ability to dissolve necrotic tissue.
It has a broad antibacterial spectrum and its effectiveness has been demonstrated on bacteria, spores, yeasts and viruses.
This action is due to its capacity for oxidation and hydrolysis of cellular proteins and its hypertonicity allows, by diffusion, the evacuation of cellular fluids.
- The limits
– Unstable agent, toxic at high concentration
– Absence of chelating action [due to absence of solvent action on the mineral substance]
b. Chelators:
Are weak acids, which react with the mineral part of the dentin walls.
They have a certain affinity to calcium ions.
The main solutions are:
- EDTA (Ethyl Diamine Tetra Acetic Acid),
- Citric acid.
EDTA-based compounds have a solvent action on the mineral fraction but not on organic tissues.
They do not have antibacterial properties. They are essential complements to sodium hypochlorite but their effectiveness depends on the concentration and pH of the solution.
Endodontic pharmacology
- Ethylenediaminetetraacetic acid [EDTA]
It is the best known chelating solution in endodontics, at 17% allows. It is mainly used in the form of gel [Glyed…] or liquid solution.
EDTA is used to remove all the mineral and therefore inorganic part of the “smear-layer” formed during canal preparation.
This requires a minimum contact time of 1 minute.
- The limits
- Absence of solvent action on the organic substance
- Interaction with sodium hypochlorite
- Decrease in dentin microhardness
c. Biguanide family
- Chlorhexidine:
Chlorhexidine (CHX) has been used for many years in periodontics for its antiseptic power on anaerobes. It is in the form of chlorhexidine digluconate that it is presented as an endo-canal irrigant.
- Properties :
-The antibacterial activity is interesting and it presents little or no cellular toxicity.
-It is active on Gram-negative anaerobes (the most frequent and most pathogenic of the endodontic flora),
-Antifungal activity on Candida albicans,
-Chlorhexidine is bactericidal at high concentrations and has a persistent antimicrobial action. It is less toxic than sodium hypochlorite, but it has no solvent power.
Nb: Its association with sodium hypochlorite is not compatible.
d. Oxidizing agents
- Hydrogen peroxide:
- Hydrogen peroxide, with the chemical formula H2O2, is the most widely used oxidizing agent in endodontics.
- Properties :
- Solvent action: the solvent properties are almost zero but it has a good hemostatic action.
- Antiseptic action, its action is brief and quickly neutralized by organic debris
e. Additional solutions:
Distilled water and physiological serum: They do not have any antibacterial or solvent properties, they have no toxic effect and do not cause any side effects. They act only by mechanical washing with suspension and evacuation of debris. Their main indication remains the final rinse.
3.2. Endodontic retreatment materials: (solvents)
– They are all irritating to mucous membranes and skin and toxic so they must be used with caution when removal of the filling material is difficult with instrumentation alone.
– After cleaning the access cavity and locating the canals, it is advisable to put a few drops of solvent using a pipette in the chamber and clear the canal entrances, then unobturate with a manual or mechanized file, renewing the solvent as needed until the end of the obturation is reached.
a. Solvents for eugenate pastes:
- Eugenol: is antiseptic and analgesic. It is a constituent of many products intended for root canal obturation and it proves effective as a solvent to dissolve or at least soften the composition cement, in which eugenol appears.
- Richloroethylene, tetrachloroethylene (endosolve-E, Eugesolv, Desoclusol).
- Essential oils (lemon, orange).
Endodontic pharmacology
b. Gutta percha solvents :
- Chloroform
- Essence of turpentine.
- Eucalyptol
- Halothane
4. Medications between sessions
4.1. Inter-session time objectives:
The current state of knowledge in endodontics favors single-stage endodontic treatment. The impossibility of conducting the endodontic triad (Cleaning-Shaping-Filing) in a single session, however, may arise in several circumstances. In these conditions, the use of intracanal medications may, or may have been, indicated for analgesic and/or antiseptic purposes.
4.2. Pain-relieving medications:
The management of endodontic pain is always multifactorial and targets both peripheral and central pain components.
It is then necessary to combine both endodontic and pharmacological procedures.
4.2.1. Necrotizing agents:
Arsenic: Arsenic anhydride (As2 O3) powerful cytotoxic, arsenic salts acted by provoking a fleeting and extremely painful inflammatory reaction in the tissue in contact with which they were placed.
Non-arsenious: such as Formaldehyde (CH2O)
As an alternative to arsenious substances, formaldehyde has been used, in particular because, a priori, it is less cytotoxic.
Formaldehyde causes cytoplasmic coagulation of the cellular elements in contact with which it is placed. Formaldehyde is also currently.
4.2.2. Pulp analgesics :
The leader of these drugs is represented by phenol (C6H5OH). Several formulations contain pure phenol, or its derivatives. The analgesic activity of phenol and its derivatives results from the inhibition of the metabolism of arachidonic acid from membrane phospholipids during acute inflammation. Studies have shown that even when placed in pulpal contact, phenol and its derivatives do not have a significant sedative action.
4.2.3. Antiseptics:
The goal of inter-session medication is to prevent the growth and multiplication of germs that may have persisted in the root canal system. This medication should only be used after root canal debridement with irrigation and is not a substitute for these steps. This step is rarely necessary after pulpectomy and endo-root canal preparation of a tooth with vital pulp.
a. Metacresyl acetate
Metacresyl acetate belongs to the pharmacotherapeutic class of local antibacterials. This molecule is contained alone in the form of a 20% solution of metacresyl acetate and in association with parachlorophenol (Endotine) or in association with dexamethasone acetate and parachlorophenol (Mepacyl). The literature data and clinical studies are poor regarding these possible antibacterial or antiseptic properties or efficacy in endodontics.
b. Chlorhexidine
c. Calcium hydroxide: Among the temporary intracanal medications, calcium hydroxide proposed in 1920 by Hermann still occupies a place of choice today.
Calcium hydroxide of formula Ca(OH)2, also called hydrated lime, disintegrated lime or slaked lime, comes from the mixture of quicklime (CaO) and water. It is a fine, white and unstable crystalline powder. Its pH is close to 12.4. This alkaline product is therefore aggressive, but its low solubility in water opposes toxic alkaline diffusion. Calcium hydroxide can be used in the form of a magistral or commercial preparation. The magistral preparation is a mixture of pure calcium hydroxide powder with physiological saline or distilled water. This preparation, which has the same radio-opacity as dentin, is condensed in the canal.
5. Materials for definitive root canal filling (technical courses for root canal filling)
Conclusion
There is a whole range of pharmacological products for endodontic use . It is therefore advisable to know them in order to know when and how to use them.
Endodontic pharmacology
Cracked teeth can be healed with modern techniques.
Gum disease can be prevented with proper brushing.
Dental implants integrate with the bone for a long-lasting solution.
Yellowed teeth can be brightened with professional whitening.
Dental X-rays reveal problems that are invisible to the naked eye.
Sensitive teeth benefit from specific toothpastes.
A diet low in sugar protects against cavities.