Impregnation and silvering method
Medicament treatment often requires impregnation, which is deep saturation of tissues with special compounds. This is necessary for instrumentally inaccessible root canals.
For classical impregnation, solutions and pastes based on parachlorophenol (e.g., Creadent, Cresoferne, Cresopast) are used. Their antimicrobial action is due to the ability to cause denaturation of microorganism proteins inside the canal. Setting of such material occurs naturally through chemical bonding with intracanal fluid.
Special attention should be given to the silvering method, which remains very popular in pediatric dental practice. To perform it, the following are used:
- Main preparation: 30% aqueous or 3% alcoholic solution of silver nitrate.
- Reducing agent: 4% hydroquinone solution.
Sterilization is ensured by the deep diffusion of silver nitrate into the dentinal tubules. The preparation has a pronounced bactericidal effect (oligodynamic effect). Upon interaction with hydroquinone, the silver mirror reaction is triggered: a dense film forms, which reliably obturates the dentinal tubules. Treatment is carried out in three appointments, and electrophoresis may be used for deeper introduction of silver ions.
Copper-calcium hydroxide depophoresis
A modern alternative for treating hard-to-reach canals is the depophoresis method. The entire course of therapy is designed for 2–3 appointments.
The mechanism of action of the method was scientifically substantiated by Professor Knappwost. The essence is that under the influence of an electric field, tissues are saturated with ions—creating a powerful depot of calcium hydroxide, copper hydroxide, and hydroxyl groups. The penetration of these compounds deep into the canal system ensures the sterilization of root dentin and reliable obturation of small foramina. After completing depophoresis, the negotiated part of the canal is obturated with an atacamite-based material.
For successful treatment by the depophoresis method, two strict conditions must be met:
- Instrumental negotiation of the canal must be performed to 1/3–2/3 of its length.
- Strict exclusion of penetration (extrusion) of copper hydroxide and calcium hydroxide into periapical tissues (beyond the root apex) is required.
Stages of resorcinol-formalin impregnation
Currently, this technique is rarely used, but it is a classical example of multi-stage medicament treatment of severely curved or impassable canals. Treatment involves the use of filling liquids based on resorcinol (resorcin) and formaldehyde (formalin).
- Devitalization and pulp amputation. Removal of the coronal part of the pulp.
- Widening of root canal orifices. Performed using a dental handpiece and burs for deep amputation. Special endodontic instruments such as Gates Glidden and Largo are also used.
- Application of impregnating liquid. The liquid is prepared on a glass slab and then introduced into the orifices using pliers' beaks or with soaked cotton pellets. As it advances into the canal, the liquid is pressed in with a manual endodontic instrument.
- Placement of a temporary filling. A cotton pellet moistened with impregnating liquid (resorcinol-formalin or parachlorophenol-based) is squeezed out and left in the tooth cavity. The cavity is hermetically sealed with a temporary filling for 2–3 days.
- Re-impregnation. During the second appointment, the procedures for introducing the liquid into the canal orifices are completely repeated. The tooth is sealed again with a temporary filling for 2–3 days.
- Permanent obturation. In the final appointment, the temporary filling is removed. Filling material mixed according to instructions is left in the canal orifices. An insulating base is placed over it, and the tooth is restored with a permanent filling.
Errors and complications
Various complications can arise during endodontic treatment, manifesting both during manipulations and in the long-term period. All medical errors are generally divided into two categories.
Errors at the diagnostic stage:
- Incorrect initial diagnosis.
- Incorrect interpretation of radiograph data.
- Errors in determining the working length of the tooth.
Errors at the treatment stage:
- Placement of devitalizing preparations on an unexposed tooth cavity (reduces effectiveness and causes pain).
- Sealing of devitalizing agents with oily artificial dentin, which disrupts hermetic sealing and the diffusion process.
Briefly: answers to topical questions
Which solutions are used for root canal irrigation during standard instrumental enlargement?
For root canal irrigation during standard instrumental enlargement, the following are used:
- Antiseptic solutions for rinsing the root canal during instrumental treatment.
- Preparations for chemical widening, including chelators and lubricants.
Which endodontic instruments are used for widening root canal orifices?
For widening root canal orifices, the following are used:
- Burs for deep amputation used with a handpiece.
- Gates-Glidden rotary instruments for widening the orifice third.
- Largo (Peeso reamer) reamers for widening canal orifices.
- Orifice opener for canal orifice enlargement.
- Beutelrock reamer type 1 and 2 rotary instruments.
What errors and complications can occur at the endodontic treatment stage?
Various iatrogenic errors and complications associated with violation of the intervention protocol may occur at the endodontic treatment stage.
- Paste application errors: overdose of devitalizing agents, placing them on an unexposed cavity, or sealing with oily dentin.
- Access cavity formation errors: incomplete opening of the pulp cavity, incorrect access shaping, perforation of the canal wall or chamber floor.
- Mechanical treatment errors: thinning or perforation of the canal wall, insufficient instrumentation, inconsistent use of instruments, instrument fracture.
- Medicament treatment errors: inadequate use of irrigants, use of an air syringe (puster) for drying.
Which instruments are used to introduce medicament solutions and dry the root canal?
Specialized instruments and absorbent materials are used to introduce medicament solutions and dry root canals.
- Syringes and endodontic needles are used for irrigation, with needles strictly having a blunt or closed end.
- Pliers and cotton pellets: liquid is introduced on the beaks of pliers or with moistened cotton pellets.
- Endodontic instruments are used to push the liquid forward as the canal is negotiated.
- Paper points (Absorbent Paper Points), sterile absorbers made of absorbent paper for drying canals before obturation.
- Cotton pellets/turundas are used to dry the root canal lumen.
Class and exam questions
In which cases is impregnation indicated?
The primary indication is the presence of complex anatomy, in particular a sharp root curvature angle, which makes the root canal instrumentally inaccessible.
What is the "silver mirror" reaction in dentistry?
This is a reaction between a silver nitrate solution and a reducing agent (hydroquinone), resulting in the formation of a dense film within the dentinal tubules that occludes the lumen.
What is the main rule in depophoresis?
It is necessary to negotiate the canal to at least 1/3–2/3 of its length and strictly prevent the extrusion of active hydroxides into the periapical tissues.
What errors occur most frequently at the diagnostic stage?
Major diagnostic errors include misdiagnosis, incorrect interpretation of radiographs, and inaccurate determination of the working length.
What else to study on this topic
- Instruments for root canal orifice enlargement (Gates Glidden, Largo)
- Restoration of a tooth crown defect after endodontic treatment
- Mechanisms of protein denaturation in microorganisms by parachlorophenol
- Methods for accurate determination of tooth working length
- Criteria for the correct interpretation of endodontic radiographs
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