Root canal irrigation: treatment protocol, irrigation solutions

V endodontic treatment disinfection is key tooth canals. It includes disinfection - the destruction of active microorganisms that caused the disease (pulpitis or periodontitis), and sterilization - a state of complete absence in the root system of any bacteria, including physiological oral microflora.

Root canal irrigation or rinsing with chemical solutions is the most common way to achieve decontamination. The widespread use of this method in dentistry is determined by:

• simplicity of execution;
• availability for each clinic due to the absence of the need for expensive equipment;
• low cost and good results.

The need and importance of sterilization

Root sterilization is the key to endodontic treatment. It eliminates the cause of the disease - bacteria that have entered with saliva through the carious cavity into the tubules of the tooth.

Symptomatic therapy for pulpitis (pain relievers, anti-inflammatory) only temporarily reduces the manifestations of the disease, after which acute stage goes into chronic. Microorganisms will continue to multiply in the dental neurovascular bundle and after some time (from 2 weeks to 6 months depending on the state of the patient's immune system) will cause a relapse diseases.

With periodontitis, the action of bacteria spreads to the surrounding tissues - the ligamentous apparatus of the tooth, gums, bone tissue of the jaw. Prescribing antibacterial therapy without disinfection and sterilization of the canals will reduce the population of pathological microflora, but will not completely destroy it. The rest of the microorganisms will continue to multiply. A repeated exacerbation will occur with a decrease in immunity (hypothermia, respiratory disease).

Endodontic disinfection methods

There are several methods for endodontic disinfection:

1. Chemical by irrigation (washing or irrigation) of the canals with antiseptic solutions. In dentistry, sodium hypochlorite and chlorhexidine 2%.
2. Physical sterilization. For its implementation, it is necessary to have an ultrasonic tip, endochka (adapter) and special files.
3. Laser disinfection. It is expensive, rarely carried out, and has limited indications (allergy to antiseptics).

The main steps for effective sterilization

Disinfection takes place in several successive stages:

• removal of root pulp;
• grinding off the lubricated dentin layer and widening the canal;
• chemical and physical treatment (disinfection);
• drying.

Each stage has an important meaning and a specific meaning. Failure to comply with at least one or to replace them in places means failure of endodontic treatment in 85-90% of cases.

Root canal treatment protocol: disinfection, sterilization, irrigation

How canals are processed in modern dentistry.

Pulp removal

Pulp is a connective tissue with blood vessels and nerves, in which 95% of microorganisms that cause inflammation actively multiply. Removing the pulp means removing most of the factors that caused the disease. A side effect of this stage is the gradual washing out of the organic part from dentin, which provokes increased fragility pulped teeth.

To work at this stage, disposable sterile instruments are used - pulp extractors. They look like a needle with barbed ends. The dentist places them in the tubules of the tooth (in the thickness of the connective tissue) and extracts the neurovascular bundle.

Removing the smeared layer

A small part of microorganisms from the pulp through the dentinal tubules penetrates to a thickness of 1-6 microns. Therefore, this part of the canal wall must also be removed by grinding it off with H-files. These endodontic instruments are serrated on the tip and have increased flexibility to prevent breakage during operation.

Expansion of the lumen

This stage is necessary for the possibility of further irrigation of the canals and their filling. A narrow channel is difficult to process and fill technically with high quality gutta pins. It is considered optimal to expand up to 35-40 files at the incisors and fangs and up to 30-35 - at molars and premolars.

Chemical and physical treatment

At this stage, there is a mechanical removal of pulp and dentin particles formed after the passage of the root files, as well as its irrigation and disinfection with antiseptic solutions. For work, special endodontic needles - instruments with a flexible tip and a lateral opening. These technical features make it possible to flush any hard-to-reach canal without causing injury to the periapical tissues and without provoking their inflammation after filling.

Physical processing can be done with ultrasonic handpieces. Low-frequency vibrations destroy the bacterial wall, causing their death. This method is used in patients who are allergic to chemical antiseptics (hydrogen peroxide, sodium hypochlorite). To work, you need machine endofiles and endochuck - an adapter for the handpiece.

In the last 10 years, the laser method has been used for disinfection in dentistry. A photosensitizer (inactivated solution) is added to the root system, and its short-term irradiation is performed. A chemical oxidative reaction is triggered, disrupting the integrity of the bacterial membrane.

The laser method is expensive and is currently used to a limited extent - with the technical impossibility of disinfection (strongly curved roots).

Drying cavities

The stage is of great importance for the subsequent stage (filling). Poor performance will lead to a leaky filling of the root with paste and gutta-percha. In the resulting voids, after 2-3 weeks, the multiplication of microorganisms will begin, falling into the canal with saliva.

Drying is carried out with sterile paper points (pins) immediately after chemical or physical disinfection. After these two stages, the tooth sealed medicinal or permanent material.

What is needed for sterilization to be effective

The complete destruction of microorganisms found in the root tubules and periapical tissues is of key importance for effective treatment and the absence of inflammatory reactions in the future. The following factors are important for a high-quality sterilization.

Correct assessment by the doctor of the initially existing pathology

The dentist must correctly diagnose, determine possible complications in the treatment process and the likelihood of failure. There are clinical cases in which there are a number of negative factors that reduce the success of manipulations to zero. These include:

• pathological periodontal pockets;
• perforation or root fracture;
• vacuum in the area of ​​the bifurcation of the tooth.

The presence of any of these cases reduces the likelihood of effective canal disinfection by at least 50%; a combination of 2 factors nullifies all efforts.

The doctor also needs to distinguish pulpitis from periodontitis. The latter means infection with a pathological microflora of the periapical tissues of the tooth, which reduces the effect of treatment.

Shape and number of channels

The anatomical structure of the root system is of great importance for a successful intervention. The presence of lateral branches, curved tubules, their small diameter provoke failures during their passage. High-quality therapy in difficult cases (for example, the last molars) is not always possible even if the doctor observes all the rules of sterilization.

Grinding the upper infected dentin layer

With periodontitis, microorganisms that multiply in the pulp partially penetrate through the dentinal tubules into the thickness of the tooth to a thickness of 2-5 microns. Therefore, to guarantee successful treatment, it is necessary to remove this layer with endodontic instruments (H-files).

Choosing the right antiseptic agent

What kind of irrigation solution is used matters:

1. Distilled water - carries out only mechanical removal of pulp fragments, dentin sawdust from the root. After processing microorganisms remain in an amount sufficient for reproduction and subsequent apical inflammation.
2. Hydrogen peroxide - when interacting with capillary blood, it forms a foam that flushes out a part of the infected dentin. Antiseptic properties ensure the destruction of microbes by only 50%.
3. 2% Chlorhexidine solution - is a powerful disinfectant. After its use, the death of microflora in the canals from 78 to 100% ¹ is noted, depending on the specific bacterial component.
4. Sodium hypochlorite - when used correctly, it reduces the risk of post-filling inflammation by 95%. For treatment, it is necessary to warm the solution to 40-45 degrees Celsius, and process the roots for at least 2 minutes.

Use of special instruments for sterilization

Quality treatment involves the use of endodontic needles. They have a lateral opening on the working part, which helps to avoid trauma to the apical tissues, as well as to reduce the risk of aseptic inflammation after the performed manipulations.

Correct sequence of manipulations during treatment

The dentist must strictly adhere to the root canal protocol. You cannot avoid any stage or change their places. For example, after washing with a solution, it is strictly forbidden to “modify” the walls with endodontic instruments. In this case, the introduction of microorganisms from the file into the cavity is carried out, which means its infection and inflammation of the peri-root tissues in the future.

¹Cantatore, J. Root canal irrigation and its role in cleaning and sterilizing the root canal system Text. / Giuseppe Cantatore // Dentsply News. 2004. — № 10. - WITH. 58 — 65.