Irrigation techniques are primarily used to clean the root canal system and rid the tooth of endodontic disease. To remove the bacteria from the endodontic system, root canal sterilization through high-level disinfection systems can work to reduce the bacterial load and assist in healing the periapical tissues. However, manual uses of irrigation techniques using rotary instruments and other mechanical instrumentations often result in less than favorable outcomes. Irrigation solutions and other techniques have become the gold standard agents for cleaning the root canal and reducing bacteria growth. In this article, we’ll be exploring these irrigation systems, and some of the techniques often used to help control this procedure and ensure safe, effective cleanings.
Chemical Agents Most Often Used In Endodontics
Several irrigation solutions are often used to accomplish bacteria growth within the root canal system and work to disinfect the system to prepare the tooth for future procedures. An ideal irrigation system will work to be systemically non-toxic on the periodontal tissues, is nonallergenic, has antimicrobial activity, is capable of dissolving endotoxins and pulp tissues, and prevents the further formation of bacteria. Because of these requirements, there are a few agents that are commonly used in the office that offer various advantages and disadvantages for endodontic irrigation, including:
- NaOCL: Sodium hypochlorite is considered by many to be the gold standard for endodontists because of its advantages, specifically its ability to dissolve pulp tissue and kill bacteria. It dissolves both vital and necrotic pulp tissue and eliminates the source for bacterial reproduction, and has a direct killing effect. It also disrupts the biofilms often produced from bacteria and interferes with the bacteria’s cellular process. However, its disadvantage is that its cytotoxic, meaning if used incorrectly can cause accidents and doesn’t stay active long and thus need to be used frequently to work properly.
- EDTA: Ethylenediaminetetraacetic acid, or EDTA for short, is often combined with NaOCL to bind and remove calcium and demineralized dentin. It can act as a lubricant during the cleaning process and, depending on the method used, can work to remove the biofilm layer that’s produced or can be left inside to work on the bacteria within the canal and let it die off. However, dentists often have to be careful about the potential interactions between EDTA and NaOCL.
- CHX: As the third most commonly used irrigant, Chlorhexidine gluconate, or CHX, is an antiseptic agent that can rupture the cellular wall of the bacteria through interacting with its phospholipids causing cell death. One huge advantage it has is its ability to bind to the dentin and create a prolonged release of antimicrobial activity that can last for months, one advantage that NaOCL doesn’t have. But even with these advantages, it doesn’t dissolve the necrotic pulp tissue, eliminate signs of biofilm, or remove the smear layers. It’s often used as a secondary irrigant at the end of a procedure, and it cannot be used together with other agents such as NaOCL because it can affect canal anatomy and prevent obturation all together.
All of these agents bring out their various advantages and disadvantages, but the second part of understanding the irrigation system is the techniques used to use these agents. Below, we’ll be going into some advanced irrigation techniques that are often used by endodontists to achieve their desired effect.
Types of Irrigation Techniques Used in Mastering Endodontics
As for techniques, the combination of chemical agents with mechanical preparations is the most used and typically performed activity among endodontists performing root canal irrigation. This method is most often used because it lacks the requirement for special devices and allows for a reasonable way to control the canal depth and amount of irrigant delivered to the site. Through conventional syringes and open/closed-end cannulas, or thin tubes, this is the primary technique that most endodontists use overall.
Nevertheless, many endodontists also like to experiment with their irrigation systems, incorporating different techniques to meet certain requirements. This is often due to the problems that the traditional method brings, including the amount of debris clogged in the cannula, inefficient amount of chemical agent delivered, lower liquid pressure produced, and other problems that can lead to insufficient irrigation.
Because of these problems, other irrigation systems have also been introduced to improve the efficiency of cleaning root canals, which include:
- Passive Ultrasonic Irrigation: PUI has been a method introduced to increase the effectiveness of canal cleanings by activating the chemical agent inside the canal itself. By pushing the irrigant laterally throughout the canal, it removes signs of irregularities through the process of acoustic microstreaming. By doing so, the solution can work to access canal areas that haven’t been touched by rotary instruments and can better penetrate the lateral canals than with the syringe and cannula method.
- Intermittent Passive Ultrasonic Irrigation: In intermittent mode, the canal is first filled with a chemical solution using a syringe and cannula, then the ultrasonic tip is then used to activate the chemical solution. This is still a more manual use for irrigation, as syringes and cannulas are still used to replace liquid inside the canal and dissolve organic tissue.
- Continuous Passive Ultrasonic Irrigation: Similarly, CPUI refers to the process of acoustic microstreaming in continuous mode rather than intermittent. Instead of using syringes and cannulas, a specially designed irrigation tip allows for the solution to be dispensed regularly, allowing for more control over the volume of irrigant used during the procedure. More consistent bacteria degradation and tissue dissolution generally occur with this method and help navigate issues most often faced with more manual approaches.
Ultimately, effective cleanings all come from the activation of chemical agents such as NaOCL, EDTA, and CHX to concentrate on the bacteria inside the root canal system and destroy signs of necrotic or infected pulp. For endodontists, controlling these amounts work to avoid potential problems with the periapical tissues, so finding delivery methods that work helps to ensure the safety of the patient. Safety in these regards should always be maintained, and thus, improving irrigation systems through these methods may prove viable for future treatments.