What Is Sodium Hypochlorite?
Sodium hypochlorite (NaOCl) can be commonly found in a dentist's office. It is used as an irrigant during root canal treatments as it dissolves organic soft tissue of pulp and predentin. It is usually used in a dilution of 0.5 % or less. Higher concentrations of sodium hypochlorite are cytotoxic. It has a foul chlorine smell and taste. When sodium hypochlorite extends through the periapex of the tooth and comes in contact with the periapical tissues, it causes acute inflammation followed by necrosis.
What Are the Advantages of Using Sodium Hypochlorite?
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It has an antifungal property.
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It helps in the disruption and removal of biofilms (a complex structure containing different colonies of bacteria).
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It aids in the breakdown of proteins to amino acids and hence has a robust dissolving action on organic tissues and microorganisms.
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It also aids in hemostasis (bleeding cessation).
What Is a Sodium Hypochlorite Accident?
When sodium hypochlorite comes in direct contact with the periapical tissues (soft tissue surrounding the root apex of teeth), eyes, or extraoral tissues, it is termed sodium hypochlorite accident. If the patient experiences a sudden severe pain during the root canal procedure, we must suspect a sodium hypochlorite accident.
What Are the Signs of Sodium Hypochlorite Toxicity?
The signs and symptoms differ for each site and include the following:
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Edema (swelling with fluid accumulation).
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Ecchymosis (discoloration of the skin due to bleeding from underneath).
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Profuse bleeding from the root canal of the tooth.
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The patient may experience the smell of chlorine and severe pain.
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Burning sensation in the eyes.
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Paraesthesia (characterized by numbness and burning sensation in the affected area).
What Are the Effects of Sodium Hypochlorite Accident?
The severity of the damage depends on the pH of the solution and the duration of exposure. Also, the exposure site plays a significant role in determining the effect.
1. Periapical Extrusion:
When sodium hypochlorite is extruded beyond the root canal, even a minimal amount, it results in profuse bleeding from the root canal cavity. It also produces rapid swelling of the involved tissues. It is attributed to the ability of NaOCl to damage the blood vessels and the release of histamine. The ecchymosis and edema can involve the affected side of the face, including the eyes and oral cavity regions. In some cases, pain and the affected region's erythema are present. A tingling and burning sensation have also been reported.
2. Contact With Eyes:
When it comes in contact with the eyes, sodium hypochlorite can lead to endophthalmitis. It can lead to severe complications in a few cases, like loss of the eye.
3. Allergic Reactions:
Allergic reactions of sodium hypochlorite cause the following complications:
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Edema.
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Urticaria (skin rashes).
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Hypotension (reduced blood pressure).
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Bronchospasm (construction of the bronchial muscles).
4. Oral Mucosal Damage:
When sodium hypochlorite comes in contact with oral mucosal tissues, it can lead to the development of secondary infections. Also, there is a possibility of swallowing the solution that might lead to further systemic complications.
How Does a Dentist Manage NaOCl Accidents?
1. Periapical Extrusion:
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Early recognition of the problem - The dentist informs the patient immediately about the accident.
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Irrigates the root canal immediately with normal saline. This dilutes the NaOCl and reduces the severity.
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Allows bleeding to occur, which helps flush out the irritants.
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Reassures the patient that things are under control.
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Explains to the patient how to manage at home and preferably gives written instructions for home care. It is also essential to monitor the patient on a daily basis.
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Palliative care - Cold and warm compresses, saline rinses, pain control, prophylactic antibiotics, and steroids if required.
2. Exposure to Eyes:
After a suspected exposure to the eyes, the patient is asked to cleanse the eye with normal tap water or saline. The patient is then referred to an ophthalmologist immediately for further management.
3. Allergic Reactions:
Intravenous administration of antihistamine medications and steroids is the first aid measure to be carried out. It is then followed by rushing the patient to an emergency department.
4. Oral Mucosal Damage:
Initially, the mucosa is washed with water, and appropriate analgesic and antibiotic drugs are given to prevent the occurrence of associated secondary infections. In case of any inhalation or ingestion of sodium hypochlorite, the patient should be immediately sent to the emergency department for preventing and managing complications.
How Can a Dentist Avoid NaOCl Accidents?
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Always prepare adequate access into the root canal.
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Good working length: Make sure that the working length is not overextended.
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Ensure the irrigation needle is placed 1 to 3 mm short of the working length and that the needle is not locked in the canal.
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Flush the canal slowly with the irrigant by moving the needle constantly in and out.
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During the procedure, observe if the solution flows out during irrigation.
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Using irrigant needles with side venting specifically designed for endodontic purposes minimizes accidents.
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Specialized needles like Luer lock needles (which have a twisted tip preventing accidental removal and injection) can be used.
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The needle top should be placed loosely inside the canal and should not be wedged.
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Increased digital pressure should be avoided.
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In teeth with an open or inadequately-formed apex, the use of sodium hypochlorite should be avoided beyond the coronal two-thirds of the root.
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Using rubber dam isolation to prevent the exposure of sodium hypochlorite to intraoral tissues.
Conclusion:
Sodium hypochlorite has a significant antibacterial property that helps in reducing bacterial infection along the root canal. But it also has its own harmful side effects when accidental contact occurs. By following adequate preventive measures, the incidence of hypochlorite accidents can be entirely avoided. When such a thing happens, it should not be neglected and should be managed immediately.
