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Complications of local anesthesia

When a strange substance is introduced into the body, it is likely to cause complications. This also occurs when local anesthesia or anesthesia is given to the mouth when performing dental procedures. Complications caused by anesthesia when performing dental procedures can be avoided or not.

What is local anesthesia?

Local anesthesia is defined as loss of sensation in one area of the body without loss of consciousness. The local anesthetic used in dental surgery is numbness.

What are the complications that can occur with local anesthesia?

Complications of local anesthesia are divided into local and systemic complications.

Complications in place:


Rarely occurs with a needle once. Small needles (30-27 gauge) are more prone to fracture than large needles (25 gauge).

Reason :

I-DENT is weak by bending.

Patients abruptly move suddenly, especially in children.



Nervous system

Facial nerve branches may be injured when local anesthesia is administered. Expression is a side of the face will be unbalanced and not able to blink an eye.

Numbness or paresthesia.

Sometimes it lasts for a few hours. Sometimes it lasts for days, weeks or months, but it is an inevitable complication.


Local alcohol-induced local anesthesia or surface antiseptic treatment leads to swelling and increased pressure on the nerve endings.

Injury to the nerve sheath.

Bleeding into or around the periphery of the cord.

The concentration of topical anesthetics is particularly at 4%.

Systemic complications:

Adverse reactions may occur due to:

Toxicity is caused by the direct effects of the drug in addition to the normal pharmacological effects:

Side effects of medications.

Reaction to overdose

Local toxic effects

Toxicity caused by changes in drug absorption:

Patients with diseases such as liver failure, body reflux, congestive heart failure.

Emotional disorders

Genetic disease (atypical plasmapseudocholinesterase)

Toxicity due to drug allergy

Dose-related reactions:

Most common in adverse reactions. It is defined as too high drug concentration in the body. The toxic dose can lead to convulsions.

Personal factors such as age, weight, drugs used (phenytoin, desipramine), sex, diseases, genetic factors, attitude.

Drug-related factors: degree of vasodilatation, concentration, dose, route of administration, rate of injection, systemic blood at the injection site, with vasodilator.

Signs of pre-seizure and central nervous system symptoms

Signs: Face, legs and hands trembling, dizziness dizziness, visual disturbances accompanied by loss of ability to focus, tinnitus, sleepiness, disorientation.

Symptoms: numbness, numbness of the tongue and surrounding area, tremors, fever, flushing, muscle twitching, narcosis.

Most overdose reactions occur in children, usually children 2-6 years old under 40kg.


Usually occurs when a treatment is indicated on the entire mouth.

Often caused by local anesthesia

Exceeds the prescribed dose on the child's weight.


Reactions include dermatitis (the most common), bronchospasm (asthma), and anaphylaxis.

Today, local anesthetics no longer use preservatives and methyl parabens. Another potentially allergenic substance is sodium bisulfite (an antioxidant). Rubber allergies can also occur when using thick rubber pistons.

Signs and symptoms of allergic reactions:

Itching, rash, swelling

Cramps, nausea, vomiting, diarrhea.

Vascular, vasodilatation, hypotension.

If you have any other symptoms, it may be an overdose.

Note: the efficacy of the treatment can vary depending on each patient’s condition.

For more information please contact:


Dental Clinic - Ho Chi Minh City An Dong 

Building 193A-195 Hung Vuong Str, Ward 9, District 5, HCMC

Dental Clinic - Ho Chi Minh City The Army Navy Swimming Pool

Building 19V Nguyen Huu Canh Str, Ward 19, Binh Thanh District, HCMC

Phone: (+84) 28 38 33 68 18

Website:  http://www.identdentalimplantcenter.com

Email: identdentalimplantcenter@gmail.com

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