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Gag Reflex


Gagging in dental patients can be disruptive to dental treatment. Some people have a pronounced gag reflex that can be a severe limitation to their ability to accept dental care and the clinician’s ability to provide it. It can compromise all aspects of dentistry, from diagnostic procedures to active treatment and can be distressing for all concerned.

This respond is called the Gag Reflex or Pharyngeal Reflex. It is actually a normal body response to prevent foreign body from entering the airway and our stomach. The muscle surrounding these structures will contract forcefully and causes any foreign body to be expelled out. Usually this reflex would not cause you to vomit unless the gagging is not able to be controlled by the patient.  Air is forced over the closed glottis producing a characteristic retching sound.

This overactivity of gag reflex can be brought on by opening of the mouth during dental examination or taking an impression of the upper and lower jaws to make prostheses. Taking intraoral radiographs, which requires the object to be in the mouth for certain amount of time may also lead to evocation of gag reflex at the slightest instance.

There are also individuals suffering from this reflex without having anything inside their mouth. Examples are people which start to gag after they see particular thing/instruments, or maybe smell something specific. Some of the examples are as listed below:

  1. Seeing dental instruments while getting treatment in dental clinic.
  2. Watching someone vomiting
  3. The smell of cigarette smoke or perfume.
  4. Thinking of something unpleasant.
  5. Sight of blood.

For children, they sometimes tend to use this reflex as a way to avoid from getting treated especially in the mouth.

On the other hand, an absence of gag reflex is marked with the patient feeling no impulse to throw up even when an object goes past the soft palate. The reason behind this is the absence of pharyngeal sensation due to defects in the nerves or neural signal transmission mechanism. Most common absent gag reflex causes are damaged glossopharyngeal or vagus nerves, brain death, or any other damage to the nerves or neural transmitters involved in the gag reflex induction process.

Trigger Zone

There are 6 areas that are known to be as trigger zone for gag reflex (picture). If these zones are disturbed, it will initiate the gag reflex. They are:

  1. Palatoglossal and Palatopharyngeal Fold.
  2. Tongue base
  3. Uvula
  4. Hard and soft palate
  5. Pharyngeal wall.
  6. Tonsil

Sign & Symptoms

When gag reflex occurred, usually it will be accompanied by some activities.

For example:

  1. Excessive production of saliva.
  2. Excessive production of tears.
  3. Excessive sweating.
  4. Reflectory increase in heart rate,
  5. Loss of consciousness (may happen if the reflex is severe)

Causes of Gag Reflex

  1. Local and systemic factors.
    1. Sinusitis
    2. Nasal obstruction
    3. Nasal Polyp (swelling inside the nose),
    4. Dry mouth
    5. Uncontrolled diabetes
    6. Chronic gastritis
    7. Peptic ulceration
    8. Mucosal congestion of the airway.
    9. Alcoholism.
    10. Severe smoking.
    11. Taking medication
  2. Anatomical abnormality (±)
    1. Large tongue and position.
    2. Large tonsil.
    3. Long uvula.
    4. Shape of hard & soft palate.
  3. Iatrogenic factors
    1. Poor clinical technique in taking dental impressions such as over loaded impression material in the tray could cause the material to trickle down the throat. Also an unstable or poorly retained prosthesis and over extended border that impinge on the trigger zones can initiate the gag reflex.
    2. Saliva suction placed too posteriorly  in the mouth that triggers the gag reflex.


Due to this condition, individuals may avoid getting dental treatment. This may lead to bigger problem as the condition of the dentition become worst and not able to be saved. And when extraction is indicated, the individual may request treatment under general anaesthesia rather than going for local anaesthesia procedure.


To treat a person that have tendency to easily gag is not easy. For the person themselves is a problem that causes them to feel ashamed and stressed sometimes. That is why the first thing to be clear is that the gag reflex is not a disease entity but is part of normal body defence mechanism. Everyone have this condition, the difference is the level of sensitivity they have.

Things that can be done:

  1. Patients need to prepare themselves before going for dental treatment.
  2. If the problem is related to the denture, then they should visit their respective dentist and get them examine to see if there modification is required or new denture is indicated. Commonly the problem is the overextended posterior part of the denture that encroaches into the trigger zone.
  3. If numbing injection is required for dental treatment, it may be given while the teeth are loosely in contact. This is a special technique known as Akinosi Technique.
  4. For taking upper and lower jaw impression, the procedure best be done with the patient in upright position with the head slightly tilted downward to reduce the irritation at the soft palate.
  5. Focusing on other part of body example tensing or relaxing certain group of muscle like the legs and hands may override the thought of gagging.
  6. To inhale and exhale in a control rhythm continuously during the process may avoid from the initiation of the gag reflex.
  7. The use of topical anaesthetic spray over the trigger zone can also be done. Example of the spray is base from Lignocaine or Benzyldamine hydrochloride given before start of treatment. Mouth washes also which contains local anaesthetics properties may be use also during treatment and also taking intraoral radiograph.

There are other methods to control or adapting to the condition or maybe stopping it. A visit to the doctors and these methods may be able to be discuss in depth to help fight the condition.


  1. C.R Means, I.E Flenniken: Gagging – a problem in prosthetic dentistry.  J.Prost.Dent. Vol.23(6), 1970.
  2. http://www.powershow.com/view/ff7b9NDljN/The_Assessment_and_Management_of_Patients_with Pronounced_Gag_Reflexes_powerpoint_ppt_presentation
  3. The Etiology & Management of Gagging: A Review of Literature. J.Prost.Dent.-G.S Bassi,G.M. Humphris, L.P. Longman (May 2004)


Last Reviewed : 3 August 2016
Writer : Dr. Rithuan bin Awang
Accreditor : Dr. Sharifah Tahirah bt. Syed Alwi Al Junid