Dr. Mahmoud Ramadan www.mrmaa_82@hotmail.com

Management of patient's gag reflex in making alginate impression

The gag reflex is a normal defense mechanism to prevent foreign objects from entering the trachea. In some individuals this reflex is active to the point that can be overridden by the desire to eject any object in the mouth. Gagging is triggered by tactile stimulation of certain Intraoral structures including the soft palate, pharynx, and base of the tongue. Wright hypothesized that gagging results from stimulation of anterior portions of the mouth. Afferent impulses are transmitted in the trigeminal or glossopharyngeal nerves to the medulla. The gag reflex also may be elicited by non-tactile sensations including visual, auditory, and olfactory stimuli. Several psychological and somatologic factors can initiate the reflex including anxiety and fear of dental treatment, revulsion to unpleasant stimuli apprehension caused by previous dental treatment, and fear of choking. Somatogenic factors such as obstruction of nasal airway, catarrh, increased salivation, or irritability of the gastrointestinal tract may elicit gagging. With completed denture, the common denture faults that causes gagging include lack of interocclusal space, non-retentive maxillary denture, inadequate peripheral seal, restricted tongue space, and over- or under-extended denture borders.

A number of techniques for reduction of gagging have been suggested, including distraction of patient's attention from the dental procedure, relaxation, hypnosis and drugs (sedatives, antihistamine, or parasympathetic depressant), Hypnosis is induced usually by a method involving eye fixation plus distraction; for example, staring at a colored dot on the dental light whilst at the same time counting backwards from 300. Some clinicians swab or spray the sensitive mucosal areas with topical anaesthetic agents, while other suggests that impressions should be made under general anesthesia or hypnosis. Anaesthetic sprays are difficult to control and their use may result in increased risk of toxicity. Schole stated that instead of reducing the symptoms of a person who gags, ``...topical anesthetics may actually increase nausea and vomiting`` It is likely that the free flow of anesthetic spray or gel to the sensitive areas may trigger the gag reflex.

Gagging becomes a clinical problem when it is elicited by dental treatment, especially in making maxillary impression. Friedman suggested that placing table salt on the tip of the tongue would reduce the gag reflex. However, dentists may feel nervous about placing an emetic substance in the mouth of a patient known to be prone to retching and vomiting. Callision proposed a maxillary custom tray in which a saliva ejector tip is embedded in order to suck excess impression material into vacuum chamber at the posterior extent of the tray. Ansari recommended the use of a high-viscosity elastomer for making a primary impression of a maxillary partial edentulous patient, in an attempt to minimize the distal flow of the material to sensitive areas. Even Chinese caves (or acupuncture cave) have been suggested to reduce the gag reflex.

Dr. Mahmoud Ramadan www.mrmaa_82@hotmail.com

Alginate impression materials have been used as vehicles for topical application of fluoride and chlorhexidine as well as for the delivery of anesthetic agent. In this study, a local anesthetic solution was incorporated in to the alginate material for reducing the gag reflex. The advantages of this technique are:

1. Controls the flow of anaesthetic agent to vomiting and gagging sensitive areas.

2. Minimizes the risk of hazard and toxicity.

3. Allays apprehension by not introducing items to the patient mouth, except the impression material.

4. Dampens the sensitivity of the entire arch during the impression making.

5. The technique is simple and does not need special laboratory work.

Procedure:

1. Prepare the patient by stimulating positive attitudes toward dental care, allay anxiety, and instill confidence; i.e., by telling the patient that gagging is normal reflex in every individual, but the position at which the reflex is triggered varies from one individual to another. Inform the patient that this alginate is specialty-prepared to eliminate gagging.

2. Instruct the patient in basic breathing & muscle relaxation exercises; i.e., inhaling through the nose and exhaling through the mouth, while concentrating on breathing.

3. Dispense one carpule of local anesthetic solution (1.8 m1 of 2% lidocaine with 1 part in 100,000 epinephrine) to the plastic measuring cylinder and then add water to the correct volume.

4. Pour the water anesthetic mixture into the bowl, add the measured powder and mix thoroughly. Insert the loaded tray gently in the patient mouth and then press until setting