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Gagging during impression making: techniques for reduction

From Volume 38, Issue 3, April 2011 | Pages 171-176

Authors

Sarah Farrier

BDS, MFDS RCS

Cardiff University Dental Hospital, Heath Park, Heath, Cardiff CF14 4XY

Articles by Sarah Farrier

Iain A Pretty

BDS, MSc, PhD, MFDS RCS

Senior Lecturer, Dental School and Hospital, Manchester, UK

Articles by Iain A Pretty

Christopher D Lynch

BDS, PhD, MFD RCSI, FDS(Rest Dent) RCSI, FACD, FHEA

Department of Restorative Dentistry, National University of Ireland, Cork, Ireland

Articles by Christopher D Lynch

Liam D Addy

BDS, MFDS, MPhil, FDS(Rest Dent)

Specialist Registrar in Restorative Dentistry, Cardiff University, Dental School, Wales College of Medicine, Heath Park, Cardiff, CF14 4XY

Articles by Liam D Addy

Abstract

In everyday dental practice one encounters patients who either believe themselves, or subsequently prove themselves, to be gaggers. Gagging is most frequently experienced during impression making, but is also reported during the taking of radiographs, in the placement of restorations in posterior teeth and, in some individuals, the insertion of a finger for examination purposes. This paper describes some techniques that can easily be mastered by clinicians that may help both operator and patient avoid this unpleasant occurrence. Techniques such as acupressure, the adaptation of trays, or even the use of alternative impression materials and breathing techniques all have their place, and clinicians may have to try several of these, perhaps in conjunction, in order to assist their patients.

Clinical Relevance: A significant number of patients attend for dental treatment that require impressions, and for those with gagging problems it can be a horrendous experience. Being able to make the procedure less of an ordeal is better for all involved.

Article

The management of patients who gag is something all dentists have been faced with at some point in their career. It can be unpleasant for both clinician and patient. In some instances, gagging prevents procedures being performed or the acceptance of intra-oral appliances.

Identifying the cause for these reactions can be difficult. Patients who suffer from these problems have been loosely divided into two groups:

  • The somatogenic group – those in whom physical stimulation produces the gagging reflex; and
  • The psychogenic group – those in whom the stimulation appears to be psychic in origin.1

    • The gag reflex is a normal, healthy defence mechanism controlled primarily by the parasympathetic division of the autonomic system. Its function is to prevent foreign bodies from entering the trachea.2 Gagging includes a range of muscular actions. It may simply consist of muscular contractions of the tongue and soft palate but often involves contraction of the pharyngeal structures.3 The respiratory muscles may also become involved in the gag reflex. Spasmodic contractions of these muscles cause air to be forced from the lungs through the closed glottis. It is this action that causes the typical retching sound. Associated with this retching sound, chest muscles go into fixation and thoracic inlet muscles contract. This causes impediment of the venous return, dilating the veins of the head and neck, with flushing and congestion of the face.4 Vomiting can be the end point of a gagging episode and this is accompanied by lacrimation and salivation.5

    Several treatment approaches have been reported in the literature to overcome the problem of gagging during dental treatment, these include:

  • Hypnosis;
  • Acupuncture; and
  • Sedation.6–8

    • Whilst these techniques have been reported to be successful, they often require further training and the purchase of more equipment. The aim of this article is to provide a description of alternative techniques that can be used by the dentist and/or patient to overcome the problem of gagging during impression making, without the need for further training/equipment.

    Management options

    Patients who suffer with an exaggerated gag reflex may be managed in one of two ways:

  • The provision of treatment to cure the problem.
  • The use of methods to abolish the problem temporarily so that dental treatment can commence with minimal discomfort.

    • It is often individual patient factors which differentiate between techniques and how successful they are. The treatment strategies outlined in this article are broadly divided into patient techniques and those which may be employed by the dentist making the impression. However, the majority of methods are based on a supportive partnership from both parties.

    Prior to embarking on any treatment, a discussion of the patient's fears, and his/her history of gagging, will help to assess the magnitude of the problem. This may affect treatment planning or may help in choosing an appropriate technique. It is important to identify all the factors which may contribute to the gagging problem and eliminate or reduce them.

    Patient-based techniques

    Systematic desensitization

    The aim of this method is to increase the patient's exposure to a gag-inducing stimulus gradually. This incremental habituation relies on increasing some feature of a stimulus, usually its size and/or the length of time the object is in the mouth, by small amounts, which allow habituation to take place. The treatment rationale is similar to that of tinnitus; by increasing the stimulation to the brain, the impression-taking stimuli become more difficult to discriminate. The progressive desensitization should not initiate the standard fear reaction of the gag reflex. Various stimuli may be used, depending on the severity of the gagging problem; a dental mirror, radiographic film packet, impression trays, a toothbrush, mouthwash, a spoon or a patient's own dentures have all been suggested.3,9 Appleby and Day advocated that patients used their own finger to massage the anterior soft palate when a foreign stimulus could not be introduced without gagging.10

    In edentulous patients, where some form of impression is possible, dentists could provide training plates: acrylic denture bases without teeth, to wear instead of a stimulus object.11 The training plate should just cover the alveolar ridge, but may have a ‘training bead’ placed on the lingual aspect (at the normal position of the central incisors), to help maintain proper tongue position.12

    During the time a patient is exposed to the stimulus, he/she should be encouraged to relax and reinforce his/her own control over the gagging. Therefore, placement of the stimuli should occur in conjunction with deep breathing and muscle relaxation. Zach suggested an imaginary light switch to the patient which he/she could use to turn the gag reflex on and off when in a state of relaxation, again reinforcing the patient's own management of the condition.13

    Patients should keep the object in their mouth for as long as possible, but remove it prior to gagging. Removal of the stimulus when gagging is perceived to be imminent, however, may enhance the notion that insertion indicates a reaction will occur, whilst removal relieves the distress.14 This theory is based on Pavlov's experiments on the conditioned reflex, which showed that behavioural association always occurred as a gradual process, involving many exposures to paired stimuli. These techniques of systematic desensitization require the patient to use the stimulus for short set periods of time, removing the object when the time period has elapsed, even if gagging is not thought to be pending; these time periods should then be gradually increased. The necessity to achieve maximum relaxation should be emphasized at each exposure.

    Gradual habituation requires ‘homework’ by the patient. A record of the progress should be kept to monitor the increasing size and/or length of time the object can be retained without gagging; this provides a visual aid from which to praise the patient for his/her efforts. Should gagging occur or the patient feels unable to complete the set task successfully, then the object should be removed, and a period of relaxation should follow. When the patient is ready, a lesser stimulus or a reduced time period should be attempted.

    Based on the method of behavioural therapy, Singer devised the ‘Marble Technique’. Patients placed 5 multi-coloured glass marbles, approximately ½″ in diameter, in their mouths one at a time until all five were in the mouth.12 Patients were then encouraged to increase the length of time the marbles were held within the mouth until they could be retained for one week, except when eating and sleeping. Accidental swallowing could occur, and it may not be appropriate for the patient to concentrate on anything else but the stimulus in the mouth. This technique therefore, should only be attempted during set periods of time allocated for the desensitization. It is obvious that, for many people, this technique may otherwise be very inconvenient for day-to day-life.

    Wilks and Marks described a similar technique, the ‘Buttons Technique’.15 The patient was asked to hold a set of buttons or plastic discs in his/her mouth for up to 2 hours a day and roll them around the mouth, recording each exercise in a diary.

    Similar in nature to behaviour therapy, the use of a graduated toothbrush has been suggested to monitor the patient's progress in conquering his/her gagging.8 The patient is asked to brush the hard palate gently with a toothbrush, as far back as possible without causing gagging. The patient then marks on the toothbrush handle the position of the upper anterior teeth to show how much of the brush can be tolerated. On subsequent attempts, the patient's aim is to pass the previous mark. The sight of new markings should give the patient encouragement. Similarly, the toothbrush technique may be used to stroke the tongue with increasing posterior advancement.

    All these techniques follow a basic principle of gradually introducing an object into the mouth of increasing size or duration, and re-learning a conditioned response. Any systematic desensitization method may take a few days to several months to work, depending on the severity of the gag reflex and the patient's dedication. Patients should eventually seek their own solution and be in control of their gag reflex so ultimately an impression can be tolerated.

    Control of breathing/relaxation

    In all gaggers, the control of breathing and relaxation is a fundamental component of self treatment and has already been touched on regarding the desensitization approach. Patients should be advised to imagine scenes that are calm and relaxing (distraction imaginary), since an exaggerated gag reflex is thought to be an exaggerated defensive response induced by anxiety. Faigenblum's study supports this method on the basis that vomiting is impossible during apnoea.16

    A breathing technique devised by the National Childbirth Trust has also been suggested.17 Patients should be guided to practise controlled rhythmic breathing 1 to 2 weeks prior to the impression-taking procedure. Breathing should be slow, deep and even and the rhythm maintained by concentrating on a particular verse or tune. The patient should be encouraged to prolong the expiratory effort at the expense of inspiration, producing a slight state of apnoea. Breathing should consist of inspiration through the nose, with flattening of the diaphragm, followed by deliberate blowing out through the mouth. During the impression, should the patient experience a gagging episode, he/she should be instructed to breathe slower and deeper.

    This method of breathing provides the patient with a focus for his/her attention, giving a feeling of self control which, in turn, improves the motivation to rely on him/herself to control gagging. In order for the technique to be successful, dental staff need to adopt a relaxed and calm environment during treatment. Hoad-Reddick used this method in conjunction with a training plate but contradicted other desensitization methods by advocating that the plate is not removed, even if the stimulus becomes very strong.1 Relaxation methods may also include tensing, followed by relaxation of different muscle groups, such as the arms and legs; this is done alongside the breathing technique and may help very nervous or anxious patients.

    Acupressure

    Chinese acupuncture caves originated from the theories of traditional Chinese medicine, which has a history of 4000 to 5000 years.18 Acupressure differs from acupuncture in that no penetration of the skin occurs. The sensitive points are known as caves or ‘Suan-Zhang’. Light pressure should be applied and increased until the patient feels soreness and distension. The pressure can be applied by the patients themselves, the dentist or the dental nurse and should take place approximately 5 minutes before the impression procedure, although sometimes up to 20 minutes is required. It is thought thumb pressure is more beneficial than finger pressure.7

    There are several relevant points in relation to the prevention of gagging. The P-6 Neikuan or Neiguan cave is located on the anterior surface of the wrist three fingers breadth above the distal skin crease of the wrist joint between the tendons of the palmaris longus muscle and flexor radialis muscle, where the median nerve passes.7 This point is used for its anti-nausea and anti-anxiety properties, but more recently its anti-gagging properties (Figure 1). The Hegu cave is the concave area between the first and second metacarpal bones and has also been advocated for its anti-gagging properties18 (Figure 2). The Chengjiang (REN-24) cave is another acupuncture/acupressure point that dental practitioners or patients can use. It is located within the horizontal mentolabial groove, approximately midway between the chin and the lower lip, and has been shown to be effective in reducing the gag reflex19(Figure 3).

    Figure 1. Neiguan cave acupressure point.
    Figure 2. Hegu cave acupressure point.
    Figure 3. Chengjiang (REN-24) cave acupressure.

    Acupressure is probably best suited to the psychological gagger and is good for patients who are needlephobic. There are no adverse side-effects and it is easy to perform, providing an effective, simple, reliable and safe temporary treatment for the exaggerated gag reflex. The benefits of acupressure are usually effective within 30 seconds to 5 minutes of application and may last for several days.7

    Dentist-based techniques

    During the impression technique it is important to give the patient confidence. It may help some patients to be in the upright position with their head slightly forward and some may even find confidence in having a kidney bowl placed beneath their chin, as a type of security.20 However, another school of thought is that this ‘security’ may also reinforce to the patient that gagging and possibly vomiting is expected and their control may be less well enforced. Edwards described a technique called the ‘dedicated sink impression procedure’.21 The intra-oral space is reduced when a patient is in the semi-supine position because the tongue drops back, and thus any flowable impression material will be subjected to the same force of gravity. The patient is therefore sitting upright in front of a sink for the impression. This carries with it several additional advantages, such as good access for the dentist and a wall mirror may allow the patient to see what is happening, thus calming the patient. Edwards thought that patients would tend not to worry so much about the possibility of gagging or even vomiting as they were already at the sink and could easily rinse following the procedure.

    Distraction

    The principle of this technique is to avert the patient's attention from the stimulus, on the basis that a current mental stimulus will override any undesirable thought process and awareness of the gagging stimulus. The distraction theory is best employed alongside relaxation and breathing techniques previously mentioned. The distraction technique is ideal for impression taking but is of limited use for other dental procedures which take some time and, unfortunately, those patients with a severe gag problem are not easily distracted.

    Methods of distraction vary widely. It may be adequate for the dentist to explain the importance of the impression, and then engage in a discussion with the patient on a topic that interests him/her, although this has obvious limitations when taking an impression. Diverting the patient's attention from the gagging stimuli may be done gently and with tact and, at other times, with stern words and action. Landa suggested manipulating the facial soft tissues, for more psychological reasons than for border moulding, although this has a dual benefit for the impression-taking technique.22

    Kovats encouraged patients to breath steadily and audibly whilst simultaneously tapping rhythmically a foot on the floor.5 One of the most commonly employed methods is that described by Krol whereby patients are asked to elevate a leg during the impression procedure.23 This has since been modified whereby the impression is not inserted until the patient is unable to converse following leg elevation; at this point the patient is encouraged to maintain the leg position. When the patient tires, he/she is instructed to raise his/her hand and then change legs and so on until the impression is removed. If a deeper ingrained gag reflex is present, then patients may also be asked to raise their head from the chair simultaneously.

    Another method of distraction reported was called the ‘sick stick’.24 A piece of broom handle, approximately 18 inches long and an inch thick, is engraved with a mark somewhere in the middle and the device polished to feel and look attractive. The stick is held by the patient at either end, at arms length during the impression procedure. Patients are asked to stare at the mark on the stick and are strongly informed to remain focused on the mark, then they will not gag. This technique combines distraction and suggestion.

    Temporal tap

    This method is based on kinesiology and suggestion involves digital stimulation of the temporo-parietal suture (Figure 4a and b). It appears to increase the suggestibility of patients, with its proponents claiming more than 95% success.25 The suture should be palpated with four fingers of each hand and two short taps given, along with the suggestion ‘you can do this without gagging’. Alternatively, 10 taps in 5 second blocks has been suggested. This method contradicts other methods by using such vocabulary, but follows the well advocated lines of suggestion, the basis of hypnosis.

    Figure 4. (a, b) Temporo-parietal suture ‘tap’.

    Impression techniques

    The choice of impression material for this group of patients is important. Choosing a material with minimal flow would certainly be advisable. When using a putty and wash technique for crown and bridge, for example, using the minimal amount of light-bodied wash should be advocated to prevent any overflow posteriorly. As well as making an appropriate decision on the impression material, modification of the impression tray can also reduce the chance of evoking a gag response. The posterior end of stock trays can be built up with wax to prevent escape of the impression material on to the soft palate.10,20

    Callison described an elaborate custom-made tray to help prevent gagging in the edentulous patient.26 Modification of the custom tray, with a salivary ejector attached from the posterior edge of the tray to the low volume suction, removed excess impression material, thereby preventing material extruding and ‘running’ down the patient's throat. This technique, although logical, is complex and time consuming. It would only be suitable for those gaggers who can already tolerate an impression tray, but are prone to gagging with excess material or the sensation of any flowable impression material on their soft palate and pharyngeal wall.

    In circumstances where full arch impressions are not required, the use of sectional trays can be quite advantageous in this group of patients. The authors of this paper have also found these useful as training aids for patients to take home and practise.

    Pharmacological

    The use of topical/local anaesthesia to reduce the sensitivity of the patient's mouth is well documented. Application of an anaesthetic, either directly or via a swab to the palatal area and dorsal surface of the tongue, can be used. Neumann and McCarthy described topical benzocaine 14%, butyl aminobenzoate 2% or tetracaine hydrochloride 2% being applied to the palatal area by means of a gauze pad.9 Other methods of application include sprays, gels, lozenges or even injection. Topical use is usually best suited to minor gagging problems, reserving the use of injections for the more severe cases.

    Lincoln injected 190 proof alcohol approximately 4 mm distal to the lesser palatine foramen.27 Whilst this provided immediate relief, it also lasted a few months; this technique is not commonly used for the gag reflex, since few patients require such extreme treatment, but it remains a useful method of controlling neuralgia. Appleby and Day placed table salt on the tongue or on the palatal region of patients' dentures to inhibit the gag reflex, but others noted concern with placing an emetic substance in the mouth of a patient prone to gagging and at risk of vomiting.10,28

    Hattab et al recommended incorporating local anaesthesia into irreversible hydrocolloid impression material.29 One cartridge of 2% lignocaine with 1:100000 epinephrine, 1.8 ml, was used with the rest of the measure being made up with water; the impression material was then mixed and applied in the usual way. This technique is said to reduce the sensitivity of the mouth, control the anaesthetic agent to only the desired areas and requires no secondary item to be brought into the patient's mouth.

    Although attempting to remove or reduce the somato-sensory input seems logical, a number of concerns have been raised. Despite anaesthesia being obtained, some have noted that elimination of the gag reflex does not always occur sufficiently enough to take an impression.30 Landa stated that an injection itself may initiate the gag reflex and the injection may also distort surrounding tissues, compromising the impression.22 Webb minimized the distortion by adding hyaluronidase to lignocaine.31

    Schole felt that topical anaesthetics may incite the gag reflex owing to a feeling of numbness.32 Whereas Krol stated that, in severe gaggers, the patient was still aware of the stimulus which produces gagging, despite areas of numbness.23 Toxic effects may also be observed because of rapid absorption into the vascular bed and the protective cough reflex may be abolished by anaesthetizing the pharynx.20

    Others

    Rinsing the mouth with ice cold water before beginning the impression procedure has been identified as a method to depress the gag reflex in some patients.20

    Fleece et al suggested using a tongue depressor to probe the soft palate and rear of the tongue repeatedly until the gag reflex fails to occur and then take the impression.2 This may not be favoured by the patient or the dentist since repeated gagging has more tendency to result in vomiting.

    Conclusions

    In managing this group of patients it is important to take a clear history of the problem. This information will enable the clinician to gauge the severity of the problem and therefore make appropriate decisions on the ideal technique to use. Each case will need to be assessed individually as the strategy needs to be adapted to that particular patient's requirements. For many patients it will be necessary to use a combination of techniques and, in a small group of patients, treatment may still not be successful.