Chapter 10

Managing Pronounced Gag Reflexes

Aim

The aim of this chapter is to describe the aetiologies and classification of gagging and to provide some practical and useful methods of providing oral healthcare for people with pronounced gag reflexes.

Outcome

By the end of the chapter you should be able to assess the factors that may contribute to patients’ gagging problems and produce flexible management strategies for this group of patients.

Introduction

Gagging is a normal reflex. It is designed to be protective and prevent entry of unwanted material into the oropharynx, upper airway and gastrointestinal tract. A pronounced gag reflex can severely affect a patient’s ability to accept oral healthcare and your ability to provide it. In its severest form it can compromise all areas of dentistry, from simple diagnostic procedures to any form of active treatment. It will influence treatment planning decisions and may be a major contributing factor to avoidance of treatment by patients. Many techniques have been described to overcome gagging reflexes. Whilst there are no data to demonstrate the prevalence of gagging in the general population, you will undoubtedly see patients with such problems and need knowledge of a variety of management strategies to aid the delivery of oral healthcare.

What is Gagging?

The terms gagging and retching are often used synonymously, but have been interpreted differently in the literature, with gagging considered as “a protective reflex to prevent unwanted entry to the mouth and oropharynx”, and retching considered as “the process of attempting to eliminate noxious substances from the upper gastrointestinal tract”. Most definitions do not include the psychological and higher cranial centre involvement in gagging even though many dental research articles focus on this aspect. For the purposes of this book, the following practical definition of gagging has been adopted: gagging is a stimulated, protective, reflex response to prevent material from entering the mouth or oropharynx. Gagging stimuli may be physical, auditory, visual, olfactory or psychologically mediated and the muscular contractions provoked may result in vomiting.

During the reflex, the trigeminal, glossopharyngeal and vagus nerves transmit sensory impulses from receptors around the tongue, mouth and oropharynx to the brain. These stimuli may be modulated by impulses received from the olfactory, optic and auditory nerves and by the higher centres (through learned behaviours, emotions and memory). The sensory impulses are mediated in the brain within a number of cranial centres. The vomiting centre lies in the medulla oblongata and is closely linked to the vasomotor, respiratory, salivary and vestibular centres. The efferent control of gagging and retching is relayed from the brain to the muscles of the oropharynx, tongue and upper gastrointestinal tract through the trigeminal, facial, vagus and hypoglossal nerves (and some spinal sympathetic nerves) to the muscles of the stomach and diaphragm.

The fact that gagging can be affected by non-physical stimuli such as sight, hearing and smell reinforces the fact that it is not just a simple reflex but is influenced by higher-centre control. This, in turn, can be subject to abnormal, learned processes or reactions to stressful and distressing events in the past. Some patients can link the onset of their gagging directly to a distressing episode.

The Classification of Gagging

Gagging has been described as simply “psychogenic” or “somatogenic” in origin where the reflex originates either from a psychological or physical stimulus.

• Psychogenic gagging can be induced without direct physical contact and, in its most severe form, just the thought of dental intervention may be sufficient to induce gagging.

• Somatogenic gagging results from direct contact with a specific trigger area. Areas such as lateral borders of the tongue, or certain parts of the palate, are common sites.

These classifications are a little simplistic as most gagging reflexes seen clinically are not wholly one or the other but have components of both psychogenic and somatogenic origin.

The Aetiology of Gagging

There is probably a multifactorial cause for gagging. If it were purely somatically induced then gagging induced by dental instruments would be reproduced by other objects, such as a fork during eating. Most patients who gag at the dentist can eat and place other objects in their own mouths with little or no effect, although some report gagging during tooth brushing. Aetiological factors such as abnormal regional anatomy, oral (hyper) sensitivity and various medical conditions have been postulated but there is little evidence to support these observations. It may be that the primary aetiology is psychogenic and other factors contribute to the severity.

Contributing Factors

A number of influencing or contributing factors have been described and are listed in Table 10-1 in four main categories: Anatomical, Medical, Psychological and Iatrogenic. Many of these factors are included based on clinical observations, and statistical association has not been possible due to the subjective nature of the data and limited sample sizes. Consequently these associations must be viewed with caution but not dismissed outright as statistical “proof may never be possible.

Assessment of the Nature and Severity of the Gagging Problem

Careful and considerate assessment, starting with a good history, will build rapport and understanding between you and the patient with a gagging problem. Patient confidence is promoted when a patient feels you are taking their problem seriously. They may find their gagging problem embarrassing and difficult to discuss. Open questioning will help the patient to explain the problem in their own terms, provide an indication of any areas of previous treatment success, and help you to understand the most significant issues. It also allows a pre-examination estimation of gagging severity which can be recorded using the index shown in Table 10-2. You need to be aware of the possible limits to future examination and treatment. For example, the treatment possibilities of someone with a history of mild gagging during impression taking will be totally different from someone that gags when a mirror is simply placed behind the upper incisor teeth.

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